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How Reliable is Your Product?

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1. Reliability Test Plan RTP The high level plan that calls out all of the reli ability testing that you will perform on a product Repair Depot Organization responsible for repairing products and tracking the repair actions Return on Investment ROI Analysis which compares the amount spent on a process compared to the amount saved 328 Appendix D Glossary of Terms Return Rate The percent of product returned in a given period of time Revolutionary Product A product unlike any product in the past with a brand new application or technology Risk Management The process of discovering evaluating and mitigating risks in your product Risk Priority Number RPN A measurement system to determine the amount of risk for a given failure mode An RPN is the multiplication of three components Severity of Failure S Probability of occurrence P and Detection D Root Cause Analysis RCA The investigative process to determine the un derlying event s responsible for a failure Run In A form of ESS powering on a system and running tests without the use of accelerated environmental stresses The key variable is the run in time Safety of Screen Demonstration that the chosen screen leaves samples with sufficient life left in them to survive a normal lifetime of field use In other words this method proves that a screen is safe Seeded Samples A sample of the product that you purposely insert defects to ens
2. Hot Carrier Injection Phenomenon in solid state or semiconductor electron ic devices where either an electron or a hole gains sufficient kinetic energy to overcome a potential barrier necessary to break an interface state 4 Hot Operating Limit HOL During HALT when stepping the temperature up the upper temperature limit above which the product ceases to function Human Factors Analysis The study of all aspects of the way humans relate to the equipment with the aim of improving operational performance reliability and safety 24 Hot Carrier Injection 2010 Wikipedia Online http en wikipedia org wiki Hot Carrier Injection 318 Appendix D Glossary of Terms Infant Mortality The period of a product life cycle in which the failure rate is decreasing in rate over time Failures in this period of time are typically due to a manufacturing defect Infant Mortality Region tThe region of decreasing slope or decreasing failure rate from time t 0 and forward Typically the probability of failure is highest im mediately after you ship the product to your customer and then after that point the failure rate reduces Input in reference to DOE These are the entries into the system from another device or from a user such as a user interfacing with the system Internally Specified Goals Goals that come from within your company rather than from external competition These goals are usually based on trying to be bett
3. to actually go beyond your operating limit but within the destruct limit As your product approaches its operating limit make sure to shut it off Then turn it back on when it comes back within the operating limit In the second part the detection portion keep your profile within the operating limits Note that each portion of the screen can be one or more cycles and each portion does not have to be the same number of cycles Prediction to ORT Factor A Reliability Prediction may not be able to give an exact MTBF number but it will give a number close enough to help determine an ORT sample size and acceleration factor necessary to provide the necessary data on going After collecting sufficient data in the ORT compare your ORT results with your prediction so that you have this difference You can then use this difference to develop a factor that you can use for future predictions Prediction to Field Factor The ratio between the prediction results from previous predictions with the field results after deploying the product After col lecting sufficient data from the field compare your field results with your pre diction so that you have this difference You can then use this difference to develop a factor that you can use for future predictions Preventive Maintenance PM A procedure of inspecting testing and re conditioning a system at regular intervals usually because of a component s that wears over time and will cause a pred
4. 332 Appendix D Glossary of Terms situations Whenever a user is involved you should pay specific attention to the possibility of the user using the product incorrectly risking either the integrity of the product or worse creating an unsafe situation Vendor Assessment A systematic evaluation of a broad range of potential reliability activities and techniques as currently employed and integrated with one or more vendors Verification HALT After you perform HALT and provide corrective action for a specific failure then perform HALT again to ensure that the corrective action improved the product performance and did not introduce new failure modes This second HALT is called a Verification HALT Vibration Operating Limit VOL During HALT when stepping the vibration up the limit above which the product ceases to function VITA 51 Working Group Formed in 2004 to investigate the state of the Re liability Prediction industry and develop a method to address electronics failure rate prediction issues They found that the MIL HDBK 217 method had become obsolete compared with current electronics technologies however it remained the most common method used in industry to predict electronics reliability Warranty A guarantee given to the purchaser by a company stating that a product is reliable and free from known defects and that the seller will without charge repair or replace defective parts within a given time limit and under ce
5. Warranty Review The identification and prioritization of warranty perfor mance tracking and cost reduction opportunities This is essentially the metric check for the Warranty Analysis that you performed in the design phase Wear Out The period of a product life cycle in which the failure rate is in creasing in rate over time Failures in this period of time are typically due to end of life events Wear Out Mechanism A failure mechanism that is related to an end of life event such as a breakdown of a material Weibull Distribution A continuous probability distribution that can take many different shapes depending on the value of the shape parameter B A B lt 1 exhibits a failure rate that decreases with time A B 1 exhibits a failure rate that is constant with respect to time A B gt 1 exhibits a failure rate that increases with time All three different phases of the Reliability Bathtub Curve can be modeled with the Weibull distribution and varying values of The distribution was named after Waloddi Weibull who described it in detail in 1951 4 Workaround Situations where you have a failure and apply a temporary change or fix so that you can continue with the testing knowing that you will have to go back after the completion of the test and perform a more detailed failure analysis and provide a more permanent fix X Ray Fluorescence XRF The emission of characteristic secondary or fluorescent x rays from a material
