SPC…What’s the Point?

I am walking the production floor (going to the Gemba) to check out a few things for myself with a new client.  Going to the Gemba is a great tool for any leader because you will learn things about your operation that you can’t learn from your office or the conference room.

The purpose of today’s Gemba walk is to look for waste on one of the packaging lines.  It becomes apparent that there is quite a bit of waste at the filler itself because the weight control is not good.  Lousy weight control in food plants results in giving away more product than you should (the difference between the actual weight of a product and the declared weight on the label is give-away).  I look at the jar-to-jar variation then naturally turn to the Statistical Process Control (SPC) charts.  It’s quite clear that the average weight of the jars is well above the declared weight.  The filler needs to be adjusted to reduce the weights.  The Filler Operator approaches and tells me that she knows that she should turn the filler down but the machine is not capable of running any lower weights.

This reminds me of another Gemba walk with another client.  The SPC charts clearly show that the weights on this filler need to be adjusted too.  I ask the operator if she is familiar with the SPC rules.  She does not know what I am talking about even though they are printed on the control chart that she is filling out every 15 minutes.   She let’s me know that she has been here for almost a year and “knows when to make adjustments.”

These real events illustrate two issues that are all too common in today’s manufacturing plants and other work sites.

• Team members don’t have the tools they need to perform their job well:  The first operator knows that every jar she produces has waste because it is needlessly over-weight.  Yet she is unable to do anything about it.  What is the point of using SPC if you cannot do anything with the information?
• Team members don’t have the knowledge to do their job well:  The second operator thinks that her experience is enough to know when to make adjustments.  Yet we know that strictly following the SPC rules is the best way to keep a process in statistical control and to optimize the weights at your filler.  What is the point of using SPC if you don’t know what to do with the information?

The bottom line is that Lean Leaders don’t implement systems like Statistical Process Control unless their team has the knowledge and tools required to use them properly.  SPC is a great tool that is under-utilized.  Many food plants use it for weight control but it could be used to help control many key metrics.

Can you share an example of how SPC is used at your site?

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This article originally posted on Jimena Calfa’s On Quality blog.  Please check it out and  leave a comment below if you liked this article. You can also connect on LinkedIn, follow me on Twitter, subscribe via e-mail (right side bar), retweet, digg, or stumble this article.  You can check out my Facebook page and continue the discussion there as well.  Your feedback is appreciated.