Page 26 - MetalForming September 2015

Servo Transfers
time became more and more of an issue. And even with the rebuilds, speed eventually suffered.
Floor-Mounted Servo
Transfers Add Speed, Flexibility
The transfer challenges were such that in 2009, Ford embarked on a replacement program, swapping out the old with new floor-mounted elec- tronic transfer feeds (ETFs). Linear Transfer Automation, Barrie, Ontario, Canada, replaced all five, beginning in 2010, with the latest ETF entering pro- duction this past July.
As was the plan, the new transfers have brought greater speed and increased flexibility to the press lines at Ford Flat Rock.
“The new ETFs are offering 35-per- cent improvement over the mechanical transfer systems,” says Sparkes.
Critical to upping transfer speed with the ETFs is the ability to add motion range profiles.
“For example, at Flat Rock, the old transfers performed big, square moves ...basic motions,” explains Paul Stir- rett, vice president of sales for Linear Transfer Automation. “On one of the lines, the old transfer only could pro- vide 350 mm of lift, and Ford asked for 400 mm. We added that, which proved essential for new dies coming in for Mustang production.”
Such an increase in range assists as Ford adjusts motion profiles.
“Instead of the big, square moves required with the old mechanical trans- fers, the ETFs can round out curves,” Stirrett says. “With electronic servo- operated movement, we can round out the lift, grip and pitch motions to allow a smoother motion profile when trans- ferring parts, which adds speed.”
Sparkes agrees.
“With electronic transfer, we can start to change profiles to increase jobs per minute,” he says. “The mechanical transfers limited us to in-out and up- down motions. With electronics, we can look for transfer shortcuts. For example, as the transfer rises, instead of performing a complete rise before any other movement, it can begin to
A Mustang fender exits a 2000-ton press at Ford-Flat Rock. The ability to smooth the transfer curve via simultaneous x-, y- and z-motion has upped strokes/min. during Class-A part production.
24 MetalForming/September 2015
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advance at the same time. We are look- ing for ways on each job to make the transfer stroke more efficient.
“As it is, electronic transfer is a little faster,” Sparkes continues, “and it takes some of the load off of the press. Where mechanical parts of the transfer had been driven from the same press motors that power everything else, we now can release some of that press energy for use only on the press and at the same time quicken the transfer motion.”
The ETFs also enable Ford, if it chooses, to add efficient pick-and- place motion to presses that never used such movement.
Unlike standard transfer motion where a transfer just enters to grab and move parts, pick-and-place trans- fer provides entry from the top, with suction cups grabbing and moving a part to the next station and the trans- fer lifting between the dies during the hit. Pick-and-place, according to Stir- rett, typically occurs at Tier One oper-
ations, which employ both standard and pick-and-place transfer modes, a regimen also known as crossbar func- tionality.
Retrofits in Buffalo and Mexico, Too
Ford’s transfer upgrades are not lim- ited to Flat Rock. The company’s Buf- falo stamping plant recently has gone through a press-controls upgrade— replacing 20 to 25-year-old control technology—across eight presses, with one also receiving a Linear ETF. Ford opted to maintain its current press- control setup at Flat Rock, as those sys- tems are much newer, according to Sparkes.
The press line at Buffalo boasting the new ETF runs new aluminum-part dies for the F-150.
The Ford Hermosillo stamping and assembly plant in Mexico also is under- going a transfer retrofit on two presses, with similar production improvements expected. MF