|CAD||Wire EDM||CNC Mill||Process||Tooling||Parts|
In the pictures above you can see one of the older wire EDM (on the left) compared to a more recent addition on the right. Our capacity and efficiency usually allows us to complete a job within 24 hours. Since we can archive customer tooling specifications, repeat jobs can done with a simple phone call.
The acronym EDM stands for Electrical Discharge Machine. This machine uses small amounts of controlled electricity to vaporize the metal of a work piece. The work is on a "grounded" fixture. A highly charged conductive wire is brought into close proximity with the work. Small discharges from the wire to the work piece cause the material on the work piece to vaporize. To control the electrical discharge the wire and surface of the work are both submerged in de-ionized water. This prevents the charge from "leaking" away into other directions. Also the wire itself is somewhat destroyed by this process, so the machine is constantly supplying new wire to the work area.
The wire and the position of the work piece are controlled by computers. The path of the wire through the work piece can be very accurately controlled. This allows tolerances within .0002 inches, in comparions the diameter of a human hair is .003 inches or 15 times larger.
Here at Gregg Tool & Die we use this process to cut die sections, extrusion dies, and other types of work that require complex shapes with high precision. For example we have customers that produce plastic extrusions. Below is an example of a plastic extrusion die.
This die was cut from a stainless steel fixture that will be mounted on an extrusion machine. Hot PVC will be forced through this opening and this extruded material will be used in the construction industry.
The computer that controls the wire machine also has the ability to receive instructions from an external source. We are currently using a PC software product called Image® to generate the EDM machine code. This software can also accept files from our CAD system. In the picture below you can see the outline of the path the machine will cut.
To the right of the PC you can see an optical comparator. We also have custom software that allows us to take measurements directly from the comparator and automatically input these dimensions into our various CAD/CAM systems.