FMEA Potential Failure Mode And Effects Analysis PDF

aiitf Effects Analysis A m '-£*& '-$m%ti*£ &?>  POTENTIAL FAILURE MODĘ AND EFFECTS ANALYSIS (FMEA) Reference Manuał...

aiitf Effects Analysis A m '-£*& '-$m%ti*£ &?>  POTENTIAL FAILURE MODĘ AND EFFECTS ANALYSIS (FMEA) Reference Manuał Fourth Edition Flrst Edition, February 1993 * Second Edition, February 1995 Third Edition, Juty 2001, Fourth Edition, June 2008 Copyright © 1993. © 1995, © 2001, © 2008 Chrysler LLC, Ford Motor Company, Generał Motors Corporation ISBN: 978-1-60534-136-1  FOREWORD 4 ,h Edition The FMEA 4& Edition is a reference manuał to be used by supplieis to Chrysler IXC, Ford Motor Company, and Generał Motors Corporation as a guide to assist them in the development of both Design and Process FMEAs. The manuał does not define requirements; it is intended to clarify questions concerning the technical development of FMEAs This manuał is aligned with SAE 11739 Sum mary of Changes in the 4th edition FMEA Reference Manuał The DFMEA and PFMEA methods described in the 4* edition FMEA Reference Manuał include those associated with design at the system, subsystem, interface, and component level and the process at manufactuiing and assembly opeiations Generał Changes The formatting used in the 4& edition is intended to provide easier reading o An index is included o icons are used to indicate key paiagraphs and visual cues aie used Additional examples and veibiage have been provided to improve the utility of the manuał and to provide a closer tie into the FMEA process as it develops Reinforcement of the need for management suppoit, inteiest, and ieview of the FMEA process and resuits Define and strengthen the understanding of the linkage between DFMEA and PFMEA as well as defining the linkages to othei tools Improvements to the Seveiity, Occunence, Detection ranking tables so that they aie moie meaningful to real woild analysis and usage Alternative methods are introduced that are currentiy being applied in industry o Additional appendices which have example foims and special case application of FMEA. o The focus on the "standard form" has been repiaced with seveial options that represent the current application of FMEA in industry The suggestion that RPN not be used as the primary means for assessing risk. The need for rmprovement has been revised including an additional method, and the use of thiesholds on RPN is ciaiified as a practice that is not recommended Chapter I provides generał FMEA guidelines, the need for management suppoit and having a defined piocess fot developing and maintaining FMEAs, and the need fot continuous impiovement Chapter U describes the generał application of the FMEA methodology, which is common between DFMEA and PFMEA processes This includes the planning, stiategy, action plans, and the need for management suppoit and responsibility in FMEAs Chapter Ifl focuses on DFMEA (Design Failure Modę Effects and Analysis), establishing the scope of the analysis, use of błock diagrams, vaiious types of DFMEAs, formation of the teams, basie piocedure for analysis, action plans, and follow-up, aftematives to RPN, and connection to PFMEAs and validation plans i Chapter IV focuses on PFMEA (Piocess Failure Modę Effects and Anatysis), establishing the scope of the anatysis, use of flow diagtams, foimation of teams, basie procedurę foi analysis, action plans, the connection to DFMEAs and the development of contro! plans The Appendices have seveial examples of foims for DMFEA and PFMEA and addresses different applications and piocedures for addressing design and piocess tisk. The Suppliei Quality Requirements Task Foice would like to thank the fbllowing individuals, and theii companies, who have contiibuted their time and eftbits to the development of this edition of the FMEA Refeience Manuał: Michael Down, Generał Motois Coipoiation Lawrence Biozowski, Generał Motois Corporation Hisham Younis, Ford Motor Company David Benedict, Chrysler LLC JohnFcghali, Chiyslei LLC Michael Schubert, Delphi Rhonda Brender, Delphi Gregory Giuska, Omnex Glen Vallance, Contiol Planning Initiatives Milena Krasich, Bose William Haughey, ReliaTiain This manuał is a copyiight of Chrysler LLC, Ford Motoi Company and Generał Motois Coiporation, with all nghts reserved. Additional copies may be obtained irom AIAG @ www.aiag.org Supply chain oiganizations of Chrysler LLC, Ford Motoi Company 01 Generał Motois Corporation have peimission to copy foims used in this manual. :i TABLE OF CONTENTS Generał Changes Chapterl Generał FMEA Guidelines Intioduction FMEA Process Puiposeof Manuał Scope of Manuał Impact on Organization and Management FMEA Explained Follow-up and Continuous Improvement Chapreill Ovetview of FMEA Sttategy, Planning and Implementation Intioduction Basic Stiucture Approach -... Identify the I eam Define the Scope Define the Customer Indentify Functions, Requiiements, and Specifications Identify Potential Failure Modes Identify Potential Effects.... Identify Potential Causes Identify Contiols Identifying and Assessing Risk.... Recoramended Actions and Results Management Responsibility Chapterlll DFMEA Design Failure Modę and Effects Analysis...... mnoduction Customei Defined.... IeamAppioach Manufactuiing, Assembly and Seiviceability Considerations Development of a Design FMEA Piereąuisites Błock (Boundaiy) Diagiams.. Parametei (P) Diagiams Functional Requiiements.. Other Tools and Infoimation Resouices Example DFMEA Header of the Design FMEA Foim (fields A-H) Body of the DFMEA Foim (fields a - n) MaintainingDFMEAs Leveraging DFMEAs Linkages Design Veiification Plan & Repoit (DVP&R) PFMEA Chaptei IV'... * PF MEA Process Failure Modę and Effects Analysis.. Intioduction Customer Defined Ieam Approach. DesignConsideiations........ Development of a Process FMEA iii  Prerequisites — Process Flow Diagram and Iinkage to PFMEA Olher Tools and Infoimation Souices.... Reseaich Infonnation , ExamplePFMEAForm Headei of the Process FMEA Form (fields A-H) Body ofthe PFMEA Fonn(fields a-n) Mainlaining PFMEAs - L«veiagingPFMEAs Linkages - ToDFMEA To Conaoi Plan APPENDICES Appendix A; Sample Foims DFMEAFoims PFMEA Forms Appendix B: System Level FMEA Inteifaces Inteiactions - Relationships Multiple Levels of Design F ME As Appendix C: Altemative Risk Assessments AItematives to RPN Altemative: SO (S x O) Alteinative: SOD, SD.... Appendi* D: Alternative Analyses Techniques Failure Modę, Effect and Ciiticality Analysis (FMECA) Design Review Based on Failure Modes (DRBFM) Fault Iree Analysis (FTA) Refeiences and Suggested Readings Index !V  TABLESandFIGTJRES Figurę III la Błock (Boundaiy) Diagram Examples 19 Figures ID. Ib, c Błock (Boundary) Diagram Examples 20 Figurę IH2 Example of a Paiametei (P) Diagram foi aGeneiic Catalytic Converter 21 Table HI 1 Sample DFMEA Form with Minimal Infoimation Elemenls & Example Entries 24 labie 1H.3 Example Potential FailureModes. 32 labie m 4 Examp!e Potential EtTects 35 labie Ci l Suggested DFMEA Severity Evaluation Criteria 37 Table III 5 Example Potential Causes 42 Table Cr2 Suggested DFMEA Occurrence Eraluation Ciiteria 46 n Table III 6 Examples of Prevention and Detection Design Contiols.. 51 labie Cr3 Suggested DFMEA/PFMEA Prevention/Detection Evaluation Ciiteiia... 54 labie III.7 Examplesof Causes, ConOols and Recommended Actions 64 Figurę III. 7 DFMEA Intbimation Intenelationships Flow 65 Figurę IV 1 Highl_evel toDetailed ProcessMaps.71 Figurę IV.2 Example Process Flow Diagiam — 72 Table IV 1 Sample PFMEA Foim with Minimal Infoimation Elements Sc Example Entries 74 labie TV 2 Example of Piocess Step/Function/Requiiements Columns on PFMEA Form including Potential FailureModes....81 IableIV3ExampleofEffects 85 Table Cr 1 Suggested PFMEA Seveiity Evaluation Ciiteiia 88 Table Cr2 Suggested PFMEA Occuirence Evaluation Ciiteria 93 Table IV.4 Examples ot Causes and Contiols 96 Table Ci 3 Suggested Process FMEA Detection Evaluation Criteria 100 Table IV.5 Examples of Causes. Controls and Actions 110 Figurę 1V.S PFMEA Infoimation Inteirelationship Flow 111 DFMEAFormA 115 DFMEA FoimB - 116 DFMEAFoimC... 117 DFMEA FoimD 118 DFMEAFormE 119 DFMEAFormF 120 PFMEAFoimA 122 PFMEA FoimB 123 PFMEAFoimC.' 124 PFMEAFoimD 125 PFMEAFoimE 126 PFMEAFoimF 127 PFMEA Form G 128 PFMEAFoimH 129 Figurę B 1 Interfaces and Inteiactions 130 F igure B 2 Item, Functions, andFailuie 132 Figurę B 3 DFMEA EffectsLinkages 134 labie C 1 Contiast among RPN, SOD and SD 136 Figurę D 1 ExampIeof DRBFM Elements 138 FiguręD2FTA TreeStructure 139 '. Vi Chapter I Geneial FMEA Guidelines Chapter I Generał FMEA Guidelines Chaptci I Generał FMEA Guidelines Introduction This manuał introduces the topie of Potential Failure Modę and EtTects Analysis (FMEA) and gives generał guidance in the application of the technique FMEA Process FMEA is an analytical methodology used to ensuie that potentia! problems have been considered and addiessed thioughout the product and process development process (APQP - Advanced Pioduct Quality Planning) Its most visible result is the documentaiion of the coIlective knowledge of cross-functional teams Part of the eva!uation and analysis is the assessment of risk The impoitant point is that a discussion is conducted regaiding the design (pioduct or process), ieview of the functions and any changes in application^ and the resulting risk of potential failuie. Each FMEA should ensure that attention is given to eveiy component within the product oi assembly Critical and safety related components oi processes should be given a highei priority One of the most important factois fot the successful implementation of an FMEA program is timeliness It is meant to be a "before-the-event" action, not an "after-the-fact" exercise To achieve the greatest valuc, the FMEA must be done before the implementation of a pioduct or process in which the failure modę potential exists Up-ftont time spem piopeily completing an FMEA, when pioduet/process changes can be most easily and inexpensively implemented, will minimize late change crises Actions iesulting fiom an FMEA can leduce oi eliminate the chance of implementing a change that would create an even larger concern. Ideally, the Design FMEA process should be initiated in the early stages of the design and the Process FMEA before tooling or manufacturing eąuipment is developed and purchased The FMEA evolves throughout each stage of the design and manufacturing development process and may also be used in problem solving FMEA can also be applied to non-manufacturing areas. For example, FMEA could be used to analyze risk in an v administration process or the evaluation of a safety system. In geneial, FMEA is applied to potential failures in product design and manufacturing processes wheie the benefits are cleai' and potentially significant 2 Chapter I Geneial FMEA Guidelines Purpose of Manuał This manuał describes the basie piinciples and iraplementalion of the FMEA1 process and how it is integialed within the product and process development cycle This includes the documentation of this process and how the analyses can be applied for timely necessary improvement of a product 01 a process in its early and fuli deveiopment stage This manuał also provides descriptions and examples of alternate and suppoiting methodologies