Big on EDM

Adron Tool Corp. considers itself the largest EDM shop in America. Not just because of its 48 wire EDM machines or the amount of production work it pumps out, but because of the workpiece sizes it handles. At the Menomonee Falls, Wis., jobshop, 10,000-lb aerospace parts are commonplace, as is burning thicknesses up to 26.5 in.

The shop is equipped with a couple 3-ton-capacity overhead cranes and every so often must rely on the help of outside riggers to load or unload parts. While maneuvering parts around may be tough, EDMing them isn't. That's because Adron has developed its own tricks for burning the big stuff.

One such trick is a modified Mitsubishi 110HA wire machine permanently set up for 26.5-in. thicknesses. "We could temporarily modify a machine by hanging a C-frame arm out over the table, which would easily cut 30 or 40-in. thicknesses. However, the cost of such machine preparation would have to be passed on to the customer," says David Carlson, a vice president at Adron. The 110's permanently modified bridge eliminates this prep work and lets the machine cut full tapers up to 21.5 in.

Adron did most of the modifying itself with engineering help from Mitsubishi. The 100 was a logical choice because a lot of the parts it runs are tall but small and light. Cutting dimensions for the 4-axis 110, or the 120 as Adron refers to it, are 12X18X26.5 (without taper). But when the parts run a little bigger and heavier, the shop turns to its Mitsubishi DWC400H1, DWC300HA, and DWC200HA 5-axis wire machines with cutting dimensions measuring 32X40X18 in., 20X40X18 in., and 16X30X10 in.

Large parts mean large slugs, and according to Carlson, it is very important to first install eye bolts for slug removal. Some slugs weigh as much as 2,500 lbs., and their shear size can greatly affect the rest of the part.

However, large parts don't always mean large cutting areas. For instance, a 65-in.-diameter part may have a cut zone of only 1 in., meaning three-quarters of the workpiece sticks out beyond the machine's table. This is why Adron designs its own fixturing, which is usually more heavy-duty than the norm. At the oppositie end of the spectrum, the shop also produces custom fixturing for extremely thin parts. For example, in one fixture, operators stack enough 0.007-in.-thick pieces of exotic alloy to burn 2,400 parts at once.

In addition, to unusual sizes and weights, Adron also faces some challenging workpiece materials. Some of which include precision strain gage ribs through 22-in. stainless steel for a NASA wind-tunnel component, 49 curved lengths from a single block of aircraft-grade almunium measuring 13.5X13.5X36 in., and test cuts in 20-in.-thick high-quality dense-grade graphite while maintaining a 0.0015-in. tolerance from top to bottom. Other exotic materials the company works with are superalloys, titanium, Hastelloy, niobium, tungsten, copper, and more.

As a production EDM shop, Adron operates with 60 employees working three shifts/day, 7 days/week. Job runs are anywhere from 1 to 1,000,000 pieces, and amazingly enough, the shop uses no robotic automation.

Basically, all the EDMs are manned, but one operator runs 4 or 5 machines simultaneously. and numerous production cells, consisting of 3 to 10 machines each, ususally run one type of part nonstop.

"We've looked at such automation as automatic wire threaders and robots, but neither has really fit in with our philosophy on EDM production jobs," comments Carlson.

Adron prides itself on fast turnaround times for high-production jobs, and it accomplishes this by running shop EDMs as fast as possible. "Speed, quality, and performance are the main reasons all our EDMs are from Mitsubishi," boasts Carlson. "We are running a production job on the same machines it started on 15 years ago with cutting speeds near 18 in./hr, nonstop, 24 hrs/day." Now, Adron faces high-production jobs that require cutting speeds up to 33 in./hr to satisfy customers.

With 48 wire EDMs running 24/7, burning parts over 27-in. thick for numerous high-volume jobs, one wonders how much wire Adron goes through. According to Carlson, the shop orders it by the skid-full and consumes enough wire in a year to circle the earth roughly 2.5 times.

(Reprinted with permission of American Machinist, December 2000. A Penton Media publication.)

For more information, contact:
Dave Carlson
Adron Tool Corp.
1-800-346-9004
dcarlson@adronedm.com