Page 20 - MetalForming magazine • December 2022

Eventually that job moved to a pro- gressive die, so now Verwys and his team divide the prototype work between its two servo presses.
linkage combined with standard AC servo technology, along with dual tim- ing belts constantly monitored elec- tronically for motion and breakage, isolating the servomotor from direct load and shock. A linear glass scale
eccentric motion and prevents side load on the gibs.
“I laugh,” Verwys says, “as there only are three decimal places on the linear glass scale, but we regularly run the presses to a fourth decimal place, using our other measurement methods to dial it in. We find the press controls very easy to use. We’re engineers, not press operators, but we have no trouble dialing the press in.” MF
“From a prototyping standpoint,”
Verwys explains, “the ability to adjust
the ram speed and position on the fly mounted to the press frame monitors
is huge. We manually can drive the press down using the jog wheel at a very slow speed while reading full ton- nage. I can set the press height and drive down until I get the tonnage I am looking for, then read the press height, adjust the height by some amount so I can get to 180 deg., then automatically run from there. And, we’re constantly changing the press speed, from jogging down at 10 or 20 percent, all the way to 50 or 60 percent; we rarely run at full speed (85 strokes/min.). We’re almost always monitoring and watching what’s going on with the material at a very slow speed.”
Verwys also points out that com- pared to a conventional mechanical press, he has not had to shim the punches in the servo presses at all since they’ve been in operation. “That makes a big difference from a prototyping standpoint,” he says. “And, we have the 10-position programmable option— another plus when it comes to proto- typing as we can develop a complete press cycle and store the parameters for as many as 10 preset process steps.”
Verwys also speaks to the need for precision with the press, as his allow- able tolerances rarely exceed ±0.005 in.
Precision, Repeatability a Must
“If the press wasn’t repeatable, we couldn’t do what we’re doing,” he says, “which keeps us in the good graces of our customers. We’ve run thousands of parts in some cases for customers, and we have an extensive metrology lab here that will let us know if we’re drifting out of tolerance. But we con- stantly check the parts coming off of the servo presses and they prove them- selves on a regular basis.”
What makes these presses so accu- rate and repeatable? Per Komatsu specs, the presses feature a rigid toggle
slide position and ensures repeatable die-height consistency at the bottom of the stroke. And, a plunger guide sys- tem absorbs thrust load from the
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