Magnesium Machining

[DavidB]

Hi all,

 

Need to know from people who have Machined Magnesium before anything that I should Know.

 

My main concern is FIRE

I can cut it dry no problem BUT the Machine a Makino A66 Horizontal uses the Coolant in the base of the machine like a river to remove swarf from the Machine.

Will Magnesium swarf falling in water catch on FIRE?????

 

Thanks in advance

[DavidB]

OOPS

 

Sorry I forgot the O/T

 

[gcode]

quote:

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Will Magnesium swarf falling in water catch on FIRE?????

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I've cut a little magnesium ansd I always used lots of coolant.The primary danger is dry fine stringy chips like you get from a light finishing cut with a flycutter.

The best defence is plenty of coolant and not letting the chips pile up.

I believe that a bucket of sand is probably

the best way to stop a magnesium fire, but you have to be very quick with it.

[J Coulston]

Check your coolant manufacture for compatibility with machining magnesium. I am pretty sure that the Blaser Swisslube I run gives a long list of machinable materials followed by except magnesium.

I would run it dry.

Related Thread

http://www.intlmag.org

 

 

I run a Kitamura HX400 that has a pallet wash. I needed to turn the wash off when I ran phenolic job. I ended up unplugging the bayonet connector on the appropriate pump. This approach might work for you.

[DavidB]

So cutting Magnesium should be done wet?

 

[DavidB]

John create reading thx

[gcode]

John

Try searching this forum. This subject has come up before and got a lot of replys.

[Mike Whitten CAD/CAM Contractors]

DavidB,

 

I seen stuff about this subject before but I can't remember where. I would get a hold of the manufacturer of the material for machining data. Your material supplier should be able to direct you.

 

Just a few ideas?

 

Thanks

[Mike Whitten CAD/CAM Contractors]

I would also check the Handbook.

 

Mike

[DavidB]

I did a search on Mag and there was a thread with a lot of input but no real conclusion.Half say flood it,half say cut it dry????

 

Im not Machining a casting but a raw billet (1000x300x100mm) of Mag that is very large down to a small component.

 

There will be a lot of roughing and small finishing cutters.Its a very detailed part.

 

[Mike Whitten CAD/CAM Contractors]

DavidB,

 

I just got to believe that the people that manufacture the material have an engineer that you can call or a data sheet. This way you know for sure.

 

Thanks

[DavidB]

I checked with coolant supplier NO GO for Magnesium.

Sepperates the water making it hard.

They have a coolant for Mag but it wont run with any other Material.Also coolant can stain part.

 

Cutting it dry im concerned about the amount of swarf which will be a lot.The operater will have to keep remoning swarf manually.

 

 

[Guest CNC Apps Guy 1]

When cutting with water/coolant mixture, Hydrogen Gas is a byproduct of the cutting process.

 

Straight cutting oil is the best solution IMHO. Keep a Halon fire extinguisher handy just in case.

[Allan]

quote:

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Keep a Halon fire extinguisher handy just in case.

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What is Halon?

 

Halon is a liquefied, compressed gas that stops the spread of fire by chemically disrupting combustion. Halon 1211 (a liquid streaming agent) and Halon 1301 (a gaseous flooding agent) leave no residue and are remarkably safe for human exposure. Halon is most effective for flammable liquids and electrical fires (rated B:C) and is electrically non-conductive.

 

Note that it is rated B:C not D

 

You would want a class D fire extinguisher

Something like this:

MET-L-X POWDER (SODIUM CHLORIDE)

 

Allan

[Guest CNC Apps Guy 1]

DOH!!! Guess it's lucky I never had to use the extinguisher eh??? That's what the boss put next to the machine.

 

Thanks for the lesson Allan.

[crazy^millman]

If cutting it dry do not use air for the chips. You might get the grain soilol effect and poof there goes half the building espically if the machine is closed in and the tool is hot. Be very careful and use aluminum jaws. If by chance you hit a hard jaw there is your ingition source for the magneisum.

 

Good luck cuts fine just use your wits and be safe.

[G Caputo]

We have cut this before dry, never had a problem. Keep a class D fire extuinguisher handy. If it does ignite, like stated before the coolant only acts as an accelerant. Same with water. the bigger the chips, the less likely of a fire. The thin chips are what lights very easily. (end mill chips). Keep the speeds up to avoid making direct heat. Keep the machine as cleaned out as possible to avoid having a "pile" of chips to burn when running the part. We do mostly work with steel here so when we get something as soft as this, it is a treat to see the machine flying. And most importantly, take some of the chips home and burn them in a safe area as to not catch anything else on fire. Great for starting bonfires, etc.

 

Greg

[A-ron1286490684]

A long time ago

in a distant galaxy

far far away...

 

Or rather an old shop I worked in used to cut a lot of Magnesium. This was about ten years ago and yes it destroyed Blaser Swisslube back then. It ruined the emulsifiers with the "salts" that were released when cut, (was what we were told). They ran it with a thin mineral oil that had a red tint to it. Don't know exactly what it was called.

