Feature Article Lean Manufacturing For The Job Shop
“Ninety percent of ‘lean’ is useless to us,” says Tricia Gerak, CEO of Canton, Ohio-based Precision Component Industries. Precision Component is a job shop specializing in high-end, low-volume, complex parts made from hard-to-machine materials. Much of the shop’s work, for example, relates to hardware for precision military systems. Lean machining tends to accept cycle time as a given, optimizing the surrounding process to minimize inventory and waste. Setup time reduction is an important component of this. However, for Precision Component, setup time is a given as well. Many of the shop’s jobs are short-run parts for which the setup has to be invented on the fly. For this reason and others, Ms. Gerak assumed that the disciplines of lean manufacturing had nothing to offer her shop. Then she attended a session on lean as part of a supplier seminar held by a major defense contractor. She posed questions to this session’s presenter. He was astute enough to perceive how her shop’s situation was different, and he interpreted lean principles for her in light of how a low-volume job shop might apply them. That conversation changed her thinking. “I realized I had to let go of my paradigm that lean didn’t make sense for the job shop,” she said. In fact, there was a part of lean that did make sense. Specifically, there was the other ten percent. Clearing The Aisles
However, there would still be fundamental change. One of the most striking examples is a move to a more lean approach to ordering raw material. The purchasing manager used to order stock as soon as the production order was received from the customer. The perceived advantage was that the shop would have the stock on hand “just in case” it had a chance to run this job. Pallets of raw stock crowded the aisles of the shop floor. Today, the aisles are clear—but that means they are also clear of this reassuring visual evidence of the shop’s backlog. Employees wondered: Does the shop still have plenty of work?
Absolutely yes, the Geraks explained. They went on to explain the reason for the change—a reason they now see as common sense. In the past, the shop had not stopped to consider just how much money it was spending to own and store that material. Today, the plant manager and the purchasing manager coordinate their actions. Material is ordered no earlier than two days before it is needed. As a result, all of that capital that used to be tied up in raw material is set free for a more productive use, such as investing in additional tooling and equipment. “I Had To Go Find X”
In analyzing how shopfloor personnel spent their time, a common theme emerged. To account for one instance of a job running long, the operator said, “I had to go find the right gage.” In another case: “I had to go find a toolholder.” Operators were walking the shop floor in search of the tools, hardware and accessories they needed. The solution to this problem was to purchase more of all of these items so that whatever operators needed could always be close at hand. The Geraks now stress this important point to employees: Whatever you are looking for is not as valuable as the time you spend looking for it. The appearance of frugality can be deceptive, they say. When the shop acquired its most recent machine, a used Mazak Integrex 50 multitasking machine able to run workpieces as long as 100 inches, the management decided to buy new toolholders that would be dedicated to it. Employees questioned the need because there seemed to be enough toolholders in the shop. However, it would be far less expensive in the long run simply to have plenty of toolholders, Ms. Gerak says. She adds, “If I can spend $1,000 on tooling to save 30 minutes per day of walking around, then that is easily worth the expense.” In fact, because they are not searching, employees now have time they didn’t have before. While the machines are running, they can now stage the next job and the job after that. Staging jobs in this way ultimately revealed another shortage that was leading to waste. Operators were walking the floor searching for the belted straps that wind around large workpieces so the crane can lift them. The shop was short on straps—a simple, low-cost item. Employees spent labor cost on looking for straps because looking around was such a common part of the shop’s practice. Now, the shop has decisively remedied this problem simply by purchasing many more straps for the shop floor.
Move To Multitasking
Many production facilities would not see a multitasking machine such as this as being consistent with their application of lean manufacturing. One station where a lot of machining is performed could be seen as a “monument”— a place where parts queue because batching is necessary to hold down the unit cost of this work. For established parts in predictable production, a series of simple stations can often avoid this work-in-process inventory. However, that doesn’t describe Precision Component. Many of this shop’s jobs involve short runs of complex parts that were unknown to the shop just days prior. Batching these jobs isn’t a danger—the quantities are too low. Running jobs such as these in one setup on a multitasking machine has proven to be much more efficient than setting up the part first on a lathe, then on a machining center. Thanks to the shop’s growing reliance on multitasking, machining centers now run just one shift instead of three. More Multitasking The result could be thought of as lean manufacturing from the customer’s perspective, because the customer’s ordering process has become much more streamlined. Instead of making separate expenditures for separate manufacturing steps, Mr. Gerak says this customer can now obtain the fully manufactured product for just one line item on a purchase order. |
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