[Ukraine Train]

Hello all. I would like to build a machine that can cut 1/2" plywood in one pass (full end mill width) and with decent speed. I'm not sure how much power and torque this takes for the spindle and stepper motors. Assuming I can make the machine rigid enough, would a 2.2kW spindle and NEMA 34 stepper motors handle it? Would closed loop motors be needed due to the loads? For the drive system would a rack and pinion be best?

[routalot]

Consider how hard you would have to push a hand held router-it isn't that hard at a moderate rate.The bigger hand held machines will be about 2.2kW.It then becomes a matter of calculating the best way to turn the energy of the stepper into a force to accomplish that and you have a choice between leadscrews or belts.Long leadscrews may whip at speed or you can fix the leadscrew and find a way to rotate the ballnut,in either case you can generate sufficient force with a NEMA 23 of reasonable size.As indeed you can with a rack and pinion.There are people on this forum who know far more about inductance than I ever will and who may guide you in the best direction and that direction may be away from NEMA 34's.

[ger21]

Hello all. I would like to build a machine that can cut 1/2" plywood in one pass (full end mill width) and with decent speed. I'm not sure how much power and torque this takes for the spindle and stepper motors. Assuming I can make the machine rigid enough, would a 2.2kW spindle and NEMA 34 stepper motors handle it

1) define "decent speed".
2) Depends on how much weight you need to make it rigid enough

You should be able to build a machine with Nema 34 steppers that is capable of stalling a 2.2Kw spindle. But you should be able to cut 1/2" plywood at a few hundred inches/minute with it.

Would closed loop motors be needed due to the loads?

Imo, closed loop steppers are never needed. They are a solution to a problem that's created by the user.

For the drive system would a rack and pinion be best?

If by best, you mean better than any other option, probably not. But, depending on the size of the machine, they are often the easiest to implement at a low price, which is why most people use them on larger machines.
Also, keep in mind that rack and pinion comes in varying degrees of precision, and different methods of implementation. You can spend $500 on a rack and pinion system, and you can spend $10,000.
So the term "best" has to be used with a lot of qualifiers.

[Ukraine Train]

For cutting speed I guess I would want around 40 in/min. Is this a reasonable expectation? I want something for light to medium duty commercial work so cycle time is somewhat important. My prior experience is with industrial large machines cutting steel so I'm not sure what to expect from a small wood-cutting machine.

[ger21]

That's incredibly slow, and will result in overheated bits that won't last long. You should be looking at 150-200ipm MINIMUM. Which is still quite slow for a commercial environment.

Industrial routers cut at 800-1200ipm, and high end machines can cut much faster than that.

[Ukraine Train]

200ipm is possible when cutting full depth through 1/2" plywood and full width of the end mill (3/8"?)? Ok, maybe I am underestimating what is possible. What components are needed to achieve this?

[ger21]

Yes, very easily with Nema 34 steppers and a 2.2Kw spindle. With a bigger spindle, and servo motors, 800ipm or more would be possible,
Keep in mind that not all Nema 34 motors are created equal. Depending on the components you choose, smaller motors are often better than larger motors.