1 inch partical board

[carlhopkins]

I have a PRT Alfa 3 HP columbo 1 Phase,
what is the best bit to cut 1 inch PB with? also feed speeds and spindle speeds if anyone has cut this nasty stuff. Any and all advise other than run like the wind. The material is waiting on me to slice and dice.
I need to cut 18 sheets, not really in a hurry but would I like to get done.
thanks in advance Carl

[Gary Campbell]

Carl...
If you are looking for good edge quality stay in the 5-6 ips range. 2 pass. 3/8 Compression. 13500 rpm.

IF you are looking for very good edge quality, same speed & rpm settings, but use a climb mill first pass (1 or 2)and leave .030 skin. Follow with a conventional pass thru to remove the skin.

This should get you close... you may have to play with both rpm & cut speed to find the sweet spot with this material for your machine.

Gary

[carlhopkins]

thanks Gary,
I will be putting HPL on all surfaces of this so getting a clean edge is not a must but I do not want to waste good bits and good time if it is not required.
If I use a 3/8" bit, sounds like I need to turn off the step down feature and then program appropriate. Is that correct?
again thanks, Carl

[Gary Campbell]

Carl...
A lot of the toolpath stategy is getting things just right for your machine. I would do a test cut with the stepdown, and if all is well, try one without. You need to make sure that your machine, bit and spindle will cut properly at your selected speeds. I prefer to get one that works and then increase. If you have good chipload, dont forget to increase rpm along with the move speed.
Gary

[rb99]

What do you mean by good chipload?

Thanks,

RIB

[Gary Campbell]

Richard...
Proper feed rates and rpm result in chips off the bit rather than dust. These can actually be measured with a digital mike. There are many chipload calculators out there, but few compare to experience and a good "ear". Another benefit of proper chipload is a cool tool. When cutting with a proper chipload your bit will be near room temperature. This can mean the difference of 2 sheets per bit to 30 or more.
Gary

[Gary Campbell]

Richard...
Here is a picture example of chips being cut, rather than dust. Wood shown is African Mahogany, bit was O Flute. As you can see, you can use a mic to measure the thickness of the chip. These measured .010-.012 on the PRStd that they were cut on. On our Alpha, we could increase to .015-.018. The idea is to keep the tool shearing off material rather than sanding it off. This allows the chips to cool the tool.

7740
Gary

[rb99]

Thanks

Richard