EDM Oil / Dielectric Fluid Tips

Use Appropriate Fluid
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 specifically designed for EDM.

For low amp fine finishing 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 EDM 3001 Lite, Clear-3, EDM 3033 provide good overall performance in most EDM situations from fine finishing to roughing.

Petroleum or Synthetic?
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 fit 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 refined petroleum EDM fluids such as EDM 3033 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, semi-synthetic Clear-3 provides some of the benefits of synthetic and is economical for most shops. Generally, if your budget allows choose a quality synthetic fluid such as EDM 3001 Lite. It will last up to 6 times longer than petroleum fluids and will pay for itself in the long run.

A simple way of extending the performance of EDM fluid is to replace filters often and to replace them with quality filters. Some filter sizes are available in “cheap” alternatives from an automotive, truck, or industrial supplier but the quality is low. Remember, your EDM machine is only as strong as its weakest link – using a cheap filter affects the performance and shortens the life of the fluid.

Combining Fluids
When dielectric fluids are combined, a mixture of a wider distillation range is generally the result. Distillation implies that lower boiling components of a mixture are among the earliest to vaporize with heat. The resulting material is often higher in viscosity than the initial mixture. Possible effects of mixing dielectric fluids of different distillation ranges are slower removal rates, rougher surface finish, and higher fluid evaporation rates. Generally mixing fluids is not recommended.

Replacing Fluid
If you are replacing your EDM fluid, there are a few things you can do to maximize the performance of the new fluid. Always try and remove as much as possible of the old oil. Clean out your system including any sludge or waste at the bottom of the work tank, base, and reservoir. Drain hoses and pump housing. Remove old filters and clean out the filter canister and replace with a new filter. If you are using an external filtration system or centralized system, take appropriate actions to clean out any hoses, tanks, and reservoirs it may have. These suggestions are especially important if you are replacing a petroleum fluid with a synthetic fluid. Some minor contamination will not affect performance, but heavy contamination will.

Recycle Fluids
It is important that you dispose of fluids properly. There are many organizations that will recycle used dielectric fluid.

Avoid Contamination
Care should be taken to prevent water from contaminating the dielectric fluid. Water in dielectric fluid lowers its dielectric strength and in some cases can cause excessive arcing making it necessary to replace the fluid. In addition, if drums are being stored outside place them on their sides to prevent any water from leaking into drum.

Hydraulic fluid should also be prevented from contaminating the dielectric fluid. In addition to possible filter system damage, it could also cause harm to your machine. Dielectric that has significant hydraulic fluid contamination should be replaced immediately.

Health and Safety
If you have been around EDM machines for a while, you know some EDM oil can smell and irritate the skin. Today, quality EDM fluid is available which can minimize odor and the effects on the skin. High quality petroleum products such as EDM 3033 have virtually no odor and usually do not irritate the skin. Synthetics and most semi-synthetics such as EDM 3001 Lite and Clear-3 also have virtually no odor and do not irritate skin. Of course, there are some individuals that are so sensitive to chemicals that they may react to even the purest of fluids. Many individuals skin is not irritated by the dielectric fluid, but by contaminates and particles introduced during the EDM process. Wiping hands with oily rags or towels which may contain small EDM’d particles could cause many very small cuts which can lead to skin irritation.

It is strongly recommended, as with all chemicals, that you limit exposure. Similar to house-hold products, it is suggested that you wear gloves and have adequate ventilation. Do not put hands in the dielectric fluid when it is not necessary. Use of a barrier lotion or gloves will aid in the protection of skin.