for these analyses, their specific advantages and limitations, guidance of how the analysis is to be cariied out for the maximum icliability impiovement or mitigation of potential safety risks. The manuał provides guidance on how the risk can be represented, measuied and prioritized for cost eftective mitigation of the failure effects As a tool in risk evaluation, FMEA is considered to be a method to identiiy severity of potential effects of faiiuie and to provide an input to mitigating measures to reduce iisk In many applications, FMEA also includes an estimation of the probability of oceunence of the causes of faiiuie and theii tesultant faiiuie modes This broadens the analysis by providing a measure of the failure mode's likelihood To minimize iisk, the likelihood of failure occutience is reduced which inereases product or ptocess reliability FMEA is a tool that is instrumental in reliability impiovement Theie aie three basie cases for which FMEA process is to be applied, each with a diffeient scope 01 fbcus: Case 1: New designs, new technology, or new process. The scope of the FMEA is the complete design, technology, or process Case 2: Modifications to existing design 01 process The scope of the FMEA should focus on the modification to design or process, possible interactions due to the modification, and field history This can include changes in regulatory recjuirements Case 3: Use of an existing design or process in a new environment, location, applicatlon, or usage profile (including duty cycle, regulatory requirements, etc) The scope of the FMEA should focus on the impact of the new environment, location, or application usage on the existing design or process The F MEA present herein also is known as a Faiiuie Modes Effects and Ciiticality Analysis (FMECA) sińce it includes a quantification of the risks 3 Chaptet I Generał FMEA Guidelines Scopeof Manuał The analytical melhods presented in this manuał are applicable to any product or process. However, this manuał will focus on those applications pievalent within the automotive industry and its suppliers Impact on Organization and Management FMEA is an impoitant activity within any company Because the development of an FMEA is a multi-disciplined activity affecting the entiie pioduct realization piocess, its implementation needs to be well planned to be firlly effective This piocess can take considetable time and a commitment of the iequired resouices is vital. Impoitant to FMEA development is a process ownei and senioi management commitment Implementation apptoach will vaiy depending on the size and stiucture of the company concemed, although the principles will be the same: The scope will cover FMEAs produced in house and by multi- tier supplieis. Address Design and Piocess FMEAs, as applicable Accomplish this by having the FMEA process an integral pait of the APQP piocess Pait of engineeiing technical reviews Pait of the regulai sign-off and appioval of the pioduct or process design An FMEA is deveIoped by a multi-functional (01 cross- functional) team The team size will depend both on the complexity of the design and the size and organization of the company Team members need relevant expeitise, available time and authority sanctioned by management A comprehensive tiaining progiam should be implemented including: Management Oveiview Tiaining foi users Supplier Training Facilitaloi Training Ultimately, management has the responsibility and owneiship for development and maintenance of the FMEAs 4  Geaeial FMEA Guidelines ned FMEAs are aa integiaL part of managing iisk and supporting continual improvement. Consequently, FMEA becomes a key patt of Product and Process development The Advanced Product Qua!ity Planning (APQP) process identifies five generał areas of focus in this deve!opment process: Plan and Define Program Product Design and Development Process Design and Developmenl Product and Process Validation Feedback, Assessment and Conective Action The APQP Reference manuał shows DFMEAs as an activity in the Product Design and Development section of the timing chart and PFMEAs in the Process Planning and Development section The development of eithei DFMEA 01 PFMEA is a process that helps to guide the tearas in developing product and process designs that meet expectations The FMEA analysis should not be consideied a single event, but a long-term commitment that complements the product and process development to ensure potential failures are evaluated and actions are taken to icduce their iisk One key aspect of continual improvement is the retention of knowledge fiom past learning which often is captured in FMEAs It is advisable for organizations to capitalize on prior analyses of similar product and process designs for use as the starting point for the next program and/oi application The language used in FMEAs should be as specific as possible when describing an item (for example, failure modę, or cause) and not extend or extrapolate beyond the team's level of understanding as to what the faihue effects may be Clear statements, concise terminology and focus on the actual effects are key to the effective identiftcation and mitigation of iisk issues * Chaptei I Geneial FMEA Guideliaes Follow-up and Continuous lmprovement The need foi taking effective pieventive/conective actions, wilh appiopiiate follow-up on those actions, cannot be oveiemphasized Actions should be communicated to all affected activities A thoroughly thought-out and well-developed FMEA will be of limited value without positive and effective preventive/conective actions. Team leadeiship (typically the team leadei/lead engineei) is