[phomann]

Hi All,

I'm converting a TM20VL mill over to CNC. The mill is similar in size to an X3 or Grizzly G0704 but with a 700mm long table. The full writeup is here, http://www.cnczone.com/forums/bencht...onversion.html The conversion has been going for about 2 years now.

I've set the machine up with 570 oz.in 5A stepper motors. The pulleys are set up for a 1:1 ratio.

I have a G540 based controller for my Taig milling machine and it was always one of my goals with this conversion was to determine how well 570oz.in motors a machine of this size would run off a G540 controller that is limited to 48V and 3.5A/ph. This was also part of the reason that I used a pulley drive setup so that I could try different ratios if need be.It must be said that the main reason for the pulleys is to tuck the motors out of the way which has worked out very well.

I set the current for the motors at the maximum 3.5A and started to tune them up in Mach3, not sure what could be achieved. To my surprise I was getting 6 meters a minute (236in/min) out of the X and Y axis. I left the Z at 4meters/min. That seemed like more than enough speed for rapids on a machine this size.

I then wrote a small G-Code file to rapid the X and Y to the extent of their travel. I'm getting 470mm travel out of the X axis and 190mm out of the Y.

A short video of the machine running this program is here;

http://youtu.be/caZ6F5MT8FA

I then loaded theMach3 road runner program as it is a good test to check for motor stalling and it ran fine, albeit a lot of rocking and shaking. I put themill head on table to add some extra weight. The video is here;

http://youtu.be/AjfhQUBjBjI

I'll end up reducing the rapids to no more than 5m/min (200in/min). I still have to test the Z-axis but I'm sure that it will be fine running of the G540.


If anyone is considering converting one of these machines, a G0704, BF20 or similar sized machine I'd suggest seriously look at the Gecko G540 as an option. I don't believe that a larger driver will provide better or useable performance. I could try using the 387 oz.in motors but they only have a 1/4" shaft and my pulleys have a bore of 3/8"

At this stage I'm not going to bother about looking at larger stepper drives for this machine.My initial plan was to use a set of G201s, but the G540 seems a perfect fit.

Cheers,

Peter

[storm2313]

Peter,

The system you assembled with the 570 oz in motors are a powerful combination especially considering those motors are also available in a 3.5a version. The G540 will easily run that setup, and if you did use the smaller motors I don't think the cost savings would justify the performance. Good luck on your new setup.

Vince

[Aaron Powter]

Hi Peter, congratulations on the conversion of your Titan TM20LV. That thing is rapid feeding like it's on steroids. Very impressed indeed. Just goes to show how versatile the little Gecko 540 really is. So when do you think it will be finished? Can't wait to see it spinning bits and spitting chips lol. Cheers, Aaron.

[phomann]

Hi Aaron,

Thanks. The rapids won't be left at that speed as I don't think they're kind to the machine.

I've still got a bit to go. I need to put the head back together, finish the stand and build the controller.

I also need to get the slot in the Z-axis column extended so I can get the head lower.

Every time I work on it I feel guilty as i has so many other jobs I should be doing.

Cheers,

Peter

[Aaron Powter]

Hi again Peter,

When you say slot the Z-Axis column do you machine the mid section down further or actually machine into the base to get the column lower. If you need a hand to machine it give me a call and I'll help you out. My new engineering workshop is only a couple of weeks away from being finished. My school (Trade Training Centre) is located in Sunshine.

Cheers, Aaron.

[morestuff]

Where can these 570 oz.in motors be purchased? The cable exit does not resemble any that I have seen advertized.

Thanks,
Steve

[phomann]

Hi Steve,

The stepper motors are these;
570 Oz-in NEMA 24 Stepper Motor (Dual Shaft) [SM-08]

The stepper motors have covers on them, similar to these.
NEMA 23 Stepper Motor Back Cover Kit [SM-10]

The 570 oz.in motors are NEMA 24 sized motors. That is, the body of the Stepper is 60mmx60mm. The covers above are for size 23 motors with a body dimension of 57mmx57mm. The covers do not the size 24 motors.


The covers on the motors on the mill are made out of aluminum, made as specials by the manufacturer of the covers in the link.

Cheers,

Peter