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BMW Rivnut® Remover - Clemson University

1. BMW Rivnut Remover CLEMSON UNIVERSITY 04 20 2010 Clemson University David Floyd Gary McNeillie Joel Knight Spencer Player ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover DESIGN ANALYSIS AND PROTOTYPING OF A RIVNUT REMOVER A Report Presented to The Advisory Committee and Project Sponsors Senior Design Course of Spring 2010 Clemson University In Partial Fulfillment of the Requirements for the Course ME 402 Internship in Engineering Design Mechanical Engineering by BMW Team B David T Floyd Joel H Knight Gary R McNeillie Spencer J Player April 20 2010 Accepted by Gregory M Mocko Mohammad A Omar Gary Palmer Floyd Player McNeillie Knight Page ll ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover ACKNOWLEDGEMENTS The team would like to thank the following people companies e BMW for sponsoring the project providing Rivnuts to test and answering any questions that we had in a timely manner e B llhoff for providing the team with a catalog of the Rivnuts e Dr Mocko Dr Omar and Mr Palmer for all the hours and effort they put into helping make this project a success e Machining and Technical Services of Clemson University for providing quotes for custom parts of final design Floyd Player McNeillie Knight Page 12 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Proj
2. 1 1mm Min NS TO Thickness M MASTER CARR 5 91169A170 http www memaster com 2009 McMaster Carr Supply Company Black Finish Spring Steel Split Lock Washer arma en in is drawing is prowided iy eier ss only Floyd Player McNeillie Knight Page LVIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover M5 x 0 8 Thread 4mm McMASTER CARR 5 90685A041 http www memaster com Black Finish Class 10 2009 McMaster Carr Supply Company krarmasan in fis drawing is provided for reference only Steel Hex Nut Floyd Player McNeillie Knight Page LIX ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover ln eee E SCALE 2 1 WEIS HT 216 57 GRAMS PROFRIETA RT SHO CONFIDENTIAL THE INFORMATION CONTAINED IH THISD RAGIN IS THE SOLE PROPERTY OF CLEMSOH UNWERSITY ANY REPRODUCTION IH PART OR AS A WHOLE WITHOUT THE i RITE PERMISSION OF CLEMSON Universe PAE 402 TEAM B E PROHIBITED 5 4 3 Floyd Player McNeillie Knight a I y A A a v L 04 20 2010 MATERIAL ua SEE SALE 1 DIMENSION MATLLIMIET ERS PART NAME COLLET N UT ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover SECTION D WEIGHT MATERIAL DIMENSION 285 4 SR AMS ALLOY STEEL PAILLIMSAETERS PROPRIETARY AND CONFIDENTIAL PART HA ME SCALE 1 1 THE IH F
3. ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Table 1 Specifications of Gesipa Rivnut installer tools Dp ji Traction Model Mass Air Working Stroke Work Capacity Power Pressure From 8 32 to 3 8 16 in all Pneumatic 586 793 materials for thin wall type GBM 95 RE kPa Variable REN rivet nuts up to 1 4 20 y steel in thick wall type rivet nuts 12 Volt 6 32 to 5 16 18 Steel and Cordless A ke z cae 14 5 kN Aluminum blind rivet nuts Firebird 3 8 16 Aluminum only Research on Current Rivnut Removal Procedure One downside of using Rivnuts is the difficulty in removing them The current process for removing damaged Rivnuts involves three steps as seen in Figure 22 The first step as seen in the left side of Figure 22 is to drill through the head of the Rivnut The second step is to pry off the head of the Rivnut as seen in the middle of Figure 22 The last step seen on the right hand side of Figure 22 is to push out the shank of the Rivnut Wee J JE PRY OFF HEAD PUSH OUT SHANK Figure 22 Removal of Rivnut The problem with this method is that when dealing with assembling vehicles pushing out the shank of the Rivnut leaves the shank inside the vehicle and is hard to remove Any Rivnut pieces that are left inside the vehicle will rattle while the vehicle is on the road so the Rivnut pieces must be removed entirely The other option is
4. Cutter mm mm mm Tests Figure 62 shows the result of the test where the Rivnut was fixed This was not an accurate test because in actuality the Rivnut will not be fixed but the sheet metal will be fixed This test illustrated that the woodruff key seat cutter will accomplish the task of cutting out the compressed ring Results Figure 62 Results From Fixed Rivnut Test Figure 63 shows the cut Rivnut from the first test using the setup 1 As can be seen there is a flange on the back side of the sheet metal that will not allow the Rivnut to be completely removed Once this was realized it was decided that two separate cuts needed to be made x u N Figure 63 1 Cut Rivnut From 1 Setup The next was test conducted with setup 1 Floyd Player McNeillie Knight Page XLII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 64 2 Cut Rivnut From 1 Setup Figure 65 Completely Removed Rivnut 2 Setup These tests proved that this concept accomplishes the goal of removing the Rivnut and now must be designed in way that will allow it to be used on a vehicle Floyd Player McNeillie Knight Page XLIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX L FIXTURE PROTOTYPE AND TESTING The fixture for the prototype can be seen in Figure 66 The prototype fixtur
5. iii XXIX Rotary Tool Material Removal Resulfs run elad s XXX Material Removal from Inside Rivnut Results XXX Master ON Sheet Meile een een ida XXXII Rod Magnet and Round Magnet in Prototype Fixture XXXIII Rims Masnet After Dill USE oa XXXIV Ma ne on Bottom Mid dle nee XXXV Masneton Top Side zn ses smart XXXV Masnelon Boton deis XXXV Shaving Distribution without Magnet ss XXXVI Threaded Portion Being Removed from Hole XXXVII Experiment Setup for Plastic Rivnut eee XXX VIII Experiment Setup for Fixed Rivnut en XXXIX Experiment Setup for Rivnut in Sheet Metal fl XXXIX Experiment Setup for Rivnut in Sheet Metal 2 XL Partially Cut Compressed Riss una Ess XLI Results From Fixed Rima Teste nn XLII 1 Cut Rivnut From 1 Setup rennes XLII 2 Cut Rivnut From 1 Setup XLII Completely Removed Rivnut 2 Setup XLII Bixt re Probs Pri elek XLIV Side View of Fixture with Router and RIVNU ee XLV Rivnut Head and Threaded Portion il XLVI Floyd Player McNeillie Knight Page 9 ME 402 Spring 2010 Figure 69 Figure 70 Figure 71 Figure 72 Figure 73 Figure 74 Figure 75 Figure 76 Figure 77 Figure 78 Figure 79 Figure 80 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Digital Wattmeter Measuring Power Usage While Cutting XLVII Colored Sheet Metalicas XLVII Reprla e mene Concent SKE Ni aaa lei
6. 1910 212 a 3 111 Special hand tools for placing and removing material shall be such as to permit easy handling of material without the operator placing a hand in the danger zone Such tools shall not be in lieu of other guarding reguired by this section but can only be used to supplement protection provided OSHA Hand Held Tool Requirements Since the final design will probably be a hand held tool the regulations that may apply are listed below OSHA Standard Number 1910 243 Subpart Title Hand and Portable Powered Tools and Other Hand Held Equipment Title Guarding of Portable Powered Tools 1910 243 a 2 11 All hand held powered drills tappers fastener drivers horizontal vertical and angle grinders with wheels greater than 2 inches in diameter disc sanders with discs greater than 2 inches in diameter belt sanders reciprocating saws saber scroll and jig saws with blade shanks greater than a nominal one fourth inch and other similarly operating powered tools shall be equipped with a constant pressure switch or control and may have a lock on control provided that turnoff can be accomplished by a single motion of the same finger or fingers that turn it on 1910 243 a 2 iv The operating control on hand held power tools shall be so located as to minimize the possibility of its accidental operation if such accidental operation would constitute a hazard to employees OSHA Cutting Tools Requirements In the case that the fin
7. MAAG NET SCALE 1 1 ME 402 TEAM B 04 20 2010 DIMENSION MILLIMETERS PART HAME ROD MAGNET ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover wee WEIGHT iA TE RLS L 170 7 GRAMS ln PROPRIETARY AND C ONADENTAL SALE I THE INFORMATION CONTAINED IN THI SD RA WING IS THE SOLE PROPERTY OF CLEMIS OA UNIVERSE ANT REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEHN PERMISSION OF CLEMSON UNWERSITY PAE 402 TEAM B IS PROHIBITED E Z Floyd Player McNeillie Knight Bu A Mm A 04 20 2010 Calvi EM on MAILLIMIETE RS PART HAME ROD MACS NET HAM DLE ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX N BILL OF MATERIALS BMW RIVNUT GROUP B RIVNUT REMOVER TOOL BILLOF MATERIALS Part Number Part Description Quantity Price Each Price Total Custom Procure From Part Number BB Handle 2 1225 92450 No McMaster Carr 6308K530 D Motor Mount Screw 4 1186 11 86 No McMaster Carr 912904256 F Motor Mount Lock Washer 4 52 06 5206 No McMaster Carr 911694170 I Collet 1 28000 280 00 Yes Machine Shop NA Collet Set Screw Base Screws lO lowerBase P Ring Magnet 1 150 00 150 00 Yes KJMagnetis NA E 2 0 Woodruff Key Seat Cutter 1 125 00 125 00 Whitney Tool R Ring Magnet Remover 1 500
8. Project Title Rivnut Remover Figure 29 Tension Test Results Table 6 shows that at a force of approximately 7824 N the Rivnut yielded and then subsequently broke in half Table 6 Tension Results This result was very interesting because most of the concepts that the group had been considering required that the Rivnut not break under this type of load To possibly remedy this problem the Rivnut was heated up for one minute by a propane torch and then the tension test was performed The same results were obtained Then the Rivnut was heated for two minutes which is the maximum time allowed to remove the Rivnut again the same results were found Therefore heating up the Rivnut has no effect on enabling it to elongate before breaking into two sections while keeping the time constraints Floyd Player McNeillie Knight Page XIV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX E MODIFICATION OF RIVNUTS Summary One dea that was explored during the concept phase of tool fixture development was to modify an existing Rivnut to see if any minor changes would allow for easier removal By making small changes to the geometry the Rivnut may yield in critical areas instead of breaking thus making complete removal possible The two tests that were completed were the hole drilling test and the turn down test The turning down method reduced the cross sectional area
9. This will remove the compressed ring of material from the Rivnut and allow the threaded side of the Rivnut to be removed from the hole The last step is to remove the compressed ring of material from the hole This concept was reviewed and was determined that t was unfeasible to obtain a solution that would meet the constraints using this concept Instructions 1 Screw bolt into Rivnut 2 With bolt stationary engage hole saw 3 With hole saw drill until hole saw is fully in place 4 Remove entire apparatus from hole 1 Does not cause damage to base material 2 User friendly operation 1 Leaves behind compressed ring and shavings 2 May not be usable if threads are completely stripped Floyd Player McNeillie Knight Page LII ME 402 Spring 2010 Final Report BMW Team B 08 23 2010 Project Title Rivnut Remover APPENDIX M DETAIL DRAWINGS 3 718 9 Power Cord Bolt Circle with Molded Plug Signal Cable i For Control Panel 3 1 4 e an T ji k UTILE gt a 1 4 3 86 http wa memaster Corm 22008 MeMaster Car Supply Company Floyd Player McNeillie Knight Page LIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover M lt MASTER CARR O i 6308K53 http www memaster com Phenolic Tampered 2010 McMaster Carr Supply Company rane R EL ES Siud formalen in fis drawing iz provided for reference oy ia AE MA i Stu Floyd
