Six Sigma

Millions of Dollars Saved in 60 Minutes

By Ron Pereira Updated on January 13th, 2011

Last night I told you the story of a measurement system analysis gone bad. Tonight, as promised, I’ll explain exactly what the issue was and how we solved it in around 60 minutes.

The Part in Question

Measurement Systems AnalysisThe plastic component in question measured approximately 4” by 2”. I’ve made a rough sketch of what it looked like (see picture).

The component was actually completely black in color but I’ve made it gray in order to point out some key characteristics.

Towards the corners of the part were two key features.

First, points “A” were a rounded black protrusion-like piece of plastic that stood up about 1/16 of an inch in three corners of the piece.

This is what the camera looked at when taking the actual measurements. The camera would first “zero itself” and then it would measure the distance of the three black protrusions from one other. From this the machine would calculate the X and Y dimensions of the part.

Next, points “B” were drilled out circles that were used the hold the part into the final product during assembly. These circles were ignored during the measurement process.

30 Minutes of Brainstorming

After we failed the MSA we all sat around a table and talked about what the issue could be. We felt sure that the actual measurement system was probably OK and that the problem had more to do with the measuring process itself.

So we started throwing out ideas… everything from the fixtures we used to the way the operator loaded the parts was discussed.

Then someone wondered if looking at the black protrusions was the best approach. This person’s theory was that the camera may be struggling to distinguish the difference between the black protrusion and the black frame.

After a few more minutes of pondering the idea of using the circles right next to the black protrusions was tossed out there.

The supplier’s engineer was skeptical. He didn’t think it would work. But after some old fashioned Texas hog wrestling (a figure of speech, no actual wrestling occurred) everyone agreed to give it a shot.

30 Minutes of Trystorming

Using the same 15 pieces and the same operators and a modified computer program we re-did the MSA in about 30 minutes. The difference this time was we used the drilled out circles instead of the black protrusions.

Once we had the data we re-did the analysis in our statistical software package. The result? We passed the MSA with flying colors.

Problem Solved

And that was that. Some simple experimentation coupled with both brainstorming and then trystorming solved a problem that had been plaguing this company for the better part of a year.  The best thing was we started in the morning and were done by lunch time.

We were also able to proceed with our DOE and optimize the injection molding process. Soon, the quality problems we were experiencing from this supplier completely vanished.  It was truly a win/win situation.

The key learning for me was that continuous improvement doesn’t have to take a long time. Problems can, and in my opinion should, be attacked and solved quickly.

It’s Time to Learn How to Conduct an MSA

Now then, in light of this story I thought it may be beneficial for me to explain exactly how to go about doing a measurement systems analysis. And that’s precisely what we’ll do over the next few posts.

So stay tuned and please forward this post to anyone who may benefit from this type of information by clicking the “Share This” button below.  From there you can email the article.

  1. Shareth

    October 31, 2008 - 8:33 am

    Thanks for writing this. I also have battled this problem with people claiming their gage is “calibrated” to some key standard. Look forward to next posts.

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