6. ability to change Corrective Action See Closed Loop Corrective Action CLCA Corrective and Preventative Action CAPA See Closed Loop Corrective Action CLCA Corrosion Deterioration of metals caused by oxidation or chemical action 10 Computer Aided Design 2010 Wikipedia Online http en wikipedia org wiki Computer_Aided_ Design 11 Conductive Anodic Filament 2010 Wikipedia Online http en wikipedia org wiki Conductive Anodic Filament 12 Confidence Interval 2010 Wikipedia Online http en wikipedia org wiki Confidence_ Interval 13 Confidence Level 2010 Wikipedia Online http en wikipedia org wiki Confidence_ Level 14 Confidence Limits 2010 Wikipedia Online http en wikipedia org wiki Confidence Limits 310 Appendix D Glossary of Terms Cosmic Rays Particles coming from outside the solar system These particles can interact with electronics and cause temporary upsets in performance Creep Degradation The loss of property or breakdown of a material due to overexposure to heat Critical to Quality CTQ Specific measurable characteristics of a product or process that are necessary for your customers satisfaction Cross Sectioning In the context of failure analysis this is the process of grinding of die and package usually perpendicular to the surface of the die to examine defects Cumulative Distribution Function CDF Describes the probability that
7. drawn on paper with logarithmic horizontal axis and logarithmic vertical axis Log Normal Distribution A probability distribution of a random variable whose logarithm is normally distributed A variable might be modeled as log normal if it can be thought of as the multiplicative product of many indepen dent random variables each of which is positive Maintainability Analysis The method of determining how to best design a product for ease of maintenance Maintainability Prediction The method of determining how long it takes to repair a product once it fails Manufacturing Screen The method of stressing a product either electrically or environmentally to accelerate time during manufacturing with the goal of uncoving latent manufacturing defects that would otherwise escape and then soon fail after your customer starts using the product Markov Analysis Process of analyzing the reliability and availability of systems whose components exhibit strong dependencies Mean Square Deviation Measure of the differences between values predicted by a model or an estimator and the values actually observed from the thing being modeled or estimated Mean Time Between Failure MTBF Predicted elapsed time between inherent failures of a system during operation It is the inverse of the failure rate 28 Mean Time to Repair MTTR The average time to repair a product and get it operational after it fails Memory Leak When software ro
8. ment modeling reliability testing collecting and using data etc Closed Loop Corrective Action CLCA To identify analyze and correct a problem with a product or process Coffin Manson Model A model used to describe mechanical fatigue in material and crack growth in solder and other metals due to repeated temper ature cycling Cold Operating Limit COL During HALT when stepping the temperature down the lower temperature limit below which the product ceases to function Commercial Off The Shelf COTS Commercially available hardware This is often used with military and space systems in which military or space grade hardware is too costly or not available or both Note that COTS does not nec essarily mean commercial quality 8 Certified Reliability Engineer 2010 Wikipedia Online http en wikipedia org wiki Certified Reliability Engineer 308 Appendix D Glossary of Terms Competitive Analysis Process by which you compare your product s reli ability performance to competitive products Use the results as input to your Gap Analysis to determine appropriate next steps to improve your organiza tion s reliability program The two main types of Competitive Analyses are Competitive HALT and Competitive Teardown Analysis Competitive HALT Subject two or more products to HALT up to their opera tional destruct limits and then compare the product margins With similar tech nologies a product that has better
9. of a product efficiently and cost effectively from concept into design and manufacturing through service and disposal Product Warranty A warranty contract that comes with your product purchase and covers you for a period of time after you buy the product Prognostics Study of being able to predict failures before they happen Proof of HASS Strength Method by which you can determine if the screen you chose for HASS is strong enough to find defects In other words this method proves the screen is effective Proof of Screen POS Process of ensuring that the screen you have developed is both safe and effective The POS consists of two different com ponents 1 Safety of Screen to prove the screen is safe and 2 Proof of HASS Strength to prove the screen is effective Rayleigh Distribution A continuous probability distribution in which the com ponents are uncorrelated and normally distributed with equal variance The dis tribution is named after Lord Rayleigh Re HALT The process of performing HALT later in the development process after the product has matured when more samples are available and test routines are more complete Relevant Failure Failures modes that occur during reliability testing which would occur in the field during normal operation Reliability Allocation See Reliability Apportionment Reliability Apportionment Take your reliability goal and budget portions of it to each of the di
10. D Glossary of Terms Accelerated Life Test ALT The process of determining the useful life of a product in a short period of time by accelerating the use environment how the product will be used Acceleration Factor Denotes how much you are accelerating the test over the end use conditions Activation Energy The minimum energy required to start a chemical reaction a chemical reaction is when a substance changes into another substance Alpha Risk Sometimes referred to as a Type Error is the producer s risk or the risk that you won t ship a good product because the data indicated that the good sample was bad In other words is the risk of rejecting the hypothesis that the mean hadn t changed when it hadn t Analysis of Variance ANOVA Estimation of fractional contributions and error variance Annualized Failure Rate The rate at which a product will fail calculated on a yearly basis Arrhenius Model Describes how component reliability is adversely affected as the temperature increases Availability The probability a system is ready for use when needed or the proportion of time a system is ready for use Benchmarking The process of determining and comparing reliability related metrics for a set of specific products in a specific market The purpose of Benchmarking is to gain a clear understanding of reliability strengths and weaknesses of competitors products in your market How Reliable is Your P
