Putting a label on metal fabrication

At Micron Metalworks, the tools needed for machine changeouts are labeled clearly for quick retrieval.

Steve Jaeger shook his head and pointed to a tooling cabinet next to the turret punch press. Other tooling cabinets around him had clearly printed labels—but not this one. “I’ve got to label those drawers.”

Jaeger is all about labels, in the literal sense. At Micron Metalworks in Ham Lake, Minn., northwest of Minneapolis, Jaeger knows how to operate various machines, but he spends much of his time making sure other operators can do their jobs as efficiently as possible.

Jaeger is a spider. The term comes from water spider, lean manufacturing speak for a material handler. “Material handler” doesn’t really do his job function justice, though. He prestages material and tooling for operators so that they have everything they need to set up their machines. Shorter setup time ensures that machines are producing parts and not just waiting for tools, a part program, or materials.

Micron Metalworks is a classic precision sheet metal job shop, with short runs and numerous job changeovers. In early June the company hosted a shop tour for participants of LeanFab, a lean manufacturing seminar sponsored by the Fabricators & Manufacturers Association. During one session, continuous improvement consultant Dick Kallage, principal at Barrington, Ill.-based KDC & Associates, made a good point: “You’re not in the sheet metal business. You’re in the setup business.” High-mix, low-volume manufacturers must move small batches of parts quickly from one process to the next, and that can’t happen with long queue and changeover times.

Micron President Ed Kittelson told conference attendees how his 60,000-square-foot, $10 million-plus job shop started down the continuous improvement path first by just cleaning up the place. Employees got rid of material, tools, templates, and equipment that hadn’t been used for five years. Then, in the middle of 2008, business picked up in a big way, but accounting wasn’t showing the expected results. The receivables equaled the payables. That wasn’t a good thing.

The culprit: Work-in-process was everywhere, eating up cash. “We had 40 jobs on the floor just sitting and waiting,” Kittelson said. “There was a box full of parts that I knew took only 20 minutes to make, but it had been sitting there for two weeks.”

Most WIP was for jobs that weren’t immediately due. Like in many shops, operators overproduced to avoid setups. If a customer ordered 20 parts every two weeks, why not produce 80 parts to cover the next two months? When operators think like this for every job, of course the WIP piles up at the bottlenecks, which at Micron included the deburring operations.

For years they had been seeing the forest for the trees—or the shop for the sheet metal. Kittelson recalled the day he approached his plant manager, Greg Engen. “I said, ‘Listen, Greg, we’re going to shut down the lasers and turrets until that’s cleaned up. It doesn’t make any sense to burn electricity and use up material if we can’t get it through deburring.’”

They soon pushed their 5S efforts into high gear. Now they organize and label punch and press brake tools, and store them near the machines. They place press brake tools on movable racks so they can be wheeled into place when needed. To minimize on-machine programming tweaks and overall press brake setup, they program and simulate bends offline at a workstation a few feet away from the brake department.

Press brake operators also use a portable hardware insertion machine, which is on wheels. This helps when a part needs hardware inserted in the middle of a bending program. So instead of making, say, two bends for a batch, walking the 75 steps to the hardware insertion area, then 75 steps back to complete the forming operations, the operator now makes two bends, turns to the adjacent hardware insertion machine, then turns back to finish forming the part—virtually no steps required.

Previously employees had good reason for wanting to overproduce to avoid setups. When Micron’s improvement team started videotaping employees, they realized what arduous affairs setups were. In one instance, a punch press operator spent about 45 minutes setting up a job, and what took the most time? It wasn’t setting up the punch machine itself—Micron has modern equipment with advanced software—it was finding the right tooling and, especially, material. The raw stock area wasn’t organized well, so machine operators spent much of their day going on material hunts.

The company invested in tooling cabinets for its punches. These cabinets aren’t cheap, but they were worth the investment. Perhaps the lowest-hanging fruit goes back to what Jaeger pointed to during the LeanFab shop tour in June: clearly marked labeling and work instructions.

This relates to what Kallage called the “two-minute rule.” Job setup sheets and tooling locations should be so clearly marked that even someone who isn’t familiar with the operation can find the tools and materials he needs within two minutes.

As Jaeger and other spiders of Micron have found, those little labels can make a big difference. That’s why every material the shop has in its raw stock inventory now is color-coded. And at this writing, all the punch tooling drawers are clearly labeled too.

Why weren’t all drawers labeled in the first place? As Jaeger explained, he and other setup people in the shop know where the tooling is. They open those draws multiple times a day, so they took a tool’s drawer location for granted. Everything had its place, but only certain people knew where those places were. But what if Jaeger or other setup people aren’t around? Without clear labeling, how efficiently could someone unfamiliar with the operation get the tools to keep parts flowing?

Boiled down, such thinking relates to good shop communication. A job can’t move forward efficiently without it. And quite often the best communication is immediate and visual, be it a simple picture on work instructions or a labeled drawer.

As Kittelson said, “It’s the simple things that matter so much.”