10. es WEISHT MATERIAL DIMENSION 10 74 GRAMS 1060 AL ALLOY MATLLIMAETE RS PART MAME PROPRIETARY AND CONFIDENTIAL SC ALE 1 THE INFORMATION CONTAINED IH THIS D RA WINS E THE SOLE PROPERTY OF ELEME OHN UNIVERSITY ANY LIPPER BASE REPRODUCTION IN PARTORAS 4 WHC LE Ye MH CUT THE ue RITTEH PERMISSION OF C LEKAS OH UHrveRsTr ME 402 TEA B E PROHIBITED 4 E Floyd Player McNeillie Knight Page LXV ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover WEIGHT MATERJAL 8 3 GRAMS 1060 AL ALLOY PROPRIETARY AND COM FIDENTIAL SCALE 2 1 THE IHF R MATOH E OM TAINED IH THELRAWIHMG E THE SOLE PROPERTY OF CLEWB OHM UNWERSITY AHY REPRODUCTION IH PART OR AS THOUT THE WHOLE W WRITTEN PERMESION OF CLEWEON UHWERSITY ME AUZ TEAM B IS PROHIBITED a E Floyd Player McNeillie Knight LXVI 04 20 2010 DIMEN SION MA ILLIM ETERS PART HA MIE MOTOR MOUNT BOTTOM ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover SECTION A A WEIGHT 22 03 GRAMS MATERIAL NEGE AL ALLOY PROPRIETARY AND CONFIDENTIAL SCALE 1 1 THE INFORMATION CONTAINED IH THEDRAWIHG 6 THE SOLE PROPERTY OF CLEWEON UNIVERSITY AHY REPRODUCTION IH PART OR AS A WHOLE vi TH OUT THE WRITTEN PERMESION OF CLEE OH UNIVERSE ME AQ TEAM E PROHIBITED a 2 Floyd Player McNeillie Knight Page LXVII 04 20 2010 DIMENSION MILLIMETERS PART NA ME LOWER BAS
11. a small vise being drilled on a drill press Holes were drilled in the Rivnut at various distances from the head flange and in different quantities as well as ranging drill bit sizes Table 8 consists of hole drilling test values Table 8 Hole Drilling Test Parameters Bit Diameter mm Number of Holes Distance from Flange mm 1 78 a 5 38 as E o ADE SIS NUS HRS DEE oo Procedure Turn Down The Rivnut Turn Down Test procedure consists of the following steps 1 Mount the Rivnut in the chuck of a machining lathe 2 Attach a cutting tool to the 2 axis tool post 3 Power on lathe and set to desired rpm 4 Move cutting tool post to desired starting axial location on Rivnut 5 Move cutting tool post to desired radial location on Rivnut to begin cutting 6 Slowly advance axially until desired amount of material is removed from the outside diameter of the Rivnut 7 Relocate tool post to a safe location on the lathe machine away from work piece 8 Power off lathe and remove Rivnut 9 Repeat steps until all Rivnuts have been modified Hole Drilling Floyd Player McNeillie Knight Page XVI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover The Rivnut Hole Drilling Test procedure consists of the following steps E 1 Secure a Rivnut in a small vise 2 Insert the desired drill bit size into the drill press 3 Locate the vise on the drill press platform
12. and Installation Tools Figure 21 below illustrates the basic principles of installing a Rivnut The first step is to drill a hole that is the same diameter as the outside diameter of the Rivnut BMW uses automated tools made by Gesipa Fasteners USA to install the Rivnuts After the hole is drilled the Rivnut is threaded onto the threaded mandrel the threaded shaft seen in step 1 of Figure 21 below Next the Rivnut is inserted into the hole and the Rivnut tool pulls the mandrel back into the tool This effectively collapses the Rivnut and now the mandrel spins in reverse to remove the mandrel from the Rivnut The Rivnut is now ready to accept a bolt or screw Complete your fastening operation with Al tale tool to properly set Drill hole to correct diameter thread fastener onto tool a bolt or Figure 21 Installation of a Rivnut Table 1 shows the specifications of the tools used by BMW to install Rivnuts on vehicles The most important specification of these tools to note is the traction power this is the maximum amount of pulling force that the particular tool can use to collapse the Rivnut Additionally it is important to note the diameters of Rivnuts that these tools can install This is shown in the far right column under work Capacity in Table 1 These specifications will be important when working on the problem of removing the damaged Rivnuts Floyd Player McNeillie Knight Page II
13. attract Floyd Player McNeillie Knight Page XXXIV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 52 Magnet on Bottom Middle Magnet on Top Side The next experiment was done with the ring magnet being placed on the side of the Rivnut As can be seen in Figure 53 only a very small shaving fell through the bottom of the Rivnut Figure 53 Magnet on Top Side Magnet on Bottom Side The last placement of the magnet that was tried was to place it on the bottom of the sheet metal to the side of the Rivnut As can be seen in Figure 54 below there were also no shavings that fell through the bottom of the Rivnut that the magnet did not attract Figure 54 Magnet on Bottom Side Floyd Player McNeillie Knight Page XXXV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover These tests should be compared to what happens when a magnet is not present when drilling out the Rivnut Percent values can be found in Appendix H and a picture of how many shavings fall through the Rivnut is found in Figure 55 below Figure 55 Shaving Distribution without Magnet When a magnet is not present some shavings fall through the bottom of the Rivnut which makes it difficult to retrieve them Therefore a magnet should be used when using a cutting operation to remove a Rivnut Magnet Distance Test The results of this tes
14. meter as well as the condition of the Rivnut 4 Once the Rivnut was either collapsed or elongated to the desired amount the reading on the multi meter was recorded 5 Repeat steps 1 4 the desired number of times Results Table 4 shows the results of the compression test In this test the sheet metal was not present It was found that it takes a load of approximately 6655 N to install a Rivnut onto a piece of sheet metal Table 4 Compression Results Compression With Sheet Metal Output mV Load IN l 1 34 6534 2 1 39 6779 3 4 1 38 6730 Average Load N A 6655 Table 5 shows the result that it takes approximately 6655 N of force to collapse a Rivnut with no sheet metal present This force is 97 43 of the force required to collapse the Rivnut onto a piece of sheet metal as seen in Table 5 Table 5 Compression Results without Sheet Metal Compression Without Sheet Metal Output mV V Load N 6388 6681 6583 6290 Average Load N 6486 The last test to determine the force required to elongate the Rivnut yielded some unexpected results Instead of stretching the Rivnut the Rivnut actually reached its tensile strength and broke Figure 29 shows how the Rivnut broke into two pieces Instead of stretching out the already yielded material the material between the sheet metal and the bolt failed Floyd Player McNeillie Knight Page XIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010
15. the desired distance from the Rivnut flange and centered radially on the Rivnut 4 Power on the drill press and advance the bit towards the work piece until a hole has been made 5 Back the drill bit out and power off the drill press 6 Loosen the vise and rotate the Rivnut to the next desired location 7 Repeat steps 1 6 until desired number of holes have been drilled Results Turn Down Test Once all of the Rivnuts had been turned down to different diameters they were compressed around a piece of sheet metal and then an axial load was placed on them to stretch them back out Upon observation during the stretching process Specimens 1 and 2 only stretched slightly until ultimately breaking Upon observation of specimen 3 the Rivnut expanded significantly and appeared as if it could be pulled through the base material hole Tolerances were very tight so more load was applied and the specimen broke Upon failure the specimen was able to be completely removed without damaging the base material Figure 32 shows the successful modified Rivnut Figure 32 Turn Down Test Specimen 3 While the Rivnut had been completely removed it had been altered from its original geometry which is not how the Rivnut was supplied The team believes that if the Rivnuts could be designed with a thinner critical wall thickness then the Rivnuts could still potentially hold a certain load but also have the capability of being removed from the base
16. to cut slots grooves in work pieces The woodruff key seat cutter has a shank diameter of 1 2 in overall length of 2 0 in cutter Floyd Player McNeillie Knight Page 114 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover diameter of 1 4 in and a face width of 1 8 in The cutter s designed to be used at an RPM of approximately 1681 based on manufacturer recommendation The proposed face width on the woodruff key seat cutter is twice as thick as the prototype to fully remove the compressed ring Figure 12 Woodruff Key Seat Cutter with Dimensions Parts R and T are the ring magnet remover and rod magnet handle respectively The ring magnet remover is used to pull the ring magnet off of the sheet metal after the cutting process is complete The rod magnet handle is used to make the process simpler and more ergonomic Parts U and V are drill bit letter K and drill bit letter T The K drill bit is used to remove threads from the Rivnut to ensure the cutter is not limited axially before tool operation The T drill bit is used to remove the head of the Rivnut after the cutting process has been completed Figure 13 Type K Drill Bit Figure 14 Type T Drill Bit Parts W and X are static cling film and strong adhesive tape respectively The static cling film is to be applied on the vehicle surface before any removal steps begin This static cling
17. was used to supply the force to collapse the Rivnut A calibrated load cell with a max load capacity of 8896 N was used to measure the force exerted on the Rivnut This load cell was powered by a 10 volt DC power supply A digital multi meter was used to read the output of the load cell Floyd Player McNeillie Knight Page IX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Compression In the first experiment the apparatus was set up as shown in Figure 26 The load cell was position to read the force required to compress the Rivnut onto the sheet metal Once this test was completed then the second test was performed This test was set up identical to Figure 26 but now the sheet metal was removed SHEET METAL Figure 26 Compression Test Setup Tension For the final test the apparatus was set up a little different As can be seen in Figure 27 the Rivnut was collapsed onto the sheet metal and a bolt was installed into the Rivnut SPACER BLOCKS VISE CLAMPS SHEET METAL nn Figure 27 Tension Test Setup Floyd Player McNeillie Knight Page XI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover As the vise was tightened the bolt pushed against the threads inside the Rivnut and caused the Rivnut to elongate With the spacers shown the load cell was positioned to read the required force that the Rivnut needed to return to
18. 500 Yes Machine Shop NA Drill Bit K X Strong Adhesive Tape 1 300 3 00 Estimated Tool Cost 2 211 57 E Floyd Player McNeillie Knight Page LXXII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX O USER MANUAL 1 Place plastic film on vehicle body 2 Place magnet around Rivnut Figure 75 Placement of Magnet 3 Remove the threads of the Rivnut by use of a type K drill bit in a portable drill Figure 76 Drilling Out Threads 4 Place the tool around the magnet Figure 77 Tool Placed Around Magnet 5 Engage the woodruff key seat cutter with the Rivnut Floyd Player McNeillie Knight Page LXXIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 78 Tool Engaged with Rivnut a Move the tool in a circular pattern provided by the base 7 Remove the tool from the hole 8 Use a type T drill bit on the head of the Rivnut to remove it Figure 79 Removing Rivnut Head 9 Place a rod magnet inside the hole to remove the once threaded portion of the Rivnut Figure 80 Rod Magnet Insertion 10 Remove round magnet and film from vehicle 11 Install new Rivnut Floyd Player McNeillie Knight Page LXXIV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover REFERENCES Ace Rivet amp Fastener Ace
