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Author Topic: Non repeatable movement  (Read 232 times)

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Offline PeteG

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Non repeatable movement
« on: December 26, 2019, 07:17:22 AM »
Hi, I'm having some issues with non repeatability. I shall explain:

X0 (Ref 0 in the software)
X15 (In inches)
X0

Cutter head moves 15" to the right, stops and returns to zero, but it doesn't. It says 0 in the software but the cutter head stops short by about 0.25". Similar situation with the Y and Z axis.

Hema 23 motors, standard driver boards, Mach 3 software (obviously), timing belt for X/Y axis, lead screw for Z axis.

So what am I doing wrong?

Offline Tweakie.CNC

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Re: Non repeatable movement
« Reply #1 on: December 26, 2019, 07:27:26 AM »
Sounds like you could be loosing steps because your max. Velocity / Acceleration is set too high.

Add the line;

G01 F30

to the start of your Gcode. Does this resolve the issue ?

Tweakie.
KEEP SAFE !

Offline PeteG

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Re: Non repeatable movement
« Reply #2 on: December 26, 2019, 10:16:44 AM »
Thanks, I'll give it a try and let you know.

Love your profile pic.
Re: Non repeatable movement
« Reply #3 on: December 26, 2019, 07:04:46 PM »
You may need to calibrate your motors to get the proper settings
Cadcam Man
Re: Non repeatable movement
« Reply #4 on: December 26, 2019, 07:05:48 PM »
Tweakie is right adding a feed line should help isolate were the problem is
Cadcam Man

Offline PeteG

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Re: Non repeatable movement
« Reply #5 on: December 29, 2019, 12:23:54 PM »
Hi everyone

I have solved the issue: I had the step pulse far too short (I used the default of 3) and the number of steps per inch way too high, this must have resulted in lost pulses. Changing these settings, along with changing the feed rate and acceleration has resulted in repeatable results and a much smoother operation.

Thanks for your suggestions, no doubt I'll be asking more questions in the future.

Cheers and a happy new year to you all

Peter