Tool Setting at the Speed of Light

Originally Published MPMN March 2003

PROFILE

Tool Setting at the Speed of Light

Noncontact laser unit slashes setup times

Zachary Turke

For many manufacturing operations, efficiently performing tool setup is critical for maintaining profitability. After examining its machine shop, Howmedica Osteonics (Rutherford, NJ; www. howost.com) found that it was no exception. The company uses roughly 1000 different tools to construct 4000 replacement hip joint components and saw that manual changeovers between jobs was hurting the bottom line. "It was readily evident that long setup times were killing throughput of our short-run jobs and rapidly increasing back orders," says manufacturing engineer Bob Mykytka. To overcome this problem, Mykytka constructed a flexible manufacturing cell that included a noncontact laser tool setter from Renishaw Inc. (Hoffman Estates, IL; www.renishaw.com).

"We wanted something similar to the flexible manufacturing cells used in the automotive industry, but that was obviously beyond our budget," he says. Undaunted, Mykytka set about building his own version of this expensive equipment.

The first step fell into place when he found a tooling pallet system in his company's storage room. This unit allowed quick pallet changeovers between jobs and provided a positioning repeatability of ±0.002 in. But he still needed a way to automate the tool-setting procedure, and for that, he turned to Renishaw's NC1 noncontact laser tool setter. "We were familiar with Renishaw's name and reputation for product support, so we purchased one for testing," explains Mykytka.

Originally designed for in-cycle broken tool detection, the NC1 tool setter also allows the setting of both tool length and diameter at normal spindle-cutting speeds. The component can measure tools anywhere along its 2-m laser beam, eliminating unnecessary movement and minimizing setup times. Evaluating utensils as small as 0.2 mm with a resolution of 1 µm, the component works by sending a visible beam across the tool path. System electronics detect when a tool breaks the beam, sending a signal to the machine's control system to instantly establish the position of tips, teeth, or cutting edges.

After installing the NC1 setter on the pallet system, Mykytka tested the new system to positive results. Standard job preparation time was reduced from 2 hours to 5 minutes, he estimates, a time savings that enabled the processing of $1 million worth of backlogged inventory. And though he had some initial concern over the NC1's ability to function in a harsh machining environment, he says that these fears were proven groundless by a continuous stream of air that flows through special apertures in the unit to protect its optics. "The NC1 tool setter is simple and reliable, right at home in the belly of a machine tool surrounded with coolant and metal chips," he says.

The company management was so pleased with the results that they made the system the standard equipment for manufacturing all but three of the department's 4000 jobs. They also ordered a similar setup for the company's femoral knee department. Here, the NC1 tool setter will be mounted on a robotic drill and used not only for tool setup, but also for broken tool detection. "If a drill breaks during a drill-and-tap routine and the machine continues, all the tools after the drill would also break," explains Mykytka. "A quick check with the NC1 between cutting routines will ensure that this does not occur," he says.

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