19. E ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover SECTION B B WEISHT MATERIEL D Iii ENSIGN 24 03 GRAMS MAIS NET MAILLIMIETERS PROPRIETARY A NO CONFIDENTIAL PART NAME SCALE z THE IH FOR MATOH CON TAIN ED IH THISOR Ar IH z E THE SOLE PROPERTY ROUND MAG NET OF CLEMSON UNIVERSIT AHY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEH PERMESION OF CLEWEON UNWERSITE WIE 40 TEAM A B E PROHIBITED 3 Floyd Player McNeillie Knight Page LXVIII ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover WEISHT MATERIAL PO GRAMS PRO PRETARYT AND O HADENTIAL SCALE 1 1 THE IHF OR MATION CON TAINED IH THISDRA WIM IS THE SOLE PROPERTY OF CLEMSON UNIVERSITY AMY REPRODUCTION IN PART OR ASA WHOLE WITHOUT THE WRITTEN PERMISSION OF CLEMSON UNIVERSITY MIE 402 TEAM B 5 PROHIBITED J 2 Floyd Player McNeillie Knight Page LXIX LE Se Sk 04 20 2010 DIM ENSIGN BAILLIMETER S PART NAME ROUND MAGNET REM YER ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover WEIGHT 2 43 GRAMS PROPRIETARY AND CONFIDENTIAL THE IHFORMATION CONTAINED IH THE D RA IH S E THE SOLE PROPERTY OF c LEMASOH UNIVERSITY AHY REPRODUCTION IW PART OR AS A w HOLE vit TH OUT THE WRITTEN PERMIBSIOH OF OLEME OW UHM ERS ITY E PROHIBITED 5 4 a Floyd Player McNeillie Knight A 4 A A 1 ASA BU A MATERIAL
20. IS OF COLLAPSING AND UN COLLAPSING RIVNUTS Summary To aid in developing some solutions to the problem of removing a Rivnut it was first necessary to determine some characteristics about the Rivnuts themselves Three experiments were conducted to determine some of the key characteristics of the Rivnuts The first was to determine the compressive force required to collapse the Rivnut so that it was installed properly on the base material This experiment was conducted with the Rivnut collapsing onto sheet metal as to accurately model the force required to install the Rivnut The second experiment was similar to the first but the Rivnut was collapsed without the sheet metal For the last experiment it was desired to determine the required force necessary to un collapse the Rivnut once it was installed in sheet metal The experimental results showed that it took 6654 N of force to compress the Rivnut on sheet metal and 6486 N of force to compress the Rivnut without sheet metal The next test showed that it took 7824 N of force to un collapse a Rivnut however the Rivnut did not stretch back out completely The Rivnut instead broke into two pieces before being fully restored Also when the Rivnut was heated it did not produce different results Experimental Setup DC POWER SUPPLY MULTIMETER VISE WITH LOAD CELL AND RIVNUT Figure 25 Experimental Setup Figure 25 shows the setup of the experiment A vise
21. M and O are the base top and bottom sections respectively These parts correspond to the base fixture on the prototype in Figure 10 These pieces act as the cam in the cam follower style operation The groove inside part O has a larger diameter than part N which allows the tool to move in a circular motion Parts M and O guide the tool and allow the tool only 2 degrees of freedom to efficiently cut out the Rivnut and reduce user error by limited allowable movement Parts P and S are the neodymium ring and rod magnets respectively The ring magnet centers on the Rivnut and provides an outer surface to which the base can be located The ring magnet is axially magnetized and has a pull of 75 62 Newtons This magnet attracts the metal shavings as well as the threaded section of the Rivnut to the backside of the sheet metal during the cutting process The rod magnet s diametrically magnetized and has a pull of 20 Newtons This magnet attracts the metal shavings the threaded section of the Rivnut after the cutting operation Part P is modified to be a lower profile magnet so the woodruff key seat cutter will be able to cut the Rivnut without interference Part S is slightly longer than the original rod magnet so it can be pressed into a handle to make it easier to remove the threaded end from the hole Figure 11 Rod Magnet and Ring Magnet Part Q is the woodruff key seat cutter This is a metal cutting mill bit designed
22. Meet all of OSHA s safety pinch points and ergonomic constraints Not alter base material finish in any way Must be able to remove a Rivnut from a 5 08 x 5 08 cm area Criteria The final design should Remove Rivstuds Weigh less than 4 5 kg Be available to the consumer at 500 or less Be usable by the Rivnut installer personnel Floyd Player McNeillie Knight Page 111 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover RECOMMENDED DESIGN CONCEPT Figure 8 Exploded view of Rivnut Removal Tool An exploded view of the recommended design solution is shown in Figure 8 Parts A T mentioned in this section can be found in th s figure while parts U X are mentioned in Appendices N and M Appendix N Floyd Player McNeillie Knight Page 112 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover contains the bill of materials which shows the cost of these parts and where they can be obtained Detail drawings of each component can be found in Appendix M The plunge router in Figure 9 s replaced by Parts A T in the final design solution These parts in the final design solution are much smaller so the tool 1s lighter and easier to maneuver Figure 9 Plunge Router Part A is a Brushless DC Motor that runs on 120 V AC using an integrated speed controller This motor generates 13 4 in lbs of torque which is 257 greater than the minimum req
23. ORMATION ONTAINED IH THEDRAWINGS E THE SOLE PROPERTY Collet OF CELEBRA UN MERSITY AMY REPRODUCTION IH PART OR AS A WHOLE Wi ITHACUT THE WRT TEH PERMBSION OF CLEMSOH UNIvERSMY PAE 402 TEAM B IS PROHIBITED 5 4 a Floyd Player McNeillie Knight Page LXI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 2 Hex MA x 0 7 Thread unser 93245A110 http www mcmaster com Black Alloy Steel 2008 McMaster Car Supply Company Flat Point Set Screw Uniess cherviss spacitad dimensions ara in milliers norma on in His drasing is provided for Floyd Player McNeillie Knight Page LXII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover WEISHT MAaTERLAL Di EME ior 7 3 GRAMS 1060 AL ALLOY MULLIMAETERS PROPRIETARY AND CONFIDENTIAL PART NAME See 2 THE IH FOR WATON CONTAINED IN THED RAIN G E THE SOLE PROPERTY OF CLEMSON UNIVERSITY ANY MOTOR MOUNT opens LEGS PERMISSION OF CLEMSOH UNIVERSITY ME 402 TEAM B IS PROHIBITED 5 4 a z 1 Floyd Player McNeillie Knight Page LXIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover M2 x 0 4 Thread vii 91290A015 Basi 12 9 Alloy Floyd Player McNeillie Knight Page LXIV Final Report BMW Team B 04 20 2010 ME 402 Spring 2010 Project Title Rivnut Remover SECTION A A DETAIL B SCALE ZO
24. Player McNeillie Knight Page LIV 04 20 2010 ME 402 Spring 2010 Final Report BMW Team B Project Title Rivnut Remover WEIGHT MATERLAL CT EE ko N 187 11 GRAMS 1060 AL ALLOY MILLIMETERS PROPRIETARY AND CONFIDENTIAL PART HA ME SCALE 1 1 THE INFORMATION COM TAIN ED IH THISD RAWIHS E THE SOLE PROPERTY H Ah COLE ALOU NT OF LE EOH UNIVERSITY AHY REPRODUCTION IH PART OR AS WHOLE WITHOUT THE Ww R ITTEH PERMISSION OF CLEMBON UNMWERSITE BAE 402 TEAMA B E PR OHIEMED a Floyd Player McNeillie Knight Page LV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Thread length may vary from 22mm to 26mm in elle M5 x 0 8 Thread tn Www memaster corm 2008 McMaster Carr nR Company Floyd Player McNeillie Knight Page LVI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover DiM EMS IO M WEISHT MATERIAL Hae deve nA Mm 1060 AL Ao MULLIMIET ERS PROPRIETARY AND CONFIDENTIAL PART HAME SEALE THE INFORMATION COW TAINED IH THED RAM IHG E THE SOLE PROPERTY OF LEON UHIVERSITI ANY REPRODUCTION IH PART OR AS A WHOLE WITHOUT THE RITTEN PERKABSIOH OF CLEMSOH UNWERSIMY MAE 40 TEAMA B MOTOR MOUNT E PROHIBITED TOF 2 1 Floyd Player McNeillie Knight Page LVII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover For M5 Screw Size
25. Rivet amp Fastener Inc Web 15 Jan 2010 lt http www acerivet com gt Blind Rivet Nut Tools Gesipa Fasteners USA Web 15 Jan 2010 lt http www gesipausa com gt Blind Rivet Nuts and Studs Kendallville IN B llhoff Rivnut 2010 Print General Repair Procedures Integrated Publishing lt http www tpub com content elecequipment TM 10 5411 207 14 css TM 10 5411 207 14_34 htm gt Jan 17 2010 Material Data Sheet ASM Web 28 Jan 2010 lt http asm matweb com search SpecificMaterial asp bassnum MA6061T6 gt Properties of Steel Table Engineer s Handbook Mechanical Engineering Design Guide Engineer s Handbook Web 28 Jan 2010 lt http www engineershandbook com Tables steelprop htm gt Rivnuts and Rivstuds B llhoff Web 28 Jan 2010 lt http www2 boellhoff com web usa en web nsf HTML index us html gt OSHA Regulations Web 3 Feb 2010 lt www OSHA gov gt Magnets McMaster Carr Web 6 Mar 2010 lt http www mcmaster com 5704k14 63mm2k gt Floyd Player McNeillie Knight Page LXXV
26. Rivnut 2 Drill out Rivnut until hole in base material is equal to diameter of the compressed ring 3 Pull out damaged Rivnut 4 Install new Rivnut Note The outside diameter of the installed Rivnut must be equivalent to the hole size Pros 1 Simple design 2 Fast and easy removal process 1 Can only be implemented one time for each hole 2 Drill shavings left behind 3 Modifies base material Floyd Player McNeillie Knight Page XLIX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 4 If not precise will destroy base material Modification of Rivnut Concept Figure 72 Modification of Rivnut Concept Sketch This concept came from testing The idea is to remove some material and drill holes in the Rivnut to increase the possibility the Rivnut will stretch all the way out This concept was scrapped because the team discovered that changing the Rivnut was not acceptable Instructions 1 Reduce wall thickness of Rivnut at critical yielding area 2 Drill holes in Rivnut in critical yielding area 3 Install Rivnut 4 When damaged apply axial load to elongate Rivnut and remove Pros 1 Leaves no material behind 2 Does not alter base material in any way 3 Fast removal and easy removal process 1 Lessens carrying capacity of Rivnut 2 May be hard to manufacture 3 May make the Rivnut more costly Floyd Player McNeillie Knight Page L ME 402 Sprin
27. Time Test Number I 2 3 4 5 6 7 8 Time s 15 37 19 23 18 25 31 22 The average time of the values in Table 15 is 24 seconds The magnets provided enough force to gather all shavings from the Rivnut and enable the process to be clean and not leave any shavings inside the vehicle The rod magnet was strong and accurate enough to enable the user to remove the threaded portion of the Rivnut without needing a specially designed fixture to grasp the piece to pull it through the hole Floyd Player McNeillie Knight Page XXXVII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX K WOODRUFF KEY SEAT CUTTER TEST It was necessary to conduct several tests to ensure that the woodruff key seat cutter design will work as desired Once the correctly sized woodruff key seat cutter was obtained some preliminary tests were conducted First off a plastic replica of a compressed Rivnut was made and the compressed ring was cut from the body of the Rivnut This allowed the concept to be tested and the apparatus to be correctly set up with no danger of damaging the cutter bit In the next test the Rivnut was fixed rigidly to a bolt and a large block that could easily be fixed in the apparatus This allowed the compressed ring to be cut with no possibility of the Rivnut rotating and damaging the Rivnut In the final two tests the Rivnut was fixed in sheet met
