One-Stop Die Shop Focused on Self-Improvement

March 1, 2013

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Lead times for the complex progressive dies designed, fabricated and assembled at True-line, Inc., La Crosse, WI, have dwindled by 50 to 70 percent in just the last few years. And when considering that the time required for design, specification and purchasing of die blocks and other components can carve out 2 to 3 weeks of that lead time, Trueline often has as little as 2 weeks to machine, assemble and try out new dies.

Change came to Trueline in form of a switch from 2D cad to 3D programming in SolidWorks. “We had to be capable of simulation,” Christopherson says, “and improve our design-review process. Now we draw, simulate (with FTI’s FastIncremental simulation software) and review on the computer using solid models. Once we turn the project over, responsibility for die fabrication and assembly shifts to a swarm of as many as 10 to 12 people working in the shop on a project simultaneously, rather than just one toolmaker.”

What’s enabled the 60-yr.-old company—also a supplier of molds, as well as a contract metal stamper and injection molder—to so dramatically streamline die and mold production? The firm’s director of tool manufacturing Dale Christopherson lays out its grand plan.

“We used to ask our staff of toolmakers (anywhere from five to 10, depending on market conditions) to manage build projects from start to finish,” says Christopherson. “We drew everything in 2D cad and a toolmaker would take the prints and run with them. He’d literally design on the fly, calculate bend allowances, determine clearances, etc. He’d also square his own blocks, order material, heattreat and so on.”

The plot thickened, as we all recall, when the market got tighter and drove down prices. Says Christopherson: “We had to change.”

Diversify is the Battle Cry

Also enabling Trueline to survive what’s been a challenging several years for most tool and die shops has been its ability to diversify. In 1981 the firm began providing contract stamping services; in 2009 it introduced injection molding, in part to bring insert-molding inhouse; and in 2010 it expanded its machining and assembly expertise to include mold design and build. Today its business is split 50-50 between die/mold production and contract stamping and injection molding. In 2012, Trueline produced 2.2 billion stamped and molded parts, Christopherson says, as well as 35 molds and 60 dies. “And of those 60 dies, 35 were for inhouse production, the rest for outside customers.”

Trueline recently added 3D multisensor metrology to its resume by commissioning this Optiv Classic 453 machine (from Hexagon Metrology) to its quality-control room. The machine combines a touch trigger probe, rotating and indexable probe heads and tool racks for stylus modules as many as six module positions, with a vision sensor with high-resolution color CCD camera. Measuring range is 400 by 500 mm, with a 300-mm z axis. Maximum workpiece weight: 60 kg.

The Trueline pressroom boasts some 20 presses, including high-speed Minster models and a brand new 200-ton hydraulic press (from Magnum Press, Jerseyville, MO) used to produce deep-drawn cans for the filter industry. Highlighting the toolroom equipment list is a trio of three-axis machining centers (Hurco models) and two CNC lathes (from Milltronics), including a 2011-vintage machine with an eight-tool turret and a bar feeder.

Working at the front end of the die design and build process are six designers—three times the number of designers working for the company just a few years ago. This is evidence of the transition to concentrate on the front end of the process in order to streamline the back end. On that back end are seven toolmakers—the same number of toolmakers employed in previous years, “while our die and mold production capacity has increased by a factor of four to five,” says Christopherson.

The firm employs seven Logopress seats, including one that enables toolmakers on the shop floor to review designs.

Looking Inward as well as Outward

Triggering much of the internal process improvements at Trueline is neither a designer nor a toolmaker. Credit, says Christopherson, goes to applications engineer Mitchell Johnson, “who maintains his focus internally, with the single-minded goal of improving Trueline. While everyone else here stays busy working on projects and maintaining focus on our customers, Mitchell only looks for s to help us work more quickly and efficiently.”

Mitchell assumed the firm’s self-improvement role in 2009, coinciding with its move into injection molding. Among his first (and most significant) process-improvement projects was tying together the firm’s design software to its cam system. “One of the biggest challenges we faced was communicating how to best fabricate specific die details. We asked Mitchell to develop a procedure for including design intent and machining requirements into our designs. Working closely with Logopress, he did just that.”

The result of Mitchell’s collaborative efforts with Logopress is the use of a fifth-place decimal on design records that indicates the process specified to fabricate a detail, “so that the toolmaker knows exactly what’s supposed to happen during die production and assembly,” says Christopherson. The firm’s cam program recognizes the extra decimal in the solid-model program and assigns the appropriate machining processes.

“This minimizes mistakes on the shop floor and further speeds the process,” Christopherson says. “Previously, our bottleneck was delivering a consistent flow of CNC programs to the shop, to keep our machines busy. Now, since machining processes are specified using our design software, that bottleneck has disappeared.”

What’s Mitchell working on now? “We recently acquired a combination coordinate-measuring machine (CMM) and vision system that will allow us to quickly and cost-effectively verify block dimensions,” says Christopherson, “for our internal needs and to streamline the repair work we do on die blocks for outside customers. Mitchell is learning to program the machine offline, using the solid models. We’ll be able to receive feedback in a more timely manner and perform quicker inspections, minimizing lead times.”

Production Lessons Passed to the Toolroom

As most stampers operating fully functional die shops know, much can be learned and applied to die design and build from actually running dies in production stamping operations. Trueline is no exception, and Christopherson shares a few such lessons learned.

“We build a lot of custom cams,” he says, “because we build so many small dies starved for space, and purchased cams often will not fit in our dies. We’re als trying to conserve space in the die to minimize the number of die stations. Based on our experience running the dies, we’ve learned numerous design tricks along the , as well as material-selection tips. The result has been the development of longer-lasting cams for ourselves and for our stamping-shop customers.

“For example,” Christopherson continues, “we’ve incorporated in-die lubrication of cams into several recent projects, to relieve press operators from having to apply grease. We can design and build the cams with an automatic lubrication system, or add an in-die lube station. Then we tie lubricant-level sensing to the press controls.” MF