Machining Magnesium

[camcrazy]

I have recieved my first part to program made out of magnesium. Although I feel good about my toolpaths I have conserns for the next operations that I am seeking advise on.
The part I am making is basically a rectangle that is .066x.250x.100. After my operation in the mill (this is were I worry) then it has to goto the wire EDM department to be sliced into .005 thick slices. I expressed my concerns about a fire with that thin of a shim and explained how magnesium and water don't mix when there is a fire but it fell upon deaf ears. Does anyone have any wire EDM experience with this material that can give some insight?

Thank you for the help

[SRT Mike]

no experience but your concerns IMO are very well founded...Mg burns in water and oil so if you do it be SURE you have a fire extinguisher *that will put out an Mg fire* nearby!

[cam1]

Hi:
Keep the chip pan on the mill clean, I've heard of the chips in the tray catching on fire......

regards

[bugzpulverizer]

Worked with a guy who was milling magnesium. Shop didn't have correct foam to put out Mg fire. The part caught fire, and burned through table, bottom of machine, and into concrete about 6". Be careful.

[suds]

I have machined several hundred MAG. Parts over the last few years, but my first encounter in 1995 was literally a baptism of fire. I had to bore a bearing housing on a MAG. Gearbox, nobody seemed to know the best way to do it, least of all me, the boss said we could not use coolant on it because it would leave stains on it and it was a prototype. The boring bar was on it’s finishing cut when there was a small spark from the tip that ignited a thin slither, it was then I made a big mistake, do not use a pressurised fire extinguisher as the blast of air fans the flames, makes for a very pretty light show but is scary as hell, fortunately it is easy to pat out.
The company I worked for recently had a much better understanding of the material, on the mills we used an oil mist to damp down the chips and we would clear the chips after every part, we also had a large bucket of sand close to hand, but never needed it.
As for the wire EDM we would make sure all the cutting conditions were as good as possible, before we started we would move or change the contact strips, change the resin bottle and make sure the water resistivity is as high as possible, we would also tweak some of the settings i.e. turn down the servo volts and increase the wire speed and tension, this gave a smaller gap and a better finish.

[TheGreenMachine]

I've done mag parts, I wanted to see how easy it was to catch fire to and found the mag must be very thin in order to get hot enough to burn, im talking 2 thou or so and that was with a torch on it. After discovering that I wasn't concerned about a part actually catching fire.

[flick]

I recall a high school chemistry teacher igniting a strip of magnesium with a match. Maybe it depends on the alloy or something, but it certainly didn't take a whole wack of heat in that case.

[TheGreenMachine]

I think we used bunsen burners in chemistry class, im sure that was pure magnesium. We are machining alloys, mostly AZ91, I would imagine alloys a relot harder to ignite. Heck they make racing pistons out of WE54. Of course use caution and common sense when working with metals that can burn.

[dertsap]

it should be run dry