Page 37 - MetalForming April 2013
P. 37
The blanking-line operator control panel controls the press, die clamps, scrap convey- ors, loop pit table, light curtains and some features of the leveler. It also displays the various pneumatic and oil pressures.
“While most of the steel we blanked in 2011 was less than 0.280 in. thick,” says Marko, “beginning in October 2012 and continuing into 2013 a lot of 0.400- in.-thick high-strength 80-ksi yield- strength steel, 70 in. wide, will run through our blanking operations.” Plac- ing the job at the high end of the tough- ness scale: coil width ranges from 12 to 75 in. wide. The wider coils allow the customer to feed the wide blanks directly into their big-bed transfer presses.
To equip the blanking department to handle the wide coils of high-strength steel from 0.050- to 0.400 in. thick, a multi-disciplinary team at Voss Clark repurposed an existing single-mandrel uncoiler capable of handling 80,000-lb. coils. The team then sent out a call for a shape-correction leveler (a Herr-Voss model) and a heavy-duty press (the firm rebuilt a 1000-ton Clearing). Then it sought a coil feeder that could stand up to the rigorous task at hand. Called to action: a four-roll servo feeder from Cooper-Weymouth Peterson (CWP), Clinton, ME.
Longer, More Accurate Progressions
The new feed (a model SMX78SE4) allows the firm to run much longer
progressions than its previous blanking line, says Marko, which it decommis- sioned when the new line came on board. “Now we can run a longer pro- gression (to 10 ft.) and still maintain the tolerances the customer demands” say Marko. “Previously, we had been limit- ed to a 3-ft. progression at the same stroke rate.”
While the firm has yet to run at the maximum progression, it has run a 40- in. progression. Coil stock feeds through the blanking press front to back, rather than through the windows, “to provide a larger usable bed size and coil width,” says Marko. “And, we can locate the feeder close to the tool— within 18 in.”
The Clearing press boasts a 72- by 108-in. bed and was upgraded with new Wintriss controls and Shadow light curtains. A new Allen-Bradley Power- Flex 700 AC variable-speed drive enables the press to run at variable stroke speeds. “Troubleshooting is sim- plified by having Allen-Bradley/Rock- well Automation controls oversee oper- ation of the entire blanking line,” adds Marko.
“We typically blank the 72-in.-wide coils of 0.400-in. material at automat- ed run rates now,” continues Marko, noting that each stroke of the press
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