# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum > Firmware Enhancements to Marlin >  Z Axis problem

## Martin Kenny

Hi
I have a problem with the Z Axis on my Ender 3 Pro.  The printer has performed well but has now developed an error in the Z Axis.  The first few layers are good.  On subsequent layers the nozzle moves up 0.1 mm greater than the layer height.  The result is that the nozzle gets further and further away from the work piece until it is too far away to make the filament adhere to the previous layer.  At around 6 to 8 layers the gap is so great that the nozzle starts to string spegetti and I terminate printing manually.  I believe the error is in the firmware but need help calibrating the Z Axis.  Mechanically all relevant parts are correct.  Another possible cause is that the stepper motor has gone unstable but I think that is less likely.  I'm using Cura as a slicer and I don't think there are any issues there.  Any advice would be gratefully accepted.

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## TommyDee

Something must be overwriting the layer height with some kind of compensation.  Take a look at the g-code and make sure the code's Z increments are what you expect.  If you have say 0.2mm as a layer height, and the g-code shows 0.3mm between layers, then the problem is Cura.  However, if the layer height is 0.2, Cura g-code confirms this by each layer incrementing by only 0.2, but the printer is physically moving an additional 33%, then I'd say you have a calibration issue with the steppers and the belt gear.  What is odd is that it worked before.  I've seen the wrong belt pulley installed before that would cause this, but in this case, yes, I'd say a bit slipped in the firmware somewhere.  You need to re-calibrate the z-motor's gear circumference... wherever you do that on your machine.  You could just try reloading the firmware.  I don't say that lightly considering the usual risk.  Firmware is indeed where this kind of calibration lives; just make sure it is not something that got bumped in Cura first.

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## Martin Kenny

> Hi
> I have a problem with the Z Axis on my Ender 3 Pro.  The printer has performed well but has now developed an error in the Z Axis.  The first few layers are good.  On subsequent layers the nozzle moves up 0.1 mm greater than the layer height.  The result is that the nozzle gets further and further away from the work piece until it is too far away to make the filament adhere to the previous layer.  At around 6 to 8 layers the gap is so great that the nozzle starts to string spegetti and I terminate printing manually.  I believe the error is in the firmware but need help calibrating the Z Axis.  Mechanically all relevant parts are correct.  Another possible cause is that the stepper motor has gone unstable but I think that is less likely.  I'm using Cura as a slicer and I don't think there are any issues there.  Any advice would be gratefully accepted.


Thanks Tommy.
I did analise the g-code and even edited the z code which had marginal sucess but after a day playing with z steps and g code I settled for flashing a later version of Marlin.  No more problem. :Smile: 
Thanks for your interest.
Martin

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## TommyDee

Love a successful solution  :Smile:

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