Process fmea work_instructions0

CADmantra
Technologies Pvt. Ltd.
PROCESS FMEA
POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS – Work Instructions
Doc No # __ , Rev N0. # ___ Page 1 of 11
Product No : FMEA Date : Rev Date:
Description : Scheduled Production Date :
Model : Process Responsibility :
Core Team
Process
Function
Potential
Failure
Mode
Potential
Effect(s) of
Failure
Severity
Potential cause(s)
Of
Failure
Occurence
Current
Process
Control
Detection
RPN
Recommended
Actions
Responsi
-bility
1
2
3
4
5
6
7
8
9
10 11 12 13
14
15
16 17
18 19

CADmantra
PROCESS FMEA
PRODUCT NO
Enter the number of the system. Subsystem, or component, for which the process is being analysed.
DESCRIPTION
Enter the name of the system, subsystem, or component, for which the process is being analyzed.
MODEL
Enter the name intended model of the final product that will utilize and/or be affected by the process being analyzed ( if known).
CORE TEAM
The responsible engineer is expected to directly and actively involve representatives from all affected areas. These areas should include, but are
not limited to, design, assembly, manufacturing, materials, quality, and service as well as the area responsible for the next assembly. The FMEA
should be a catalyst to stimulate the interchange of ideas between the functions effected and thus promote a team approach.
FMEA DATE and REV. DATE
Enter the date ythe original FMEA was compiled, and the latest revision date.
SCHEDULED PRODUCTION DATE
Enter the scheduled production start date. The initial FMEA date should not exceed the scheduled production start date.
PROCESS RESPONSIBILTY
Enter the department(s) responsible for the process being analyzed.
PROCESS FUNCTION
 Process function is a description of the manufacturing processing that occurs, as indicated on the Process or Operational Sheet.
 If the process involves numerous operations (for example, assemble) with different modes of failure, list the operations as separate processes.
Typical examples of operation descriptions:
Turning
Tapping
Broaching
Gage ___________dimension
POTENTIAL FAILURE MODES
 The Potential Failure Mode is a description of “What part features can be negatively affected by this operation?” This description can be
presented in terms of a process characteristic (Prevention Strategy), or a part characteristic (Detection Strategy).
2
1
3
4
5
7
8
9
10
6

CADmantra
PROCESS FMEA
 The potential failure modes may also be a cause of a potential failure mode in an upstream manufacturing process/operation, or be the effect
of one in a downstream operation.
 Do NOT describe what could go wrong at this operation at this time. It tends to confuse failure mode with causes at later time.
 List each potential failure mode one at a time.
 The assumption is made that the failure may occur, but does not necessarily have to occur.
 All incoming material/parts/components are assumed correct, and defect free.
 A recommended starting point is either a review of past quality reports, test reports, dock auditing reports, equipment corrective maintenance
logbook, rework/repair reports, or existing Process FMEA on similar process/operations.
Typical potential failure modes:
bent eccentric rough
tight binding unstable
hole missing warped unstable
blurred leaking noise
brittle over/under size
deformed porous
contaminated open/shot circuit
damaged misassembled
POTENTIAL EFFECTS OF FAILURE
 Enter the potential effects of each potential failure mode under consideration.
 Effects of failure are the consequences the identified failure will have on the end product and downstream process. The basic questions to
answer are “What does the end user experience as a result of the failure mode?” and “How is the downstream process affected as a result of
the failure mode?”
Typical effects of failure on end product:
noise seal failure
water leaks loss of power
vibration corrosion
11

CADmantra
PROCESS FMEA
Typical effects of failure on end product the downstream process:
interference on drilling fixture
excessive tool wear or breakage
cannot assemble
will not balance properly
Control, Critical Or Significant Item
 Enter the symbol representing the condition defined below for each potential failure mode.
 Control, Critical and Significant Items which are identified here are product/part/components, NOT operations or manufacturing processes.
 control item – is an item controlled by industry or government regulations. Failure may impact the general public.
 critical item – is a safety related item.
 significant item – is an item of significant importance to the product.
 When we deal with Control or Critical items we shall study parts to the lowest possible level.
 Separate and distinct control Plans should be developed for all control, critical, and significant items.
SEVERITY RATING
 Severity rating is an assessment of, Failure Effects on local and next level process/operation and the end user.
 Severity rating is driven by Failure Effects and criticality.
 Severity rating applies to process/operation and product.
 Severity rating should be the same each time the same failure Effects occurs.
12

