Page 21 - MetalForming January 2011

Changeover Time Slashed from 40 min. to 15 min.
“Before upgrading the stacking sys- tem on the blanking press, we would hold a full run of blanks in inventory, because it took so long to change over the press from job to job,” shares Jeff Thomas, group leader/stamping and tool and die at Newman Technology. Thanks to a new two-out continuous- run stacking system (engineered by Wayne Trail Technologies, Fort Loramie, OH), the pressroom has no need to store blanks, says Thomas. “Instead, we now can inventory fin- ished stampings to help meet just-in- time unscheduled orders from our cus- tomers (the plant blanks full coils rather than inventory partial coils, and then stamps the complete run of blanks).
Newman upgraded the blanking- press stacking system when it was chal- lenged with producing a set of six blanks that comprised a large two-out tailor laser-welded door-frame blank ( TWB).
“We ran all six blanks (from 0.6 to 1.2 mm thick) each day and laser-welded them here,” Thomas says, “which meant six changeovers per model on the blank-stacking system
(at least) per day. So, it’s
easy to see why reducing
changeover time became
such a critical goal.”
Newman outsources large blanks for stamping one-piece door frames on its monster twin press (two 2000-ton transfer presses robotically integrated as a tandem line). Note the squared-off center section cut from each door frame—Newman repurposes that offal for other, smaller stampings.
installed a new belt conveyor on the end of the press that pivots up and out of the way.
TWBs Extinct,
but Benefits Remain
While the tailored blank design for door frames has been eliminated by Newman and replaced with the stamped and rollformed design, the
blanking-press stacking system con- tinues to pay dividends. The line toils at 110-percent capacity to churn out door-frame blanks. Its adjustable side guides (±30 deg.) and backstop safely and neatly handle the array of oddly- shaped blanks Newman stamps. Adjustments are made manually during changeovers; Thomas notes that Wayne Trail designed the system to accept an
Thomas credits what he refers to as a “simple and efficient stacking-sys- tem design” with allowing the pressroom staff to complete a blanking-line changeover in 15 min., compared to the previous 40 min. required for changeovers. (Adding a second bolster to the press contributed greatly as well). The system simul- taneously stacks blanks from the front and exit end of the press. To allow the blanking line to run pro- gressive dies, which it does at least once per week, Wayne Trail designed and
The 400-ton blanking press works overtime to provide blanks primarily for door-frame stampings to Newman’s pair of 1200-ton transfer presses. A simplified stacking-system design helps pressroom staff complete blanking-line changeovers in 15 min. The system simultane- ously stacks blanks from the front and exit end of the press. Driven roller conveyors move full pallets outside of each stacker at the same time that a conveyor on the opposite side moves new pallets into the stacking location, maximizing press run time.
upgrade to servo-motor adjustment, but can’t as of yet justify the upgrade.
Other significant stack- ing-system features: it was designed specifically to avoid dinging blank edges, to ensure precise alignment for TWB laser welding; and, a pallet-conveying system allows loading of perma- nent pallets on both of the conveyors outside of the stacker position. At each of the two stacking stations, a roller conveyor drives one of the pallets onto a driven roller conveyor mounted on a hydraulic lift. The lift rais- es the pallet up to the stack- ing position, and then low- ers the pallet as the stack builds, thanks to a sensor that detects stack height. A driven roller conveyor then
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