1.7*0.74*0.4m Mill / Router building...

[Jonathan]

Irving2008,



Would you be so kind so as to post the link to this thread? I am unable to find it.

Many thanks,

Kenneth

Here it is...

http://www.cnczone.com/forums/showth...=13593&page=26

I can't find the link to the shorter thread where the method I use is dicussed, but it's linked off that thread somewhere!

I may use the method discussed in the above link for the Z axis as I'm running out of space.

[Kenneth Paine]

Lee, thanks for letting me know.

Jonathan, thanks for the link. Fascinating!

Kenneth.

[Jonathan]

Been at university recently so have not had much chance for router building. I came back on a couple of weekends and made a few bits - stepper motor mounts for X-axis and bearing mounts also for X-axis. I decided to scrap the latter and buy two SBR25-2000mm rails, which have now arrived. No customs charges either

Also had a change of plan with the Z axis. I couldn't get the drive mechanism I've used on the Y-axis to fit at all easily, so I decided to go for the easy option and bought a RM1605 ballscrew at the same time as the above bearings. I got back for Christmas holidays on Friday and on friday/saturday CNC milled the bearing mounts and ballnut mount for Z. One angular contact bearing at the stepper end of the ballscrew, and a normal bearing on the other end.

Somewhat randomly I picked a 42T pulley for the stepper and 22T for the ballscrew, so effectively the pitch is now 9.545 mm. PM752 driver with 3Nm motor as with the other axis and I'm getting 10,000mm/min :exclaim: with 1000 acceleration. That means only 2.5 seconds to travel the whole 400mm Z axis. I might try some other pulleys/ratios but that can wait until I've done the X-axis and found which of the pulleys I have is most optimal...
Backlash on Z is negligible. I've not measured it with the more accurate DTI yet, but the 0.01mm resolution DTI moves just over one division if I move the motor back and fourth one quarter-step (0.012mm)...To be expected really since the mass of the Z axis itself should eliminate the backlash.


All that's left now is to mount the spindle/router, mount the X-axis linear bearings and do some wiring. If I had the metal to mount the bearings I'd probably be 'making chips' by tomorrow morning. Can't wait

I'll add some photos soon.