in charge of ensuring that all iecommended actions have been implemented 01 adeąuately addressed The FMEA is a living document and should always reflect the latest level, as well as the latest relevant actions, including those occuuing aftei the staitof pioduction The team leadei/lead engineei has seveial means of assuring that iecommended actions aie implemented They include, but are not limited to the following: Reviewing designs, processes, and related iecoids to ensiue that iecommended actions have been implemented, Confuming the incorpoiation of changes to design/assembly/ manufactuiing documentation, and, Reviewing Design/Piocess FMEAs, special FMEA applications, and Coratiol Plans 6 Chaptei II Sbategy, Planning, Implementation Chapter I! Overview of FMEA Strategy, Planning and implementafaon 7 Chaptei II Strategy, Planning, Implementation Introduction FMEA development, eithei design or piocess, usys a common ♦ appioach to addiess: Potential pioduct oi piocess failure to meet expectations Potential conseąueaces Potential causes of the failure modę Application of cuirent controls Level of iisk Risk reduction Befoie the FMEA dokument is started, the team must define the scope of the project and collect existing infoimation which is necessaiy for an effective and efficiem FMEA development ptocess Basic Structure The purpose of the recommended FMEA fbimats described in this manuał is to oiganize the collection and display of relevant FMEA infoimation Specific formats may vaty based on the needs of the oiganization and the requiiements of the customei J Fundamentally, the format utilized should addiess: Functions, requirements, and deliveiables of the product 01 piocess being analyzed, Failuie modes wheti functional reąuiiements aie not met, Effects and conseąuences of the failuie modę, Potential causes of the failure modę, Actions and contr ols to address the causes of the failure modę, and, Actions to pievent lecunence of the failure modę Approach There is no single or unique piocess ioi FMEA development; howevei there aie common elements as described below ł s  Chaptei II Sttategy, Planning, Implemenlation Identify the Team As pieviously mentioned, FMEA developraent is the responsibility of a multi-disciplinaiy (or cross-functional) team whose raembers encompass the necessary subject mattet knowledge This should include facilitation expeitise and knowledge of the FMEA piocess A team approach is recommended to benefit the FMEA development piocess to ensuie input and collaboration fiom all affected ftinctional aieas. The FMEA team leadei should select team membeis with the relevant expeiience and necessaiy authoiity In addition to the design and piocess engineeis, the following aie examples of additional resoiuces: FMEA development topie Relevant Resources or Expertise Scope Program Management, Customer, Integiation responsible individual(s) Functions, iequirements and expectations Customei, Program Management, Integiation iesponsible individual(s), Seivice Opeiations, Safety, Manufactuiing and Assembly, Packaging, Logistics, Materials Potential failure modę - the way a piocess 01 Customer, Piogram Management, Integiation responsible pioduct might taił individual(s), Service Opeiations, Safety, Manufacturing and Assembly, Packaging, Logistics, Materials, Quality Effects and conseąuences of the failure - to Customer, Program Management, Integiation responsible both the organization's piocesses 01 to a individual(s), Seivice Opeiations, Safety, Manufactuiing downstieam customer and Assembly, Packaging, Logistics, Materials, Quality Causes of the potential failure Customei, Manufacturing and Assembly, Packaging, Logistics, Materials, (^uality, Reliability, Engineering Analysis, Equipment Manufactuier, Maintenance Freąuency of occunence of potential failuie Customer, Manufacturing and Assembly, Packaging, Logistics, Materials, Quality, Reliability, Engineeiing Analysis, Statistical Analysis, Eąuipment Manufactuier, Maintenance Application of cuirent controls-prevention Manufacturing and Assembly, Packaging, Logistics, Materials, Quality, Equipment Manufacturei, Maintenance Application of current contiols-detection Customer, Manufactuiing and Assembly, Packaging, Logistics, Materials, Quality, Maintenance Recommended actions requiied Customer, Program Management, Integiation responsible individual(s),-Manufactuiing and Assembly, Packaging, Logistics, Materials, Quality, Reliability, Engineering Analysis, Statistical Analysis, Eąuipment Manufactuier, Maintenance 9 Chapter II Stiategy, Planning, Łmplementation Define the Scope Scope establishes the boundaiy ofthe FMEA analysis It defines what is included aod excluded, deteimined based on the type of FMEA being developed, i e., system, subsystem, 01 component Befoie the FMEA can begin, a elear undetstanding of what is to be evaluated must be deteimined What to exclude can be just as impoitant as what to include in the analysis The scope needs to be established at the stait ofthe piocess to assuie consistent diiection and focus Ihe following raay assist the team in defining the scope ofthe FMEA: Function Model Błock (Boundaiy) diagiams Paiameter (P) diagiams Intei face diagiams Process flow diagiams Inteiielationship matiices Schematics Bili ofMateiials (BOM) System FMEA A system FMEA is madę up of vaiious subsystems Examples of systems include: Chassis System, Poweitiain System, 01 Inteiioi System, etc The fbcus of the System FMEA is to addiess all inteifaces and inteiactions among systems, subsystems, the enviionment and the customei. Subsystem FMEA A Subsystem FMEA is a subset of a system FMEA. An example of