Guidance for Developing Inspection and Test Criteria

[Davey]

I work at a facility that is manufactuing an implantable medical device. Manufacturing consists of building a number of sub-assemblies then combining these sub-assemblies into the final assembly.

One area that requires improvement is inspection criteria. There are numerous in-process and final inspections included in the overall manufacturing process. However, the inspection criteria have not been very well defined or written. For example, an inspection may require confirming the dimensions of a sub-assembly, but not ensuring the sub-assembly actually does what it is supposed to do.

I would like to begin this project by developing a guideline for writing inspection criteria. Obviously, the critieria have to be appropriate the item that is being inspected, but having some general guidance for developing the criteria is necessary. The guideline can then be used for identifying and selecting the critical items to be inspected at each inspection.

So far, I have come up with the following broad categories:

- visual (inspect for obvious damage, dirt, workmanship, etc.)
- dimensional (confirm critical dimensions by measurement or fit check)
- functional (make sure the thing does what it is supposed to do)
- documentation (including labelling)

Does anyone have any suggestions, ideas or comments on developing inspection criteria?

[counj3fl]

Good question!! As I read the scenario one important critical factor that would not leave my mind was whether the team (or individual) conducted an FMEA (failure mode effects analysis).

This is a process approach used to identify inspection criteria but more importantly the team involved with product design/development and manufactiure identifies the risks, the liklihood of occurrence, rate the effects numerically (considering costs and benefits). Also, based on any needed risk reduction, brainstorm ways to reduce the effects of those risks.

FMEAs are an analytical approach and take more time but the greatest value is you make informed decisions on what should be inspected (what's critical) and what does not. Also it gets all the key players involved upfront who will be involved later in dispositioning any non-conformances.

Hope this helps! Let me know if you help locating resources on the FDA.gov/cdrh device guidance website.

counj3fl

[Rick St]

During the design stage of the project, a list of design inputs should have been developed (often called the product specification). From this set of requirements, you should be able to develop test and inspection criteria that allow you to verify the design requirements. What kind of qualification testing was performed? Checking the qual test information may also lead you to test and inspection criteria and methods.

[Davey]

Thank you both for your suggestions.

If I may, I think I can summarize your observations by stating that the inspection criteria should be a logical outcome of rigorous and documented design, verification, validation and risk assessment processes.

I agree entirely and thank you for pointing out what should have been obvious to me.

However, the necessary process have either not been implemented or have been poorly implemented. Therefore, trying to develop the inspection criteria without having done the necessary background work will be difficult and may not achieve the desired results.

Time to go back to the drawing board....