Cutting black MDF issues

[Rundover]

I am cutting black MDF that is water, and fire retardant. The cuts a small, odd shaped cuts and there are a lot of them in a 4' x 8' x 3/4" sheet. The 1/4" bits are burning up and getting dull fast. I would say 1/3 the way through a sheet is about all I can get a clean cut. Tried compression, up , down, and single flute. Have tried 3,000 RPM on my spindle and as fast as 5"/sec and as slow as 2"/sec cutting 1/8" each pass but because these shapes are small and have tight corners it will never get up to any speed. Has anyone ever cut this type of wood or had this experience that can enlighten me on how to better cut this ****?

[Gary Campbell]

If there aren't any copyrighted materials in the design (crv) file, can you post it? That will allow us to provide proper advice

[Rundover]

Attempting to add attachment.28554

[Gary Campbell]

Without the crv file its hard to make suggestions, but I can give a few pointers. Based on those vectors you should be in the 2ips range, 3 at best, assuming the machine is adjusted tight and your ramp settings are optimized for the curved vectors.

You should be taking 1/4 to 3/8 per pass, not 1/8. Your rpm should be 12 -15K cut direction conventional

[Rundover]

I tried to cut 1/4" @ 2"/sec with 12K RPM but the bit heated up and broke 1/3 the way in the program. Cutting 1/8" will allow me to at least cut the hole sheet. In the attached image you can see a brand new bit cutting just fine but as it progresses down the board you can see the cuts getting worse.
Where is this cry file?

[Gary Campbell]

Can you post the bit specs: Mfgr, material, etc

[Rundover]

The attachments photos show a new bit next to one that just ran one panel - 6,000RPM with a 3"/sec cut speed cutting 1/8" each pass. This bit looks better than most after the cut but as you can see it is done. Close ups show the bit getting clogged. The final image is where I cleaned the tip so I could see the cutting edge getting rounded over.
Bit is a Southeast Micro-grain solid carbide spiral - SRD220

[Rundover]

Material is Black diamond MDF 18mm
http://packardforestproducts.com/wppackard/wp-content/uploads/2012/02/BLACK-DIAMOND-MDF-WEBPAGE-2016

[knight_toolworks]

I thought I had it bad thats really bad. did the upcut last any longer then the downcut? the only thing I could think of is a roughing bit like this but you never know. maybe it is time to get a waterjet involved. did you contact the manufacturer and ask them about cutting it?
http://www.talkshopbot.com/forum/attachment.php?attachmentid=28570&stc=1

[Rundover]

Contacted the manufacture and they said that they have never herd of any issues with cutting their product.

[Gary Campbell]

Rundover...
Can you verify which router or spindle you have and what method you use to change the RPM? What CAD/CAM program are you using to develop your toolpaths?

[Rundover]

I have been cutting the last of the sheets at 12,000rpm, 3"/sec, and added a 3 second pause before the plunge which had the best results. I was getting about 15% clean cuts before they started going bad but the bit would last cutting the whole sheet. Interestingly my shop manager accidentally set the Z zero 1/4" too low and was cutting into the spoil board but the sheet cut clean for 80% until the bit broke. So somehow the MDF spoil board was cleaning the bit on the way down.