Losing steps, smooth jogging, choppy running.

[Ranscon]

Hi all,

Hope someone can help me. New machine, just setup, Keling 425 motors, 4030 drivers, c10 bob, 24v dc 8.3 amp ps. 10tpi Acme screws, delrin anti backlash nuts, Wood routing. Pc is 2.2ghz, 512 ram.Mach3

When I jog the motors manually, I can move all 3 at the same time and they all sound smooth and move nicely. When I try to run a g-code program (with z up so it's not even cutting anything) the motors sound really choppy and it loses a few steps at z and a lot of steps at y, X looks pretty good. I have calibrated the machine with a digital caliper and it is perfect(.000). I am full stepping but have tried 1/2 and 1/4 with the same results. The motors are set at 3 amps on the driver boards. Tried them at 2.7 and 2.1 same results.
My velocity is at 18 and accel is at 4 (much slower on the vel and they run choppy when jogging).Speed is not a big issue but I beleive these motors should run much faster than this shouldn't they? I can set "home" and run thesample "roadrunner" program with mach3 and when i'm done, if I hit Return to z, z is off about .125 and y is off by about 2 inches +- .

Any advice will be greatly appreciated.

Thanks, Jeff

[TOTALLYRC]

Hi all,

Hope someone can help me. New machine, just setup, Keling 425 motors, 4030 drivers, c10 bob, 24v dc 8.3 amp ps. 10tpi Acme screws, delrin anti backlash nuts, Wood routing. Pc is 2.2ghz, 512 ram.Mach3

When I jog the motors manually, I can move all 3 at the same time and they all sound smooth and move nicely. When I try to run a g-code program (with z up so it's not even cutting anything) the motors sound really choppy and it loses a few steps at z and a lot of steps at y, X looks pretty good. I have calibrated the machine with a digital caliper and it is perfect(.000). I am full stepping but have tried 1/2 and 1/4 with the same results. The motors are set at 3 amps on the driver boards. Tried them at 2.7 and 2.1 same results.
My velocity is at 18 and accel is at 4 (much slower on the vel and they run choppy when jogging).Speed is not a big issue but I beleive these motors should run much faster than this shouldn't they? I can set "home" and run thesample "roadrunner" program with mach3 and when i'm done, if I hit Return to z, z is off about .125 and y is off by about 2 inches +- .

Any advice will be greatly appreciated.

Thanks, Jeff

Hi Jeff.
I took a lok at what you have and I can see several problems.

You have part of the answer right in front of you. When you jog the motors are going full speed and you said if you set the velocity below 18ipm they get choppy. When you run the g-code they are running well below 18ipm I am assuming.

Try changing the step setting to 1/8 or possible even 1/16. Large step settings will give you chopyness at low speeds.

Those motors are rated at 83v max and at 24v you are sacrificing a lot of speed. Info from the keling website 6.8mh inductance = 83v max.
At 24v you may be disappointed in their performance.

The amp rating is 2.8, don't set the drivers any higher or you will cook a motor or 2.

Verify that you have the motors wired in bipolar parallel. See kelings diagram if you are not sure what this means. If the motors are 4 wire then disregard.

Try all that and let us know how you make out.

Mike

[Ranscon]

I microstepped my motors to 1/8 and it seems to be fine now. When I calibrate "steps per unit" It comes back with 32000(instead of 16000) . Is this because I have sherline 1/2 step active? Should I have it active? It was reccomended by Keling I beleive. Is this the same as 1/16 stepping?

Thanks, Jeff

[TOTALLYRC]

I microstepped my motors to 1/8 and it seems to be fine now. When I calibrate "steps per unit" It comes back with 32000(instead of 16000) . Is this because I have sherline 1/2 step active? Should I have it active? It was reccomended by Keling I beleive. Is this the same as 1/16 stepping?

Thanks, Jeff

I know nothing about the sherline half step mode. I am sure somebody will know. If Keling suggested it and the machinje runs fine, don't worry about it.

Mike