LEAN MANUFACTURING
techniques can make huge improvements to your productiv- ity and profi tability, as Rable Machine (Mansfi eld, OH) has shown over the last 10 years.
The problem: “Too many jobs to keep in your head” When Scott Carter joined Rable as their president eleven years ago, the shop produced roughly 1700 unique precision parts. The parts were all relatively small (few bigger than a 3" cube) and came from a variety of industries, from oil and gas to aerospace, telecommunications, and medical. Production runs were mostly low-to-medium volume, with a wide mix of processes. There wasn’t any obvious grouping.
had a part that was run through a lathe, we would calcu- late how many run hours we had on that part in an average quarter. If we had another part that was a lathe-lathe-mill operation, we’d quantify those. We started adding these together and then added in factors like material and size. As we progressed, we even added the type of tooling we’d use for each job. In doing this we found that there were indeed certain mixes of jobs that fi t together.
The quarterly volume data also told us how much we
could group together from a capacity standpoint. This lead to a reorganization of the shop fl oor into different process family cells. So, for example, we could see that a lathe-lathe-mill cell would be fully occupied year round.”
Carter says that while some “no brainers” took little analysis and lead to the creation of the fi rst few cells within a year, it took about 10 people three years to get everything in place and optimized. That’s because aside from a few obvious cases, they didn’t really get a handle on things until they’d put every job in the shop into what they call a “process family code system.”
Typical parts produced at Rable for use in fl uid management systems, industrial automation, network power systems, climate control systems, oil and gas transmission, petroleum refi ning, and medical devices.
More importantly, Carter knew they weren’t as profi table as they could be. The shop was organized by department: lathes in a line here, mills there, screw machines over there, and so forth. Parts bounced around the shop based on the required machining steps. It was diffi cult to keep track of anything, though it was pretty clear time was being lost. It was equally clear that growth would add to the confusion without necessarily adding to the bottom line. Rable needed to change. Carter took his 20 years of lean experience and introduced “focused common sense.”
Categorize and Count The fi rst step into lean production was also the most
diffi cult: Categorizing each of the 1700 parts they produced. As Carter recalls: “Our fi rst attempt to categorize was to count the processes used by quarter. So, if, for example, we
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AdvancedManufacturing.org | February 2015
The code system gave them a way to describe each job by machine or cell number,
material, size, shape, whether or not it required live tooling, whether or not it required a subspindle, the specifi c type of machine required for the primary operations, and the type of machine required for the next operation. And because they could sort this database by each fi eld, they could quickly determine what part numbers could go together in greater detail. This lead them to further refi ne their cell arrangements and in some cases, to buy new machines. Moving the machines to create the cells was the easy part. The hard part was the engineering task of assessing all the parts.
What’s So Great about Cells?
When Rable organized the shop into groups of process capabilities that each produced expected part volumes, they eliminated all the hassle and time lost in moving parts from
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