28. al just as t would be in a car body The compressed ring was then removed from the Rivnut Experimental Setup All the tests run used the same basic setup with small variations in the way that the Rivnut is fixed As can be seen in Figure 58 the bas c setup consists of a milling machine A rotary table was fixed to the mill table while the woodruff key seat cutter was fixed to the spindle The center of the rotary table was centered directly below the spindle of the mill Preliminary Tests The first test to run was with the plastic Rivnut Figure 57 shows the setup for this test The purpose of this test was to ensure that the team knew how the setup would work once a real Rivnut was tested Figure 57 Experiment Setup for Plastic Rivnut In the second test the Rivnut was welded rigidly to a bolt and the bolt was welded to block of steel that was fixed to the vise on the rotary table Figure 58 shows this setup Floyd Player McNeillie Knight Page XXXVIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 58 Experiment Setup for Fixed Rivnut Final Tests These tests are the most accurate representations of how the Rivnut will actually be removed in the final design In the first of these tests the Rivnut was fixed to a piece of sheet metal that was fixed in the vise on the rotary table Figure 59 shows how this is set up 4 m 3 vi Figure 59 Ex
29. al Removal Results Figure 48 shows the results from removing material from the inside of the Rivnut via a lathe before installation Figure 48 Material Removal from Inside Rivnut Results Floyd Player McNeillie Knight Page XXX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover The Rivnut will not stretch out enough even under modifications to allow it to be removed from the hole The final conclusion from this test is that to remove the Rivnut the compressed ring of material has to be removed or separated from the Rivnut Floyd Player McNeillie Knight Page XXXI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX J MAGNET TEST One idea to remove the shavings from the vehicle was to not let the shavings fall down to an unreachable area This could be done by use of a magnet A ring magnet was placed around the Rivnut while it was being drilled out to observe if the magnet caught any or all of the shavings that were made Also the distance that shavings can be drawn to the magnet was measured Experimental Setup Magnet with Drill Test The experiment was set up similar to the setup in the shavings test Paper was put into a vise to catch any shavings that fell through the threaded end of the Rivnut Parallel plates were put on top of the paper to hold the sheet metal that held the Rivnut in place while drillin
30. al design utilizes a cutting procedure the OSHA regulations that apply to this project are listed below OSHA Standard Number 1910 252 Subpart Title Welding Cutting and Brazing Title General Requirements 1910 252 a 2 x111 Management Management shall recognize its responsibility for the safe usage of cutting and welding eguipment on its property and 1910 252 a 2 x111 A Based on fire potentials of plant facilities establish areas for cutting and welding and establish procedures for cutting and welding in other areas 1910 252 a 2 x111 B Designate an individual responsible for authorizing cutting and welding operations in areas not specifically designed for such processes 1910 252 a 2 x111 C Insist that cutters or welders and their supervisors are suitably trained in the safe operation of their eguipment and the safe use of the process Floyd Player McNeillie Knight Page V ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 1910 252 a 2 x1v E Shall determine that the cutter or welder secures his approval that conditions are safe before going ahead Floyd Player McNeillie Knight Page VI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX C ANALYTICAL ANALYSIS OF COLLAPSING RIVNUTS Summary A preliminary stress analysis was performed on a Rivnut to determine approximately how much force is required to c
31. be worthwhile to perform more tests using the Turn Down method to ensure that the results of Specimen 3 could be repeated Load carrying capacity tests need to be performed as well to ensure the Rivnut still performs its intended job Hole drilling in the Rivnut has proven to be an unsuccessful route for modification and removal Floyd Player McNeillie Knight Page XVIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX F BORE CUTTING TEST Some of the concepts that are being considered require that the compressed ring of material on the Rivnut be removed by some type of cutting or grinding process A simple experiment was conducted to determine the feasibility of this concept Experimental Setup T 7 Figure 35 Experimental Setup Figure 35 shows the setup of the experiment The Rivnut was secured in the rotating end of a lathe A bore cutting tool was fixed so that it could enter the center of the Rivnut Procedure The procedure that was followed to conduct this experiment 1s as follows 1 Fix the Rivnut in the rotating end of the lathe Fix the bore cutting bit in the other end of the lathe so that it properly aligns with the center of the Rivnut 3 Start the lathe 4 Move the bore cutting bit into the Rivnut slowly until the blade is aligned inside with the compressed ring of material 5 Horizontally move the bore cutting bit slowly until the Ri
32. ct Title Rivnut Remover Table of Contents INE AN NAAA A 2 EXSGuUUYe SUMA e islas e O el dl Ena 3 Int NCC espias 11 Problem ls Pe SEE EEE a ee MORI 11 CORSA ooo ane aasssosesbeusgoansanientahentsnauteoue 11 CR ens A NE A ENE MIO A ME AE DAR 11 Recommended DEI IK OCEN een 12 Verification of Design Solutions Against the Requirements 16 Appendix A Background Information of RiVNutS ena I Research of the Various Properties of RivnutS res I Installation Procedure and Installation Tools issues II Research on Current Rivnut Removal Procedure esse MI Appendix B OSTAR EI AO es een IV Pinch POIS ee ae ee ee ee ee IV OSHA General Machine Requirements rer IV OSHA Hand Held Tool Requirements res V OSHA Cutting Tools Reguirement res V Appendix C Analytical Analysis of collapsing Rivnuts ann VII A PL VII CAO a Ra ENE VII Appendix D Experiemental Analysis of Collapsing and un collapsing Rivnuts X SOA o ME a A RE MA X Experimental SOUND a ab ea eo ie ee X OC A E Eat A ENE AVE ER NE XII RES E A A a a a a A a NE EN ER XIII Appendix E Modification of Rivnuts ene XV PEAY AA O Po io o ES E A ME RA MOP ENE A MMA XV D ASE AAA e E RO SOS UU DE O iN in ea oka nana XV POS EEE EEE A N EEE EEE NE A a Mi A O IE RA a a RE VEN XVI REUS ects sect ais esac se sain EN ME XVII Floyd Player McNeillie Knight Page I5 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Ri
33. dures were used Floyd Player McNeillie Knight Page XXV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Drill Test 1 Ensure that the sheet metal the Rivnut is set into is clamped into the vise and unable to move Line up the middle of the Rivnut with a 0 909 cm diameter drill bit on the drill press 3 Plunge the drill bit into the Rivnut slowly letting chips go to their respective areas until the Rivnut has been removed 4 Carefully remove the top paper with the Rivnut top and shavings and place the shavings in a bag Carefully remove the bottom paper with the shavings and place the shavings in a bag 6 Weigh both the top and bottom portion shavings Hacksaw Test 1 Ensure that the Rivnut is clamped into the vise and unable to move 2 Place the hacksaw in the middle of the clamped Rivnut 3 Very slowly move the hacksaw to make a small grove on the Rivnut for the hacksaw blade to rest 4 Keep working the hacksaw until the Rivnut is completely cut on that side 5 Unclamp the Rivnut rotate 90 and re clamp being very careful not to deform the Rivnut 6 Repeat steps 2 4 7 Carefully remove the Rivnut and the piece of the Rivnut that was cut Remove the paper and place the shavings in a bag 8 Weigh the shavings Results Table 11 shows the mass and percentage of the shavings from the drill test Table 11 Drill Test Results End of Rivnut Mass g Pe
34. e are outline below OSHA Standard Number 1910 212 Subpart Title Machinery and Machine Guarding Title General Requirements for All Machines 1910 212 a 1 Types of guarding One or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation ingoing nip points rotating parts fly ng chips and sparks Examples of guarding methods are barrier guards two hand tripping devices electronic safety devices etc 1910 212 a 2 General requirements for machine guards Guards shall be affixed to the machine where possible and secured elsewhere f for any reason attachment to the machine is not possible The guard shall be such that it does not offer an accident hazard in itself 1910 212 a 3 1 Point of operation is the area on a machine where work is actually performed upon the material being processed 1910 212 a 3 G1 The point of operation of machines whose operation exposes an employee to injury shall be guarded The guarding device shall be in conformity with any appropriate standards therefore or in the absence of applicable specific standards shall be so designed and constructed as to prevent the operator from having any part of his body in the danger zone during the operating cycle Floyd Player McNeillie Knight Page IV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover
35. e consisted of a single piece of particle board which was milled down using aCNC machine to proper specifications as well as a piece a sheet metal bolted to the board Figure 66 Fixture Prototype Experimental Setup The fixture prototype was assembled from particle board a piece of sheet metal and two sections of 2x4 for stability The particle board was 1 59 cm thick 25 4 cm wide and 30 5 cm long A router was placed on top of the fixture as seen in Figure 67 Along with using the router a dimmer switch had to be used to get the RPMs of the router down to a lower level so that the woodruff key seat cutter would not wear quickly and become unusable A wattmeter was used to determine the power needed to run the router at the desired speed A stroboscope was used to determine the speed of the woodruff key seat cutter and a marker was used to determine if the surface was being scarred or scratched n any way Floyd Player McNeillie Knight Page XLIV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Ch os O MA 7 me ae tu Se x hy AO me ae to i y Figure 67 Side View of Fixture with Router and Rivnut bud 4 D Per Ms Procedure Procedure for Making Fixture Use a CNC Machine to get 0 762 cm hole of exact radius of 8 3058 cm in board Use a hole saw of 2 54 cm radius to cut hole for sheet metal and Rivnut to be accessed through Drill hole in sheet metal for Rivnut Attach
36. e cutting operation has been completed Appendix J shows the magnet tests that were conducted in order to prove that using magnets is an acceptable way to collect and remove shavings Floyd Player McNeillie Knight Page 117 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX A BACKGROUND INFORMATION OF RIVNUTS Research of the Various Properties of Rivnuts Material head s ze thread type and many other important features must be known in order to develop a tool fixture that can accommodate an assortment of Rivnuts While BMW may only use a few different Rivnuts the ideal tool should be able to remove most if not all of the Rivnuts researched Figure 18 shows a variety of Rivnuts as well as Rivstuds provided by B llhoff Figure 18 Common and Specialized Rivnut and Rivstuds by B llhoff The Rivnuts are available in various materials such as steel with zinc finish steel aluminum and 430 stainless steel The different Rivnut materials are used for different applications that include sheet metal tubing and plastics Knowing the material properties for both the Rivnuts and the base material will help govern the design of the tool by determining the required tool material properties as well as the method chosen for removal The above Rivnuts in Figure 18 have two different cross sections The circular cross section is common for drilled or punched circu
