CNC Programming System Cuts Micromachining Time
09/09/2010

Die Technology Inc. is a Minnesota shop that performs precision machining, with a specialization in producing dies for materials less than 0.005 in. thick. The company prefers to perform operator-intensive jobs during the day and, whenever possible, run its machines unattended at night. It has made substantial additional time-savings by switching to ESPRIT® from DP Technology and using that software’s mold capabilities to create CNC programs for producing electric discharge machining (EDM) electrodes. Only about four hours were required to train each of the company’s programmers to use the software, and they have been able to program nearly every part in substantially less time than was required by the software used in the past. For example, it took just 90 minutes to program the first of a family of EDM electrodes for making molds for catheter tips, and only 10 minutes to program subsequent parts.

Tight clearances for thin materials
Die Technology Inc. was founded in 1988 as a contract machining shop with a specialty in wire EDM, focused on building progressive dies and precision stamping dies. It designs and builds precision stamping dies, tools and fixtures for customers in medical, electronic, defense, and telecommunication industries. It also provides precision wire and sinker EDM machining services for a range of OEMs. While Die Technology is still heavily involved in wire EDM, in recent years its primary focus has turned to precision machining and micromachining. At least 95 percent of the dies and tooling it produces now are for materials that are 0.005 in. thick, or less. Some of these are less than 0.001 in. thick.

Cutting clearances between the punch and die are typically no more than 10 percent of the material thickness, which means that clearance on a 0.001-inch thick material is in the range of 0.0001 inch. A high degree of accuracy is required to guide the punch into the die with such minute clearances. This means that tolerances have to be very tight on all critical components, including dies, punches, guided stripper plates, die plates, die inserts, etc. Die Technology uses 4-axis wire EDM to produce the entire die assembly. A high degree of accuracy is necessary to produce the wire EDM electrodes used by the company.

Autonomous machining
One of Die Technology’s unique capabilities is performing many machining operations without operator attention. The company uses Agie Charmilles Progress V2 machines, which have a number of features that make them suitable for autonomous operation. For example, these machines handle standard wire spools up to 25 kilograms and thread reliably in multiple parts or multiple openings in a single workpiece. They provide considerable flexibility for operators to set up multiple workpieces on the machine table.

“We are normally manned for 12 hours a day, from 5:30 am to 5:30 pm,” explained Die Technology owner Dale Skoog. “When we have a backlog of work, we focus during the day on jobs that cannot run at night. When it’s time to go home we leave the machines on and take advantage of the night hours. We have increased the average time that our machines operate from 2,500 to 3,500 hours per year. The cost of operation is much lower at night than during the day since the only variable expenses are consumable tooling, electric power and wear and tear on the machines. We also use the autonomous features during the day to enable operators to run two or three machines.”

Die Technology has used a number of different CNC programming systems. As it implemented more advanced machine tool technology and methods, these programs failed to keep pace and were replaced. The company then switched to ESPRIT CNC programming software for wire EDM and later began using ESPRIT for metal cut