How to move Z axis during preheat?  

Eminent Member

Hi Mini users, as I wait for my SuperPinda to arrive I am doing a preheat as usual to help get a good first layer without adjustment. By doing this and using the same filament reel for a long run of prints my Mini is really stable and producing excellent results. Problem: my last model printed was about as high as the Mini can handle. On power on, the hot end is high, meaning it is not benefitting from warming as it is so far away from the print bed.


Having initiated preheat, if I then go to Settings - Move Axis - Move Z, turing the control knob will allow me to raise the hot end even higher but not lower. Why is this and what can I do to move the hot end nearer to the bed during preheat?


I don't understand what Auto Home does but I did try this on a previous occassion to see it that would allow me to lower the hot end but it didn't make any difference.


Many thanks for your guidance.

Posted : 30/11/2020 3:49 pm
Noble Member

Not sure on the specifics on the mini as I don’t have one but in general a printer won’t allow you to lower the extruder if the height of z is not known. This is to stop you driving the extruder into the bed and damaging things. 

Auto homing establishes the position of x/y/z for the zero position so it’s has that known location. Home has to be established before every print generally and always at switch on, which is why it’s almost always done at the start of every print. You can home each axis individually though if needed.   
Preheat can be selected before any homing (at least on all the printer I have) so it’s not surprising it won’t let you lower the extruder. 
If you auto homes previously then the extruder should move to 0,0,0 so at that point the extruder is already at the lowest safe position so you still wouldn’t be allowed to go lower until you have moved it up.  After that you should be ble to go back down as far as zero. 

Posted : 30/11/2020 5:06 pm
Eminent Member


Thank you Neophyl. I understand I should do auto home first then preheat. I will switch to this way around.

Posted : 01/12/2020 11:04 pm

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