37. e nada aan neo dan donation dia XI Fisure 2 7 Tension Test SUD anne ee een XI Figure 28 Load Cell Calibration Curves anne de kazale ni dai kai XII Figure 29 Tension Test RT ee a Re XIV Figure 30 Turned Down Rivnut on Lathe iii XV Figure 31 Hole Drilling Rivnut en XVI Figure 32 Turn Down Test Specimen VO csi iii XVII Figure 33 Hole Drilling Test Specimen 2 Compressed in Sheet Metal XVIII Floyd Player McNeillie Knight Page I8 ME 402 Spring 2010 Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 43 Figure 44 Figure 45 Figure 46 Figure 47 Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 Figure 53 Figure 54 Figure 55 Figure 56 Figure 57 Figure 58 Figure 59 Figure 60 Figure 61 Figure 62 Figure 63 Figure 64 Figure 65 Figure 66 Figure 67 Figure 68 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Hole Drilling Result with Flared Edges XVII Experten ARS D RS ae ee ae a int XIX Riva Completely Cine XX Bor CUR e ee XX DO A me Na XX ATRIA FT S O O te eee MN XXII Experimentalki So parent rocio XXII Compressed IDO a an a ea XXII Foe MC Mba E ee ee ee Ale een Denen XXV Rivnot Shavines wich PIUS ta XXVII Rivnut Pieces from Hacksaw Test XXVIII Rotary Tool Material Removal Sc da XXIX Material Removal from Inside Rivnut
38. e seven tests that were timed and the times for each can be found in Table 18 Table 18 Time Recorded for Removal Test Run 1 2 3 4 5 6 7 Time s 85 90 365 93 87 84 90 The average time for Rivnut removal was calculated to be approximately 88 seconds Test 3 was the unsuccessful removal and can be seen as taking over 6 minutes to remove These times of the successful removals help show that the process described in this paper works as designed Scratch test The colored portion of the sheet metal can be seen in Figure 70 Figure 70 Colored Sheet Metal Floyd Player McNeillie Knight Page XLVII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover The coloring test on the sheet metal revealed that as long as the woodruff key seat cutter does not come in contact with the sheet metal no scratches are made to the base material Floyd Player McNeillie Knight Page XLVIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX M FAILED DESIGN CONCEPTS Replacement Concept Figure 71 Replacement Concept Sketch This concept drills out a hole the width of the flange This would remove the entire Rivnut but leave a larger hole thus a larger Rivnut must be put in its place This concept was scrapped because we could not alter the base material Instructions 1 Insert center drill bit in damaged
39. eat cutter to remove a Rivnut works As one can see from Figure 68 the entire compressed ring was not removed by the woodruff key seat cutter With this problem in mind further testing was done and six out of seven Rivnuts were removed but still had this flange This meant that the bottom of the Rivnut could not be pulled back through the hole that the Rivnut was installed If the woodruff key seat cutter had a thicker face width 1 6 mm larger it is hypothesized that this flange would be completely removed For reporting purposes it was assumed that since the flange problem could be fixed each removal was counted as a success as though we had used the larger cutter even though the bottom of the Rivnut still had a flange on it During these tests the dimmer switch was replaced with a Veriac in order to more accurately control the power going to the router A digital wattmeter seen in Figure 69 was used to determine that the router was using 108 Watts during the cutting operation Floyd Player McNeillie Knight Page XLVI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 69 Digital Wattmeter Measuring Power Usage While Cutting A stroboscope was also used during the testing to determine at what rate the woodruff key seat cutter should rotate This was determined to be 1550 RPM The woodruff key seat cutter manufacturer recommends that the tool be run at 1681 RPM Each of th
40. ect Title Rivnut Remover EXECUTIVE SUMMARY Many vehicles require the installation of a special fastener called a Rivnut These fasteners are useful because they allow threaded components to be attached to sheet metal They are inserted into a hole and a tool pulls the Rivnut causing it to collapse against the sheet metal This process makes a compressed ring that causes the Rivnut to be tight against the vehicle and allow a threaded component to be inserted into it Some failure modes for these Rivnuts include becoming cross threaded or they freely spin in the hole In either of these cases the Rivnut must be removed The current process for removing the Rivnut is to drill through it causing the back of it to fall into the vehicle This process also leaves the head of the Rivnut on the hole which must be pried off and also leaves the compressed ring on the threaded part of the Rivnut making it impossible to come through the hole in which it was installed If the Rivnut or the back of it cannot be removed in a timely manner the BMW automobile continues to be assembled and is sent to the rework station after it has completed assembly This vehicle may have to be disassembled in some areas in order to retrieve the back of the Rivnut or remove the Rivnut entirely This wastes BMW s time and money The new method and tool must completely remove the Rivnut in under two minutes without causing any scratching denting or mar
41. film is to ensure the surface s integrity during the entire Rivnut removal process The strong adhesive tape is used to remove any shavings attracted to the magnets The tape will allow the magnets to be reused for further Rivnut removals without scratching the surface Floyd Player McNeillie Knight Page 115 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Each part in the recommended solution plays a key role in removing a Rivnut These components were based off of the original prototype The complete prototype can be seen in Figure 15 Plunge Router Rivnut Woodruff Key Seat Cutter oe Voltage Ring NE u Regulator Magnet dimmer Rod Magnet Fixture Base Figure 15 Labeled Prototype Verification of Design Solutions Against the Requirements The two columns below compare the key aspects of the prototype and the recommended modifications made in the final design The paragraph below these columns explains why these changes should be made Prototype Recommended Design Woodruff key seat cutter has a 1 16 e Woodruff key seat cutter has a 1 8 face face width width Uses a base that is 305 x 254 x 16 e Uses a base that is 50 8 mm in diameter mm x 13 mm thick Total fixture weight is 7 23 kg e Total fixture weight is 2 78 kg Device must use a dimmer switch to e Motor designed to specific task no step reduce motor output down of power 1s required Difficult
42. g 2010 Final Report BMW Team B Project Title Rivnut Remover Reciprocating Saw Concept Figure 73 Reciprocating Saw Concept Sketch 04 20 2010 A test was performed using a hack saw to make four separate cuts along the length of the back of the Rivnut to imitate what would occur with the Reciprocating Saw Concept Upon inspection it was clear that this concept would not be feasible because not enough material was able to be removed When the Rivnut was pulled on axially the compressed ring still held tightly despite having 4 cuts in the length Instructions 1 Insert saw into Rivnut 2 Engage saw until a slit is cut through the back side of the Rivnut 3 Cut another slit 90 from previous cut 4 Repeat step three until four cuts are made 5 Remove saw blade 6 With clamping device grasp Rivnut head and pull out of hole Pros 1 Only leaves small particles of material behind Floyd Player McNeillie Knight Page LI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Cons l Complicated multi step process 2 Time consuming process Hollow Mill Concept nn RTE TL Figure 74 Hollow Mill Concept Sketch This concept utilizes a hollow mill bit to cut out the threaded part of the Rivnut The bolt remains stationary while the mill bit rotates independent of the bolt If the Rivnut starts to rotate on the bolt it will then be rotated towards the cutting mill bit
43. g occurred This setup can be seen in Figure 52 below Magnet Distance Test Shavings from various tests were placed on the table The magnet was then slowly lowered by hand to get an approximation of the strength of the magnet Magnet with Woodruff Key Seat Cutter Test This magnet test consisted of a round magnet placed over the top of the Rivnut on the prototype fixture The back of the Rivnut and shavings were then placed underneath the sheet metal and the distance was measured This can be seen in Figure 49 below Figure 49 Magnet on Sheet Metal Procedure Magnet with Drill Test 1 Place Rivnut into sheet metal and collapse it Floyd Player McNeillie Knight Page XXXII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 NAAR WN Project Title Rivnut Remover Place ring magnet around the flange end of the Rivnut Place sheet metal into clamping device on drill press and secure Center 0 90932 cm diameter drill relative to center of Rivnut Plunge drill into Rivnut until it is cut into two pieces Observe shavings on and around magnet Repeat steps 1 6 varying step 2 by placing the magnet in various places Magnet Distance Test l 2 Lower magnet until shavings are attracted to it 3 Record distance Place shavings on a table Magnet with Woodruff Key Seat Cutter Test l 2 3 4 5 6 7 8 9 l 0 Place Rivnut into sheet metal and collapse it Place ring magnet around the flange e
44. ht by the ring magnet along with any shavings produced shown in Figure 5 Using a T size drill bit drill out the head of the Rivnut show in Figure 6 Place the rod magnet inside the hole to remove threaded end of the Rivnut as well as any shavings shown in Figure 7 Remove the ring magnet and install a new Rivnut Compressed Ring Placement of Magnet Figure 3 Drilling Threads Figure 4 Cutting Out Rivnut WR Magne Using this method and the prototype 88 of the Rivnuts tested were removed in an average time of 112 seconds one pass All of the Rivnuts were not removed successfully because the prototype requires two passes to completely remove the compressed ring In the first pass the bottom half of the compressed ring is cut off The second pass s required to cut the top half of the compressed ring however while making the second pass the top half of the compressed ring spreads apart instead of being cut This s the cause for the unsuccessful removal attempts This is solved in the final design when the cutter face width is doubled resulting in only one pass to remove the compressed ring The final design meets all the constraints and the proposed design solution will cost approximately 2211 Associates can be taught how to remove a Rivnut using this tool and method in under an hour Floyd Player McNeillie Knight Page l4 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Proje
