A switch to a new CAM system that enables single-setup production reduced the time needed to manufacture extrusion dies from 5 or more days to 2 days. Alcoa Engineered Products (Cressona, Pennsylvania) previously produced its dies by machining backside 3D contours on a machining center, heat treating the dies and cutting the die opening using wire EDM. The company wasn't able to manufacture the dies in a single setup and perform the contouring operation with EDM. This was because the CNC programming system it used was unable to synchronize the upper and lower position of the wires accurately enough to produce the contours.

This is an Iso view showing the match lines connecting the upper and lower geometry in DP Technology's Esprit software.

Jeff Kline, CAD systems administrator, searched for alternatives and discovered a CAM system, Esprit from DP Technology (Camarillo, California), with the needed synching capability for advanced XY/UV four-axis programs. Now the company creates synch points that hold the upper and lower positions tightly enough to accurately create the complicated geometries and produce the completed die in one setup.

Alcoa engineers thought that it would be possible to completely machine many dies on a four-axis wire EDM machine if they used a CAM system capable of synchronizing independent freeform shapes. When they tried to program, they had no difficulty defining the path traveled by each end of the wire but ran into problems synchronizing the two ends.

Overcoming this critical difficulty led to the development of a process that makes it possible to generate a program in less than an hour that produces the die in one setup on a wire EDM machine.
First, the designer uses the company's CAD system to generate the upper and lower profiles of the die. Then the programmer opens the file in Esprit and, by using its feature recognition tool, selects the profiles as features that need to be machined. The only manual operation that needs to be performed is picking the synch points for the upper and lower wire paths.

"This new process with Esprit allows us to produce the most complex die geometries in a fraction of the time required with the conventional process ," Mr. Kline says. "The blank is prepped through heat treating while the CNC program is being created. Then the blank is brought to the wire EDM operation and the bearing, taper and die cut are all generated in a single operation. The new process makes it possible to design and build even more complex dies in a single setup.


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