11. a real valued random variable X with a given probability distribution will be found at a value less than x Intuitively it is the area so far function of the probability distribution 1 Customer Specified Goals When your customers specify the reliability re quirements for your product Mean time between failure MTBF mean time to repair MTTR availability dead on arrival DOA rate and return rate are common reliability goals but there are many others Date Code Product build dates that vendors stamp onto their product These date codes can be very useful if you discover a failure on the manufacturing line or in the field that may be related to a particular date range of when the product was created Dead on Arrival DOA The rate of products that don t work when your customer first receives and installs the product Decapsulation During failure analysis the process of removing the cover of a semiconductor package Defect Insertion Rate The rate at which you introduce new defects to a software process Dendrite Growth A type of failure that is caused by grain development that resembles the increasingly smaller branches of a tree 15 Cumulative Distribution Function 2010 Wikipedia Online http en wikipedia org wiki Cumulative Distribution Function How Reliable is Your Product 50 Ways to Improve Product Reliability 311 Derating Analysis The practice of operating at a lower stress condition than t
12. act result with a determin istic algorithm No Problem Found NPF When your product fails in your customer s hands and you can t duplicate this failure when you retest in your facility Noise Factor Effect of all the uncontrollable factors in an experiment Nonlinear Finite Element Analysis FEA A form of Finite Element Analysis which is more general and includes the full spectrum of effects such as large displacement contact large strain and nonlinear material response Non Recurring Engineering NRE Engineering resources that you use once or for a period of time in a program and then stop Nonrelevant Failure Failures modes that occur during reliability testing which would not occur in the field during normal operation Normal Distribution A continuous probability distribution that often gives a good description of data that cluster around the mean The graph of the asso ciated probability density function is bell shaped with a peak at the mean and is known as the Gaussian function or bell curve 29 Monte Carlo Simulation 2010 Wikipedia Online http en wikipedia org wiki Monte_Carlo_ Simulation 30 Normal Distribution 2010 Wikipedia Online http en wikipedia org wiki Normal_Distribution How Reliable is Your Product 50 Ways to Improve Product Reliability 321 Obsolescence The process of going through your parts lists to determine which vendors will be discontinuing their parts a
13. al Distribution A continuous probability distribution that describes the times between events in a Poisson process i e a process in which events occur continuously and independently at a constant average rate 2 Extended Warranty A warranty contract that you can purchase to increase the amount of time a product is covered under the manufacturer s warranty period 19 Electronic Design Automation 2010 Wikipedia Online http en wikipedia org wiki Electronic_ Design Automation 20 Exponential Distribution 2010 Wikipedia Online http en wikipedia org wiki Exponential_ Distribution 314 Appendix D Glossary of Terms Facilitation The process of designing and running a successful and impartial meeting Facilitation services the needs of any group who is meeting with a common purpose whether it be making a decision solving a problem or simply exchanging ideas and information Facilitation of Code Reliability Review The use of reliability reviews to target the core and vulnerable sections of code to allow the owner of the source code to develop sufficient synergy with a small team of developers in finding defects Facilitation of Team Design Review Conducting brief informal reviews that are highly interactive at multiple points throughout the progression from system architecture all the way to low level design Facilitation of Team Design Template Review Conducting group pre design review meetings to p
14. ays to Improve Product Reliability 313 Electronic Design Automation EDA A category of software tools for designing electronic systems such as printed circuit boards and integrated circuits 1 Electronic Manufacturing Service EMS See Contract Manufacturer CM Electrostatic Discharge ESD The release of static electricity when two objects come into contact Typically this is when a person has a build up of charge comes in contact with electronics and causes a discharge event transferring the charge to the electronics End of Life EOL Analysis An estimate of the onset of wear out failures for consumables e g electrolytic capacitors fans motors drives An EOL Analysis can aid in planning warranty costs and scheduling Preventive Maintenance PM Engineering Change Order ECO A system by which you make a change to your product including all of the documentation involved Environmental Stress Screening ESS The process of applying external stresses to a manufacturing sample of a product usually temperature and or vibration to accelerate time in order to expose any manufacturing defects before shipping the sample to a customer HASS Run In and Burn in are types of ESS Evolutionary Product A product that is similar to a previous generation but with modifications for new features Expert Reliability Review When a senior engineer expert reviews the work of an engineer or junior engineer Exponenti
15. cs to characterize the material s resistance to fracture 22 Fretting Wear and sometimes corrosion damage at the edges of contact surfaces This damage is induced and in the presence of repeated relative surface motion as induced for example by vibration 22 Fracture Mechanics 2010 Wikipedia Online http en wikipedia org wiki Fracture_ Mechanics 23 Fretting 2010 Wikipedia Online http en wikipedia org wiki Fretting 316 Appendix D Glossary of Terms Functional Testing The method of testing a product to ensure it is perform ing its intended functions When performing a reliability test it is usually important to functionally test the product at all times Fundamental Limit of the Technology FLT The limit at which you can t go any higher with a stress without changing the failure mechanism and producing nonrelevant failures Gap Analysis The process of determining the spread between your reliability goals and your current capabilities Goal Setting tThe process of setting targeted goals at the beginning of a de sign development program and then putting forth a plan to achieve the goals Golden Nuggets Those few techniques that your team does well and recog nizes they do them well so these become engrained into your culture Grms Gravity Root Mean Squared A unit of measure for vibration in which you calculate the total amount of the vibration under a Power Spectral Density PSD curve wit
