Z Axis calibration

Hello,

I'm having a bit of a issue, I calibrated the z-axis by telling Repetier (using the manual controls) to move Z by 10 and measured the distance moved using my callipers and updated the firmware accordingly (Marlin). Brilliant every time I tell it to move 10 it moves 10mm, great....however when I print something the prints are approximately half the height they should be.

Have I missed something am I failing to take something into account?

Repstrap built from 4 Epson Stylus Colour printers (2x600, 1x640x 1x670) and parts from 1x Kodak Hero 7.1
Ramps 1.4
Z-Axis = 1/8 stepping
X/Y Axis = 1/16 Stepping

Any advice would be greatly appreciated.

Thanks in advance

Johnny

You may have the acceleration or the max jerk speed set too high, so that every time you do a Z movement, it loses a few steps. So lots of short movements will lose more steps than one long movement. A slipping gear on the Z motor shaft can have a similar effect.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks, I'll have a look at the firmware and check the gearing and let you know how I get on.

Edited 1 time(s). Last edit at 07/01/2015 09:40AM by johnny2377.

Suggest doing Z axis calibration with a larger total distance then 10mm. Try 100mm if you can.

Quote
AquaticsLive
Suggest doing Z axis calibration with a larger total distance then 10mm. Try 100mm if you can.

+1

I have adjusted the jerk setting and that does appear to have solved the problem. I will check again with larger distances.

I have created a little gcode file take 50 steps at 0.2mm intervals (sleeping for half a second between each instruction).

Thanks for all your suggestions.

I was bored of writing out all of the lines of gcode so I wrote this script to produce movements tests for me. Hopefully others will find it useful.

http://www.thespicers.me.uk/gcode.html

Edited 1 time(s). Last edit at 07/02/2015 02:56PM by johnny2377.