Graphite Machining

[Brian B 74]

For those of you who machine graphite electrodes on a regular basis - do you rough, semi-finish, and finish your electrodes?  Or do you just rough and finish?

 

We rough to .010"/s and finish to 0".  I sometimes wonder if it would be advantageous to put a semi finish pass in there. 

[FROZEN]

Watch for chipping out. Otherwise just rough and finish

[Brian B 74]

I don't struggle with chipping.  I sometimes struggle with gouging on a wall where the finishing and rest-finishing tools come together.

[FROZEN]

I would then suggest semi finishing.

[toddm]

myself i  rough, semi, then finish

rough with a diamond burr .005/s left, 300ipm 25k rpm

semi finish .001/s left

finish 

[jlw™]

That's making some dust.

[BenK]

I always ran a semi-finish path. It will help your finish tool cut more consistent in the long run. As for finish stock I found leaving 10% of my finish tool diameter always helped. Any less and your just rubbing the cutter, more and you deflect it.

[Compaq007]

depending on the graphite quality (grain size).. we rough everything down to +0.002 stock then finish.... semi-finish only when tool size (.4mm ball end-mill or smaller), precision (+/- 0.00005) are critical...

 

 

[Compaq007]

myself i  rough, semi, then finish

rough with a diamond burr .005/s left, 300ipm 25k rpm

semi finish .001/s left

finish 

I love those diamond burr...I run a 3/8 dia. diamond burr in a Mikron HSM 400U at 850ipm.. is quite a show!!..got to find the video to upload..

[g huns]

Rough to +.010. Finish to 0. Unless it's a big trode, then we rough to +.020 with a 1/2" diamond, the go +.010, and 0. We have Roeders mills for trodes and the operators can set the tolerances for each path. They really open it up for roughing. I used to go +.010 with the 1/2", but had some trodes not clean up.

[g huns]

I love those diamond burr...I run a 3/8 dia. diamond burr...

 

Where do you get them?

[Compaq007]

Where do you get them?

From Niagara Cutter, we use the 3/8" diameter with 1.5" cutting length (flute) mostly and it last for months and months. it's a great investment.

[g huns]

Thanks. Think I found them. You use the coarse pitch with endmill bottom?

[BenK]

I was always a fan of IDI tools. Worked great and lasted a long time.

[Compaq007]

I use the fine-pitch fiber router Burr with Burr end.. it does a better job at roughing out , no chipping..

I remember using the end-mill bottom once but it does not clear the material as well as the Burr end specially in more than 35% step over..

[#Rekd™]

Contact Rickster, they only machine graphite at his shop. He should have this down to a science.