16. d by a company and retailed under the purchas ing company s brand name 2 31 Original Design Manufacturer 2010 Wikipedia Online http en wikipedia org wiki Original Design Manufacturer 32 Original Equipment Manufacturer 2010 Wikipedia Online http bit ly O_E M en wikipedia org wiki Original_Equipment_Manufacturer 322 Appendix D Glossary of Terms Orthogonal Array lIn a DOE this type of array enables a fair comparison of tolerance factor main effects and advanced statistical tools like Analysis of Variance ANOVA It also enables an estimation of fractional contributions and error variance Out of Box Audit OOBA The process of randomly taking a boxed up system from the shipping area opening it up and performing an inspection and or functional test on the sample in order to measure outgoing quality and reliability Output in reference to DOE What the system is supposed to do or the results the system is supposed to produce Parameter Diagram P Diagram A diagram to help focus the brainstorming into four different areas Piece to Piece Variations Environment Customer Us age Duty Cycle and Deterioration Each area is called a Noise Factor or a factor that you can t control Start with one area and brainstorm all of the failure modes in this area and then move on to the next area For each failure mode you also have Inputs Outputs Control Factors and Error States Pareto Chart A type
17. er testing for a pre determined amount of time or until a pre determined number of failures occur Process Benchmarking Comparison between two or more products to determine what techniques each team uses in developing their product It entails comparing process methodologies such as in house versus outsource builds quality philosophy and screening methods Process Capability The inherent failure rate of a particular process Process FMEA FMEAs performed on the manufacturing processes They are conducted through the quality planning phase as an aid during production The purpose is to analyze and correct the possible failure modes in the manu facturing process including limitations in equipment tooling gauges operator training or potential sources of error Producer s Risk See Alpha Risk a Product Benchmarking Comparing product reliability related metrics for a set of specific products in a specific market such as mean time between failure MTBF annualized failure rate AFR and dead on arrival DOA rate Product Life Cycle PLC The life of a product in the market with respect to business commercial costs and sales measures 36 Probabilistic Evaluation 2010 Wikipedia Online http en wikipedia org wiki Probabilistic Evaluation How Reliable is Your Product 50 Ways to Improve Product Reliability 325 Product Lifecycle Management PLM Tool A tool that aids companies in managing the entire lifecycle
18. er than previous products One of the executives of a company may put forth some sort of edict such as our next product will have half the field returns than our previous product You can then take this and turn it into a goal statement lon Chromatography Process that allows the separation of ions and polar molecules based on their charge Latent Defect Density The number of defects per lines of code still remaining in the software after you start shipping the software Leading Indicator An ALT that is run not to the point of a failure but rather until you detect an indication that a parameter has changed First you should determine what parameter s you should monitor and then you should run a calibration step in order to be able to properly extrapolate the failure Lessons Learned tThe process of capturing all of the issues that occur in a program in a centralized system for all personnel to share and then reviewing these issues prior to embarking on a new design Life Cycle Cost LCC Refers to the total cost of ownership over the life of a product Also commonly referred to as cradle to grave or womb to tomb costs 7 25 lon Chromatography 2010 Wikipedia Online http en wikipedia org wiki lon_Chromatography 26 Life Cycle Cost 2010 Wikipedia Online http en wikipedia org wiki Life Cycle Cost How Reliable is Your Product 50 Ways to Improve Product Reliability 319 Log Log Graph A graph
19. fferent assemblies in your system Reliability Assessment See Reliability Program Assessment Reliability Bathtub Curve A relationship between failure rate versus time that expresses the three distinct phases of a product life cycle infant mortality steady state and wear out 37 Rayleigh Distribution 2010 Wikipedia Online http en wikipedia org wiki Rayleigh Distribution 326 Appendix D Glossary of Terms Reliability Block Diagram Diagram often used during Reliability Apportion ment to show the contribution of different portions of your system to the overall system reliability Reliability Case Special form of Reliability Program Plan in which the supplier guarantees that their product will meet an agreed set of in service re liability requirements The onus of responsibility is on the supplier to build the case by gathering evidence showing that the product will meet the reliability re quirements The supplier then develops a Reliability Case Report which contains a summary of the Reliability Case with supporting evidence Reliability Critical Item List List of components that require special attention and reduction of this list is a key goal early in a program Some of the reasons for putting items on this list are low reliability high criticality and long lead time Reliability Demonstration Test RDT The process of demonstrating the steady state reliability of a product through testing Reliabil
20. he rating specified for a component Design FMEA FMEAs performed on the system at the design level The purpose is to analyze how failure modes affect the system and to minimize failure effects upon the system Design for Maintainability Part of the DfX Design for Excellence method ology in which you consider during the design phase the preventive mainte nance and repair of your product Design for Manufacturability DFM Part of the DfX Design for Excellence methodology in which you consider during the design phase how your manu facturing team or partner will assemble and build your product Design for Reliability DFR Part of the DfX Design for Excellence meth odology in which you consider during the design phase how to optimize the re liability of your product Design for Warranty Part of the DfX Design for Excellence methodology in which you consider during the design phase how to optimize your warranty period set the warranty rate for your product to minimize the number of products that fail within your product s warranty period while maximizing the length of warranty you can offer Design Margin See Operating Margin Design of Experiments DOE An experiment which can focus on a wide range of key input factors or variables and will determine the optimum levels of each of the factors Destruct Limit In HALT a limit in which the failure doesn t recover when you reduce or remove the stress Detect
21. hin a band of frequencies Guard Band Limits During a HALT a guideline as to the limits you meet as a minimum HALT to AFR Calculator A mathematical model that when provided with the appropriate HALT and product information will accurately estimate a product s actual failure rate AFR in the field Highly Accelerated Life Test HALT A design technique that you can use to discover product weaknesses and design margins The intent is to subject a product systematically to stress stimuli well beyond the expected field environ ments in order to determine the operating and destruct limits of your product Highly Accelerated Life Test HALT Plan The plan by which you document the information on the types of stresses levels of stresses and order of stresses You should also determine the number of samples functional tests what parameters to monitor and what constitutes a failure Decisions in this plan will dictate the relative success of the HALT Highly Accelerated Life Test HALT Report The report by which you document all of your findings in HALT including at what point each failure occurred and what steps you took to work around each failure Pictures charts and graphs are great for your management However the most important parts of the report are your recommendations and the follow up actions you plan to take How Reliable is Your Product 50 Ways to Improve Product Reliability 317 Highly Accelerated Stress Audi
