Phil and Sandy -
To properly perform
FMEA, you need to consider WHAT you are evaluating - is it the Design of the product or the Process which makes it? FMEA is all about RISK MANAGEMENT.
Design and Process FMEA are very different in terms of what's evaluated - in a Design FMEA, you evaluate things from an engineering perspective and seek to ensure your requirements ARE DEFINED and ARE MET, or THE GAP between then.
DFMEA helps with taking high-level requirements and flowing them down component-level requirements - it also ensures that you've evaluated how requirements are fulfilled. It ensures that if you set out to design, say a ballpoint pen, that you don't end up making a pencil instead. For molding injections - this would be things like specified hardness, color, rigidity, density, shape, thickness, etc.
In a Process FMEA, you're evaluating the process's ability to carry out the design and the ways you could deviate from the specified design. Here you're analyzing things like maintenance failures (leaks, lack of equipment, equipment breaks), inspection equipment failures, people failures, mixups, supply shortages, supplier failures etc.
If you already have a solid product design, start with the
PFMEA - when complete, it will reveal a lot about your DFMEA.
Mark - your problems sound related to lack of a comprehensive rating scale, or one that is ambiguous enough to be meaningless.
To perform a PFMEA, start by:
1) Defining your processes - Scope, Inputs, Outputs; If you don't already have this documented, then do it. What are the boundaries of the process you're evaluating, what information/materials do you have to start the process, and what is expected when the process is complete. It's really good to be specific here - particularly with your outputs. Always reference internal specs where you can.
2) Define your RATING SCALE (I recommend 1-10 for Severity, and 1-5 for occurrence and detection) On a 1-10 Severity, 9 should always be Serious Injury or Death WITH warning (there is some detection), where a 10 would be WITHOUT warning (there is no detection). Send out the rating scale before having FMEA meetings
3) Pre-Plan your FMEA meetings with a defined time and set one person as the facilitator/moderator - above all other creative input, this person's main job during the meeting is to keep it focused and end on time. Start by allotting 30-45 minutes per process with the intent of being broad and complete like a sketch rather than a high-definition photo.
4) Dig up any internal / external customer complaints, nonconforming material, corrective actions, design changes, process changes, material changes, etc. and bring copies of them to your FMEA activity meeting - use them as inputs - and show how these actions affected the risk (by increasing or decreasing it).
5) Maintain your FMEA documents - they are a living and breathing document which rationalizes "The Way of Thinking" - Risks are OK, so long as you know what they are. When your team identifies new risks - add them to the FMEA - when you change the process - evaluate and update your PFMEA if you reduced or changed a risk and most importantly to ensure you haven't added new risks that went unnoticed.
You won't be able to correct your FMEA activities overnight - unless it's already done and just your rating scale needs an update or review. Other than that, it's an ongoing process that should be triggered by things like design changes, process changes, nonconforming material, management reviews, etc.
Please feel free to contact me privately if you need assistance - I have several forms that would help you if I knew your specific needs, and would be happy to help any way that I can.
Sincerely,
JayJay