45. ical Plunge Sheet Metal SEM mm mm mm Thickness mm Setup LS 6 90 O Aa Ta st n m 1115 ni y Setup ey Cut 1115 ni 4 etu caras T fais a etu j Note In all other vertical plunge depths the distance s measured with the bottom of the cutter lined up with the top of the Rivnut flange But for the starred dimensions the measurements are to be taken with the top of the cutter lined up with the top of the Rivnut flange In these final test it is necessary to drill out the inside diameter of the Rivnut to ensure that the woodruff key seat cutter has the required clearance in the Rivnut Additionally two cuts have to be made with the woodruff key seat cutter because it is not thick enough to completely remove the entire compressed ring with only one cut as seen below in Figure 61 t m par TI PARA AN ma zm m y JAH ri JF Fey gt a N x o e a a ERRUR E gt s 4 Wil This can be remedied by purchasing a woodruff key seat cutter of correct dimensions Table 17 shows the dimensions for the cutter in these tests along with the dimensions of the cutter that is needed to completely remove the compressed ring from the Rivnut in the future Floyd Player McNeillie Knight Page XLI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Table 17 Woodruff Key Seat Cutter Dimensions Cutter Cutter Cutter Width Shank
46. its uninstalled condition Calibration Before using the load cell the group calibrated t This was performed by having each group member weigh themselves on a scale Next they stood on the load cell and the output of the load cell was recorded After performing th s calibration t was compared to a cal bration performed by the manufacturer in 2008 It was found that the cal brations were within 3 of each other Figure 28 shows both the curve from the manufacturer s calibration in 2008 and the calibration performed for this experiment in 2010 Because the calibration was performed on a range of 0 1157 Newtons it was decided that this calibration was unacceptable because we were tested in a range much higher than 1157 Newtons Load Cell Calibration Curve 4 2 13 2008 E 1 29 2010 Oo Z A A A A AA LE O xe u 1 Signal mV V Figure 28 Load Cell Calibration Curves Procedure Once the test was set up two group members performed the experiments Below are the steps used to conduct the experiment so that uniformity was maintained 1 Ensure the load cell spacers Rivnut bolt andsheet metal are in line between the vise clamps 2 One group member began very slowly to tighten the vise in a smooth uniform fashion Floyd Player McNeillie Knight Page XII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 3 The other group member monitored the reading on the multi
47. lar holes In order to reduce spin out some contain a keyed head which fits into a slot in the hole The hexagonal head is best suited for softer components aluminum plastics etc and provides high turning resistance The circular and hexagonal external geometries are implemented by BMW so it is important to study both and understand their applications Finally the Rivnuts are offered with varying size heads As can be seen in Figure 19 the head has two different styles Figure 19 Flat Head left Rivnut and Thin Head right Rivnut Floyd Player McNeillie Knight Page I ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover The flat head Rivnut installs easily in punched or drilled holes and offers a larger surface area for easier installation The thin head Rivnut installs flush with the base material in order to allow a component to be mated to the base surface Rivstuds are also used and serve the same basic function of securing a component to a base material that is only accessible from one side Rivstuds however are more commonly used in hanging applications where they are mounted on a vertical surface Rivstuds are offered only in metric threads and examples of Rivstuds can be seen in Figure 20 f f ma ai Ci Figure 20 Rivstud Examples Steel with Zinc finish Rivstud left and Un worked Worked Rivstud right Installation Procedure
48. mal ESS dad AS LXXII Retorno LXXV Floyd Player McNeillie Knight Page 17 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Table of Figures Pietro Le Recommended OO a ES er 3 Pree 2 Placement of Maei a ena ka nee dan alli 4 Feno D AS Ehre ds esse een E tnret see terntre Teer AN rrr trey see terre Terre 4 Figure 4 Cutting Out Ryan 4 ua M e AA AAA a E E ND TJE 4 Figure 6 Drilling Rivnut Head ire 4 Figure 7 Rod Magnet Insel 100 een nT EN TT Tein 4 Figure 8 Exploded view of Rivnut Removal Tool rs 12 Freue POS Te OU se eeneutrersbentadenveatess 13 Penedo BASS ER fur OV Proton DE a ou en 14 Figure LL Rod Magnet and Ring MAS ie a ae 14 Figure 12 Woodruff Key Seat Cutter with Dimensions 15 Poewe Type Dill BE un een 15 al ao DAA o ction ea 15 Fre Labeled ca C8 0 DE er teca 16 F 1201 16 ROOY De ci een I Fute Me IRC OM anded OU AMM a oo on I Figure 18 Common and Specialized Rivnut and Rivstuds by B llhoff oooooncncnnonaninonininnnnnninicicncnnnns I Figure 19 Flat Head left Rivnut and Thin Head right Rivnut nennen I Figure 20 Rivstud ExampleS ire Il Figure 21 Installation of a Rivnut enana Il Figure 22 Removal of RiVNUT rennes II Figure 23 Preliminary CAD Drawing for B llhoff RivNUt ee VIL Figure 24 Stress Acting on Cylindrical Section of the Rivnut en VIH P 180162 gt Experimental OU a nenne een X Pour 20 Compression Lest SE dr sd
49. material Further testing is required to determine the load carrying capacity of a turned down Rivnut Hole Drilling Test Once the holes had been drilled into all of the Rivnuts they were compressed in a piece of sheet metal as can be seen in Figure 33 Floyd Player McNeillie Knight Page XVII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 33 Hole Drilling Test Specimen 2 Compressed in Sheet Metal Each specimen was then loaded axially to stretch them back to the original geometry Upon observation all specimens stretched and broke at the locations of the holes These results were expected and while the deformed compression ring area had been stretched back out a significant amount the break at the holes caused another issue The places where the holes were drilled flared when the Rivnuts were compressed but upon stretching they remained close to the same shape Figure 34 shows a specimen that was nearly able to be removed because of the reduction of the deformation ring but remained in the hole due to the drilled holes flaring Figure 34 Hole Drilling Result with Flared Edges None of the hole drilling test specimens were able to be removed from the sheet metal without either extreme force or methods that would damage the base material It should also be noted that the threaded section would not come through the hole in any of the hole drilling cases It would
50. n en etienne XLIX Modification of Rivnut Concept Sketch serres L Reciprocanng Saw CONCEDE SKEE ieres nase u a LI Hollow Mill Concept Sket IN seus soar a LU Placement OF MASNE nin a A NENE LXXIII Drie ut Thread ee lea us LXXII Tool Placed Around Ma NEL zes ek LXXII ToolEnsasedwilh Rivmut ias LXXIV Removing Rivnut Head errors LXXIV Rod Magnet Isern en eu Dell LXXIV Floyd Player McNeillie Knight Page 110 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover INTRODUCTION Rivnuts are sometimes poorly installed during the assembly process If the Rivnut is unable to be removed in the line a note s made in the computer system and the car continues to be assembled After the vehicle is assembled the vehicle s taken to the rework station where associates must remove the damaged Rivnut which may involve disassembling other components in order to reach the Rivnut These measures take up valuable time and can incur significant costs BMW is seeking a tool or fixture that can easily remove these damaged Rivnuts quickly and effectively Problem Statement Design a tool and method to completely remove cross threaded or slipping Rivnuts from sheet metal without causing damage to the base material including scratching marring or denting Constraints The final design must Weigh less than 6 8 kg Remove a Rivnut in less than 120 seconds Be no larger than 50 8 x 25 4 x 25 4 cm
51. nd of the Rivnut Place back of Rivnut and shavings under sheet metal and measure distance they travel Place rod magnet into hole Rotate rod magnet around to find threaded portion of Rivnut Position threaded portion near the hole Remove rod magnet and threaded portion Place rod magnet back in hole Remove cylinder magnet Remove rod magnet from hole making sure to not lose any shavings from rod magnet The rod magnet can be seen in Figure 50 below Prototype Fixture Results Magnet with Drill Test Floyd Player McNeillie Knight Page XXXIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover There were four positions of the ring magnet that were tried in the experiment as described below Magnet on Top Middle The results of most of the tests were successful The first experiment was done with the ring magnet being placed around the Rivnut as seen in Figure 51 after the test was performed Figure 51 Ring Magnet After Drill Use Observing the bottom piece of paper there were no shavings that fell through the bottom of the Rivnut All the shavings either stuck to the magnet or exited through the flange end Magnet on Bottom Middle The next experiment was done with the ring magnet around the Rivnut on the bottom of the sheet metal As can be seen in Figure 52 below there were no shavings that fell through the bottom of the Rivnut that the magnet did not
52. nough to remove it from the hole the Rivnut was installed It was determined that the force required to compress this ring enough to remove it from the hole the Rivnut was in is 489 N To quantify this force another test was done to determine how much force a person could apply to the ring with one hand and a pair of pliers This force was found to be approximately 1139 N Experimental Setup The rings were cut from collapsed Rivnuts using a rotary cutting tool Figure 39 shows the three test rings before compression Figure 39 Rivnut Rings Once these rings were obtained a vise as can be seen in Figure 40 was used to compress these rings A load cell was used to measure the force required to compress the rings a Figure 40 Experimental Setup Floyd Player McNeillie Knight Page XXII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Procedure One member of the team monitored the reading from the load cell while one member slowly and smoothly compressed the Rivnut with the vise Once the ring was sufficiently compressed enough to allow it to be removed from the Rivnut hole the load cell reading was recorded Additionally a second test was performed for comparison In this test one group member used one hand to apply a compressive load to the load cell via a pair of standard pliers This test was performed only to allow the group members to get a better under
53. nt values of 50 8 x 25 4 x 25 4 cm The recommended design concept will remove a Rivnut from a 5 08 x 5 08 cm flat surface One constraint is that the final design must not alter base material in any way A scratch test seen in Appendix L was performed which showed that the designed process would not scratch or alter the base material OSHA safety pinch points and ergonomic constraints were considered in the design of the tool and process Once set up for a specific size of Rivnut the process can be performed by the installer of the Rivnut Two final design criteria that were not met in the recommended design concept were that the device should be able to remove Rivstuds and that the design concept be available to the consumer at less than 500 The proposed design solution has a projected cost of 2211 This difference in price has resulted from half of the parts for the recommended design concept needing to be custom made A more detailed view of the cost can be found in Appendix N The basic process of the recommended design concept was tested and proven to work using a prototype fixture as seen in Appendix L The prototype fixture used a router which was turned down to an appropriate cutting speed using a dimmer switch A motor with an appropriate RPM and torque was included in the recommended design concept Also included in the design concept are magnets which are used to collect shavings and the threaded end of the Rivnut after th
