Cnc router wood "roughing bits" anyone used these before?

[gavztheouch]

I am working on a job right now profiling some OSB 18mm sheets. The dimensions are somewhat important say plus or minus 1mm but the edge quailty is not, just as long as it does not right the board to shreds with tear out.

I am currently running a 9.5mm compression spiral from wealdon tools, they are about £50 each :nightmare: the finish is good for about 10 to 15 sheets of a mixture of birch ply, mdf and standard ply. I feel this bit is too good to use on OSB, the edges are crisp on both side of the part but this is overkill.

With the compression bit I am running the machine at 3.6-4m/min, its a 3 axis thermwood with a 10hp head. I currently cut the 18mm board in two passes.

I know I should be doing this in one pass and prob at a higher feedrate but im scared about breaking bits at £50 each.

I think I need a rougher bit, apparently these should stay sharp for more boards, cut with more speed and less noise. The trade off is the cut is not as clean as the cutting edge is serrated.

Looking for some advice from anyone with experience cutting OSB or plywood with these bits. Where should I be looking to buy these from. Should I go for a larger diameter bit than 10mm to avoid breakages.

Many thanks

[Ger21]

With a 2 flute bit, you should be cutting that at about 15-18m/min in one pass with that tool, at around 17,000 rpm. I cut plywood and particle board with a 3/8" compression all the time at 20m/min.

Bump the speed up to 15m/min and your bit will last at least 5x longer. And they won't break.

A roughing bit would need to be run at 20-25m/min to really take advantage of it, Running it too slow will dull it very quickly.

[JAZZCNC]

I think I need a rougher bit, apparently these should stay sharp for more boards, cut with more speed and less noise. The trade off is the cut is not as clean as the cutting edge is serrated.

Looking for some advice from anyone with experience cutting OSB or plywood with these bits. Where should I be looking to buy these from. Should I go for a larger diameter bit than 10mm to avoid breakages.

I Don't cut wood with Carbide serrated edge rippers but I do often cut aluminium with them and I've cut 10mm deep with 8mm 3 flute for testing purposes and didn't snap it and thats with Chinese WC 2.2Kw spinlde. I regularly cut at 6mm in Ali and it's like knife thru butter so I don't see any reason why they shouldn't shred OSB without any effort.
Infact I've just cut 100 slots 1000mm length @ 10mm DOC with a very very tired ripper in Trespa Athlon resin board which is much much harder than OSB and quite abrasive and it didn't flinch so OSB wouldn't touch it. I get decent tool life in Ali so think you will have no problem in OSB.

[gavztheouch]

Hmm so I have been going way to slow. My spindle speed is fixed at 10,000 rpm. I need to check this with a tach but asuming it is 10,000 rpm I would need to adust that 15m/min feedrate down I guess. Something around 8m/min?

Gerry what brand/type of compression cutter do you use?

[Ger21]

I typically use either Onsrud or Vortex ( Vortex Tool: Solid Carbide Router Bits and Compression Spirals for woodworking, plastics and non-ferrous industries. (http://www.vortextool.com) )
At 10,000 rpm, 8M/min sounds like a good start. You might even start with your FRO turned down a little, and work your way up to the 8m/min I don't have any experience with a low speed spindle like that.

I have used wood roughing bits, and as Dean says, they do cut like butter. But I don't think that you really need one. I can suggest not cutting MDF with the bit your using on OSB, as MDF will dull the bit a little faster.

[gavztheouch]

10,000 rpm does sound a bit slow, will need to check out what it is actually is running at.

[gavztheouch]

I just checked out the spindle and its running bang on 15,000 rpm this means I can get closer to the 15m/min feedrate which has got me quite excited to see what it can do.