Graphite milling data

[El Scotthead]

Hey all,

 

Does anyone out there have any decent feeds/speeds for milling graphite? The data my cutter supplier gave me is not working well(cutters are wearing too fast and finish/geometry is not great).

 

Defiance VTX, Creative Evolution control, 45k rpm spindle, 600 ipm max

 

common cutter diameters are 0.03125, 0.0625, 0.125, and my big hogger is 0.2500

[Midwest]

Cutters for graphite clicky here

 

Feeds and speeds Click Here View with Acrobat reader

[P_Scott]

El Scotthead,

 

Welcome to the forum.

What are the speeds and feeds you've been given from the cutter supplier? There's actually a free little program someone introduced to this forum not too long ago. It's called "ME Consultant" and can be found on the forum FTP in the "unspecified_uploads" folder. It has loads of materials and you can calculate the feeds and speeds using just about any tool diameter and cutter material. Click on "cadcam's FTP site" link above and look for the folder. If you can't get that program, I'm sure there are more members here who could help you with speeds and feeds in that black stuff. I hope you have plenty of good vacuum to remove the dust and "chips". HTH

[Mito@DeeringBanjos]

great link from midwest. just use a good vacum system. you dont want that dust flying around.

[Matt Berube at Ferron Mold]

I was going to offer to send you my standard tools for graphite until I noticed your machine is soooo much faster than what I use. The only tip I can give is you may get better results by soaking the graphite in edm oil before machining. It's messy but the tools last more than twice as long.

[Guy Arseneault]

Peter,

 

It doesn't have GRAPHITE as a material reference.

 

I use what midwest suggested. I run a Bosto 12g machine.

 

[ 02-18-2005, 02:38 PM: Message edited by: Guy Arseneault ]

[Jody]

quote:

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better results by soaking the graphite in edm oil before machining. It's messy but the tools last more than twice as long.

---

I have never heard that before. Does anyone else do this.

 

At the last place I worked We had a mill setup just for cutting trodes not high speed. but it used edm oil for coolent so we did not need a sucker system, that was nice.

 

Jody

[Guy Arseneault]

Jody,

 

Doesn't that get messy?

[Jody]

Guy

 

the coolent took all the graphite down to a big tray with a fancy paper towel that collected the graphite and let the coolent through. every two weeks or so i would cut the paper and throw out the graphite it collected. the paper was on a roll that was 24" wide. When I came here and saw them fighting with the crappy portable sucker I was sure that even if you had to handle the wet trodes it was worth not have the dust and have the big sucker nozzle in the way. I was new in the trade at the other place so i do not know if the tools lasted longer there or not.

 

Jody

[Rekd™]

quote:

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I run a Bosto 12g machine.

---

FU! I mean... LUCKY!

 

Graphite is abrasive. Use diamond coated tooling when available, (see Crystallume).

 

They cost 10 times carbide tooling, but last at least 10 times longer.

 

Also, when you can, rough and finish with 2 different tools.

[P_Scott]

quote:

---

It doesn't have GRAPHITE as a material reference.

---

OOps!! My bad. Sorry El Scotthead. I had ME Consultant installed on my computer before but seems I've lost it since. Follow the advice of Midwest and Matt. It's been years since I worked in a graphite shop. All I can remember is coating a Kleenex with black dust every time I sneezed. The shop I worked at didn't have adequate vacuum to remove all the dust in the air. To make things worse they only had a 10k spindle Fadal 3016 and I was using old carbide micro-cutters (.125-.015") which got ground down to uselessness after a few cavities. I learned a lot there though.

 

ctmJody,

 

What a unique way of collecting the graphite dust. I was always told that using coolant would ruin the graphite and it would clog the pump in the coolant tank with the dust. What was the weight of the paper? I wonder if it was anything like coffee filter paper.

[specprogrammer]

X2 on the crystallume end mills. That PVD coating makes the end mill last soooo long. Their web site has good cutting speeds and feeds that I have also used for uncoated carbide EMs too. We run about 750-1000 sfm.

[betts]

quote:

--------------------------------------------------------------------------------

better results by soaking the graphite in edm oil before machining. It's messy but the tools last more than twice as long.

--------------------------------------------------------------------------------

 

I have never heard that before. Does anyone else do this.

 

At the last place I worked We had a mill setup just for cutting trodes not high speed. but it used edm oil for coolent so we did not need a sucker system, that was nice.

-------------------------------------------

 

Yes but I only do it when I know the probability of chipping is high. Small detail, thin ribs and the like.

 

Never really considered doing it full time. I'll have to think about that.?

[Lucky]

Soaking the graphite works. The part will look better and tool life is improved. We rarely take the time to do it however.

[g huns]

I use PCD inserted tools for roughing. Get them from Harvey Tool. 1/4 inch is as big as I can go and I run that at 25K. I usually program feed rate at 250IPM, but with the Fanuc HPPC it's not really that fast. More like 150IPM. +1 to the SP3. It's good stuff. Electrode Inc. carries tooling from CVD Diamond Corp, very good as well. Plus they give you 50% off your first order so make it a biggie. I got a .046 diameter with 1/2 in. of reach from them 5 months ago, use it a bunch and it's still great.

[g huns]

Here's the link to CVD Diamond end mills

[jimspac]

+1 to soaking the graphite in oil but I recommend only the dielectric oil used in the EDM. I have noticed less chipping when redressing or making a new trode from used graphite. Also better results with fine detail.

[jimspac]

Guy, we also use a Bostomatic 12g with the 3200x control. What post do you use? I had S4A modify the post on the CD and ended up modifying a BOSS9 post to get useable code. Love the machine and also use a HAAS TM-1 with a shop vac for bigger trodes.

[Matt Berube at Ferron Mold]

quote:

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+1 to soaking the graphite in oil

---

WOW ! My first +1 !

[Guy Arseneault]

jimspac,

 

Same control. I use Mp3200 from a guy that trainned me on the machine. What version of software are you using on the control? Mine is ver4.01 Beta.

[El Scotthead]

Wow,

 

thanks for the great response!

As far as soaking the trodes in edm oil, it's not really an option at this point (mill cabinet leaks more than a sieve). Just out of curiosity though, how does the edm oil affect trode geometry? I would think the trodes would change slightly if they dried out.

 

g huns: Do you buy graphite from 'trodes Inc? If so, do you use/like the I85 they sell? I've been wanting to try it, just haven't gotten around to it yet.

[jimspac]

We have not seen an effect on the geometry as the trodes are used full flush or submerged in the dialectric so really I feel geometry is maintained very well.