a subsystem is the fiont suspension subsystem, which is a subset ofthe chassis system The focus ofthe Subsystem FMEA is to addiess all inteifaces and inteiactions among the subsystem components and inteiactions with othei subsystems ot systems Component FMEA A Component FMEA is a subset of a subsystem FMEA Foi » example, a biake pad is a component of the biake assembly, which is a subsystem of the chassis system NOTĘ: Any subseąuent adjustments to the scope may icąuire a modification ofthe team structiue and membeiship 10 Chaptei II Strategy, Ptanning, Implementation Define the Customer There are foui major customeis to be considered in the FMEA piocess, all need to be taken into account in the FMEA analysis: END USER: the person or oiganization that will utilize the pioduct The FMEA analysis affecting the End Usei could include, for example, durability. OEM ASSEMBLY and MANUFACTURING CENTERS (PLANTS): the OEM locations wheie manufactuiing opetations ( e g , stamping and poweitrain) and vehicle assembly take place Addiessing the inteifaces between the product and its assembly process is critical to an effective FMEA analysis SUPPLY CHAIN MANUFACTURING: the supplier location wheie manufactuiing, fabiicating oi assembling of pioduction mateiials oi parts takes place This includes fabiicating pioduction and seivice paits and assemblies and piocesses such as heat tieating, welding, painting, plating oi othei finishing seivices This may be any subsequent or downstieam opeiation or a next tier manufactuiing piocess REGULATORS: govemment agencies that define iequiiements and monitoi compliance to safety and enviionmental specifications which can impact the pioduct oi piocess Knowledge of these customers can help to define the functions, teąuiiements and specitications moie robustly as well as aid in deteimining the effects of related failuie modes Indentify Functions. Requirements, and Specifications Identify and undeistand the functions, reąuiiements and specifications ielevant to the defined scope. The puipose of this activity is to claiify the item design intent or piocess puipose This assists in the deteimination of the potential failuie modę foi each attiibute or aspect of the function.1 Chaptei n Strategy, Planning, Implementation Identify Potential Failure Modes Failure modę is defined as the way 01 mannei in which a pioduct or piocess could fail to raeet design intent 01 piocess ieąuiiements The assumption is madę that the failure could occur but may not necessaiily occur A concise and undeistandable failuie definition is impoitant sińce it piopeily focuses the analysis Potential failuie modes should be desciibed in technical teims and not as a symptom necessarily noticeable by the customer. A laige number of failuie modes identified for a single iequirement may indicate that the defined iequiiement is not concise Identify Potential Effects Potential effects of failuie aie defined as the effects of the failuie modę as perceived by the customei The effects or impact of the failure aie desciibed in teims of what the customei might notice or expeiience The customei may be an intemal customei as well as the End User Deteimining potential effects includes the analysis of the consequences of the failures and the seveiity 01 seriousness of those conseąuences Identify Potential Causes Potential cause of failuie is defined as an indication of how the failuie could occur, desciibed in teims of something that can be conected oi can be contiolled. Potential cause of failuie may be an indication of a design weakness, the cohsequence of which is the failuie modę. Theie is a diiect relation between a cause and its tesultant failuie modę (i e , if the cause occurs, then the failuie modę occuis). Identifying the ioot cause(s) of the failuie modę, in sufficient detail, enables the identification of appropiiate contiols and action plans A sepaiate, potential cause analysis is perfoimed foi each cause if theie are multiple causes i 1/ Chapter II Strategy, Planning, Implementation Identify Controls Controls aie those activities that pievent oi detect the cause of the failuie oi failure modę In deve!oping contiols it is impoitant to identify what is going wrong, why, and how to prevent oi detect it Controls aie applicable to pioduct design or manufactuiing processes. Contiols fbcused on pievention will provide the gieatest return. Identifying and Assessing Risk One oi the impoitant steps in the FMEA piocess is the assessment of iisk This is evaluated in thiee ways, severity, occunence, and detection: Severity is an assessment of the level of' impact of a failiue on the customei Occurrence is how often the cause of a failuie may occui. Detection is an assessment of how well the pioduct ot piocess contiols detect the cause of the failuie oi the failuie mode. Oiganizations need to undeistand theii customei iequiiements for iisk assessment Recommended Actionsand Results The intent of recommended actions is to reduce oveiall iisk and likelihood that the failure modę will occur The recommended actions address ieduction of the severity, occuirence and detection. The fóllowing can be used to assuie that the appropiiate actions aie taken, including but not limited to: Ensuiing design reąuirements including reliability are achieved, Reviewing engineering drawings and specifications, Confirming incorpoiation in assembly/manufacturing processes, and, Reviewing telated FMEAs, control plans and opeiations instiuctions. „ Responsibility and timing to complete the iecommended actions should be recoided. Once actions aie completed and results captured, the updated iatings for seveiity, occunence