Failure Mode and Effect Analysis

* Learning Objectives Provide familiarization with FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools. Learn how to integrate FMEA into your Company SOPs Our objectives are to present an overview of FMEA. This will be a working session. Later we will divide into teams and prepare both design and process FMEA’s for actual disc drive components. It is a relatively simple tool - no statistics, no advanced engineering principles are required.

* Definition of FMEA FMEA is a systematic design evaluation procedure whose purpose is to: 1. recognize and evaluate the potential failure modes and causes associated with the designing and manufacturing of a new product or a change to an existing product, 2. identify actions which could eliminate or reduce the chance of the potential failure occurring, 3. document the process. What’s new about FMEA? Are we already doing this? FMEA has been proven in many industries to be a very important early preventive tools to prevent failures and errors in the product design and process from occurring and reaching the customer. FMEA is a systematic design evaluation procedure whose purpose is to: 1. recognize and evaluate the potential failure modes and causes associated with the designing and manufacturing of a new product or a change to an existing product, FMEA works best when you look ahead into the unknown, it is not an effective tool for looking backwards - analyzing existing designs 2. identify actions which could eliminate or reduce the chance of the potential failure occurring, We do this already - its called Design Engineering, so what’s different? - FMEA allows you to go deep into analysis asking why a design or process problem could occur it brings out interfaces, coordination and communication required between departments; it shows where potential design flaws exist and risks involved; 3. document the process. As people and teams reorganize, it provides a history of the design process and record of steps leading up to design decisions. It also provides communication to other engineers and other design centers who may be working on similar designs.

FMEA FMEA: Failure Modes and Effects Analysis FMEA is a systematic approach used to examine potential failures and prevent their occurrence. It enhances an engineer’s ability to predict problems and provides a system of ranking, or prioritization, so the most likely failure modes can be addressed. FMEA is generally applied during the initial stages of a process or product design. Brainstorming is used to determine potential failure modes, their causes, their severity, and their likelihood of occurring. FMEA is also a valuable tool for managing tasks during defect/failure reduction projects.

FMEA is Function-driven * FMEA is Function-driven FMEA begins with a definition of the FUNCTIONS an item is supposed to perform. The inputs must come from several sources to be effective: Manufacturing Engineer Supplier Quality Reliability Design Program Management Production The main difference between FMEA and typical “post-mortem” analysis done on a program is the FMEA is FUNCTION-DRIVEN. The first step is to identify all of the functions of a part, component or system. This is a very important first step and must not be short-circuited. INSTRUCTOR NOTE: use a simple, everyday item and develop a list of functions - i.e.. mechanical pencil or paper coffee cup are a good ones. Also use a disc drive component and discuss how functions are defined differently by different departments. A motor is a good example - design people will list characteristics, process people will require ease of assembly and interchangeable parts from different suppliers, etc.., Materials want them all alike and painted black, Finance wants them for minimum cost. What are the functions of a base deck? provides air-tight container Mounting surface for PCBA provides dimensional stability for internal components Mounting to customer host fit within minimum profile (dimensionally) Manufacturable at high volume Mechanically stable throughout operating conditions inexpensive Thermally stable provides resonance and vibration dampening no outgassing or contamination critical dimensions are measurable provides aerodynamic characteristics (air flow)

* Background Developed in early 60’s by NASA to “fail-proof” Apollo missions. Adopted in early 70’s by US Navy . By late 80’s, automotive industry had implemented FMEA and began requiring suppliers do the same. Liability costs were the main driving force. Used sporadically throughout industry during 1980’s. Adopted by Seagate in 1996. Initial application in design centers. Now it’s time to apply FMEA to process applications in Seagate. Six Sigma is the catalyst. FMEA is not new - it has been around since the early days of the space program. In fact, anyone with background in aerospace, NASA, electronic fabrication, automotive and defense contracting knows FMEA because it is a basic tool. The Seagate method is based primarily on the Ford Motor Company application. Health care and construction industries are recently using FMEA. Hospitals are enhancing traditional quality management tools such as SPC with FMEA and looking at such things as adverse patient outcome, medication errors and risks, etc. This could have helped the Denver airport baggage handling problems!

and we thought we had No problems! NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy & loss of mission). How many did they find? 420 and we thought we had No problems! NASA used FMEA to detect SINGLE POINT FAILURES where failure of a system or component would cause loss of mission. In other words, there is no redundant system. In the Apollo system, FMEA identified approximately 420 single point failures. FMEA was used to reduce the risks to acceptable levels. Even NASA doesn’t think of everything. Woodpeckers delayed a recent Shuttle mission for several days. It seems that the birds liked the adhesive on the ceramic tiles and proceeded to peck away. The problem was further complicated by the fact that these were and endangered species of woodpecker so removal had to be done under the watchful eye of environmentalists.

