Appliance Maker Follows a Trusted Quick-Die-Change Recipe

By Brad Kuvin, Editor
Article from November, 2013 issue of Metal Forming.

 

(Partial article. Use this link to read it in full): In 2007, the 30,000-sq.-ft. pressroom at the Sub-Zero and Wolf manufacturing plant in Fitchburg, WI, nearly doubled in production capacity. Welcomed that year: three Williams, White & Co. hydraulic presses (a 400-ton model and two 600-ton models), and a 600-ton Minster mechanical press with coil-feed line. It added the presses to support new-product introductions and to bring inhouse previously outsourced stamping work. “Those pressroom investments really strengthened our core competency in stamping and tool and die work,” says Jeff Soule, fabrication supervisor for the manufacturing facility.

All of the new presses came outfitted with the same die-load/unload and clamping quick-die-change (QDC) equipment originally specified on the firm’s existing hydraulic presses (300-, 600- and 900-ton models). QDC-system components, all Hilma equipment from Carr Lane Roemheld: hydraulically operated rollblocks; spring-return ledge clamps on the front side of each press; and hollow-cylinder-type T-slot clamps on the press backsides and upper slides. The hollow-piston cylinder clamps, according to Hilma literature, are designed to clamp dies on subplates with U-slots. With single-acting spring return, the cylinder’s spherical washer adjusts to irregular clamping surfaces.

“Hydraulic die clamping provides the safe yet quick die changes we strive for,” says maintenance superintendent Mark Long.” “We don’t have to worry whether or not the clamps are torqued appropriately, as we would with mechanically actuated clamps. Any chance for operator error is eliminated. We just have to program the required setpoints for the pressure on each clamp, and the press control monitors the hydraulic system to ensure we get the pressure we need.

“And, when we change dies,” continues Long, “proximity sensors at each clamp location sense whether the clamps are in their home positions. The system prevents a die from being opened until every clamp is ready, so we don’t open the die with one clamp still activated.”

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