Machining Calcium Silicate (Insulation Board)

[mcpgmr]

Hello,

Any Speed and Feed recommendations? Carbide, diamond coated end mills?

[CEMENTHEAD]

I use Cobalt end mills (razor sharp & ease of regrinding), slow speeds to keep the dust down. no coolant, although you could use distilled water but not if you want to hold any close tolerance (due to absorption).  we use a light air blow into a vac.

If possible try and keep the cut / chip direction always spinning into the part as it would chip if you pull a chip off the edges.

[mcpgmr]

34 minutes ago, CEMENTHEAD said:

I use Cobalt end mills (razor sharp & ease of regrinding), slow speeds to keep the dust down. no coolant, although you could use distilled water but not if you want to hold any close tolerance (due to absorption).  we use a light air blow into a vac.

If possible try and keep the cut / chip direction always spinning into the part as it would chip if you pull a chip off the edges.

SFM ? RPM? Was going to use 60 SFM which is what's recommended for graphite machining. Also was going to use a carbide 1/2"ball e.m. Helical milling holes through 1" plate. Holes are Ø.515 and Ø.750

[CEMENTHEAD]

60 sfm is a good start.  450 rpm 7 ipm at a .004 cl.

 

[Justin Beebe at Folsom Tool]

Paul we run a composite job at our shop and the parts get a 1.00 diameter bore approximately 1.00 deep.  We tried drilling the hole but it would delaminate the part.  We ended up roughing the bore with a half inch PCD Diamond endmill with a .030 corner radius.  I used a contour toolpath with the ramp option selected so it will helix through the part much like you intend to do.  Then I go back and finish the bore with a half inch diamond coated endmill.  We have been running the job on and off for about a year and the PCD tool has never worn out. The half inch diamond coated endmill gets about 70 parts but it does more work than just fiishing the bore.  I run the half inch diamond coated endmill at 3000 RPM and 30 inches per minute.  I can get you the feed and speed on the PCD tool but I won't be back at work until wednesday.  I wish I could give you more info on the composite material but it is proprietary so we don't even know what it is.  We had to learn by trial and error. We do not use coolant but we do have an airblast  that runs on the M7 command and really good vaccum sytem that we desinged in house. I get the diamond coated tools from Buzz.  I can let you know where we get the PCD tool.  It's been so long since we had to change it I can't remember.