Types of FMEA’s * SYSTEM DESIGN PROCESS System FMEA is used to analyze systems and subsystems in the early concept and design stages. SYSTEM Design FMEA is used to analyze products before they are released to production DESIGN System FMEA [2]: Used to analyze systems and subsystems in the early concept and design stage. Its goal is to define and demonstrate a proper balance among operational components. Outputs of the system FMEA can be inputs to the design FMEA. Design FMEA: Focuses on the design stage - systems, subsystems, parts, and components. The Design FMEA technique parallels and formalizes the mental disciplines that an engineer normally goes through in any design activity. A Design FMEA is conducted early in the design process once the initial design information (concepts, parameters) is available. It is performed and updated iteratively as the design evolves so that the analysis can be used to influence the design and to provide documentation of the eventually completed design. Process (Manufacturing) FMEA: focuses on the process flow, sequence, steps, work stations, operators, equipment, machines, tooling, gauges, methods and maintenance. A process FMEA is conducted during the quality planning phase but before the beginning of production. It identifies potential deviations from specification, and eliminates or minimizes them by preventing or detecting changes in the process variables. Supplier Process FMEA: Analyzes the supplier process. It is identical to the process FMEA in that it looks at all aspects of the supplier process and identified potential deviations from specifications. This overview focuses on the PROCESS FMEA Process FMEA is used to analyze manufacturing, assembly and administrative processes PROCESS

When Is the FMEA Started? AS EARLY AS POSSIBLE Guideline: Do the best you can with what you have. As we mentioned, FMEA is a methodology to maximize customer satisfaction by eliminating and/or reducing known or potential problems. To do this, the FMEA must begin as early as possible even though all of the facts and information are not yet known. A good guideline is DO THE BEST YOU CAN WITH WHAT YOU HAVE. If we wait for everything - drawings, specifications, clear concept - we will never begin or will begin so late that the design will have been established and the FMEA will be ineffective.

When to Start When new systems, products and processes are being designed When existing designs and processes are being changed When carry-over designs or processes will be used in new applications or environments After completing a Problem Solving Study, to prevent recurrence of a problem

Process FMEA Form * The form is almost identical to the design version. the only difference is that the process verification is measured with DETECTION rather than effectiveness. This will be discussed later. Refer to the FMEA Handbook starting at page 32 for a detailed description of the columns. Like the design FMEA, this section is important because the differences between the two types of FMEA are clearly detailed. This section should be used as a reference when conducting FMEA sessions.

Process Failure Mode The potential failure mode is the manner in which the process could fail to perform its intended function. The failure mode for a particular operation could be a cause in a subsequent (downstream) operation or an effect in associated with a potential failure in a previous (upstream) operation. PREVIOUS OPERATION NEXT OPERATION FAILURE MODE This illustrates the relationship between process steps. EFFECT CAUSE

Process FMEA considers process variability due to: Process Causes Process FMEA considers process variability due to: OPERATOR SET-UP MACHINE METHOD ENVIRONMENT MEASUREMENT When listing causes, take into consideration the source of the failure as it relates to: Operator-induced errors due to training, skill, attention, or fatigue Set Up induced failures where set-up inconsistencies directly affect quality Machine caused failures, including tooling, where the problem is encountered due to an equipment failure or is introduced over time due to machine or test set drift. Method inconsistencies where the defined method is not robust to differences in operators Environmental conditions, especially concerning cleanliness or contamination Measurement inconsistencies where it is possible that incorrect or erroneous information can lead to poor decisions concerning product operation or acceptance Typical failure causes include such things as: handling damage incomplete prior operation improper change improper tool set up inadequate packaging worn tools improper torque inadequate process information improper training

Current Controls Assessment of the ability of the control to detect the failure before the item leaves the manufacturing area and ships to the customer. Capability of all controls in the process to prevent escapes Current controls are descriptions of the controls the either prevent the failure mode from occurring or detect the failure mode should it occur. These controls can be process controls or preventative steps that are taken prior to manufacturing start up or on an ongoing basis. They include inspection, testing, and audit at the operation being evaluated or at a subsequent (downstream) operation. Process Capability Sampling DoE Testing Gage R&R SPC

