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22 PCB007 MAGAZINE I MAY 2021 money when it was running. Strict adherence to this simple axiom would have you running your machines at maximum throughput all the time, creating all kinds of problems. In- stead, we've learned that a machine should only run when it needs to, and not a minute more. is seems a minor change in thinking but applied to 90 processes on a 100,000 square foot manufacturing floor, this minor differ- ence changes how you operate. In this case, keeping the WIP (work-in-progress) on the floor low, resulted in improved yields, shorter feedback loops, less stress for employees, and most importantly shorter cycle-times. An important indicator of a successful busi- ness is cycle time: the amount of time it takes between receiving an order and shipping an order. Cycle time is equal to backlog divided by throughput. For example, if you have 14,400 panels on your manufacturing floor at any giv- en time and you complete 720 panels per day, your cycle time is 20 days. By reducing your WIP by 20% or 2,880 panels on the floor, your cycle time just dropped to 16 days. Now you're shipping everything four days earlier than be- fore, giving your company a competitive edge in the marketplace. e ability to maintain a low cycle time is now a standard measure of operational excellence at Calumet because ev- erything must go right to maintain a low cycle time, from employee time and attendance to preventative maintenance on manufacturing equipment. Johnson: And to that end you made the sacri- fice on idle time? You're willing to have more idle time if necessary? Brassard: at's right. Since the machines in a multi-step process run at different speeds, it makes little sense to run any machine faster than the slowest machine in that process. Do- ing so would just cause a pile-up of panels, in- creasing WIP, and increasing cycle time. You need to go slow to go fast when cycle time is the measure of performance. e goal is to re- duce WIP as much as possible, with the best possible configuration being conveyorized sin- gle unit flow, reducing cycle times from weeks to days and days to hours. Traditional lines of thinking would have you hire an employee per machine, but this only feeds into the idea that all machines must be running all the time. e world class manufac- turing approach is to organize areas into "re- sponsibility centers," where a team of employ- ees is responsible for a set of machines for a process. e team runs the right machines at the right time and keeps WIP low and through- put high, yielding a minimal cycle time for that process. Line enough processes up that are each minimizing their cycle time and your fac- tory is minimizing overall cycle time. Also, processes organized in this way tend to require fewer employees and are more resilient to em- ployee absences since people can move around to fill gaps and go where help is needed. I mentioned this is counterintuitive. Typi- cally, it's the buildup of WIP in a department that creates a sense of urgency that pushes people to work faster and make mistakes. But with responsibility centers, the lack of WIP reduces pressure caused by pile-ups of work, eliminates the time to find the next job, min- imizes unnecessary handling, speeds up qual- ity feedback loops, and improves yields. We have, however, found there is such a thing as too lean or too little WIP where a department runs out of work all together. In this case, em- ployees need to go to another department that An important indicator of a successful business is cycle time: the amount of time it takes between receiving an order and shipping an order.