54. of the critical section of the Rivnut by use of a lathe The hole drilling method placed small holes in the critical section of the Rivnut to weaken it and allow for yielding instead of breaking before and after the compression ring Both methods were then tested in a tension test as in Appendix D to see if yielding would occur instead of breaking The turn down test yielded one successful removal of a Rivnut while the hole drilling test only flared out the Rivnut making the problem worse where it was drilled After speaking with BMW it was discovered that modifying the Rivnut was not an option so these tests were not further explored Experimental Setup Turn Down Figure 30 Turned Down Rivnut on Lathe Figure 30 shows a Rivnut that has been turned down on a lathe The Rivnut was inserted into the chuck on a lathe and a cutting tool was used to remove material from the outside of the Rivnut Arbitrary amounts were removed for three different Rivnuts and the values were recorded before testing was performed Table 7 consists of turn down test parameters Table 7 Turn Down Test Dimensions Test Original Diameter Number mm Turn Down Diameter mm Diameter Reduction mm 2 Floyd Player McNeillie Knight Page XV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Hole Drilling Figure 31 Hole Drilling Rivnut Figure 31 shows a Rivnut installed in
55. ompress a Rivnut Measurements were taken using vernier calipers These measurements were used to create a CAD model and to do an analysis on how much force it takes to yield a Rivnut Since the type of steel was unknown many types of steel and aluminum were analyzed and averaged The theoretical force it takes to collapse a Rivnut is 3843 N Calculations Using a set of vernier calipers Rivnut measurements were taken and recorded These values were then used to generate a CAD Computer Aided Design model The model was used to better understand the geometry of the Rivnuts and get a perspective of how the cross section varied throughout the Rivnut length without having to cut into one of the provided Rivnuts The CAD model may also be used for FEA Finite Element Analysis if more stress information s required after the preliminary analysis Refer to Figure 23 for a preliminary detailed drawing y f f 4 7 RX yy CLEMSON UNIVERSITY ME 402 SPRING 2010 DRAFTER PART DESCRIPTION GARY R MENEILLIE BMW RIVNUT PART NIIMRER SECTION A A ae Figure 23 Preliminary CAD Drawing for B llhoff Rivnut Floyd Player McNeillie Knight Page VII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Using superposition the applied load over the entire Rivnut could be modeled as a load acting axially on a cylinder with inside and outside diameters matching the thinnest cro
56. periment Setup for Rivnut in Sheet Metal 1 Floyd Player McNeillie Knight Page XXXIX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 4 Figure 60 Experiment Setup for Rivnut in Sheet Metal 2 The final test was very s milar to the previous one but in this test the Rivnut was set in a much more rigid setup Figure 60 shows how this test was set up The purpose for this test was to represent the removal process in the most accurate fashion possible Procedure Again the procedure for cutting out these Rivnuts is similar in all the tests with slight variations 1 Once centered the woodruff key seat cutter is plunge the desired depth into the Rivnut with the mill spindle spinning 2 Next the table is moved on the positive Y axis direction until the shank of the cutting bit comes into contact with the inside diameter of the Rivnut 3 Using the rotary table the Rivnut is turned 360 in the counter clockwise direction This will cut out the entire compressed ring on the Rivnut The exact parameters for the final tests are included below in Table 16 These parameters show how to exactly run the final tests to ensure accuracy Floyd Player McNeillie Knight Page XL ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Table 16 Woodruff Key Seat Cutter Test Parameters Test Cuts Mill Initial Drill Final Drill Vert
57. rcentage of Total Weight 0 311 78 3 Threaded 0 086 21 7 After this test was performed a similar test was done with a bolt to enclose the bottom portion of the Rivnut The same procedure was followed as before and the vast majority of the shavings came out of the top as can be seen in Figure 43 below Floyd Player McNeillie Knight Page XXVI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 43 Rivnut Shavings with Plug The shavings that are in the bag are the shavings that came out the top of the Rivnut and the shavings that are outside the bag are the ones that were left in the Rivnut Table 12 shows the weight of the material shaved off from the hacksaw test Table 12 Hacksaw Test Weight g To understand how little the shavings weigh several Rivnuts were weighed and are shown below in Table 13 Table 13 Mass of Rivnut Rivnut Mass g As one can see the weight of the shavings was very small when compared to the overall weight of the Rivnut Another important note is that the shavings that were collected were as fine as dust This as well as the size of the piece removed can be seen in Figure 44 below Floyd Player McNeillie Knight Page XX VII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 44 Rivnut Pieces from Hacksaw Test The drill test results showed that when the Rivn
58. ring to the surface In addition the new design must be light and small enough for an associate to handle it with ease Woodruff Key Seat Cutter Ring Magnet Figure 1 Recommended Solution The recommended solution is shown in Figure 1 This design consists of a motor that rotates a woodruff key seat cutter that rides along a circular path to cut out the compressed ring of material It also uses a powerful magnet to catch the once threaded portion of the Rivnut from falling in the vehicle after it has been cut off Floyd Player McNeillie Knight Page 13 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover f To remove a Rivnut one must follow a series of steps l 2 3 Figure 5 Magnet Ability Figure 6 Drilling Rivnut Head Figure 7 Rod A z de Figure 2 Place the ring magnet over the Rivnut to be removed shown in Figure 2 Using a K size drill bit drill out the Rivnut threads to make room for the woodruff key seat cutter shown in Figure 3 Place the tool around the ring magnet This will place the woodruff key seat cutter inside the Rivnut and cutting may begin when the tool engages the Rivnut shown in Figure 4 Move the tool in a circular pattern provided by the base Once the tool has completed a full rotation the threaded end of the Rivnut is cut off Remove the tool from the vehicle The threaded end of the Rivnut is caug
59. sheet metal to particle board using four bolts Attach two stabilizing pieces to particle board using self tapping wood screws ve pa Procedure for Removing a Rivnut 11 Drill out Rivnut threads with drill 12 Plug router into dimmer switch and dimmer switch into wall 13 Place router with woodruff key seat cutter installed into hole cut in particle board 14 Center the woodruff key seat cutter over the Rivnut 15 Turn on router and set to appropriate speed using dimmer switch 16 Plunge router to specified depth 17 Move router until base hits edge of cutout part in particle board 18 Move around the router in cutout portion of board until threaded portion of Rivnut is separated 19 Use drill to remove head of Rivnut Procedure for Scratch Test 1 Color specified area with a permanent marker Floyd Player McNeillie Knight Page XLV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 2 Run Rivnut Removal Test 3 Observe area that was colored after completion of the test for any scratches made to the surface Results Rivnut Removal Using the prototype fixture and router with the woodruff key seat cutter the Rivnut was successfully removed from the sheet metal The Rivnut head and removed threaded portion can be seen in Figure 68 Figure 68 Rivnut Head and Threaded Portion This fixture and set up was able to prove that the idea for using a woodruff key s
60. ss section of the Rivnut This method should give an approximate value for the required deformation load See Figure 24 for reference Figure 24 Stress Acting on Cylindrical Section of the Rivnut The load acting on the Rivnut is purely uni axial due to the Rivnut design and the installation tool Using the equation for stress seen in Eq 1 the required deformation force could be found F 1 Ge A Where o is the yield strength of the material F is the required deformation force and A is the effective cross sectional area Table 2 shows the measured Rivnut dimensions used for the stress force analysis Table 2 Rivnut Dimensions Inside Diameter mm Outside Diameter mm Effective Area mm Using the values in Table 2 and the stress formula from Eq 1 the required deformation forces could be obtained for the Rivnut material The material of the Rivnuts was given in the catalog provided by Bollhoff These properties were then looked up and put into Table 3 Floyd Player McNeillie Knight Page VIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Table 3 Required theoretical deformation force of Actual Rivnut Yield Strength Pa Force to Yield Rivnut N Steel C1010 1008 5521 Floyd Player McNeillie Knight Page IX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX D EXPERIEMENTAL ANALYS
61. standing of the amount of force required to compress the ring compared to the amount of force that a person can apply using only a pair of pliers Results Figure 41 shows the rings after the test was performed These rings can now pass through the hole that the Rivnut was installed in Figure 41 Compressed Rings Table 9 shows the average load required to compress one of these rings and Table 10 shows the force an average person using one hand can compress with using only a standard pair of pliers Table 9 Ring Compression Load Ring Compression Test Output mV V Load A Standard Pliers Compression Output mV V Load N 1139 Therefore the ring can be compressed using only 43 of a person s strength using standard pliers It must be noted that this ring must be compressed while inside the hole that the Rivnut was installed in Floyd Player McNeillie Knight Page XXIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover because this is the only access point to the ring It is possible to compress this ring but a special tool must be made to fit in the confined space Floyd Player McNeillie Knight Page XXIV ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX H SHAVINGS TEST One of the constraints that BMW set was that no shavings from the Rivnut can be left inside the body If the final design consists of a cu
62. t can be seen in the table below Table 14 Magnet Distance Test Shaving Type Dust like shavings Appendix H Figure 11 Larger shavings Appendix H Figure 31 The distance the shavings traveled were about the same but did vary a little This test was done to get an idea of the strength of the magnet in which the pull is rated at 5 8 N In respect to other ring magnets that are available this 1s a relatively weak magnet These results show that a magnet can be used almost anywhere near the Rivnut in order to collect shavings to keep them from falling when a drill bit is used Further testing must be done with other tools to determine if this 1s a feasible option Woodruff Key Seat Cutter Test The cylinder magnet successfully held the shavings and threaded portion of the Rivnut in place on the underside of the sheet metal after they were attracted as can be seen in Figure 56 The distance the Rivnut back and shavings traveled was about 2 cm The rod magnet successfully removed the shavings from the hole and was strong enough to pull the threaded portion of the Rivnut through the hole The time 1t takes to completely remove the threaded portion and shavings are shown in Table 15 below Floyd Player McNeillie Knight Page XXXVI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 56 Threaded Portion Being Removed from Hole Table 15 Threaded Portion of Rivnut Removal
