Belt-driven spindles
 

Copied from another thread:

take a look here G'

http://www.buildyouridea.com/cnc/pcb...pcb_drill.html

Irfan, from that site I found also this spindle idea:
http://www.buildyouridea.com/cnc/Shr...e/spindle.html
I tought about doing something very similar for a long time.
What do you think about it Gerald?


Pablo

Belt-driven spindles have been around much longer than high-frequency spindle motors.

Years ago I had great success with Habasit belts.

Just get the spindle and be happy.

This goes up to 10 000 rpm:
http://www.atlanticequipment.com/54.html
. . . . which is still a bit slow for the type of V-cutter work that Irfan is doing.

But you can see that a flat belt is used instead of a "O-ring" round belt. Drilling PCB's requires much, much less power/torque than v-carving.

Some belt-driven spindles

We are using words than can cause confusion. . . . .

A "spindle" is simply a shaft running in bearings. Spindles have been around since the Industrial Revolution, when they were powered by steam engines and flat leather belts. Electric motors integrated inside the spindle are a newish invention, from when methods of making high-frequency AC became more available (via thyristors and VFD's).

"Electro-motor spindle" is a more correct term for the thing we simply call a "spindle" in the CNC world today. But let's not confuse ourselves, we more or less know what you mean when you say just "spindle" :)

Has anyone ever considered using the spindle from an industrial drill press - or even from a vertical milling machine? The Z-axis motion would come from the spindle only and the motor would remain stationary. You can find these things in the 3+ hp range quite easily and with z motion of up to 6" or more - what I don't know is what the maximum rpm would be for the bearings, etc. I suspect that it would be well south of 20k, but it may be possible to address this by using "better" bearings on a spindle rebuild. By using the spindle from a turret mill, you would be able to use R8, or ER32-40 collets and create a real ATC as well.

Brian