Types of Measures * Typically, three items are scored: SEVERITY As it applies to the effects on the local system, next level, and end user OCCURRENCE Likelihood that a specific cause will occur and result in a specific failure mode DETECTION Ability of the current / proposed control mechanism to detect and identify the failure mode Several systems exist for quantifying potential failure modes in order to drive corrective actions. The actual system used depends on the needs of the organization. The following is typical of many of the FMEA analysis systems in use today and should be customized to meet the specific needs of Seagate. Three items are scored as follows: 1. Severity: assessment of the failure effects on the local area, next level, and end user. Severity rating applies to the effects and the effects only. A change in severity rating can only be achieved through design or application change. 2. Occurrence: The likelihood that a specific cause will occur and will result in the specific failure mode considering: * history / judgment - is design, application or end use a carry-over from a previous product? * significance of changes from the previous design and application * environmental conditions * customer expectations 3. Effectiveness / Detection: An assessment of the ability of the current / proposed controls to identify the failure mode prior to occurring or prior to release to production, or prior to shipment to the customer. This rating can be improved only by improving the control system or the design. Each of the above is typically scored on a scale of 1 - 10 with a 1 being desirable (low occurrence, low severity, high detection). The forth measure is the product of the three and is referred to as the Risk Priority Number (RPN). The higher the RPN, the more likely that the identified failure mode will cause end-user problems. A final priority (Action Priority) is then established using the RPN and other factors, including judgment, the team feels pertinent.

Severity

Occurrence

Detection (“Escape”) This is best thought of as Escape Potential - the higher the score, the greater the problem

Risk Priority Number RPN = O x S x D Occurrence x Severity x Detection * Risk Priority Number RPN = O x S x D Occurrence x Severity x Detection The forth measure is the product of the three and is referred to as the Risk Priority Number (RPN). The higher the RPN, the more likely that the identified failure mode will cause end-user problems. A final priority (Action Priority) is then established using the RPN and other factors, including judgment, the team feels pertinent.

Basic Steps Develop a Strategy Form a FMEA team Why is this first? Why is a strategy important? The risks with FMEA are oversimplification and undersimplification. If its too simple, or looked at from too high a level, then root cause many never be found. If the analysis is too complicated, then time may not be well spent ad people will loose interest. The best strategy for a BB is to look at parts or processes within the project. Or the whole project in areas that: Involve new technology Have changed from previous Are chronically in trouble Have a high degree of operator control Have a high degree of variation

Basic Steps 2. Review the design/process 1. Develop a Strategy 2. Review the design/process Develop process map and identify all process steps This should have been completed as a work flow diagram. It would be helpful to use the diagram to “frame” the scope of the FMEA.

Basic Steps 3. List functions List all the value-added process 1. Develop a Strategy 2. Review the design /process 3. List functions List all the value-added process For each process step, list process inputs (process characteristics List the FUNCTIONS or PROCESS STEPS This is an important 1st step that is often overlooked or short circuited in a rush to take some sort of action

Basic Steps 4. Brainstorm potential failure modes 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes EFFECT CAUSES Begin with loss of function and determine the ways in which the process can fail to meet requirements or can create too much uncontrolled variation.

Basic Steps 5. List the potential consequences of each failure mode 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode There can be many potential failure modes identified. Often many of them can be combined into a few. An affinity diagram is a good tool for organizing and categorizing the identified failure modes.

Basic Steps 6. Assign severity (SEV) score 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode 6. Assign severity (SEV) score PRODUCT: FMEA NO. PROCESS/OPERATION: PAGE OF DESIGN (OR PROCESS) FMEA PLANNING REFERENCE: DATE: BY: Oklahoma City POTENTIAL S O CURRENT D RPN ACTION CORRECTIVE RESPONSIBILITY RESULTING FUNCTION FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS PRIORITY & DATE DUE TAKEN FAILURE DETECTION OCCURRENCE SEVERITY RPN = S x O x D Now we get to the form.

Basic Steps 7. Identify the cause(s) of each failure mode. 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode 6. Assign severity (SEV) score 7. Identify the cause(s) of each failure mode.

