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76 The PCB Magazine • July 2014 by Gray McQuarrie grayrocK & aSSociateS Why Removing Your Bottleneck is a Bad Idea c o l u M n solViNg dam Problems I received a number of comments about my column, Are Boringly Predictable Operations Possible? (February 2014). An argument repeat- ed to me again and again was, "We don't have a capacity problem! We have a sales problem! I have plenty of capacity!" To which I think, but do not say, "No you don't, otherwise you wouldn't have a sales problem." Let me give you an example. Let's say you have one LDI machine for building your HDI product. This machine is only utilized 40% of the time. The orders coming off this machine generate 80% of your profits. You would tell me, "Gray, we do not have a capacity problem at LDI." And I would likely be unable to convince you otherwise. Let's say you have a number of orders going through your shop that are not only HDI, but HDI quick-turn premium orders. If you complete these orders on time you will have revenue and profitability numbers for the month that will be record breakers. Then the LDI machine suddenly goes down. You have zero throughput for a week as the machine is repaired. This lack of a second machine, this ex- tra capacity, is going to have a negative impact on your current and future sales. You could say that isn't what you meant about not having a capacity problem—of course having only one machine for doing critical work is risky. Then why did you let the Lean expert strip you of all excess capacity in order to level load and balance the production line if you knew intuitively this would increase your risk? On a recent internet search, I found this: "Line balancing is leveling the workload across all processes in a cell or value stream to remove bottlenecks and excess capacity." The article stated, "Match the production rate after all wastes have been removed to the takt time at each process of the value stream." This is a very popular, yet insane thing to do. Some years ago I got into a discussion with a CEO about process bottlenecks. He asked what happens if you don't have any bottlenecks, because his operation didn't have one. I was speechless. The process that defined his busi- ness (it wasn't PCBs, but it is related to a popu- lar chip assembly option) had several machines where one machine fed another and then an- other in a connected one-piece flow, where a single job couldn't break the chain, with no ex- tra machines in parallel, and with everything proceeding downstream at the same time. The work in process (WIP) was extremely low. He didn't understand, with such a perfect, Lean, linear assembly line, why his business was strug- 76 The PCB Magazine • July 2014

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