Micro Mark Mini mill converstion

[CNCadmin]

Well I'm finally done with my Micro Mark mini mill cnc conversion. I converted it it all ball screw and servo motor. I'm using Gecko 320 drives and camtronics power supply at 80 volt and 20amps. The system is geared 20:1 the ways were lapped and I replaced the gibs with brass.

The z axles was machine from Ron steels plans, and modified for servos.

[CNCadmin]

Here are some pics of my z axis assembly.

[CNCadmin]

The belt pulley for the z axis is too big in dia and the motor for the spindle hit's it so I'm in the process of changing it.

[JFettig]

I assume you wont be running any coolant? Also, it looks like the X axis motor will be mighty close to the column? will it fit?

Have you considered converting your spindle to belt drive? Its much quieter and you can calculate the speed of your liking to an extent. 3000rpm is great for that motor, I have taken .25" deep cuts with a 3/8" rougher on mine at about 2500rpm and the machine started chattering before the motor crapped out.

Jon

[CNCadmin]

No problem with clearance everything fit perfect just the one belt pulley I have to change.
I have looked every where for info on converting to belt drive, please share how to do it.

[balsaman]

Why the brass gibs?

Eric

[CNCadmin]

Lower coefficient than the iron on iron. When I lapped the stock set-up what i found was I was just wearing away the metal and had to keep tighten the set-screws, with the brass that did not happen and because of that I ended up with no play in the x and y.

[JFettig]

I took my spindle and all that other stuff apart so long ago that I dont even remember how it all went together and all, but basicly when you take off the motor mounting plate, theres a spacer ontop of the top bearing and on top of that is the spanner nut, I think thats how it goes, What I did is cut the spacer down, made a pully that goes over it and use the spanner nut and tighten it down on top of it, I made a pully that I press fit onto the motor shaft and a motor mounting plate. I am making a new motor mount for my new motor along with new pullies.

-edit- I too have brass gibs on my machine

Jon

[HomeCNC]

Paul,

On your first post in this thread you said you have the camtronics box running the servos at 80VDC!!! Thoes Clifton servos are rated at 12-60 with a nominal at 36VDC. Are they getting very hot when you run at that voltage?

[CNCadmin]

Yes I'm running 80vdc and no their not getting hot at all so far.

[balsaman]

They will only see the 80 volts when near stalled. Otherwise they see much less voltage.

Eric

[balsaman]

Did you use the Mcmastercarr ballscrews? One nut or two per screw? Any backlash?

Eric