Longer Nozzle sticks out of hot end slightly, how do I change the Minimum Z so that I can Home and set offsets

General Discussion
1

Basic Information:

Neptune 4 Max
Klipper Firmware listed as
v0.10.0-530-g3387a9c2-dirty → v0.12.0-60
I have a 2nd hotend with a different nozzle that extends further than the stock nozzle does
When I try to home the printer, it hits the PEI plate and wont stop… wont lift… just gets stuck trying to lower itself all the way down…

how do I change the Z value in clipper to set an offset for the nozzle length so I can home the print head and do Leveling Functions without the worry of it just drilling don into my PEI plate
its about 4mm longer than the stock nozzle
…

2

im new to klipper but im pretty sure you run PROBE_CALIBRATE and then run TESTZ command. use TESTZ z=-.1 until you reach paper height off the bed then use the ACCEPT command. but you might have someone confirm that cause im pretty green to klipper

1 Like
3

See Bed leveling - Klipper documentation

4

@daronfritts
this doesnt do anything other than help you set your Z-offset

the Z Offset doesnt help when initializing the routine to set z-offset
the machine goes to the endstop first, which is not measured by the probe or the head hitting something…

I’ve even set the Z offset to 10, changed heads, and then tried to get it to do the Z-Offset routine, and it always drives down into the plate because its trying to get to the bottom of its physical travel and to hit the endstop…ignoring your previous Z-offset values while doing this.
with the longer nozzle, it cant get to the endstop to start the routine to set the Z-offset

5

@Sineos
Not useful at all… did you even read the question or understand what I am asking for?

6

Think about what you’ve written here. If the printer is physically incapable of reaching the Z endstop because the nozzle hits the bed first, how would it be possible to home the Z axis?

7

Z is Virtual on the Neptune 4…
yet the virtual endstop doesnt seem to allow it to happen anywhere except negative numbers

the point of the Z offset is to allow you to set your new zero based on the endstop…but I cant seem to make the virtual endstop match when its hitting the plate.
looking for HOW to change the virtual endstop to be when it cant go any further…meaning, when it hits the plate.

8

If the printer homes with an endstop, then you have a fundamental misunderstanding of how the homing process works. You haven’t posted a log so I can’t offer any more advice.

2 Likes
9

Well, as @jakep_82 already noticed, you seem to be lacking the fundamental understanding of what homing and (virtual) endstops means or how this works in general.
So, reading (and understanding) this might have provided you with the necessary insights.

General blurb

  • This machine uses a modified Klipper installation and Elegoo has not released the sources, thus is in violation of the GPL
  • Updating anything (Klipper, Fluidd etc) on this machine can bring you into trouble, rendering it useless

Virtual endstop

  • Virtual endstop means that the endstop is not, e.g., a micro-switch on the axis but the probe used for levelling also takes over the functionality of the endstop
  • It seems that this machine is using an inductive probe
  • Different probes have different trigger points and need to be mounted in a specified Z-distance to the nozzle tip, or they might fail to trigger properly

Spitballing on your issue

  • You installed a 4mm longer nozzle
  • You did not correct the offset between nozzle and probe
  • Failing to do so has brought your probe outside the specified detection range
  • Now your nozzle crashes into the bed before the probe triggers

Likely solution

  • Lower the probe by the same amount you increased the length of your nozzle
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