PFMEA for Phosphating Process

We are preparing the PFMEA for our one product in which phosphating is recommanded. We don't know anything about phosphating. Can anyone help me or give some example of Phosphating Failure Mode.

bhartigambhir said:

We don't know anything about phosphating.

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I assume that you are outsorcing this part of the process, then? If so, I suggest that you enlist the help of the supplier for this part of your FMEA.

bhartigambhir said:

Can anyone help me or give some example of Phosphating Failure Mode.

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Well, for starters: How about phosphating layer too thin, too thick, uneven or not covering the entire surface?

/Claes

There is also chrystal size (too large/too small) and poor adhesion.

prototyper said:

There is also crystal size (too large/too small) and poor adhesion.

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Absolutely! (...although difficult to measure without SEM). Also, control of the bath chemistry, BUT equally important - if not more so - is control of the washes and rinses prior to the phosphating!!

bhartigambhir said:

We are preparing the PFMEA for our one product in which phosphating is recommanded. We don't know anything about phosphating. Can anyone help me or give some example of Phosphating Failure Mode.

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I second Claes' advice to work with the supplier on this. What you need to do, if you're unfamiliar with the process, is consider the reasons for the coating (corrosion resistance, lubrication, providing a base for paint, etc.) and determine the potential failure modes of the supplier's process that could affect design intent.

I would suggest that your supplier create the process FMEA since it is their process. They own it and your company doesn't. You can contribute with failure modes from a customer perspective but the process changes, controls, etc. are a supplier's responsibility.

If they don't know how to create an process FMEA, it would be mutually beneficial that you participate in their initial FMEA but with more of a training perspective.

If you continued to develop a process FMEA on your own, it would be more customer show than value.

David DeLong said:

I would suggest that your supplier create the process FMEA since it is their process. They own it and your company doesn't. You can contribute with failure modes from a customer perspective but the process changes, controls, etc. are a supplier's responsibility.

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Might want to share the DFMEA criteria. What is the point of the phosphate? Pass through SC's.

Thanks, everyone for your valuable suggestion. Actually I had asked to our supplier also but they are on very small level so they told me where they fails but in technical langauage want to know what are the failures normally have this process

What type of phosphating process do your supplier use? Is it a dip process or a spray process? The failure modes are slightly different.

Also, it may help to think of the effects that could be seen in the finished coating then work backwards.
Consider poor corrosion resistance and poor adhesion. Ask your supplier what phosphate condition could lead to this, what in their process could cause this and what controls they have in place for each failure mode they suggest.

PFMEA should be a collaboration of expert opinion. Your suppliers are the expert in the phosphating process, but if they are not familiar with PFMEA it will be down to you to ask the appropriate questions to get the necessary information out of them.