22. ictable failure Printed Circuit Board PCB Used to mechanically support and electrically connect electronic components using conductive pathways tracks or signal traces etched from copper sheets laminated onto a non conductive substrate It is also referred to as printed wiring board PWB A PCB populated with elec tronic components is a printed circuit assembly PCA also Known as a printed circuit board assembly PCBA 34 Power Spectral Density 2010 Wikipedia Online http en wikipedia org wiki Power_Spectral_Density 35 Printed Circuit Board 2010 Wikipedia Online http en wikipedia org wiki Printed Circuit Board 324 Appendix D Glossary of Terms PRISM Ties together several tools into a comprehensive system Reliability Prediction methodology This concept accounts for the myriad of factors that can influence system reliability combining all those factors into an integrated system Reliability Assessment resource Probabilistic Evaluation When randomness is present and variable states are not described by unique values but rather by probability distributions Probability of Occurrence P In an FMEA a score that indicates how often the failure will occur Probability Ratio Sequential Test PRST Based on the ratio of an acceptable MTBF which should have a high probability of acceptance to an unacceptable MTBF which should have a low probability of acceptance They are set up as eith
23. ield Data Tracking tThe process of collecting product performance data from the field and analyzing it using statistics to determine trends and to measure your reliability against your original goals Field Failure Rate The rate at which a product fails in the field This is usually expressed as a percentage Finite Element Analysis FEA A technique to estimate the responses of structures and materials to environmental factors such as fluid flow forces heat and vibration With complex mechanical components it is possible to model these factors by subdividing a component down into small finite elements and to analyze the component as an assembly of these small simple elements First Pass Yield The percentage of samples that pass the testing process the first time through without requiring any rework First Year Multiplier FYM A factor applied to a reliability prediction for the increased failure rate due to manufacturing imperfections Fourier Transform Infrared Spectroscopy FTIR Technique which is used to obtain an infrared spectrum of absorption emission or photoconductivity of a solid liquid or gas An FTIR spectrometer simultaneously collects spectral data in a wide spectral range Fracture Mechanics Field of mechanics concerned with the study of the formation of cracks in materials It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechani
24. in MOSFETs when the gate oxide breaks down as a result of long time application of rela tively low electric field as opposite to immediate breakdown which is caused by strong electric field The breakdown is caused by formation of a conducting path through the gate oxide to substrate due to electron tunneling current when MOSFETs are operated close to or beyond their specified operating voltages Tolerance Design The use of Design of Experiments DOE techniques along with economic considerations to control the output variation of a design Tolerance Stack Up The use of Design of Experiments DOE techniques along with economic considerations to control the output variation of a design Trade Off Analysis Method of performing several different analyses with the purpose of comparing the results of each to determine the best course of action Type Error See Alpha Risk Type Il Error See Beta Risk Uprating Using a component outside of its specifications and determining how much of a reliability impact this will have on your design This is the opposite of derating User FMEA FMEAs that focus specifically on the end user and how they will use misuse or possibly even abuse your product An input to the User FMEA is the user manual The User FMEA will look at installation use and end of life 43 Thermo Gravimetric Analysis 2010 Wikipedia Online http en wikipedia org wiki Thermo Gravimetric Analysis
25. ion D In an FMEA a score that indicates the ability to detect a failure if it does occur Detection Shift Level tThe shift in percentage from your current production failure rate to a new production failure rate due to a process change In most cases you can t detect this shift immediately resulting in shipping product at this higher failure rate for a period of time until you can detect this shift The lower the detection shift value the more samples you must test before you discover this change 312 Appendix D Glossary of Terms Dielectric Breakdown The complete failure of a dielectric material that is characterized by a disruptive electrical discharge through the material that is due to deterioration of material or to an excessive sudden increase in applied voltage Duty Cycle The percentage of time a product is operated compared to the total calendar time Early Reliability Testing ERT A development strategy that can provide higher reliability and quality with less cost and time for development as well as less development risk Electrical Overstress EOS An unusual spike in voltage applied to the system that causes damage usually at the component level resulting in a failure Some signs of EOS are blown metal line or molten damage Electrostat ic Discharge ESD is a subset of EOS Electromagnetic Interference EMI Disturbance that affects an electrical circuit due to either electromagnetic conduction or e
26. ity Demonstration Test RDT Decision Matrix During an RDT there are many different parameters for the test as well as choices for each pa rameter You can enter all of these into a matrix to help decide on the optimal combination of values These then get entered into the RDT Plan Reliability Demonstration Test RDT Plan Document the different parameter values you have chosen from the RDT Decision Matrix including types of stresses number of samples length of test and confidence level along with advantages and disadvantages for each Reliability Goal A statement you make early in the reliability program and enter into your Reliability Program Plan that defines the reliability you plan on achieving for the product The goal consists of the following four elements _ Probability of product performance 2 Intended function 3 Specified life and 4 Specified operating conditions Reliability Integration The process of seamlessly cohesively integrating re liability techniques together to maximize reliability and at the lowest possible cost How Reliable is Your Product 50 Ways to Improve Product Reliability 327 Reliability Maturity Matrix Method of categorizing responses and coming up with a summary of where your organization is compared to the rest of the industry This tool is used to map the results of the Reliability Program Assessment Reliability Metrics Provide the measurements and milestones the a
