SPC and Lean
Got a question yesterday from Eric Christiansen, my guest for episode #18 of the LeanBlog Podcast.
Can a company be considered a lean company if it does not use some method of statistical process control?
I toured a manufacturing plant in a non-US, non-Asia country. This place had a very nice flow system, things were in their proper place and clear markings were available to show people where to put tools and other items. And while most of their competitors are focused on mass production, these guys have built a flexible production system that does one-off or small batch jobs and a really good price.
But as I toured the facility, one question that I asked them was do they use any kind of statistical method to know if their processes are in control? Or how well their machines are performing? Or when it is time to do maintenance because variation of the product output is increasing? The response to the maintenance question was “When the noise changes on the machine, we know its time to do maintenance.”
I’ll be interested to see what your thoughts are on this.
My response follows (and I’m curious about your responses, click “Comments” to chime in):
I think you CAN be a “lean” company without SPC…. although it’s dangerous to say who is “lean” or “not lean” as if it’s a binary construct. SPC is a tool. I think if you have a continuous improvement philosophy of PDCA without SPC you are “more lean” (again, I hesitate to say that) than if you have SPC without the right mindset.
We used SPC, badly, at GM, because the managers wouldn’t listen to the charts. If something was out of control, but in spec, you had to keep running. That was frustrating to the line workers (who cared more about quality than management at times) and it was frustrating to me. I’m sure you would say, in my example, they were keeping the SPC charts, but they weren’t “doing statistical process control.”
Listening to the machine or monitoring it by “gut feel” is a pretty common thing and I’ve heard that described as part of TPM methodologies, that you should be so intimately familiar with the machine that you know when it’s going bad. But, that “gut feel” isn’t very standardizable or transferable. Personally, I’d worry about relying on that the same way I’d use kanban instead of relying on a person who knows when to order by “gut feel.”
Everything else you describe about the system sounds and smells like “lean,” the methods at least. The philosophy is much harder to gauge.
Again, what do you think?