and detection should also be lecoided 13 Chapter II Strategy, Planning, Impleraentation Management Responsibility | Management owns the FMEA piocess Management has the ultimate responsibility of selecting and applying iesources and ensuiing an effective risk management piocess including timing Management iesponsibility also includes providing diiect suppott to the team through on-going ieviews, eliminating loadblocks, and incoipoiating lessons leamed I ł 14 Chapter III Design Failuie Modę and Effects Analysis Chapter !li DFMEA Design Faiiure Modę and Effects Analysis Chapter III Design Failuie Modę and Effects Analysis Introduction $ The Design Failuie Modę Effects Analysis, lefened to as DFMEA, suppoits the design piocess in leducing the risk of failures by: Aiding in the objective evaluation of the design, including functional ieąuiiements and design alteinatives, Evaluating the initial design for manufactuiing, assembly, ser vice, and recycling ieąuiiements, Increasing the probability that potential failuie modes and theii effects on system and vehicle operation have been consideted in the design/develt>pment process, Providing additional infoimation to aid in the planning of thotough and efficient design, development, and validation piograms, Developing a ianked list of potential failuie modes accoiding to theii effect on ihe customer, thus establishing a piioriTy system for design impiovements, development, and validation testing/analysis, Pioviding an open issue format for recommending and tracking risk-ieducing actions, and, Pioviding mtuie refeience, ( e g , lessons learned), to aid in f addiessing field conceins, evaluating design changes, and developing advanced designs Ihe DFMEA is a living document and should: Be initiated befoie design concept finateation, Be updated as changes occui 01 additional infoimation is obtained thioughout the phases of pioduct development, Be fundamentally completed befoie the production design is ieleased, and, Be a souice of lessons learned foi futurę design iteiations. Customer Defined The definition of "Customei" provided in Chapter U applies to DFMEA It is important to conectly identify the customei(s) because such knowledge diiects the development of the DFMEA, including the impact of the function of the design I. 16 Chapter Tli Design Failure Modę and Effecls Analysis Team Approach The DFMEA is developed and maintained by a multi- disciplioaiy (oi cioss-functional) team typically led by the design responsible engineei fiom the responsible design source (e g, OEM, Tier 1 supplier or Tiei 2 supplier and below) The iesponsible engineei is expected to directly and actively involve iepresentatives fiom all affected areas The areas of expeitise and iesponsibility may include, but are not limited to, assembly, manutacturing, design, analysis/test, reliability, materials, quality, seivice, and supplieis, as well as the design aiea iesponsible for the next higher or tower assembly or system, subsystem, or component Manufacturing, Assembly and Sen/iceability Considerations The DFMEA should include any potential failure modes and causes that can OCCUI during the manuractuiing oi assembly process which aie the result of the design Such failure modes may be mitigated by design changes ( e g , a design featute which prevents a part fiom being assembled in the wiong orientation - i e., eiior-proofed) When not mitigated during the DFMEA analysis (as noted in the action plan foi that item), theii identification, effect, and control should be transfeired to and coveied by the PFMEA The DFMEA does not rely on process controls to overcome potential design weaknesses, but it does take the technical and physical limits of a manufacturing and assembly piocess into consideiation, foi example: Necessaiy mold drafts Limited suiface finish capability Assembling space (e g , access for tooling) Limited haidenability of steels Tolerances/process capability/per foi mańce The DFMEA can also take into consideiation the technical and physical limits of produci serviceability and iecycling once the pioduct has entered field use, foi example: Tool access Diagnostic capability Materiał classification symbols (foi recycling) Materials/chemicals used in the manufacturing piocesses 17 Chaptei III Design Failure Modę and Effects Analysis Development of a Design FMEA The DFMEA focuses on the design of the product that will be delivered to the finał custoraer (End Usei). The pretequisite tasks for an effective analysis of the product design include: assembling a team, deteimining scope, creating błock diagiams 01 P-diagrams depicting product function and requirements. A elear and complete deflnition of the desired product chaiacteiistics better facilitates the identification of potential failure modes A DFMEA foim is used to document the results of the analysis including any recommended actions and responsibilities (See Table III 1) The DFMEA piocess can be mapped to the customer or oiganization's product development piocess Prereguisites A DFMEA should begin with the development of information to understand the system, subsystem, oi component being analyzed and define their flinctional requiiements and characteristics In ordei to determine ihe scope of the DFMEA, the team should consider the following as applicable to component, subsystem ot system DFMEAs: i What processes, mating components, oi systems does the product inteiface with? Are there functions oi features of the product that afłect other components or systems? Aie there inputs provided by othei components or systems tha: are needed to peifoim intended functions of the pioduct? Do