63. th the Rivnut installed in sheet metal it was clamped in a vise for stability The rotary cutting tool was used to remove material from the compressed ring Figure 45 Rotary Tool Material Removal Setup The second experiment was set up as in Figure 46 A small cutting tool was used to remove material from the inside of the Rivnut The Rivnut was fixed in the rotating side of the lathe Figure 46 Material Removal from Inside Rivnut Floyd Player McNeillie Knight Page XXIX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Procedure Rotary Tool Procedure 1 Install Rivnut in sheet metal 2 Using the diamond tipped cutting tool remove material from inside the Rivnut 3 Conduct the tension test to determine if Rivnut can be removed Note The cutting tool lasted only long enough to complete one Rivnut Lathe Material Remove Procedure Set up experiment as shown in Figure 46 Engage the cutting tool in the inside of the Rivnut Once the desire amount of material is removed the cutting tool should be removed Conduct the tension test to determine if Rivnut can be removed Repeat steps 1 thru 4 three times nm A Results Both of these tests essentially are testing the exact same theory Consequently the results from both tests are the same Figure 47 shows that the Rivnut fails in a manner similar to if no material has been removed Figure 47 Rotary Tool Materi
64. to fill the compartment with foam so that the pieces do not rattle Floyd Player McNeillie Knight Page III ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX B OSHA REGULATIONS One of the constraints of the final design is that 1t must meet all of OSHA s safety pinch points and ergonomic constraints These constraints are in place to save lives by preventing workplace injuries and illnesses To ensure that the final design meets all the required regulations research was conducted to determine the exact conditions regarding these requirements Pinch Points OSHA defines a pinch point as any point other than the point of operation at which it is possible for a part of the body to be caught between the moving parts of a press or auxiliary equipment or between moving and stationary parts of a press or auxiliary equipment or between the material and moving part or parts of the press or auxiliary equipment Therefore it is desired to eliminate any pinch points in the final design by redesigning the tool or fixture If it is found that eliminating the pinch point is not feasible then guards should be designed and installed to protect the user from injury Additionally there must not be any pinch points created by the installation of the guard itself OSHA General Machine Requirements OSHA has general requirements that all machines and their respective guards have to meet Thes
65. to remove round magnet e Includes round magnet removal tool Floyd Player McNeillie Knight Page 116 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 16 Prototype Picture Figure 17 Recommended Solution The prototype design utilizes a woodruff key seat cutter w th a 1 16 face width because this size was commercially available and inexpensive The recommended design uses a 1 8 inch cutter face in order to complete the cutting operations in one pass The recommended design uses a base that has a 50 8 mm diameter and fits in the flat area around a Rivnut specified by BMW Also in reducing the size of the design the total weight s reduced from 7 23 kg to 2 78 kg in the recommended design A dimmer switch is required in the prototype design in order to reduce the motor output to an appropriate speed for the cutting operation but in the recommended design a motor designed for the specific task has been selected and does not need to be modified To ease the removal of the ring magnet a handle was incorporated in the final design concept The recommended design concept meets all of the constraints and most of the criteria for the project The final design concept has a weight of 2 78 kg which s below the set criteria of 4 5 kg The process proposed in this report takes an average of 112 seconds Final dimensions of the design concept are 27 x 23 x 10 cm which falls within the constrai
66. tting operation then inevitably there will be shavings It was decided that these shavings needed to be quantified Two different tests were performed In the first a hack saw was used to make two parallel cuts in a Rivnut The shavings from this test were then collected and weighed The second test was performed to determine the percentage of shavings that would exit the Rivnut through the threaded end compared to the shavings exiting the flange end when the Rivnut was drilled Experimental Setup Rivnut Parallel Plates Figure 42 Experimental Setup Drill Test Figure 42 above shows the setup of the experiment Paper was put into a vise to catch any shavings that fell through the threaded end of the Rivnut Parallel plates were put on top of the paper to hold the sheet metal that held the Rivnut in place while drilling occurred A hole the size of the Rivnut was punctured into another piece of paper in order to catch any shavings that exited the flange end and a Rivnut was placed into the hole in the paper The same test was performed but this time the Rivnut was plugged at the threaded end with a bolt Hacksaw Test For this test a similar setup was used as in Figure 42 Paper was put into a vise to catch any metal shaving from the Rivnut The Rivnut was then clamped with the vise orientated so that the hole in the Rivnut was horizontal Procedure After the experiment was set up the following proce
67. uired 5 2 in Ibs needed to cut a Rivnut using the technique illustrated in Appendix O This motor also rotates from 0 1750 RPM which is around the suggested 1681 RPM provided by the woodruff key seat cutter manufacturer Part B is the handle which will provide the user with enough leverage to easily maneuver the tool during operation The metal handles are covered by a layer of phenol formaldehyde resin which protects anything the tool handles may encounter unpredictably This resin layer will also protect the handles from becoming dinged which could result in sharp burrs that could injure the associate or mar the vehicle Part C 1s the handle mount which is made from 1060 aluminum alloy and provides a rigid connection between the handles and the motor Parts E K and N are the motor mount top legs and bottom respectively These pieces are made from 1060 aluminum alloy and are welded together The mount will be bolted to the motor for rigidity The bottom section acts as the follower in a cam follower style operation Parts H and I are custom collet nuts and collets respectively Since a key shaft is used on the motor a custom collet was created which resulted in a custom collet nut A collet is necessary to mount the cutting tool to the motor Floyd Player McNeillie Knight Page 113 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Figure 10 Base Fixture of Prototype Parts
68. ut was drilled out more shavings came out the flange end however some shavings did exit though the threaded end When the Rivnut was plugged almost no shavings were left in the Rivnut and most of the shavings came out the flange end as one would suspect The hacksaw test results showed that only a small amount of shavings were made from sawing the Rivnut Also these shavings were very small when compared to the shavings from the drill test Floyd Player McNeillie Knight Page XX VIII ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX I MATERIAL REMOVAL STRETCH TEST Summary One idea that was tested was whether it is possible to adequately remove material from the inside of the Rivnut that would allow the Rivnut to be stretched enough to remove it from the hole There were two methods to test this theory One was to remove material from the critical yielded area once the Rivnut was already installed using a rotary cutting tool The other was to remove material from the inside diameter of the Rivnut at the critical yielding area using a lathe Both methods tested to see if once this material has been removed the Rivnut could be then stretched in tension and removed Both tests showed that when material is removed either before or after installation the Rivnut cannot be stretched to be removed Experimental Setup This first experiment was set up as in Figure 45 Wi
69. vnut Remover Appendix Fr Bore Cutina Test a een XIX Experimental Selina daa sE XIX Proc dur nee see es ee XIX RSS RO a o O O ER ENERN XX Appendix G Ring Compression Test XXII SUNMAR En een dl ER un XXII Experimental SUD rees XXII D C UNI SR 0 0 O Ru ma a XXIII A a en XXIII Appendix He Pavi SS Testa Os XXV Experimental SED aeos eat XXV Prog d ster ten ete XXV PRES UES a ee XXVI Appendix I Material Removal Stretch Test XXIX SUM e E E O EO RE eisen XXIX EXpermenta NOE ea tenu ne insu ii en XXIX Procedure ze sn ee E Desire XXX Re UO PE O OE OO RO OI XXX Appendix J Magnet Testen ada XXXII Experimenta kS c ena XXXII Proc NS O NE cias XXXII Res RO O IE XXXIII Appendix K Woodtutf key seat cutter test aii I XXX VIII Experimental SetuP sn ee Ti Hand hdi XXX VIII Proc UN O EI A de etes D O eee XL Release ee een XLII Appendix LL Fixture Prototype and Testini oi nj aa EI XLIV Experimientabse passte eek XLIV Proc dl Een rn ee en re ne ee ee XLV Resten een Be re err er err ee a eee XLVI Appendix NE Failed Desisn Concepts ana eee aa a XLIX Replacement Concept todita titles Dit XLIX Floyd Player McNeillie Knight Page l6 ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover Modification of Rivnut CONCEPt ae L Reciproc tine Saw Conce PE deis LT ACUSAN Besseres esse LU Appendix NE De ail Craw 1S cise ace Re LUI Appendix N Bill f Materials ee LXXII APpendi x OF User ma
70. vnut is completely cut into two pieces as in Figure 36 Floyd Player McNeillie Knight Page XIX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover 6 Turn off the lathe 7 Repeat as desired Figure 36 Rivnut Completely Cut Results Two Rivnuts were tested in this way The first Rivnut was cut immediately after the compressed material Figure 37 show the result of this test Figure 37 1 Bore Cut Rivnut The next Rivnut was cut directly in the center of the compressed ring which can be seen in Figure 38 Figure 38 2 Bore Cut Rivnut Floyd Player McNeillie Knight Page XX ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover In conclusion it was found that cutting Rivnuts in this manner is possible however a different type of cutting operation will have to be used such as a grinding wheel that could completely remove the compressed ring Floyd Player McNeillie Knight Page XXI ME 402 Spring 2010 Final Report BMW Team B 04 20 2010 Project Title Rivnut Remover APPENDIX G RING COMPRESSION TEST Summary Some of the potential designs being considered leave behind a ring of material that is larger in diameter than the hole the Rivnut was installed This ring of material must be removed from inside the body therefore a test was performed to determine the force required to compress this ring e

BMW Rivnut® Remover - Clemson University

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BMW Rivnut&reg; Remover - Clemson University

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BMW Rivnut® Remover - Clemson University