Basic Steps 8. Assign occurrence (OCC) scores. 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the cause(s) of each failure mode. 8. Assign occurrence (OCC) scores.

Basic Steps 9. Identify current controls to detect the failure modes. 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes.

Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control.

Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA.

Basic Steps 12. Determine the action to be taken. 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA. 12. Determine the action to be taken.

Basic Steps 13. Recalculate the RPNs based on the actions plans. 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA. 12. Determine the action to be taken. 13. Recalculate the RPNs based on the actions plans.

Shortcomings of RPN * SAME RESULT A 8 4 3 96 B 4 8 3 96 Effectiveness Occurrence Effectiveness RPN Failure Mode Severity A 8 4 3 96 B 4 8 3 96 Multivariate measures, like RPN, could mask the importance of potentially critical individual factors. For example, two failure modes may wind up with the same RPN which could lead you to believe that they carry the same weight as far as establishing priorities: Failure Mode A is half as likely to occur as B but this may not make up for the fact that it is twice as severe. If the product is going to fail at a customer site, it may not matter that it will only occur a small percentage of the time. Intuition and logic must take precedence in establishing action priorities from RPN. SAME RESULT

Action Priority

INITIAL PROBLEM . WALK INTO DOOR CAN’T SEE BUMP HEAD PAIN GET GLASSES POTENTIAL PROBLEM WALK INTO DOOR LIKELY CAUSE LIKELY EFFECT CAN’T SEE BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE GET GLASSES WEAR HELMET REMOVE DOORS

1st WHY . WALK INTO DOOR CAN’T SEE BUMP HEAD PAIN GET GLASSES PROBLEM BECOMES EFFECT CAUSE BECOMES NEW PROBLEM POTENTIAL PROBLEM WALK INTO DOOR LIKELY CAUSE LIKELY EFFECT CAN’T SEE BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE GET GLASSES WEAR HELMET REMOVE DOORS

1st WHY . CAN’T SEE WALK INTO DOOR AND NEAR SIGHTED BUMP HEAD PAIN POTENTIAL PROBLEM WALK INTO DOOR AND NEAR SIGHTED LIKELY CAUSE LIKELY EFFECT BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY GET GLASSES

2ND WHY . CAN’T SEE WALK INTO DOOR AND NEAR SIGHTED BUMP HEAD PAIN POTENTIAL PROBLEM WALK INTO DOOR AND NEAR SIGHTED LIKELY CAUSE LIKELY EFFECT BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY GET GLASSES

2ND WHY HAVE WE FOUND ROOT CAUSE? . NEAR SIGHTED CAN’T SEE WALK INTO POTENTIAL PROBLEM CAN’T SEE WALK INTO DOOR AND LIKELY CAUSE LIKELY EFFECT TOO MUCH T.V. BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY CUT OUT STAR TREK HAVE WE FOUND ROOT CAUSE?

2ND WHY OR GONE TOO FAR ! . NEAR SIGHTED CAN’T SEE WALK INTO DOOR AND POTENTIAL PROBLEM CAN’T SEE WALK INTO DOOR AND LIKELY CAUSE LIKELY EFFECT TOO MUCH T.V. BUMP HEAD PAIN TRIGGER . Note the different types of actions. PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY CUT OUT STAR TREK OR GONE TOO FAR !

Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DESIGN FMEA DRAWING OR SPEC REFERENCE: Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS PROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT This slide illustrates the previous technique using FMEA and a disc drive example. See page 43 in the FMEA Handbook. Successful application of FMEA is dependent on the ability to get to root cause. Once the analysis has begun, there may be a tendency to oversimplify (or over complicate) the analysis and not provide useful data. It is important to remember that: The definitions of failure modes, causes, and effects depend on the level of analysis and they may be interchanged depending on the level addressed. For example, a failure may be an effect, and a cause may be a failure depending on the level of analysis. Also, as the design progresses, failure effects defined at a lower level may become failure modes at a higher level, and failure modes at lower levels may become causes at higher levels. This is illustrated with the next slide. This is a very important concept and takes time and experience to master. TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Here’s a Seagate Example Handbook pg. 43

Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DESIGN FMEA DRAWING OR SPEC REFERENCE: Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS PROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Cause becomes Failure Mode Handbook pg. 43

Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DESIGN FMEA DRAWING OR SPEC REFERENCE: Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS PROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Failure Mode becomes Effect Handbook pg. 43

Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DESIGN FMEA DRAWING OR SPEC REFERENCE: Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS PROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE WHY? SPINDLE ROTATES FAILURE OF FLEX SOLDER NO SPIN, OR DRIVE MEDIA AT FIXED RPM JOINT DUE TO RUNS IN REVERSE INSUFFICIENT STRAIN CAUSING DRIVE TO RELIEF BE INOPERABLE This has the same effect as asking WHY. It forces a deeper level of analysis The KEY TO SUCCESS with FMEA is knowing when to quit It is knowing when the analysis has gone deep enough to provide value. It is also knowing when to rearrange the columns. This comes with experience. A good rule of thumb - You have gone too far when you begin asking irrelevant (or stupid) questions, or begin saying such things as : I WALK INTO DOORS BECAUSE I GOT HOOKED ON STAR TREK AT AN EARLY AGE. PROVIDES A DEEPER LEVEL OF ANALYSIS BY ASKING YOU FOR THE DESIGN CAUSES AND VERIFICATION OF INSUFFICIENT STRAIN RELIEF Handbook pg. 43

What’s Wrong With This Picture? * NUMBER OF PROCESS FAILURE CAUSES Only specific errors or malfunctions should be listed (e.g., operators fail to install seal) should be listed. Ambiguous causes (e.g., operator error, machine broken) should not be used. Operator training is often used as a catch-all and should be avoided unless specific details are listed. If operator errors seem to be persistent, first assume that the system - machines, tools, job information, conditions - is causing the problem. When OPERATOR ERRORS tend to be #1 cause, then the true root causes are not being addressed. When this occurs, ask WHY as many times as necessary to get to the true cause. Remember that operators are directly responsible for only about 15% of the errors that are made. The remaining 85% are due to the system in which they work and can be attributed to defective parts, inconsistent methods, poor tooling, inadequate maintenance, etc.

Actions * A well-developed FMEA will be of limited value without positive and effective corrective actions. The design or process must be improved based on the results of the FMEA study. The corrective actions should be directed first at the highest action priority items. A corrective action may apply to more than one cause. Not every problem has a practical solution and if no action is taken, this should be indicated. Emphasis must be placed on preventing defects, i.e., reducing occurrence and severity rather than improving detection. Generally, improving effectiveness controls is costly and not suited for continuous quality improvement. The need for taking specific, positive corrective actions with quantifiable benefits, and follow up to insure effective implementation, is critical to the success of FMEA. A well-developed Design FMEA will be of limited value without positive and effective corrective actions. The design must be improved based on the results of the FMEA study.

Elements of FMEA Failure Mode Any way in which a process could could fail to meet some measurable expectation. Effect Assuming a failure does occur, describe the effects. List separately each main effect on both a downstream operation and the end user. Severity Using a scale provided, rate the seriousness of the effect. 10 represents worst case, 1 represents least severe. Causes This is the list of causes and/or potential causes of the failure mode. Occurrence This is a ranking, on a scale provided, of the likelihood of the failure occurring. 10 represents near certainty; 1 represents 6 sigma. In the case of a Six Sigma project, occurrence is generally derived from defect data. Current Controls All means of detecting the failure before product reaches the end user are listed under current controls. Effectiveness The effectiveness of each current control method is rated on a provided scale from 1 to 10. A 10 implies the control will not detect the presence of a failure; a 1 suggests detection is nearly certain.

FMEA is most effective when It is conducted on a timely basis and It is applied by a product team Its results are documented It is conducted on a timely basis, early in the product or process development cycle. A design FMEA should be started as soon as initial design information and parameters are available. It is updated continually as changes occur throughout the phases of product development and is fundamentally completed at the time the final drawings are released. It is applied by a product team made up of individuals with diverse experience and expertise from across the organization. The existing product team environment at Seagate provides an excellent basis for implementing FMEA. The results are documented in a consistent manner and updated throughout the life of the product. Future product teams can benefit from the actions of past teams. The documentation is a by-product of the FMEA process, not an end in itself. The actions of the product team identifying potential problems early in the process and driving effective corrective actions is the intent of FMEA and leads to the most profound successes.

Integrating FMEA into SOPs Example of how FMEA can be used in SCAR. Section of SCAR procedure FMEA can be used to identify the potential cause of failure and determine whether the current control is sufficient.

Link Tools Integration Tasks to Work Breakdown Structure The effort to integrate FMEA into SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.

End of Topic Any Question ?