Quick look at modified rotab

[tonyfoale]

I recently bought a 200 mm rotary table to fit up with a motor as a 4th axis on my CNC mill. I wanted to largely automate making clutch centres with my pneumatic slotter previously posted here Slotter or broach driver. , and also as a camshaft holding and rotating headstock for a planned CNC cam grinding machine.

Click images for full size.

In addition to being purely CNC driven I wanted to have a manual control with some useful automatic features. So I built a suitable control box with three operational modes. Viz:
1. Jogging. The table rotates as long as I hold a button down. Speed is variable between dead slow to plenty fast enough.
2. Indexing. I enter a number of divisions in a circle and each time I press the GO button it indexes around to the next division.
3. Go To. I enter an angle and press GO. It then moves to the angle at the set speed.



A couple of days back I needed to do some indexed milling and drilling on some motorcycle brake hubs for my race bike. This was the first job for the device and it was a great time saver. These are the BEFORE and AFTER pix.



I made a 55 second short video which shows the use of the indexing and continuous mode.

I will make a full post showing full details of the motor conversion and control unit in due course. For now I only have time for this quick look

[hemmjo]

Very nice.

[Saltfever]

Very nice. Is there backlash compensation in the software? Or is there a brake of some kind? How do you "tighten" the table? Looking forward to learning more about the controller. THANK YOU for all your contributions.

[tonyfoale]

Very nice. Is there backlash compensation in the software? Or is there a brake of some kind? How do you "tighten" the table? Looking forward to learning more about the controller. THANK YOU for all your contributions.

No, I did not put in any backlash compensation. Any work that I anticipate can be done by always going in the same direction.
A brake has been made but I am waiting on a pneumatic cylinder to power it. I could not find a suitable solenoid, which would have been my first choice. The controller releases the brake, moves to position and then reapplies the brake. I won't have time to elaborate on the controller until mid March.

Click thumbnails for full size pix.

The brake. I do not seem to have photos of the actual brake shoes but these show the cardboard templates for the shoes. I had that air cylinder but it is "push" only and I need a "pull" so a two way version is on order.

[Saltfever]

Thanks, Tony. I like how the brake fits within the thickness of the table. Nice and compact.

[hemmjo]

This pad anchor block makes me wonder about a small mechanical caliper and disk to lock the table. Just thinking out loud. Very nice project.

[tonyfoale]

This pad anchor block makes me wonder about a small mechanical caliper and disk to lock the table. Just thinking out loud. Very nice project.

That is your motorcycle influence shining through. I did consider a disk brake but it just seemed more complex to fit the disk. Using the inside out drum brake uses the existing table as the "drum" and the brake shoes are probably easier to make than a caliper. So I'm quids in.