27. lectromagnetic radiation emitted from an external source The disturbance may interrupt obstruct or otherwise degrade or limit the effective performance of the circuit The source may be any object artificial or natural that carries rapidly changing electrical currents such as an electrical circuit the Sun or the Northern Lights Electromigration High current density that can move atoms out of the active regions leading to emergence of dislocations and point defects acting as non radiative recombination centers and producing heat instead of light 17 Electron Microscope EM Type of microscope that produces an electronically magnified image of a specimen for detailed observation The EM uses a particle beam of electrons to illuminate the specimen and create a magnified image of it It has a greater resolving power than a light powered optical microscope because it uses electrons that have wavelengths about 100 000 times shorter than visible light photons and can achieve magnifications of up to 2 000 000x whereas light microscopes are limited to 2000x magnification 18 16 Electromagnetic Interference 2010 Wikipedia Online http en wikipedia org wiki Electromagnetic Interference 17 Electromigration 2010 Wikipedia Online http en wikipedia org wiki Electromigration 18 Electron Microscope 2010 Wikipedia Online http en wikipedia org wiki Electron Microscope How Reliable is Your Product 50 W
28. margins is generally a more reliable product Competitive Teardown Analysis Compare two or more products by disas sembling each and then comparing a number of different attributes The two key elements to this process are to 1 develop a meaningful set of attributes and 2 develop an objective scoring system for each attribute Component Counterfeiting Process by which a third party company tries to copy the design of another company The counterfeit component could have a whole range of issues from having parameters that don t meet the specifica tions of the genuine component all the way to a complete empty package that has no functionality at all Component Parameter Testing When the situation arises in which your supplier can t or won t guarantee component parameters then you should write a custom specification for the product and test those specific parameters on an ongoing basis either using a sampling plan or 100 testing Component Selection The purpose of selecting the appropriate compo nents for the particular application and environment is to optimize reliability versus cost in the given use environment Most designs have a few compo nents that account for the majority of reliability or quality issues and it is these few components that you should analyze in more detail during the design to mitigate these issues before they occur Computational Fluid Dynamics CFD One of the branches of fluid mechanics that uses
29. milar methodology as Design for Reliability except with Software Software Failure Modes and Effects Analysis SFMEA FMEAs that focus on potential software bugs as well as errors in interfaces and errors in boundary conditions This is an excellent technique if you have a set of bugs and are trying to determine the likely cause Software Fault Tolerance Software that is designed to keep a system working to a level of satisfaction in the presence of faults Software Phase Containment Metric Tracking A method of tracking software bugs to prevent a particular class of bug from reappearing This is similar to the corrective action portion of the Hardware RCA where you not only need to fix the problem and prevent that particular problem from recurring you need to also fix the process that caused the problem in order to show continual improvement Software Prediction Model A model which provides estimates of the number of faults in the resulting software greater consistency in reliability leads to increased accuracy in the modeling output Software Reliability Assessment Similar to a Reliability Program Assess ment but specifically focusing on the software team Software Robustness and Coverage Testing Techniques Techniques effective at finding software failures during software testing such as fault injection 39 Signal to Noise 2010 Wikipedia Online http en wikipedia org wiki Signal to Noise 330 Appendix D Glo
30. nd when so that you can mitigate this before the event takes place Ongoing Reliability Test ORT A method of deriving a reliability figure through testing typically during the manufacturing process Ongoing Reliability Test ORT Decision Matrix During an ORT there are many different parameters for the test as well as choices for each parameter You can enter all of these into a matrix to help decide on the optimal combina tion of values These then get entered into the ORT Plan Ongoing Reliability Test ORT Plan Document the different parameter values you have chosen from the ORT Decision Matrix including types of stresses number of samples length of test and confidence along with advan tages and disadvantages for each Operating Limit In HALT a limit in which the failure recovers when you reduce or remove the stress Operating Margin The difference between the operating limit and the product specification Optical Microscopy wUses visible light and a system of lenses to magnify images of small samples Original Design Manufacturer ODM A company which designs and man ufactures a product which is specified and eventually branded by another firm for sale Such companies allow the brand firm to produce either as a supple ment or solely without having to engage in the organization or running of a factory Original Equipment Manufacturer OEM Manufacturer of the products or components that are purchase
31. numerical methods and algorithms to solve and analyze problems that involve fluid flows 9 Computational Fluid Dynamics 2010 Wikipedia Online http en wikipedia org wiki Computational Fluid Dynamics How Reliable is Your Product 50 Ways to Improve Product Reliability 309 Computer Aided Design CAD The use of computer technology for the process of design and design documentation Conductive Anodic Filament CAF A form of electrochemical metal migration or dendritic growth between two conductors within a printed circuit board PCB Confidence Interval A particular kind of interval estimate of a population pa rameter Instead of estimating the parameter by a single value an interval likely to include the parameter is given Thus confidence intervals are used to indicate the reliability of an estimate How likely the interval is to contain the parameter is determined by the confidence level or confidence coefficient In creasing the desired confidence level will widen the confidence interval 1 Confidence Level A confidence interval is always qualified by a particular confidence level usually expressed as a percentage 1 Confidence Limits The end points of the confidence interval Consumer s Risk See Beta risk f Contract Manufacturer CM A company that specializes in manufacturing products for other companies Control Factor In an experiment these are all of the factors that you have the