CADmantra
PROCESS FMEA
SEVERITY RATING TABLE
Evaluation Criteria:
Rating On Process On product Effect
1 No effect Not noticeable. No effect to the product and end
user.
None
2 Minor disruption to production line. Very Low % of
product have to be reworked on-line
Defect noticed by discriminating customers. Very Minor
3 Minor disruption to production line. Very Low % of
product have to be reworked on-line . No downstream
processes impacted.
Defect noticed by average customers. Minor
4 Minor disruption to production line. Product may have
to be sorted and very low % reworked. No downstream
processes impacted.
Defect noticed by most customers Very Low
5 Minor disruption to production line. 100 % of product
may have to be reworked.
Product operable with some convenience items
operable at reduced performance. Customer
experiences some dissatisfaction.
Low
6 Minor disruption to production line. A portion of the
product may have to be scrapped (no sorting).
Customer will notice defect upon receipt Moderate
7 Minor disruption to production line. Product may have
to be sorted and low % scrapped
Customer dissatisfied. Product operable but at a
reduced level of performance
High
8 Major disruption to production line. May cause serious
disruption to downstream operations. 100 % of product
may have to be scrapped
Effects on major system, but not on safety or
government regulations.
Very High
9 May endanger machine or assembly operator. Tool or
fixture damage. Failure will occur with warning
Product Safety affected or involves noncompliance
with regulations.
Hazardous with
warning
10 No build condition (Production line down). Injury and
harm to process or assembly. Failure will occur
without warning
Effect safety or involve noncompliance with
regulations. Failure will occur without warning
Hazardous
without warning
13

CADmantra
PROCESS FMEA
POTENTIAL CAUSE OF FAILURE
 List all conceivable process related potential failure causes for each potential failure mode.
 Causes of failure are set-up or processing conditions that induce or activate the failure mode.
 The listed causes should be as concise and complete as possible so that the corrective actions can be effective and timely.
 Describe the causes in terms of something that can be corrected or controlled.
Not Recommended Preferred
Operator error Seal not installed
Fixture bad Worn stop on fixture
Typical causes of failure:
Handling damage improper heat treat
Improper tool set-up improper weld time
No lubricant worn/improper tooling
Worn bearings inaccurate gauging
Operator fails to… machine set-up
We can also use the “Five Why’s, to help us arrive at “root” cause for the Process FMEA.
OCCURRENCE RATING
 Occurrence is the likelihood (probability) a specific cause will result in a specific failure mode under Current Controls.
 A relative rating scale of 1 to 10 is used.
 Only methods intended to prevent the cause of failure from occurring should be considered here; failure detecting measures are not
considered here.
 In addition to considering current controls we should examine the following:
Process maturity and stability
Similar processes
Significant changes from previous processes
Significant difference in parts being processed
State-of-the-art technology
14

CADmantra
PROCESS FMEA
Evaluation Criteria:
If a process is under statistical process control or similar to a previous process under SPC, then the statistical data should be used to determine the
probability of occurrence.
Techniques such as dock audits and historical data such as warranty information on similar products should be used to estimate probability.
OCCURRENCE RATING TABLE
Rating
Qualitative Approach Quantitative Approach
Possibility of failure Possible Failure Rate Cpk
1 Remote: Failure unlikely. No failure ever associated with
identical process
1 in 1,500,00  1.67
2 Very Low: Only isolated failures associated with almost
identical processes.
1 in 150,000  1.50
3 Low: Isolated failures associated with similar processes. 1 in 15,000  1.33
4 Moderate: Generally associated with processes similar to
previous processes which have experienced occasional failures,
but not in major proportions
1 in 2000  1.17
5 1 in 400  1.00
6 1 in 80  0.83
7 High: Generally associated with processes similar to previous
processes, which have often failed.
1 in 20  0.67
8 1 in 8  0.51
9
Very High: failure is almost inevitable
1 in 3  0.33
10 1 in 2 < 0.33
CURRENT CONTROLS
 Enter Current Controls for each Potential Cause of Failure under consideration.
 Current Controls are those controls that either prevent the failure mode from occurring, detect the failure mode should it occur or reduce the
impact of failure effects.
 Inspection/testing to detect the subject cause from resulting in a failure mode may occur at the subject operation or at subsequent operations.
15

CADmantra
PROCESS FMEA
Examples of Current Controls are:
Mistake Proofing Statistical Process Control – SPC
Design of Experiments – Process DOE Equipment/Machine Tolerance Build-up Study
Process Capability Study Gauge Repeatability & Reproducibility Study
SQA Approval Production Validation, Functional Test
DETECTION
 Detection rating is an assessment of the existing controls, to identify any potential failure mode or potential failure prior to occurring, or
“prior to shipping out the product.”
 Assume the design weakness is present and evaluate the capabilities of the current controls to detect and prevent the failure mode to be
released for production.
 To receive a better rating, generally the current control must be improved.
Rating Qualitative Approach Quantitative
Approach
Detection
1 Current controls almost certain to detect the failure mode. 1/ 10,000 Almost Certain
2
Very high likelihood current controls will detect failure
mode
1/ 5,000 Very High
3 High likelihood current controls will detect failure mode 1/ 2,000 High
4
Moderately high likelihood current controls will detect
failure mode
1/ 1,000 Moderately High
5
Moderate likelihood current controls will detect failure
mode
1/ 500 Moderate
6 Low likelihood current controls will detect failure mode 1/ 200 Low
7
Very Low likelihood current controls will detect failure
mode
1/ 100 Very Low
8 Remote likelihood current controls will detect failure mode 1/ 50 Remote
9
Very remote likelihood current controls will detect failure
mode
1/ 20 Very Remote
10
No known controls available will detect failure mode
1/ 10
Almost
Impossible
16

