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MarlinFirmware / Marlin

Marlin is an optimized firmware for RepRap 3D printers based on the Arduino platform. Many commercial 3D printers come with Marlin installed. Check with your vendor if you need source code for your specific machine.
https://marlinfw.org
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[BUG] Z_CLEARANCE_FOR_HOMING has no effect on Homing (Delta printer) #26664

Closed Orion3090 closed 10 months ago

Orion3090 commented 10 months ago

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

In a delta printer you need some height before homing to avoid mechanical damage on the printer, Z_CLEARANCE_FOR_HOMING seems to be the configuration needed, as it should raise the extruder to the configured clearance height an then home each axis, but homing does not raise to the specified height for homing, seems to ignore the Z_CLEARANCE_FOR_HOMING which i got at 215, the max height on my printer is 290

Bug Timeline

First time trying with bugfix-2.1.x

Expected behavior

When homing below the specified Z_CLEARANCE_FOR_HOMING the extruder should raise to the specified height and then home all the axis.

Actual behavior

When homing below the specified Z_CLEARANCE_FOR_HOMING the printer attempts to home all the axis without raising to any height.

Steps to Reproduce

With bugfix-2.1.x installed:

  1. Home all axis with the extruder close to the top
  2. Move Z axis down close to the hotbed
  3. Home all axis when close to the hotbed, the printer attempts to home each individual axis which leads to collition of the extruder with the belts and towers

Version of Marlin Firmware

bugfix-2.1.x

Printer model

Anycubic Kossel linear plus

Electronics

SKR 1.4 turbo

LCD/Controller

RepRapDiscount Smart Controller

Other add-ons

No response

Bed Leveling

ABL Bilinear mesh

Your Slicer

None

Host Software

Pronterface

Don't forget to include

Additional information & file uploads

this is my configuration.

EvilGremlin commented 10 months ago

Tis would be bug indeed, bit not the one you describe. Z_CLEARANCE_FOR_HOMING is not needed and not applicable to deltas. So if this value used at all - it's a bug. Moreso, you trying to use it wrong even for cartesian. Z_CLEARANCE_FOR_HOMING 215 means "raise Z up 215mm from wahtever current unknown position is"

Orion3090 commented 10 months ago

EvilGremlin

Ok i did not know that, what configuration should be used for avoiding the crash between extruder and print parts when homing on deltas?

EvilGremlin commented 10 months ago

There should be no crash possibility at all. Homing goes straight up.

Orion3090 commented 10 months ago

There should be no crash possibility at all. Homing goes straight up.

Maybe i didn't explain the mechanical problem correctly, on a Delta, when the extruder is close to the bed, if one of the axis (only one) is raised too much without the other two, it causes the extruder to collide with the belts and the tower of one of the axis (maybe there's a name for that, i don't know it), which is what happens when you home (G28) with the extruder too low.

That would be avoided if the extruder is raised to a considerable height, close to the top of the printer, in which height each axis can raise and home without any collition of the printer parts, which i toght to be the Z_CLEARANCE_FOR_HOMING according to the commets on the firmware.

robherc commented 10 months ago

When using G28 on a delta, all three towers are supposed to lift at the same time & same speed, with each tower stopping when it reaches its endstop.

Orion3090 commented 10 months ago

When using G28 on a delta, all three towers are supposed to lift at the same time & same speed, with each tower stopping when it reaches its endstop.

Ok, i didn't knew that either, i have everything configured but with G28 each tower attempts to home one at a time, that's the bug then? is there a configuration so that G28 does it with each tower simultaneously?

EvilGremlin commented 10 months ago

Then you did not enable DELTA kinematic in config

Orion3090 commented 10 months ago

Then you did not enable DELTA kinematic in config

I did configure #define DELTA on line 964 of my Configuration.h, what other reason could it be for the G28 behaving like that?

EvilGremlin commented 10 months ago

Some other user error (you still somehow flashed build for cartesian) or very fresh bug in delta homing. Try 2.1.2.1

Orion3090 commented 10 months ago

Some other user error (you still somehow flashed build for cartesian) or very fresh bug in delta homing. Try 2.1.2.1

You are totally right, i just migrated my configuratoin to 2.1.2.1 and two of the issues i had (a problem with endstops) and this one with the Homing of axis seem to me solved, thanks a lot!

github-actions[bot] commented 8 months ago

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.