U1 - Nozzle cleaning path on bed plate

[Cainmos]

I have had my U1 for about two weeks with mostly successful prints. I swapped my build plate to a BQ Cryogrip and loaded dried SUNLU PETG. I went to run the max flow calibration to dial it in and after the initial nozzle clean, a second erroneous clean was performed at the edge of the build plate and damaged it. I am honestly more worried about the nozzle but it seems to still be printing fine. Has anyone else run into this? Any ideas on how to be sure it doesn’t happen?

Double points on heated nozzle bed contact for the initial print bed height calibration step and it leaving marks on the build plate.

[Zoe_M]

@Cainmos

BQ Cryogrip

Hi, how about the current firmware version on U1?

Have you tried the wiki guide here:

https://wiki.snapmaker.com/en/snapmaker_u1/troubleshooting/nozzle_scraping_the_build_plate

If the same issue continued, please export the system log on the U1 and submit a support ticket to us:https://snapmaker.formcrafts.com/u1-troubleshooting-request

[ColdCoffee]

Is that a Frostbite plate? I’ve been using a Glacier for a few weeks without issue, please post back here when you get the issue solved

[Cainmos]

Hi Zoe_M. I am using Snapmaker Orca v2.3.5 and firmware 1.5.1.

I find that the issue is not so much a bed leveling issue but where the toolhead is performing a cleaning operation. I went into the gcode to see what was actually going on and this is part of the pre-build operation:

;===== 粗回零 =================
T0
M106 S255
M106 P2 S0
MOVE_TO_DISCARD_FILAMENT_POSITION

M109 T0 S130
ROUGHLY_CLEAN_NOZZLE_WITH_DISCARD
MOVE_TO_XY_IDLE_POSITION_EXTRUDER
G28 Z I140 J140

;===== 检测钢板 =================
DETECT_BED_PLATE

;===== 深度清洁喷嘴 =================
G90
G0 Z5 F10000
MOVE_TO_DISCARD_FILAMENT_POSITION
M109 S170
ROUGHLY_CLEAN_NOZZLE
MOVE_TO_XY_IDLE_POSITION_EXTRUDER
FINELY_CLEAN_NOZZLE_STAGE_1
M104 S130
G0 Z5 F10000
MOVE_TO_DISCARD_FILAMENT_POSITION
ROUGHLY_CLEAN_NOZZLE
MOVE_TO_XY_IDLE_POSITION_EXTRUDER
FINELY_CLEAN_NOZZLE_STAGE_2

I went into the Fluidd interface and commanded the nozzle cleaning individually. Both “finely_clean” commands position the nozzle on the edge of the build plate where damage can be seen. This obviously isn’t cleaning the nozzle and in worst case can damage the build plate or nozzle.

I don’t know how to dissect the macros themselves to understand or fix the positioning error.

[Cainmos]

Yes, this is the Frostbite. I also have the Glacier to try. I did find that the stock PEI coated plate is quite good though. I’ll have to pull bedmesh data to see if the plate is slightly proud in the rear by the toolheads.

[Zoe_M]

Hi, Have you tried to update the v1.5.2 here:

U1 Firmware V1.5.2 Beta Testing is Now Available

Hi Everyone, We know V1.5.0 and V1.5.1 caused more headaches than they should have, and we sincerely apologize for that. To make sure we get things right this time, we’re taking a more cautious approach with the next firmware update. So now we’re opening up V1.5.2 Beta Test before an oficial release. This version has actually been shared with a small group of users through technical support channels over the past few weeks, as a workaround for the print quality issues in V1.5.0/V1.5.1. The fee…

I checked with the engineer earlier. He didn’t explain directly whether the macros could be changed but he implied the new V1.5.2 version might help.

[Cainmos]

@Zoe_M I have updated to firmware 1.5.2 and tried a first layer test print with toolhead 4 where no previous damage was on the Frostbite build plate. Firmware update was unsuccessful.

Process:

1. Unload filament
2. Update firmware 1.5.1 → 1.5.2
3. Perform multi-toolhead-offset-calibration
4. Wash build plate with soap and hot water, dry with clean microfiber cloth
5. Load Snapmaker PLA Snapspeed (red)
6. Slice first layer test print in Snapmaker Orca 2.3.5 with default parameters for 0.4mm nozzle, 0.2 standard layer height and Snapmaker PLA Snapspeed filament profile
7. Send to printer via Snapmaker Orca with extrusion calibration and auto bed level selected

Monitor print - The same “FINELY_CLEAN_NOZZLE” macros are performed on the build plate and caused nozzle contact infront of toolhead 4:

I searched through the configuration files and in FLUIDD.cfg found:

gcode_macro FINELY_CLEAN_NOZZLE_STAGE_1

gcode:

M204 S10000

MOVE_TO_XY_IDLE_POSITION_EXTRUDER

G91

{% if printer.toolhead.extruder == 'extruder' %}

    G0 Y26.5

{% else %}

    G0 X-2 Y26.5

{% endif %}

*# SET_HEATER_FAN  FAN=e0_nozzle_fan SPEED=0.5*

*# PROBE SAMPLE_TRIG_FREQ=450 SAMPLES=1 PROBE_SPEED=5*

*# SET_HEATER_FAN  FAN=e0_nozzle_fan SPEED=1*

PROBE_BED_CONTACT

G91

G0 X-1 Y1 F500

G0 X-1 Y-1

G0 X1.25 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 Y-0.8

G0 X6

gcode_macro FINELY_CLEAN_NOZZLE_STAGE_2

gcode:

