Wednesday, February 22, 2017

What Can EDM Graphite Dust Do To You

What does all that EDM graphite dust do to your body? Even with the best of suction systems there remains quite a bit of dust in most injection mold making shops. Just try wiping your hand along the tops of machines or surface plates to find out.

The health and welfare of toolmakers that use EDM graphite to make electrodes for use in the electrical discharge machining process should be a high priority for management. In addition to the health issues for the workers, the very expensive machinery, such as the EDM machines and milling machines, must be protected from the damaging effects of graphite dust.

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.

SST Graphite Machining Services
SST Graphite Machining Services

The simple but very ineffective solution is to wear particle masks. Experience shows that this stop-gap measure is a failure.

Who likes breathing carbon dust anyway?

The mask soon is clogged with the fine dust and the poor guy making electrodes for electrical discharge machining is left breathing a disgusting blend of bad-breath and graphite 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.

Centralized vacuum systems are the way to go

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.

EDM graphite
Coal Miner Face

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.

A Clean Shop Environment
Graphite dust is highly conductive and has been responsible for the damage of many expensive tools and machines. Glass scales can give false measurements due to the settling of dust. Electronic equipment can be short-circuited by the dust as well. The grimy nature of graphite makes it especially annoying if it accumulates on work-benches and desks.

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. This is really just good mold making training 

Here is the MSDS paper on graphite, in case you want to know more.

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