The book on hydraulic toolholders list that they are fussy to set, fragile to operate and expensive to buy So why do many shops choose them over other holders that seemless demanding? This Chicago mold builder has good reasons for its choice.

GM Tool Corporation (Elk Grove, Illinois) manufactures plastic, diecast and compression molds. The company has been a custom mold builder since its inception in 1965. Its customers are involved in the medical, automotive, consumer products, appliance and computer industries.

The company also understands the production side of injection molding because, in addition to a stable of commercial customers, it also has its own molding division--called Sun Plastics. That company has been in business for 15 years.

A big part of the success of a custom mold shop is keeping itself ahead of competition. "That used to mean beating mold shops in the region," says GM Tool's plant manager Ken Moeller. "Today that competition is global."
For GM, the way to compete is to focus on the tough jobs. "The easy work goes overseas or south of the border," he adds. "What's left are jobs that demand the highest skills." So to play in this market, GM Tool, and companies like it, must not only be good metal cutters, they must also be heavily slanted toward engineering.

While Ken Moeller is responsible for the manufacturing side of GM Tool, his nephew Rick Moeller runs the engineering and programming. GM Tool has seen commercial demands and available technology change its approach to the business. The company has evolved an effective business plan that could be relevant to many other shops in increasingly competitive markets.

Taking Out Guess Work

For a custom mold builder such as GM Tool, the competitive edge flows from engineering. "Our shop is run basically with engineering," Rick Moeller says. "Data is crucial to development of the tools we build. Our design engineering is done on a Unigraphics platform. It also generates the tool path for our machines. Engineering and machine programming are critical skill areas for our mold shop."

The output of this strong engineering and programming focus is the ability to, in effect, automate much of the core and cavity machining. Of course, that means carrying the sophistication of the CAD/CAM system to the shopfloor.

DNC is the carrier of this information to the machine tools. GM Tool has been downloading programs to PCs for dissemination on the shop floor for almost 15 years. "We were very early into DNC," says Mr. Moeller.

Making molds is among the most complex metalworking applications. It involves numerous operations including, in GM Tool's case, high speed machining of cores, cavities and graphite electrodes for EDM.

Each of the manufacturing process steps depends on the accuracy of the preceding operation. "We try to look at the process as a continuum," says Mr. Moeller. "At each juncture we look at what is the best technology to bridge to the next step. Of course, as a custom molder, we don't get second chances. It has to work."

While this pressure to make it right the first time is often manifested in shops as conservative practice or a resistance to change from the known, GM Tool approaches the problem differently. To keep moving forward, but at the same time keep risk to a minimum, the company does its homework on a potential new tooling, process, or automation enhancement before it becomes integrated into the shop.

Good Tools Need Goad Toolholdors

To make sure the shop has confidence in its process, rather than letting the process be a limit on capability, GM Tool invests in good quality equipment. The hope is if everything is done correctly upstream, the actual machining of the mold is almost anti-climactic.

About 5 years ago, GM Tool invested in a high speed machining center to improve processing of graphite electrodes for the EDM operations. The company installed an OKK machining center and, because of high speed machining techniques, saw a huge reversal of what was once a bottleneck.

"High speed changed our entire electrode machining process," says Mr. Moeller. "We applied the Erowa modular workholding system to further automate this part of the mold making process. It has eliminated our need for manual EDM machines. All of our equipment is CNC with orbiting capability and other features to get the finishes demanded by our customers.

"Before getting into high speed graphite milling, we basically machined electrodes by hand or using laminates," continues Mr. Moeller. "The tool path for machining electrodes is downloaded directly from engineering. Now the operator has time during the machining cycle to perform other tasks. We have much more unattended machining time available with our high speed graphite milling operation."

High speed machining techniques are also applied to core and cavity production. The company has a Makino V55 for semi-finishing and finishing operations. Like the graphite milling system, automation of the metalcutting process frees up the operator for additional tasks.