Help select Servo type, conversion from steppers.

[fabhund]

Ok I understand your thinking slightly better know but still don't think servo's are required.! Also not so sure why you'd want to go so slow as 50mm/min but sure you have a good reason.?

From the comment above I'm notsure you have the machine setup very well. For instance you say Z axis is using 6mm pitch and you are set to 80 steps/per.? This would mean the drives being set at 480 micro steps which is an odd number for micro stepping and I havent ever seen any drive with this setting.!

Higher micros stepping really helps smoothen out stepper motors and with good quality digital stepper drives then motor smoothness is excellent. Throw into this mix external motion control card and it gets even better as the smoother and higher pulse rate also helps smoothen motor action.

By the time you have bought servos and motion control card along with probably having to use some gearing ratio to account for faster spinning servo's you'll be well outside your $300 per axis max budget.
1 x $300 would nearly buy you 3 x digital drives and motion control card which will make big difference to machine performance if setup correctly.

Servo's don't always make for a better machine and there is much more involved to getting the best out of servos. Often the extra resolution etc is wasted due to rest of machine not matching up.!

Dear Sir.
Thank you for your feedback.

The 50mm/min is just for touch off the tool height, so youre correct it's not so often it's used.

I didn't want to come with all my details. I just wanted to mention that I ran it around 80 puls/unit
X axis: 3200 steps/rev, 40mm lead = 80 puls/mm
Y axis (+1 slave): 800 steps/rev, 10mm lead = 80 puls/mm
Z axis: 500steps/rev, 6mm lead = 83,33333333 puls/mm

My drives are from JMC, type: 3M660
And i'm running it on a 48VDC switchmode 8,3A (Rated) 400W (I do have a 2000W toroidal trafo, but the inrush current blows my 13A fuse :-/

I will start out with an external motion controller: Warp9 ESS smooth stepper ?
And try to bump up the microstepping.

Thanks for your comments.

Best Regards, Bo Andersen.

[fabhund]

Update:
Got the ESS Smooth stepper from Warp9. Connected it directly to my 2 existing BOB's. And after a few tries on the ethernet connection, it works.

So I'm up to 416,6666 steps/mm on the Z-drive and giving a speed of 12500mm/min
Y+1 slave axis, is 400 steps/mm and 18500 mm/min
X axis is 160steps/mm and 25000+ mm/min.

Most of the Z-axis resonance is gone, I guess there will always be some. But much lower noise.

Now is left to find the Acceleration/speed trade off.
Y axis (the worst one) is around 1200mm/s^2 I could set the rapid speed down, and increase the Acceleration.....

Further I need to figure out some 'issues' with the smoothe stepper, but that's a different thread.

Best Regards, Bo Andersen.

[JAZZCNC]

Great news.!! . . . Now buy some Lead shine EM806 Digital drives and take it to the next level. They are light years better than those drives you are using now.
Digital drives are SOOOOO much smoother than analog drives and run the motors much cooler and allow higher feed rates still.

With Digital drives and ESS you'll be able to run much higher Micro steps which give smoother running motors. Only way to appreciate the difference is to see it for your self.!