Is EDM Graphite Dust Dangerous?

Anyone who has worked with graphite in the manufacturing of electrical discharge machining electrodes is keenly aware of the need for proper dust removal during the machining process. Many ill-equipped shops have very little equipment to handle the dust generated during milling and grinding operations.

Safety

This is not to say that graphite is totally harmless though. It can be very irritating to the skin, eyes, and nasal passages. It can cause stinging, redness and watering of the eyes, and itching of the skin. This can be a very annoying experience when a toolmaker is expected to produce a close-tolerance electrode with a fine finish. The use of graphite in electrical discharge machining is increasing all the time, therefore the efficient removal of the dust is a priority that is often overlooked by management.

Controlling the Dust

Portable vacuums are the next best solution, but this also has many drawbacks. Often the filter in the portable shop vacuum is not fine enough to trap the microscopically sized particles, and they are simply blown back into the air. Also, because the vacuum hose is often cumbersome to manipulate, operators fail to properly align the hose to capture the most dust.

Many shops use a centralized vacuum system designed for the removal of fine dust particles, such as graphite. It is important to have enough air velocity in the vacuum system to be effective. It is recommended to have an air velocity of 500 ft. per minute and the air in the lines should travel at a rate of 2,000 ft. per minute in order to prevent the dust from settling inside the duct work.

With a centralized system it is much easier to efficiently manage the dust from the various machine tools because the system is more efficient and the hoses can be strategically placed. Special wheel guards are available for surface grinders that act as a turbo to remove the dust into the vacuum system.

Newer milling machines, which are more or less dedicated to electrode machining for electrical discharge machining, are equipped with extremely effective dust removal systems. The sealed chamber around the work area enables the vacuum to capture a high percentage of the dust. This development has dramatically reduced the amount of graphite dust in the shop environment.

An additional method of dust removal is the use of a curtain of coolant surrounding the milling cutter. This prevents the dust from ever escaping and is very efficient. This feature is available on some milling machines as well as an accessory that is easily installed.

A Clean Shop Environment

It is in the best interest of everyone to make every effort of maintain a clean and pleasant atmosphere in a moldmaking or electrical discharge machining shop. The toolmakers will be happier, the work will be better and the machinery will perform as it should. It is also very impressive for visitors to see a clean, dust-free shop.