32. of chart that contains both bars and a line graph where individual values are represented in descending order by bars and the cumu lative total is represented by the line The chart was named after Vilfredo Pareto Peck s Model A model which predicts the acceleration factor of a test based on the stresses of temperature and humidity Periodic HALT HALT that is performed on a scheduled interval in order to discover issues that may enter into the design either from design changes vendor changes or vendor process changes Phase Transition Point The transformation of a material from one phase of matter to another Physics of Failure POF The process of using knowledge of root cause failure processes to prevent product failures through product design and man ufacturing practices Physics of Failure POF Model A model which predicts the behavior of ma terials including when and how they will fail 33 Pareto Chart 2010 Wikipedia Online http en wikipedia org wiki Pareto_Chart How Reliable is Your Product 50 Ways to Improve Product Reliability 323 Pick and Place Equipment Equipment used to install components onto a circuit board Power Spectral Density PSD Describes how the power of a signal or time series is distributed with frequency Precipitation Detection Screen This is a HASS technique that consists of a two part profile In the first part the precipitation portion develop your profile
33. re we there yet feedback that your organization needs to ensure you are on track toward meeting your goals Reliability Performance Reporting A method of reporting back how you are doing against your Reliability Program Plan Reliability Prediction A method of calculating the reliability of a product or piece of a product from the bottom up by assigning a failure rate to each indi vidual component and then summing all of the failure rates Reliability Program Assessment A detailed evaluation of your organiza tion s approach and processes involved in creating reliable products The as sessment captures the current state of your organization and leads to an actionable Reliability Program Plan RPP The results of the assessment are mapped onto the Reliability Maturity Matrix Reliability Program Integration Plan RPIP Similar to an RPP but with a special emphasis on ensuring all of the reliability techniques you choose as part of your RPP are integrated together to ensure all areas are covered without duplicating efforts Reliability Program Plan RPP A plan that ties together customer require ments business opportunities and employee opportunities It includes a reli ability goal statement along with supporting evidence and methodologies on how you plan to achieve this reliability goal Reliability Test Goal Similar to a Reliability Goal but set during a reliability test plan to set a goal for the reliability testing
34. roduct 50 Ways to Improve Product Reliability 307 Beta Parameter 6 The slope of the Weibull Distribution f Beta Risk B Sometimes referred to as a Type II Error is the consumer s risk or the risk that you will ship a defective product because the data indicated that the failed sample actually is good In other words is the risk of accepting the hypothesis that the mean hadn t changed when it had Black Box Testing Functional testing based on requirements with no knowledge of the internal program structure or data Boundary Interface Diagram A diagram used as part of a brainstorming exercise often used during FMEA It is useful when you have a complex system or if your system has interfaces with other systems In the diagram draw lines showing the interfaces between the different systems The interfaces can either be physical energy material or data Burn In A form of ESS running a system at elevated temperature to take advantage of heat as an accelerant The key variables are the burn in temperature and the amount of burn in time Certified Reliability Engineer CRE The American Society for Quality has a program to become a Certified Reliability Engineer CRE Certification is based on education experience and a certification test periodic recertification is required The body of knowledge for the test includes reliability manage ment design evaluation product safety statistical tools design and develop
35. rovide your team with forums to expand their knowledge base of design techniques by exchanging design templates Failure Mechanism The cause of the failure mode such as corrosion or vibration Failure Mode The actual symptom of the failure such as failed component or degradation of performance Failure Modes and Effects Analysis FMEA A systematic method of iden tifying and preventing product and process problems before they occur Failure Modes Effects and Criticality Analysis FMECA Similar to an FMEA with the C standing for criticality The process is the same except now you capture one more score the criticality of the failure See MIL HDBK 1629 for a more detailed explanation on the term criticality Failure Reporting Analysis and Corrective Action System FRACAS See Closed Loop Corrective Action CLCA Failure Review Board FRB A team assigned to a company to review each failure and determine its disposition Fatigue The effects of dynamic loading causing a loss in strength of a material 21 Facilitation 2010 Wikipedia Online http en wikipedia orq wiki Facilitation How Reliable is Your Product 50 Ways to Improve Product Reliability 315 Fault Tree Analysis FTA A systematic deductive method for defining a single specific undesirable event and determining all possible failures that could cause the event in question to occur A top down approach to failure mode analysis F
36. rtain conditions Warranty Analysis Part of the Design for Warranty DFW methodology in which you use warranty goals strategies and data to jump start your analysis with the development team during product design The objective is to identify and prioritize the appropriate warranty metrics goals strategies and action plans to reduce warranty expenses Warranty Burden This defines who is responsible for warranty claims if a product fails within the warranty period The warranty burden isn t uniformly distributed throughout the design and manufacturing supply chain In the supply chain you have contract manufacturers CM s original design manu facturers ODM s and component suppliers Companies are starting to ask their supply chain to share the burden of warranty costs Warranty Cost Analysis Method of predicting the amount of money a company will have to pay during the warranty period of a product Warranty Event When a product fails within the warranty period How Reliable is Your Product 50 Ways to Improve Product Reliability 333 Warranty Expenditure The amount spent on warranty events Warranty Period Period of time that a product is covered under a warranty Warranty Projection A prediction for the number of products or amount of money that will be spent on products failing within the warranty period Warranty Reserve The money set aside to cover the cost of products failing within the warranty period
