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Machining Griphite
- Thread starter JPigg55
- Start date
I have machined some. It cuts easily, is a bit brittle and fragile in thin/small sections. It is also very "dirty", and the dust will get everywhere. Best done with a good shop vac positioned to draw the dust as you cut. If you drill it, be very careful near any edges. It is dimensionally pretty stable, but hard to get a proper feel with a micrometer due to it's "slickness". Nothing really bad about it other than the dust. Best not to breathe it.
I don't know how you are planning to machine you graphite, but you may want to rethink it. The graphite dust will migrate everywhere, especially into critical electrical components, thus shorting them out. Think motors, switches, contacts, etc.
Randy
Randy
Other than using a shop vac and what Tony said there are no problems. Graphite comes in a lot of different grades and each has there strengths and weekness. Some are less brittle and cut much cleaner others chip easier and such. Graphite getting in things and shorting them out is a non issue. I have literally machine'd 1000's of lbs of the stuff in my 30+ years as a moldmaker, never shorted anything out or even heard of any shop having that problem.
Re: Machining Graphite
As Tony said the edges can be fragile and chip out is very possible. There are a couple types that I have used. Die grade carbon which almost no void. Very smooth texture and smallest grain size. The other is more course grained and I would have to say less forgiving to handling of the sharp edges as it chips worst than the die grade stuff.
I use a surface grinder to touch up the interior of our continuous casting dies. The surface grinder has a very good dust system as they all should and even then, I find the carbon dust on my face, in my nose and hands. I also have milled the stuff on the Bridgeport and try standing to the side away from the outflow from the tool. Placing a large box fan to blow away can help but that puts the stuff everywhere else! One really needs to make a high sided box with a high capacity dust system, a shop vac will help but it is not enough.
We also have placed the dies in the machining center where flood coolant is used. This is the best way if machining it alot, for our situation. No dust at all!
If you can, do your work in a pan with water over the carbon to control the dust. We have made water tight pans with ears that we bolt down to the milling table and inside of it is a work table that allowed us to clamp down parts that required machining under coolant or water. This was before we got the machining center with it's built in coolant system.
If you ever go to a shop that grinds alot of their work, carbon or metals, you would be amazed at how dirty the place looks.
Pierre
As Tony said the edges can be fragile and chip out is very possible. There are a couple types that I have used. Die grade carbon which almost no void. Very smooth texture and smallest grain size. The other is more course grained and I would have to say less forgiving to handling of the sharp edges as it chips worst than the die grade stuff.
I use a surface grinder to touch up the interior of our continuous casting dies. The surface grinder has a very good dust system as they all should and even then, I find the carbon dust on my face, in my nose and hands. I also have milled the stuff on the Bridgeport and try standing to the side away from the outflow from the tool. Placing a large box fan to blow away can help but that puts the stuff everywhere else! One really needs to make a high sided box with a high capacity dust system, a shop vac will help but it is not enough.
We also have placed the dies in the machining center where flood coolant is used. This is the best way if machining it alot, for our situation. No dust at all!
If you can, do your work in a pan with water over the carbon to control the dust. We have made water tight pans with ears that we bolt down to the milling table and inside of it is a work table that allowed us to clamp down parts that required machining under coolant or water. This was before we got the machining center with it's built in coolant system.
If you ever go to a shop that grinds alot of their work, carbon or metals, you would be amazed at how dirty the place looks.
Pierre
Thanks for the info and suggestions.
Tollerences not very critical for what I'm doing. I've worked with it a little before, but outside and still had black dust all over me.
Shorting issue was my main concern as it's very conductive. Have plans to install small exhaust fan running outside to help with dust problem.
Will need to cut inside diameter of tube graphite so I don't think I'll be able to use the water bath method on my mill or lathe, but sounds like a great idea. I'll keep it in mind.
Any recommendations on spindle speeds, feed rates, etc ???
Tollerences not very critical for what I'm doing. I've worked with it a little before, but outside and still had black dust all over me.
Shorting issue was my main concern as it's very conductive. Have plans to install small exhaust fan running outside to help with dust problem.
Will need to cut inside diameter of tube graphite so I don't think I'll be able to use the water bath method on my mill or lathe, but sounds like a great idea. I'll keep it in mind.
Any recommendations on spindle speeds, feed rates, etc ???
I just remembered I recently machined some vanes for a nitrogen powered motor, similar to a die grinder or typical air motor. All millwork. This stuff was very dense, and lots of dust, but the shop vac did the job. I would guess that since it isn't a HEPA filter, it didn't get it all, but I didn't notice any real bad mess.
I cut it all with carbide end mills, running wide open. With my mill, that's 2600 RPM I believe. The material came to me in sheet form, and I believe it must have been the die grade that Pierre mentioned. I wouldn't mind running more of it. It was customer furnished, so I didn't get the specifics on it.
Cutting speed should be around 1000 sfm and around 800 for hard graphite.
I cut it all with carbide end mills, running wide open. With my mill, that's 2600 RPM I believe. The material came to me in sheet form, and I believe it must have been the die grade that Pierre mentioned. I wouldn't mind running more of it. It was customer furnished, so I didn't get the specifics on it.
Cutting speed should be around 1000 sfm and around 800 for hard graphite.