Page 41 - MetalForming March 2023 - PMA Chairman Jeff Aznavorian
P. 41

 New Die Steel
Reduces Wear
on Form Details
     ...for this Indiana automotive manufacturer, prolonging tool life between sharpenings and reducing the amount of sharpening needed during maintenance.
 BY BRAD F. KUVIN, EDITORIAL DIRECTOR
Stamping locking mechanisms for automotive applications—locks on doors, trunk lids, tailgates and the like—can punish tooling, in particular form tools, as these mechanisms com- monly are stamped from Type 4130 Cr- Mo steel. These steels, heat-treat hard- ened, have a 670-MPa yield strength and a 92 Rockwell B hardness, ideal properties when machining drill bits and taps or for fabricating rock-crushing machinery. But try to form them in stamping presses and the form steels can become suscep- tible to premature wear.
Such has been the case at locking- mechanism manufacturer Gecom Corp., Greensburg, IN, which operates a variety of presses from 80-ton sin- gle-hit presses performing secondary operations, to 600-ton progressive-die presses. The 400,000-sq.-ft. Gecom facility employs nearly 500 people to supply several major OEMs consistent- ly and reliably. To help ensure that pre- mature die wear doesn’t negatively affect its ability to remain a preferred supplier, the firm recently upgraded its tool steel of choice for select form details to prolong life between sharp- enings, and to reduce the amount of sharpening needed during tool main- tenance. So says assistant tool and die engineering manager Jackie Bishop.
“We’re consistently innovating and trialing new tool-material types,” Bish- op shares, “rather than locking into a routine of constant repair and main- tenance, which our toolroom found itself in when relying solely on D2 or
DC53 tool-steel grades. We recently saw an opportunity to trial new die steels that not only have improved pro- duction-hit counts, but also decreased the maintenance and replacement times within the toolroom. We’ve enjoyed a lot of cost savings on the maintenance and repair side as a result, and any premium we’ve paid for the new form details has resulted in better profitability and better workflow within the toolroom and plant. The added investment has been easily justified.”
The Push for Maintenance-Friendly Tooling
Efforts to make its tools more “main- tenance-friendly,” says team leader Scott Davidson, led the firm, late in 2021, to trial form tools fabricated from two matrix-grade high-speed steel alloys—YXR7 and YXR33, exclusively distributed by Diehl Tool Steel, a Pro- terial Group company. Both grades, say Diehl representatives, prove ideal in tooling that requires high impact toughness and resistance to chipping.
After plenty of trial runs begun late in 2021 (using an aluminum-chromi- um-nitride tool coating), Gecom has found that YXR7 (0.8 C, 4.7 Cr, 1.3 W, 5.5 Mo, 1.3 V) performs best in trim- ming and forming applications. The firm has used the alloy for six trim punches and six forms, and on several additional small details.
“Our form details machined from D2 and DC53 tend to wash out pretty quickly,” says Davidson, “sometimes
after only 50,000 hits, and then require resharpening. With the matrix-grade tool steels, not only do we get 200,000 hits or more between sharpenings, but each sharpening only requires our machinists to remove 0.010 in. or so of material, a dramatic improvement from the need to remove as much as 0.2 in. of D2 material for sharpening.”
Blanking Tools Require a Tougher Grade
For jobs requiring optimum tough- ness—progressive-blanking tools— Gecom trialed YXR33 (0.5 C, 4.2 Cr, 1.6 W, 2.0 Mo, 1.2 V ). The performance has been stellar, the Gecom team reports, “outperforming a previously used pow- dered-metal tool steel by more than four to one,” says Gecom journeyman tool and die maker Kyle Land. “We’ve made well over 400,000 hits so far with that tool since the change without resurfacing. The tool holds three punch- es to blank out three parts per stroke.”
“We’ve been trialing the new steels for just over a year,” Davidson adds, “and the greatly improved performance has led to placing additional work orders with Diehl Tool Steel to try the matrix grades on other die details. The program has been a big hit so far, so we’re prioritizing the applications that we want to work on next.”
When the conversation turns to cost-justification, “the return on invest- ment is a no-brainer,” Davidson insists. “The grades are more expensive than D2 but not as pricey as S7; however,
38 MetalForming/March 2023
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