37. ssary of Terms Steady State The period of a product life cycle in which the failure rate is constant over time or independent of the amount of time that has passed Stress Analysis Engineering discipline that determines the stress in materials and structures subjected to static or dynamic forces or loads Structural Fatigue Progressive and localized structural damage that occurs when a material is subjected to cyclic loading The nominal maximum stress values are less than the ultimate tensile stress limit and may be below the yield stress limit of the material Supportability Deals with all the aspects related to the maintenance repair and support of systems and products to ensure continued operation or func tioning of the systems or product s 42 Technology Risk Assessment tThe identification categorization and prioritization of hardware and software risks to achieve key reliability business objectives Telcordia SR1171 Titled Methods and Procedures for System Reliability Analysis this special report issued by Telcordia offers guidelines around different types of modeling methods Telcordia SR332 Titled Reliability Prediction Procedure for Electronic Equipment this special report issued by Telcordia offers guidelines around performing a reliability prediction on a product As part of the report there is a table of failure rates for many common components in use today Temperature Cycling A form of ESS c
38. t HASA Similar to HASS except that you will screen only a portion of the product called an audit rather than 100 as in HASS As with any audit you will need to set up criteria for when to decrease the sample size and when to increase the sample size mostly based on the results of the audit Highly Accelerated Stress Audit HASA Plan tThe plan that documents how to move from 100 HASS to a HASS audit also known as HASA When writing the plan make sure to describe what criteria need to be met in order to move to HASA The two key criteria that you need to satisfy before switching from HASS to HASA are 1 The defect rate must be at its target and 2 The process must be stable In the plan decide on the following param eters detection shift level alpha risk and beta risk levels and sample size Highly Accelerated Stress Screening HASS A process comprising a set of stresses performed on a product before it is shipped with the goal of finding manufacturing related defects The set of stresses combined together make up the screen Highly Accelerated Stress Screen HASS Plan The plan that documents the HASS process from start to finish including choosing the stress types de veloping the screen profile the equipment trade off analysis fixture design POS HASS implementation strategy and the trend analysis The plan will serve as your roadmap and you can use it as a decision tool during the imple mentation process
39. that has been excited by bombarding with high energy x rays or gamma rays The phenomenon is widely used for chemistry analysis particularly in the investigation of metals glass and ceramics 44 Weibull Distribution 2010 Wikipedia Online http en wikipedia org wiki Weibull_Distribution 45 X Ray Fluorescence 2010 Wikipedia Online http en wikipedia org wiki X Ray Fluorescence 334 Appendix D Glossary of Terms
40. ure that the screen is able to detect these types of defects Service Affecting Reliability Rather than considering every component failure this reliability figure discounts failures which don t affect system performance Serviceability The ability of technical support personnel to install configure and monitor computer products identify exceptions or faults debug or isolate faults to root cause analysis and provide hardware or software maintenance in pursuit of solving a problem and restoring the product into service Severity of Failure S In an FMEA a score that indicates how severe the effects will be if the failure mode does occur 38 Serviceability 2010 Wikipedia Online http en wikipedia org wiki Serviceability How Reliable is Your Product 50 Ways to Improve Product Reliability 329 Signal to Noise S N A measure used in science and engineering to quantify how much a signal has been corrupted by noise It is defined as the ratio of signal power to the noise power corrupting the signal A ratio higher than 1 1 indicates more signal than noise Simulation Program with Integrated Circuit Emphasis SPICE Program that simulates electronic circuits Software Bug Tracking Database Central repository for all software errors found during the software product life cycle The databased also contains the status of each bug as well as the final disposition Software Design for Reliability SDFR Si
41. utines use up a portion of memory after they load a program and then don t give the memory back after they close the program This causes the available memory to shrink which in turn results in the product slowing down because the processor must spend more time looking for available memory 27 Mean Square Deviation 2010 Wikipedia Online http en wikipedia org wiki Mean_ Square Deviation 28 Mean Time Between Failure 2010 Wikipedia Online http en wikipedia org wiki Mean Time Between Failure 320 Appendix D Glossary of Terms MIL217G An effort being developed by the VITA 51 Working Group to inves tigate the state of the Reliability Prediction industry and develop a method to address electronics failure rate prediction issues This standard is meant to replace MIL HDBK 217 MIL HDBK 217 In the 1950s the Department of Defense DOD first stan dardized electronics Reliability Predictions through the analysis of historical data This led to the publication of the first edition of MIL HDBK 217 in 1961 providing the basis of Reliability Predictions that is still widely used today Monte Carlo Simulation A class of computational algorithms that rely on repeated random sampling to compute their results Because of their reliance on repeated computation of random or pseudo random numbers these methods are most suited to calculation by a computer and tend to be used when it is unfeasible or impossible to compute an ex
42. ycling the temperature of a system between cold and hot The key variables here are temperature ranges temper ature rate of change dwell time at each temperature extreme and the number of cycles Test Analyze Fix A form of testing program in which you test a product to failure analyze the failure fix the failure and test the product again but apply more stress This is an iterative process in order to make the product more robust 40 Stress Analysis 2010 Wikipedia Online http en wikipedia org wiki Stress Analysis 41 Structural Fatigue 2010 Wikipedia Online http en wikipedia org wiki Structural_Fatigue 42 Supportability 2010 Wikipedia Online http en wikipedia org wiki Supportability How Reliable is Your Product 50 Ways to Improve Product Reliability 331 Thermal Analysis To estimate the temperature distribution throughout a product based on the thermal boundary conditions and specified heat sources Thermo Gravimetric Analysis TGA A type of testing that is performed on samples to determine changes in weight in relation to change in temperature Such analysis relies on a high degree of precision in three measurements weight temperature and temperature change Thermo Mechanical Analysis TMA The measurement of a change of a dimension or a mechanical property of the sample while it is subjected to a tem perature regime Time Dependent Dielectric Breakdown A failure mechanism

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