calibration not going well

[Terry1956]

report_B4107B778E04-1109237681_2025-02-08_15-36-22.zip

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hi, for some reason my milling machine will not calibrate. it was ok until i needed to fit a new drive belt and now its just not playing ball.
my stepper driver is set to 12800 steps per revolution. it takes 6 revolutions of the drive sprocket to move 25mm or 1 inch and 12 for the motor sprocket. if i input the command G1 G0 Y5 the mill moves over 30mm. I have tried using the turns per revolution calculator from Marty's Garage which i used before with good results, but this time its just not helping. no mater what i change the results in the wizard and restart c12 the results are the same with distant travelled, its just the speed that changes. can anyone help me out here. i have attached the acorn report to this post thanks

[suntravel]

25mm/12=2.0833 rev/mm not 2.6514 from your report in x

But the backlash 0.29 / 0.92 mm needs to be fixed first. Anything over 0.04 is not good and over 0.06 not acceptable.

Uwe

[cnckeith]

25mm/12=2.0833 rev/mm not 2.6514 from your report in x

But the backlash 0.29 / 0.92 mm needs to be fixed first. Anything over 0.04 is not good and over 0.06 not acceptable.

Uwe

what uwe said.

12,800 steps per rev? motor/drive make and model?
photos of machine? this info would go a long way in helping you out!

[Terry1956]

Thanks for your interest. I am using Nema 23 motors with CL57T closed loop stepper driver. The bullscrew is on a 2 to 1 sprocket system. So two turns of the motor = one turn of the bullscrew. It takes 12 turns of the motor to move 25mm or 1 inch.
I have set the driver to 12800 pulses.
Watching Marty’s garage he starts with a setting of steps per revolution at 200. However with this setting I get no visual movement at all. The back lash is not an issue at this point as I am getting nowhere near a true command movement and I am always setting off from the same point with any free movement taken out.

[cnckeith]

why do you have the driver at 12800?

12 turns per inch?

what is the ballscrew pitch?

what kind of machine is this? photos please.

- 2:1 with a 5mm pitch screw = 2.5 mm / rev ( or 10.16 turns / inch)

- 2:1 with an imperial screw pitch of 5 turns per inch = 10 turn / inch ( or 2.54 mm /rev )

[cnckeith]

you are also using a very old version of CNC12.

now would be a good time to install the latest version (v5.30) which is free.
so we are all using the same version of CNC12, that way we can give you the best advice.

you have a lot of communication errors in the CNC12 error log.
02-08-2025 15:17:32 946 PC resending # 638
(4) 02-08-2025 15:17:33 944 MPU requested resend # 16
(4) 02-08-2025 15:17:33 946 PC resending # 652
(4) 02-08-2025 15:17:33 944 MPU requested resend # 17
(4) 02-08-2025 15:17:33 946 PC resending # 655
(1) 02-08-2025 15:17:33 406 Emergency stop detected
(4) 02-08-2025 15:17:34 944 MPU requested resend # 18
(4) 02-08-2025 15:17:34 946 PC resending # 657
(1) 02-08-2025 15:17:45 204 Exiting CNC...Normal Exit (66)
(1) 02-08-2025 15:17:50 199 CNC Started
(4) 02-08-2025 15:17:55 9039 Software Exited, Cycle E-Stop/Reset to Continue
(4) 02-08-2025 15:17:55 944 MPU requested resend # 19
(4) 02-08-2025 15:17:55 946 PC resending # 952
(1) 02-08-2025 15:17:56 CNC12 Acorn Mill v4.82
(4) 02-08-2025 15:17:56 9033 Reset Initiated, Press Reset to Clear
(4) 02-08-2025 15:17:56 944 MPU requested resend # 21
(4) 02-08-2025 15:17:56 946 PC resending # 1031
(4) 02-08-2025 15:17:59 4032 Reset Cleared
(4) 02-08-2025 15:19:04 944 MPU requested resend # 22
(4) 02-08-2025 15:19:04 946 PC resending # 1036

these need to be solved first. here is how you do that. follow every detail.
viewtopic.php?t=1451

[Terry1956]

Hi, thanks again for replying. Last night I updated C12 with a clean installation. I used the preset clear path setting and set the microsteps both on the stepper driver and within C12 to 4000. At the start C12 was showing steps per revolution at 5.08 which I know is wrong as it takes the motor sprocket to turn 12 times to move the bullscrew an inch or 25mm as I use metric.
At this point I just wanted to see if the axis would move ok, which it did. So out of interest I tried to calibrate the axis leaving the revolution at 5.08. I used the command G1 G0 Y4. Asking the machine to move 4mm, I did not want it to go screaming off. The machine moved 19mm. So using Marty’s turns calculator I adjusted the steps, it asked for please see attachment. However the machine on the same command has before moved 19mm yet again. Not the 4mm has commanded, what is going wrong here. I have checked and rechecked all the wiring, dip switches etc.

[Chaz]

Hi, thanks again for replying. Last night I updated C12 with a clean installation. I used the preset clear path setting and set the microsteps both on the stepper driver and within C12 to 4000. At the start C12 was showing steps per revolution at 5.08 which I know is wrong as it takes the motor sprocket to turn 12 times to move the bullscrew an inch or 25mm as I use metric.
At this point I just wanted to see if the axis would move ok, which it did. So out of interest I tried to calibrate the axis leaving the revolution at 5.08. I used the command G1 G0 Y4. Asking the machine to move 4mm, I did not want it to go screaming off. The machine moved 19mm. So using Marty’s turns calculator I adjusted the steps, it asked for please see attachment. However the machine on the same command has before moved 19mm yet again. Not the 4mm has commanded, what is going wrong here. I have checked and rechecked all the wiring, dip switches etc. IMG_3821.jpeg

Can you post an updated report? What country are you in? I'm in the UK and happy to give you a hand on WhatsApp via video chat as needed.

1. Is your driver actually set for 4000 itself? This needs to match between Centroid and the driver.
2. 5.08 is the starting point which is generic. What is the amount you are actually using?

If 5.08 and the 'new' amount both gives you 19mm travel, then it implies the new settings were not saved, hence asking for an updated report.

[Terry1956]

Thanks for reply, yes I am in the U.K., Somerset. Will do the new report later today and post.

[Chaz]

Thanks for reply, yes I am in the U.K., Somerset. Will do the new report later today and post.

Ill send you a PM with my number. Got a call at 12h30 for 30 mins and then another at 16h30 for 30 mins. So anytime between those or after 5pm will work if its suits you.