Z error at first layer when heating time is long

[Dirkkro]

The strating G-code is not perfect when long heat up time is happening. The stepper are powered off during a long preheat preheat Therefore a missalignment may happen at the Z axes up to 0.1 mm

To solve this, a new homeing after preheat solves it

Describe how it would work The printer will run homing again and adjust again after preheat

Describe alternatives you've considered This might be a problem in the Marlin Firmware ? I did not find the timout parameter there for the holding time of the steppers

Additional context This is very clear at my Ender 3 Printer and my old MendelmMax

My Script for Troxy XY2 ....... G28 ; home all axis ;G29 ; auto bed levelling G1 Z50 F240 G1 X5 Y10 F3000 M104 S[first_layer_temperature]; set final nozzle temp M190 S[first_layer_bed_temperature] ; wait for bed temp to stabilize M109 S[first_layer_temperature] ; wait for nozzle temp to stabilize G28 z ; home Z axis ; this is the extra homing after preheat G1 z0.28 G1 X2 Y10 F3000 G92 E0 G1 Y140 E10 F1500 ; prime the nozzle G1 X2.3 F5000 G92 E0 G1 Y10 E10 F1200 ; prime the nozzle G92 E0

[neophyl]

Why are your steppers powered off during preheat ? On all 3 of my printers they don't power off and I have zero trouble with z height. Any z height differences to the platter are usually caused by thermal expansion, the platter itself moves as it warms up. This is why things like mesh bed levelling are best performed AFTER you have heat soaked your print surface, get thermal expansion out of the way beforehand and make probing more accurate.

[Dirkkro]

I verified it, I am not sure why this is happening on my Troxy XY2 aand on my Ender 3 (first model) maybe it is doe to Marlin Firmware? If this is not a common problem, then I know how to solve it for me. Thank you for answring!