Generally a synthetic ﬂuid is better; longer life, better performance, and excellent operator acceptance. However, synthetic ﬂuids cost more and depending on what applications you are using your EDM for, sometimes it makes sense to choose petroleum over synthetic. BUT, be careful when selecting a synthetic.
Some low cost synthetics are not ft to be called synthetics. A low grade “synthetic” or “synthetic blend” is not any better than a good petroleum ﬂuid...and it may be worst!
Keep in mind that highly refned petroleum EDM ﬂuids perform almost as good as many synthetic EDM ﬂuids on the market. However, a petroleum ﬂuid life span is usually less than a synthetic. In addition, semisynthetic provides some of the benefts of synthetic and is economical for most shops. Generally, if your budget allows choose a quality synthetic ﬂuid. It will last up to 6 times longer than petroleum ﬂuids and will pay for itself in the long run
Use the appropriate ﬂuid - in sinker EDM machines use dielectric ﬂuid. Sounds simple enough, but many shops use a cheap mineral oil in an effort to save money. Fluids not designed for use in an EDM system may be dangerous to the operator, the workplace, and could damage your EDM equipment. Mineral oil does not have the ﬂuid properties to be effectively used in EDM. The savings of a couple hundred dollars isn’t worth the risk. Remember, use ﬂuid specifcally designed for EDM.
For low amp fne fnishing work, choose a ﬂuid with a low viscosity. The low viscosity allows the ﬂuid to get into the cut of material and help ﬂush out particles.
Generally, because these ﬂuids have a low viscosity they also have lower ﬂash point - not for rough cutting with high amperage. For roughing work, choose a ﬂuid with a high ﬂash point.
If you are like most shops and the machine is used for every application, choose a good overall performer. Dielectric ﬂuids of good quality normaly provide good overall performance in most EDM situations from fne fnishing to roughing.