 

You should try to keep it all on one machine if you are going to use regular coolant then toss it out without cross contaminating the other sumps.

 

We never had ignition problems and we were really aggressive with it. We did have class "D" extinguishers on hand which back then were full of a type of powdered grahpite if I'm not mistaken.

 

We used to rough all we could then lightly re-finish everything we could because of the tendancy of the magnesium to deform everywhere cause it was so damn malleable/soft kinda like copper bulges and deforms when cutting it.

 

HTH

[Trapper Paul]

Cut it all the time down in a Off-Road motorcylce shop in Trinadad, Co.

 

Not any problems, Ran it with coolant!

Not sure of the brand but could find out for you!

 

The posibilty of a fire is there. Bring some chips home with you and light them for your kids or kids in the neighborhood, hey you'll be "god" in there eyes! I keep some in my camping stuff in case of an emergency!

[DavidB]

Thanks for all the replys,

 

I spoke to a guy Down Here that Machines Mag and he cuts it wet using a Neat oil.He was using the same souluble oil as we are and it went "bad" as he put it.

 

I spoke to another guy and he cuts it dry.

 

I spoke to my Dad who is a Engineer at Chubb Fire and said its a class D Extinguisher.

 

Being a large part with a lot of swarf I think Coolant is the way to go.The remonal of swarf manualy would be to risky.Also its an acurrate part I cant aford any expansion from heat.

 

Thats brings the problem of remoning the Coolant in Machine as It cant be used on Mag.Putting in a Neat oil.Machining 3 Parts.Removing neat oil and putting New Coolant back in the Machine.

 

So other than that the risk of Fire its going to be a great jod

 

[Nominal]

quote:

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Not any problems, Ran it with coolant!

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I agree with this gentleman. We have a few mag jobs on contract. We ran one 100+ pc casting job a couple months ago. Turning, milling drilling etc. No big deal. There are people machining explosives at los alamos. I'm sure you can handle magnesium. And yeah we did keep the powder handy but no fires. I did have a mag fire once when I was an apprentice and was turning a piece on a bench lathe with no coolant. The finer the chips the easier it is to ignite.

[T_MALENA]

I've also cut Mag. before. But had good & bad results! The stuff cuts like butter when you cut it like alum. but when things get too HOT look out! If you cut it using high positive/ high shear type inserts & cutters you'll be fine. We have used oil,kerosene,coolants & dry. It all depends on what you're doing. I would suggest taking lots of light cuts with high spindle speeds & flood coolant. The idea being that the small chips mixed with lots of coolant will keep things cool. Heat is the enemy here!

 

ALSO DO NOT LET THE CHIPS BUILD UP!!

 

KEEP A CLASS D FIRE EXTINGUISHER NEXT TO THE MACHINE!!

 

ALSO A 25#-50# BUCKET OF SODIUM CLORIDE WITH A HAND SCOOP NEXT TO THE MACHINE.

 

Take some home to start camp fires. Burns real bright!

 

You may want to talk to your local Fire Dept. They may be able to use the chips for fire training! Good for PR too. You may need them.

 

Have a blast!

[DavidB]

Im in the process of getting prices for Mag the steel sellers want to know what grade of Mag I want.I have no idea, neither does the customer he just wants Mag for the wieght benifits.So I can choose any type of Mag i want.

 

Any suggestions?

 

[DavidB]

quote:

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I would suggest taking lots of light cuts with high spindle speeds & flood coolant.

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From metals handbook.

The possibilty of chips or turnings catching fire must be considered when machining Magnesium.Chips must be heated close to thier melting point before ignition can occur.Roughing cuts and medium finishing cuts produce chips too large to be readily ignited during machining.Fine finishingcuts,however,produce fine chips that can be ignited by a spark.

 

Factors that increase the probability of chip ignition are (a)extremely fine feeds,(b)dull or chiped tools,©improperly designed tools,(d)improper machining techniques and (e)sparks caused by tools hitting iron or steel.

 

Regarding "COOLANT"

In machining of Magnesium alloys,cutting fluids provide far smaller reductions in friction than they provide in machining of other metals and thus are of little use in improving surface finish and tool life.Most machining of magnesium alloys is done dry,but cutting fluids sometimes are used for cooling the work.

Numerous mineral-oil cutting fluids of relativly low viscisity are satisfactory for use as coolant in machining magnesium.Only mineral oils should be used as coolants;animal and vegetable oils are not recomended.

Water-soluble oils,oil-water emulsions or water solutions of any kind should not be used on magnesium.Water reducess the scrap value of magnesium turnings and introduces potential fire hazards during shipment and storage of machine shop scrap.

 

[TheePres]

Ive cut plenty of magnesium in past, if you have operator, cut it dry....let him suffer the dust, itching, rash..etc. If u get stuck running it, use coolant, but insure clean supply, some contaminants will corrode magnesium instantly. What i used to do was immediately after running wet, completely immerse parts in bucket of WD-40.