MSA Requirement for PPAP - Where to Start?

[Kurt Smith]

Apologies for this being a fairly common question, but in my researching and reading through posts I haven't found a solid answer for this question.

My company has never performed a MSA. We are only certified ISO 9001 but work as a secondary supplier for automotive parts. As we are working to get bigger and bigger jobs, we have started working on PPAPs. It has been a steep learning curve and Elsmar.com has been invaluable to me. Now as we are getting to the deadline for our largest PPAP submission our customer is asking for our MSA for all tools used. In the small mountain of learning and preparation for this, MSA was overlooked. I assumed it would be a document we prepare similar to PSW. Now upon researching further I am learning that it is much more intensive, and is a long form improvement process rather than a simple document built for PPAP.

We are a small shop, and currently I am serving as both QM and the only inspector. (With plans to add a dedicated inspector by the end of the year) We operate with simple inspection tools like calipers and height gages, with a small CMM arm for prove out / FAI. We use a 3rd party calibration service for inspection related tools. Are customer tolerances are always ±0.5mm and greater. We have 7 parts with this customer that will go high volume, but typically do low volume high mix parts.

My problem now is: Where do I begin? I have done a fair bit of reading both here and on the AIAG website/E-learning pages. So I am familiar with the terminology and have found spreadsheets to help calculate and analyze the data once collected. But I do not know which tests to preform for our needs. What study types are most required, or will I need them all? What is the minimum that can be used as a baseline and built upon later? It seems like once I can begin moving, we can maintain and add as needed. But with the deadline bearing down and so many details being new, I simply don't know where to begin. Any advice would be appreciated.

 

[Scanton]

When submitting a PPAP I include MSA studies using the templates attached for each measurement device used (NOT every feature).

I take a measurement device like a 0 to 25mm Digital Micrometer and select a feature of the component that the micrometer is used on and select 10 components with a bit of variation (within specified tolerances) and number them 1 to 10. (see Digital Vernier template attached)

I then have three people say myself, the setter and the operator measure all 10 components once 1 to 10, once at random, and once 10 to 1 ensuring they can’t see the previous results and in that sequence so that they don’t try and remember the previous measurements.

Once I have this data I place it into the template for inclusion in my PPAP.

If I use a micrometer, digital calliper, projector, and height gauge I would create an MSA study for each one.

If I am using attribute gauges like plug/pin gauges or thread plug/ring gauges I would use a different attribute gauge template (see Plug Gauge template attached)

The templates include some data as an example however if you want to validate the attribute data template to show that it is functioning as it should, create a copy and enter the example data from the MSA manual, and you should get the same/almost identical results.

There are many here with much more knowledge than me on this subject that I am sure also have much valuable advice to give, however I have submitted many hundreds of these to many customers over the last decade+ and not had any complaints or arguments.

 

[Miner]

MSA is a broad, umbrella term that covers multiple types of studies:

• Bias (covered by calibration)
• Linearity (covered by a well designed calibration system)
• Stability (only required for tight tolerances and/or measurements affected by ambient conditions)
• Repeatability & Reproducibility (expected in PPAP for all critical/significant characteristics on your control plan)

I recommend that you read my MSA blogs for more details, particularly Intro MSA Parts 1 through 5b, and Advanced MSA Part 4.

 

[Golfman25]

First you need to have the AIAG blue book on MSAs. That will give you the ”instructions“ the auto people are looking for. Second, look at your customer requirements and determine if they require anything specific.

Absent any specific requirements, I would just start with a simple gage R&R. You’ll need one for each feature of the part, unless you can limit to critical features. A bottle of Vodka will help. Good luck.

 

[Kurt Smith]

Ok. It looks like I will be starting with a GR&R using the template Scanlan recommended. Is it expected that there is one GR&R per tool? Or for each part? Or each feature?

 

[Scanton]

In my experience, that is dictated by the customer so ask them directly as they can have specific requirements.

I know there are many things stated in the MSA manual (and yes I would take Golfman25's recommendation and purchase the AIAG blue book on MSAs) however most of my customers just want an MSA study for each measurement device used on the component selecting one feature that the device is used on.

So if you were using a digital calliper, 0 to 25 Digital Micrometer, 25 to 50 mm micrometer, Projector and a surface tester they would want one for each of those 5 measurement devices, however as I said please previously "talk to you customer and find out exactly what they want" or you could find yourself doing many many hours of work only to find you have to repeat it to include a specific requirement you missed first time around.

Best of luck and please let us know what they say and how you get on.

 

[Golfman25]

Ok. It looks like I will be starting with a GR&R using the template Scanlan recommended. Is it expected that there is one GR&R per tool? Or for each part? Or each feature?

You have a part you are going to measure. Say it has an OD, 3 IDs and a thickness. You'll generally need a gage R&R for each feature. So the OD, measured by a caliper, for example. One of the ID's measured by a caliper. And say the thickness measured by a micrometer. Technically, I suppose you should match the tool to the R&R, but we don't as they are replaced regularly. A lot will depend on how critical your measurements are. You can then use those R&Rs for similar parts in the family.

 

[Benboaz98]

From my experiences in automotive industry, MSA study for PPAP focuses only on equipments that are used for checking special characteristics in mass production. For example if you use the caliper to check one or more special/critical characteristic of a part then you will do MSA only this caliper for each SC or CC mentionned on the drawing or technical specification of customer.

 

[GagetechKLC]

I have a question about Gage RNRs. There is an entry called % Tol. What is an acceptable percentage for that? I suspect this how much variation takes up the tolerance

 

[Bev D]

So this is a very deep topic

In general if you use the AIAG method 10% is acceptable without concern and 10-30% may be OK with rationalization. The method does talk about % tolerance as the amount of the tolerance that the measurement ‘consumes’ of the tolerance. Of course if you know anything about math you know that’s a crock of