Page 26 - MetalForming September 2014

Rapid Die Changes
The Lenzkes clamp is height-adjustable from 3.5 to 7.2 in. The design ensures that the 6.7 tons of clamping force is directed downward on the tool with zero side force. Note the tall T nut that allows the bolt head to stay on top of the clamp regardless of clamp height.
2012. Contacts made there led Engel to local machinery dealer TCR Metal- forming Solutions, Wisconsin Rapids, WI, and TCR president (and article author) Todd Wenzel.
By the time TCR finished working its quick-die-change magic at Atlas, it had several new products on hand that have reduced die-swap times by 50 to 75 percent. Engel says the operators love the new technology and are able to focus on making more parts with less setup time.
How did TCR Help Atlas Achieve its Goals?
The job started with a survey of the existing tooling and discussions of what new tools were needed. The tooling drives everything else. With a good feel for the existing tooling that needed to be run on the new press, press selection narrowed to one or two options.
Discussion of future tools further narrowed press selection. In the end, Atlas installed (in June 2013) a 165-ton Aida gap-frame press with 30- by 46-in. bed and 7.87-in. stroke, rated at 30 to 60 strokes/min.
Regarding die-change technology,
the tendency is to focus on the clamps themselves—mechanical, hydraulic or magnetic clamping—because they are the products that the end user buys, so the costs are clear. All three technologies have their place, with advantages and disadvantages to each and calculating their relative is quite simple.
What is not simple is identifying the
Atlas Precision
at a Glance
Headquarters: Minneapolis, MN; more than 75,000 sq. ft. of manufacturing space among plants in Minn. and Wis.
Founded: 1962
Capabilities: Contract manufacturing,
precision sheetmetal fabrication, powder coating, engineering and design, assembly and logistic sup- port, machining
Certification: ISO 9001:2008
Industries served: Telecommunications,
retail, store fixtures, computers, elec- tronic data racking and enclosures, industrial products, medical and commercial applications.
Atlas wanted its next press to have more tonnage capacity.
“We wanted not only to be able to run legacy tools, but saw value in increasing press size so we could use the press for larger parts in the future,” Engel says.
An increase in tonnage capacity would mean a larger ram, making it impossible to put holes in the ram of the new press that matched the old tooling’s tapped-hole locations.
Several proposed new tools would be as large as the new ram, so there was no way to use mechanical clamps that need to rest a heel on the ram face next to the tool. And none of the tools had slots milled into them that would line up with the new press’s T slots.
The Right Clamp Style for the Job
There was one common feature for all the tools, though: a flat steel surface on the top. This made magnetic clamp- ing (from Soph Magnetics, Inc., Brighton, MI) for the upper a simple choice. It required no die modification of any sort, a big savings compared to what would have been needed if
hidden costs of tooling modifications that may be required. For example, if there are a substantial number of lega- cy tools, tooling-modification costs can be many times higher than new clamp- ing technology.
Atlas’ legacy tooling had been clamped to the press ram using bolts dropped through the ram plate into tapped holes in the top of the tools. The lower tools had been clamped using traditional strap clamps with heel blocks that varied in height to position the clamp to match the tool. There was no common clamping height for the low- ers, positioned anywhere from 3.5 to 4.5 in. from the die plate; lower tools were on parallels with no quick-die-
change plates.
In addition to the tooling,
24 MetalForming/September 2014
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