the producfs functions include the prevention or detection of a possible failure modę in a linked component or system? The following sections describe tools that may be applied, as appropiiate, to assist Ihe team in developing the DFMEA Błock (Boundary) Diagrams The błock diagram of the pioduct shows the physical and logical lelationships between the components of the product There aie different appioaches and foimats to the constniction of a błock diagiam The błock diagiam indicates the inteiaction of components and subsystems within the scope of the design This interaction may include: flow of information, energy, fbice, or fluid The objective is to understand the requirements or inputs to the !S Chapter HI Design Failuie Modę and Effects Analysis system, the activities acting on the inputs or function peifotmed, and the deliverables or output The diagram may be in the form of boxes connected by lines, with each box corresponding to a major component of the pioduct oi a major step of the piocess. The lines coirespond to how the pioduct components aie related to, or interface with each other The organization needs to decide the best approach or foimat for the błock diagram. Figurę III.la, b, and c contain examples of błock diagrams Copies of the diagrams used in DFMEA pieparation should accompany the DFMEA Lift Gale Bali LiftGate Waadier Studs Strtps Hamess H.:nS« MFG Plant Sttuts ,3J Rip Glass xxx N ses| tosd xxx N łoad xxxN £nviT-mwni FKp Glass -j- U - J S - -. -. -. Applique Studs Z Assembly TH SCIM cc =Hp Glass Wlper Stnkw.4.:5r"i-.ir Customet ixxxN O ad Lalch Assembly Koy: Ora way action/Tunctlon: * TWiMWy interactionffunction: « ». Soundary Une — Cmical Meriace focus Cłrtical Assembly tbcus Numbere miale to detali on interface Analysis Figurę IH.la Błock (Boundary) Diagram Esamples 19 Chaptei III Design Failuie Modę and Effects Analysis 9- c o i? £ co -o 0) CL CG CU co 'co iiiill I II ^ Ł - II r> 5 j£ n n ^? — cł tancoQ iiii "" lilii U) 2 1 S* A ; ^- - i^ r: I I - '-. ,. - , - j i :....- """>* B Dosi^t Respcnobłly H _Compon»n Model YeaflsyPiogiamls). D Kev D0I9 __ FMEADaislOńa,) F 5 Cijg TMIP. Current pesKir* A c u o n ReHilta ll e m Potential r'otu-i>;.' Polenlial Reconuii«nde i i y - o BitdA8»yO^ 0X1215 EwA>«ian i n o « M > : - , ' ". Lr KCCOH («) sio" x r o r h t a d WŁDfc ojtnia 3 i- AiHT.ii. iaa q T-11B m 7 al a2 ci !. 9 h m :it: t "-  Design Failure Modę and Effects Analysis Potential Effect(s) of Failure (c) Potential effects of failuie aie defined as the effects of the failure modę on the fiinction, as peiceived by the customei(s). Desciibe the effects of the failuie in teims of what the customei might notice or expeiience, iemembering that the customei may be an internal customei as well as the ultimate End User State clearly if the failuie modę could impact safety or non- compliance to regulations. The effects should always be stated in teims of the specific system, subsystem, 01 component being analyzed Remember that a hieiarchical relationship exists between the component, subsystem, and system levels4 For example, a pait could fiactuie, which may cause the assembly to vibrate, resulting in an inteimittent system opeiation The inteimittent system operation could cause peifoimance to degiade and ultimately lead to customei dissatisfaction The intent is to piedict the potential failure effects to the team's level of knowledge Typical failure effects should be stated in teims of product or system peifoimance Table III 4 shows example effects of the failure modes nom Table JII.3 Item Failure Modę Effect Disk Biake Vehicle does not Vehicle control impaired; Regulatory non-compliance System stop Vehicle stops in excess of specified Vehicle controE impahed; Regulatory non-compliance distance Stops vehicle with morę than xx g's of Regulatoiy non-compliance foice Activates with no demand; Decreased pad life; dirninished vehićle control Vehicle movement is paitially impeded Activates with no demand Customer unable to drive vehicle Vehicle cannot move *&JK':.-:*;;'.- ; ; '-"''' ~.":''.-1 ; -.' ' Tab!e HL4 Esample Potential Effects 4 See also Appendix B 35.Syslem POTENTIAL FAILURE MODĘ AND EFFECTS ANALYSIS FMFA N t m l w r. A _ SgbŁyalom (DESIGN FMEA) B Design R e & p o r a b i l f y.C H Model Core ftam. Yt&i{e¥PK>9tam{*)- D KevQoW FMEADauiOrtg.). Current Design *£"onR«i*i Potenlial Polential Potenlial ResponstolliN RecommendBd -"I :... ' ,1 Failure E f f e c t ( s ) of Cause{s) of Controls Conlrols w ^ c m * : CI t'ii.'jl..." us-ieai PW. ISES H I - W. i- 0iiT4ix(vmL i-iiB PI c o n t r oua«n < [-..;. I I.! 'S i'»Y.nfc lont&il: l » *. i W i ił«av ł t u p alłlnai- o u O M i b n iKing Bofly EnglDMł SMdMMWwn IKOI iMcrmg a l fcjIinfilMIt) F"*J!il>n s c i a. Md *«av O n i ,.:::. ;....:I.-J , W i v r « r t IB) ' ".l-.i- icnor-li-oatol! ttutabilytefl. 1-118 ffł SAMPLE i;i.ll.:.: tKftrrcn paneli _ [ '.-.i ?