M204 S10000

G90

MOVE_TO_XY_IDLE_POSITION_EXTRUDER

G91

{% if printer.toolhead.extruder == 'extruder' %}

    G0 X-10 Y26.5

{% else %}

    G0 X7 Y26.5

{% endif %}

*# SET_HEATER_FAN  FAN=e0_nozzle_fan SPEED=0.5*

*# PROBE SAMPLE_TRIG_FREQ=450 SAMPLES=1 PROBE_SPEED=5*

*# SET_HEATER_FAN  FAN=e0_nozzle_fan SPEED=1*

PROBE_BED_CONTACT

G91

G0 X-1 Y1 F500

G0 X-1 Y-1

G0 X1.25 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 X1 Y-0.5

G0 X-1.5 Y1.5

G0 X-0.5 Y-1

G0 Y-0.8

G0 X6

It appears that the relative position moves from the " MOVE_TO_XY_IDLE_POSITION_EXTRUDER" position are incorrect and position the nozzle over the build plate and not the nozzle cleaning area.

First layer test completed successfully:

[Zoe_M]

Huge kudos to you for digging into the macro and fixing the offset yourself!

By the way, If you ever switch back to the original PEI plate, remember to revert the offsets to their default values. Otherwise, the cleaning position may land outside the plate and fail to clean the nozzle properly.

Since the defaults are tuned for the official build plate, other users might face the same problem with third‑party plates. If you’re up for it, sharing how your adjusted offsets and the validation steps you took on the forum would be a great help. I’m sure many would appreciate it.

Tips & Guides

[ColdCoffee]

I’m curious now about the hole placement on various plates - if you hold the frostbite and SM plates together do the holes line up?

I can’t test my glacier as its being printed on, but I just checked the new Eibos plate I received yesterday against the SM the back of the slots lines up, but the slots on the Eibos are about 1mm wider to the front if that makes sense?

Interestingly this plate has no front or back so you can use it any which way, but it only has the slots at one end, so go figure???

Just one more thought, did you buy the Biqu plate from them or aliexpress etc as maybe its a fake?

[Cainmos]

So I was a bit of an idiot with this, but it was a good learning lesson. This is occurring where it is supposed to at the edge of that lip to ensure no hard pieces of filament are stuck to the nozzle prior to probing. I was more immediately concerned with the amount of surface damage I saw with it happening only twice on the Frostbite plate.

I bought the plates directly from Biqu so they are legit. They match perfect to the Snapmaker plate.

The issue is with the Frostbite plate having a soft coating. When probed I think it very slightly sinks into the coating on the built plate. Then when the nozzle wipe happens it is happening in the actual coating surface because the probed Z height is actually slightly low. This is causing it to quickly wear away. I was concerned that the nozzle was really grinding against the build plate.

PSA - This is normal and will look bad on the BQ Frostbite plates. I did not know that and was concerned.

[ColdCoffee]

I was going to say about some BambuLabs printers actual wear right through the coating at the back of the plate as part of the nozzle cleaning routine, I just wondered about yours being so close to the slot and if the toolhead might get caught on it?

[Cainmos]

Right. That was also a bit of a concern with all of that. Can easily tweak that in the macro code to just nudge towards the middle of the cleaning area. Would be interesting to see what that tolerance is on peoples’ machines and where it lands. I thought it might also be part of the cleaning strategy that anything stuck would get sheared off and drop down through the slot.

[hho]

@Cainmos

So I was a bit of an idiot with this

Quite the opposite: You’ve learned, and you shared your learnings with us. That’s very different from idiocy!

@Cainmos

I thought it might also be part of the cleaning strategy that anything stuck would get sheared off and drop down through the slot.

I think the slot is there so the tab flexes a little and limits the resistance to the nozzle by the build plate.

What you seem to be seeing (at least judging from your photo) is that the nozzle starts in the slot and then laterally gets pushed into the tab of the plate… I think that’s quite bad and might bend your hotend, at least in the long run. I would definitely try to fix the offsets, so the center of the tab becomes the contact point.

[Cainmos]

@hho

What you seem to be seeing (at least judging from your photo) is that the nozzle starts in the slot and then laterally gets pushed into the tab of the plate… I think that’s quite bad and might bend your hotend, at least in the long run. I would definitely try to fix the offsets, so the center of the tab becomes the contact point.

Appreciate the second opinion on that. I am fairly new to having my own FDM printer so little things like this I’ve been unsure about. Position tweak should be fairly easy and I’ll post the edit once I verify it.

[ColdCoffee]

I wonder if the calibration of your toolheads is slightly off? thus its touching the build plate in the wrong area?

checked my glacier plate and there’s no marks whatsoever anywhere around those tabs?

[Cainmos]

Interesting. Maybe? I can rerun calibration for that and look through the wiki for validating it. As of now everything seems to be printing without problem otherwise, just finished a 10hr print and it came out great.

[ColdCoffee]

Good to hear, the above was just a brain fart of anything else I could think of that might be affecting you?