CADmantra
PROCESS FMEA
RISK PRIORITY NUMBER (RPN)
RPN = Occurrence Rating x Severity Rating x Detection Rating
 The RPN is a weighted assessment number used for prioritizing the multi-effect of Occurrence, Severity, and Detection.
 The RPN focuses our effort on factors which provide opportunity to make the greatest improvement (RPN is similar to the Pareto Analysis
Principle).
 Risk assessment should be performed to determine when corrective action is required. The following table shows extreme cases when corrective
action must be taken.
RISK PRIORITY NUMBER (RPN) TABLES
Assessment Rating Action
O S D Cause of Failure Taken
1 1 1 Ideal situation (Goal) N/A
1 1 10 Assured mastery N/A
1 10 1 Failure doesn’t reach user N/A
1 10 10 Failure reaches user Yes
10 1 1 Frequent failures, detectable, but costly Yes
10 1 10 Frequent failures, reaches user Yes
10 10 1 Frequent failures with major impact Yes
10 10 10 Trouble!!!!!! Yes
We will not establish an absolute number where the RPN will require action. Each RPN must be treated on an individual basis.
17

CADmantra
PROCESS FMEA
RECOMMENDED ACTIONS(S)
Action which influences the Process FMEA Risk Assessment
Corrective Action O S D
1 Redesign the Product Yes Maybe Yes
2 Improve Current Control Maybe Maybe Maybe
3 Change material parts No No Yes
4 Change the application Maybe No Maybe
5 Change the field environment No Maybe Maybe
6 Improve Reliability Program Yes No Yes
7 Improve Employee Training Maybe No Yes
8 Implement FMEA program Yes Yes Yes
9 Implement SPC program Yes No Yes
10 Improve Quality plan Yes No Yes
 When failure modes have been rank ordered by RPN, corrective action should be first directed at the highest ranked concerns and critical
items.
 The intent of any recommended actions is to reduce the severity, occurrence and/or detection rankings.
 If no actions are recommended for a specific cause, then indicate this by entering “None” or “NA” in this column.
RESPONSIBILITY
 Enter the individual responsible for the recommended actions, and the target completion date.
18
18

CADmantra
PROCESS FMEA
How FMEA Objectives Have Been Realized
Use in the earliest stages of product and process design, FMEA’s will have benefited us in the following ways:
 Minimize the probability that the product will fail in the market place.
Pro-active analysis to identify and test for potential design weaknesses.
Focus on high-risk areas of design and process (RPN and severity).
Structure method of defining process control.
 Mistake proofs a design and process from both a functional and manufacturability standpoint.
Drive product design to reduce probability and severity rating.
Drive process design and process control methods to reduce probability, severity, and detectability ratings.
 Help insure the product meets life expectancy goals.
Product FMEA probability ratings tied into component reliability assessment.
FMEA review meetings will help identify design for manufacturability issues.
 Provide a basis for the test program during development and final validation of the design.
Weaknesses in test program will be highlighted by high detectability ratings and resolved through documented action plans.
 Provide basis for quality control program.
Process of rating design and process FMEA items will assist in the identification of critical characteristics.
Process FMEA ratings will assist in the development of gaging requirements and the need for mistake proofing.
 Document design and process considerations for future reference by new personnel not familiar with the design and/or, analysis or decisions
regarding design or process changes.
FMEA documents maintained in central file would be available as reference for all personnel.
 Prove due care was taken in the product design- litigation issue.
FMEA documents identify potential failure modes and their severity, and reflect actions taken to resolve them.
 Promote a better understanding between engineering disciplines.
FMEA review meeting provide for the exchange of ideas and concerns from all engineering disciplines.
 Reduce the number of product changes that are required to fix design or process problems.
FMEA activities undertaken at the correct point in the design cycle will allow for the identification and correction of design weaknesses
prior t o production.
 Provides a basis for continuous improvement.
The concept of RPN allows engineering to rank order the concerns of the product and process design, and identifies improvement.

Process fmea work_instructions0

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to Process fmea work_instructions0 (20)

More from CADmantra Technologies (20)

Recently uploaded (20)

Process fmea work_instructions0