>4fiMfa>ec> sam e»tft*tiOn IMMQ t f c * 9 n a a one* W1315 *xu»i i*) W U 15 whkto durabt* i *>H. T-11B P) a1 a2 b i g rn -~n— -°*»V- -«*. Chapter 1H Design Failuie Modę and Effects Analysis Severity (S) (d) Severily is Ihe value associated with the most seiious effect fot a given failuie modę Seveiity is a relatiye lanking within the scope of the individual FMEA Suggested Evaluation Criteria The team should agiee on evaluation criteiia and a ranking system and apply them consistently, even if modified for individual piocess analysis (See Table Crl below for criteiia guidelines) \ lt is not recommended to modify criteria ranking values of 9 and 3 10- Faiiure modes with a rank of severity 1 should not be a analyzed further Criteria: Effect Severlty of Effect on Product Rank (Customer Effect)_ Failurc to Potential faiiure modę afiects safe vehicle opeiation and/oi ińvolves 10 Meet Safety noncompliance with goveinment legulation without waining and/oi Regulatory Potential failuie modę affects safe vehicle opeiation and/oi involves 9 Requh ements noncompliance with govemment regulation with waming Loss of piimary function (yehicle inopeiable, does not affect sale 8 Loss oi- vehicle operation) Dcgradation (lt PMTliaiy Degiadation of piimary function (vehicle opeiable, but at reduced 7 Function level of performance) Loss of secondaiy function (vehicle opeiable, but comfort / 6 Loss o» convenience functions inoperable) Degiadation of Secondaiy function Degradation of secondaiy function (vehicle opeiable, but comfoit / 5 convenience functions at reduced level of performance) Appearance oi Audible Noise, vehicle opeiable, item does not 4 confoim and noticed by most customeis (> 75%) Appeaiance or Audible Noise, vehicle opeiable, item does not 3 Annoyance conform and noticed by many customeis (50%) Appearance or Audible Noise, vehicle operable, item does not 2 conform and noticed by disciiminating customeis (< 25%) No effect No disceraible effect 1 Table Crl Suggested DFMEA Severity Evaluation Criteria 37  POTENTIAL Sysiein FAILURE MODĘ AND EFFECTS ANALYSIS FW6ANun*et_ (DESIGN FMEA1 n. Sobsyslejn Pago » ___Cocnponent B Dragn Ro»poo»b»(y C PropareO Bv: H MoOeł Yesr(aVPro9fafii(8ł_ D FMGADatefOflg.; I CofeT«am Currenl Design Al '.' C.;-.. rlf l r.f.:. '. ' i -. - Dcalji..f.IT.' i i-i:.-i :.'i :.! ir.-.r. , , :/. A. K M I ł t o m cmtrsa 'I ( I I.. W l i PuMlHU pana accmsolura MCłcafcm tp*ita) - -" j i o i Wsi 14*1) u r t W fłdo* Cdi '- S.»;;r--H-» Q*C003 l^OC(BKad12S mwb* ppaun W»30 *n» bodAg v> I UnuKibcMiy appcwanceoiiew oic( Imc. i:-- i ' VCM:K HiKgQHvKal 7-118 (T) ' LJL". !..: Mac BodvE i:-, I.' IU>. U81)*KW :; i ' i.lll li 1IS1.T OXH30 ; :. J Sray.no :,.»-.I. Bod.' Engneer nsLUi- i- :-. |DC€!in*ftt IhKtaMtt Ot tt 18.1' V. >. I ,.....'... Melry - lomuiihnii^.^h-1 UMyJnrO OemkaiLab 3 Ph>. (MS (5) ou**rtivte*i I-11B 17) 1TB leam T.l on ISH PRAWI* w a w n p -iinfon- «Bfcl*t»n uang i...r-....... 3 o43U^vX vom tmm roadaig al '. : t " KiMhKlwn spqn irniM proM^d ^ 3 arcos dcpipmenl o/id adMłMarNG.dieto JX11 15 trNOC-^IMiod) = OiueiiUvkai. 0X U i* S T-11B pj FI x SAMPLE u (tom «ibł>dłiOnal HM&M ( » ex £ Z u < Q UJ C II [fsii _ O : iii: ucfiesyiss&e^ M =-; a> Iii II1 s«s!l li U i PIW o H LU cnn a U CL- i CN i s l lii ca i iii I to co Table III-I Sample DFMEA Form with Minimai Iniormation Elements & Example Entiies 48  Design Failuie Modę and Effects Analysis Current Design Controls (h) Cunent Design Controls aie those activities conducted as part of tbe design process that have been completed 01 committed to and that will assuie the design adeąuacy for the design functional and reliability leąuirements under consideiation. Theie aie two types of design controls to consider: PreventioD: Eliminate (prevent) the cause of the mechanism of failuie or the failuie modę fiom occuning, oneduce its tatę of occurrence. Detection: Identify (detect) the existence of a cause, the lesulting mechanism of failuie or the failure modę, eithei by analytical or physical methods, beibie the item is released foi pioduction. : The preferred approach is to first use prevention controls, if j possible The initial occurrence rankings will be affected by the l prevention controls provided they are integrated as part of the design intent Detection contro! should include identification of those activities which detect the failure modę as well as those that detect the cause. The team should consider analysis, testing, ieviews, and othei activities that will assure the design adeąuacy such as: Prevention Controls Benchmaiking studies Pail-safe designs Design and Mateiial standards (interna! and exteinal) Documentation - records of best piactices, lessons Iearaed, etc fiom similar designs Simulation studies - analysis of concepts to establish design reąuirements Eiioi-proofing Detection controls Design reviews Prototype testing VaIidation testing Simulation studies - validation of design Design of Expeiiments; including reliability testing Mock-up using similai parts 49  POTENTIAL. SvsMm FAILURE MODĘ AND EFFECTS ANALYSIS FMEANumbar A iDtSKti FMEA1 _5..:'.v.;-.;i-r Paot- w.Componsnl B Design RssponsiDMIf H ŁtoOsi Y*ai(3yprogram(a)_ D K«v Ctai« FM£ADato (Ora.! 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I& LU _l -Q=- CM flł co cc Table HI.l Sample DFMEA Form with Minimal Information Elemeots & Example Entries 62  Design Failure Modę and Effects Analysis Table III.7 below provides an example of the application of causes (Column f), controls (Column h) and recommended actions (Column k) Rssponsibility & Target Completion Datę (I) Entei the name of the individual and organization responsible for completing each lecommended action including the taiget completion datę The deslgn-responsible engineei/team leader is responsible for ensuiing that all actions iecommended have been implemented or adequately addiessed Action Results (m-n) Ihis section identifies the results of any completed actions and their effect on S, O, D rankings and RPN Action(s) Taken and Completion Datę (m) After the action has been implemented, entei a bfief description of the action taken and actual completion dale Severity, Occurrence, Detection and RPN (n) Aftei die preventivev'conective action has been completed, determine and lecord the resulting seveiity, occuirence, and detection rankings Calculate and record the resulting action (lisk) priority indicatoi ( e g , RPN) All ie