Find Out Why EDM Graphite Is The Top Choice For Electrodes

In electrical discharge machining, EDM graphite is the most popular material for making the complicated electrodes needed to make a plastic injection mold. Even though EDM copper still has a huge market in Europe and Asia, the use of EDM graphite is gaining momentum there as well.

The reason is actually rather simple: EDM graphite is so easy to machine, it performs very well in the EDMmachining process, and is relatively inexpensive. Electrodes that are machined using graphite can be re-dressed over and over again, sharp details can be machined into it, and the wear ratios are very favorable as well.

It does have one nasty drawback, however: it is dirty and dusty! With proper removal of the dust generated during the machining process, this is not a problem. Newer high-speed milling machines are equipped with negative pressure shrouds that remove nearly all the dust from the work area.

Moldmakers in Asia, Europe, and the USA have an ongoing debate as to which material is best for electrical discharge machining, copper or graphite. Really, both choices are excellent, and your unique application and equipment will determine which is best for your needs. This page is all about EDM graphite; you can find out more about EDM Copper here.

EDM Graphite

Graphite has many outstanding characteristics, here is a partial list:

• No need to redress grinding wheels; the details remain sharp almost indefinitely.
• Ability to achieve fine finishes
• Low wear
• Very good for roughing operations, less expensive grades can be used

Grades of graphite

There are four primary grades of graphite used in EDMmachining .

• Angstrofine- Less than 1 micron particle size. This is used when an extremely fine finish is required.
• Ultrafine- Less than 5 micron particle size. Most finishing electrodes are of this type.
• Superfine- 6-10 micron particle size. This type is generally used for roughing in cavities with larger details.
• Fine- 11-20 micron particle size. Used for roughing in large cavities.

Cost of graphite  

Choosing the correct grade of EDM graphite for the job can mean substantial cost savings. For example: using an Ultafine grade for roughing a large cavity is wasting money. A lesser grade of graphite will actually outperform a fine grade in such a case.

Conversely, using a Fine grade instead of an Ultrafine grade to machine fine details will not only waste money, but not produce the desired results.

Good electrode material choices and correct EDM machining parameters can greatly affect the bottom line. It is important as well, to have an organized system of storing your graphite, so precious time is not wasted on using the wrong type by mistake.

EDM Oil can also have a dramatic impact on the performance of your CNC EDM%20machining process. Find out more here.