Printer: Creality K2 Plus + CFG
Filament: Creality CR-PETG
CFS Humidity: 5%
Print Surface: Mirror
Bed Mesh Range: 0.2560
Bed Temperature: 70c
Nozzle Temperature: 250c
Nozzle Size: 0.6mm Hardened Steel (Creality)
Layer Height: 0.36mm
Line Width: 0.62mm
Z-Offset: 0.055
Z-Hop 0.5mm All Surfaces, Auto
Slicer: Creality Print V6.1.2.2458 Release
Slicer Profile: 0.36mm Standard@Creality K2 Plus 0.6 nozzle
Printer Profile: Creality K2 Plus 0.6 nozzle
I’ve had the K2 Plus for about 2 months now and recently, the print head would scrape across the print surface after layers 2-3 (see below). I am using the default print profiles from Creality Print as they seem to work the best. I have done various tests with settings, fiddling with the Z-Offset, flow rates, speeds etc.
My first layers (with the above Z-Offset configuration), is near perfect. I have also managed to improve my bed level (see image below) by swapping it out for a mirror, going from a very warped 0.8+.
In the images below, you can see the scratch from the top left corner all the way to the bottom right corner (diagonal). This happens on all prints after about layer 2 onwards and stops at about layer 10’ish.
Here are some of the things I have tried over numerous prints:
Countless bed levels
Countless tweaks and configuration settings in Creality Print (from other blog posts and forums)
Numerous Z-Offset tweaks (ended with the above that seems to work the best)
Replaced the hot-end and heating block (twice)
Replaced the nozzle (stopped counting)
Numerous maintenance runs (from the Creality Youtube videos)
Added vibration feet to the printer
Wiggled (to check if it is loose) the extruded and tightened all screws
Tightened all the screws inside the case (I could find and that felt like it needed a good tightening)
Dried my filament (days)
Tried various rolls of filament (this issue persists regardless of filament type or brand as well as with the 0.4mm nozzles)
Fiddled with the fade configuration in Klipper printer.cfg (basically made no difference)
Ran all the calibrate options in Creality Print
Numerous Calibrate runs from the printer’s control panel
Do not cross walls had zero effect
Z-Hop various distances, types and distances - Sadly no effect.
Travel speed (slower made it worse and sometimes just ripped the print off the bed)
It almost feels like this is not a Z(offset/hop) issue as it only does this when it travels from one corner of a print to the opposite corner of the print.
Apart from this horrible scratching thing, this printer is amazing! Really good quality, stability and performance which motivates me to rather fix this one issue.
It looks like you’ve covered all the tests to see why this is happening. I would check the bed temperature accuracy with a temp gun. I say this because on my K1 Max i generally run a little higher temp as the middle and outside edges don’t always reflect the temp being shown. So for example 70C might actually be 68C or 67C around edges. Might not be much but it could be a cause for the middle part of the piece to warp enough to hit the nozzle…?
Also try bumping up the temp for the PETG a little if you haven’t tried that already.
Hi @jimandyen Thank you for the nice welcome message!
Thank you for the tip! From all the things I’ve tested, I never thought about testing at different temperatures . I have a few prints in my backlog that I will use to test some different increments (perhaps 5c at a time?). I will relay my feedback. Maybe just some further info, this happens with PLA, PLA+, EN-PLA and CR-PLA at roughly 60c.
What are the max temps for PETG / PLA? For some strange reason, I really do not have any bed adhesion issues (at all). My first layers are also (from what I can see others complain about) near perfect!
Will also invest in a heat gun to further my investigations.
Not sure what the max temps are but if I remember correctly the profiles show a different temp depending on what kind of plate you are using. (Smooth, textured etc.)
Temperature did not seem to make a difference (apart from learning that at some point, PETG fuses with Glass
I am back on the default PEI Plate and sadly had to sacrifice my perfect first layers and level bed for a the all too familiar Taco (0,6150 the best I could get it after HOURS of paper levelling attempts and 3 new blisters)
Back to the default profiles with the default temps
0.250 z-offset
The scraping is gone, but so is my first layer quality. I am now able to print very fuzzy items (perhaps a new style unlocked)
Not ready to admin defeat just yet
To further my debugging (and lower my bank balance), I have ordered the following:
Creality Bed Levelling Silica Columns (perhaps this will assist with the heat expansion?)
Creality K2 Plus Epoxy Resin Build Plate (perhaps this will turn the Taco in to a Pizza?)
Extruder Gear Kit (they were shiny, so why not?)
Creality Metal Hand-Twist Bed Levelling Nut (the default ones do not go well with my current hand designs)
Heat gun (so I can monitor the temps with the new plate)
Once these parts arrive, my debugging journey will continue! I will provide updates on my findings to hopefully identify the winning change and share my learnings with the community struggling with the same.
I’m unfortunately not here to offer much help, but just to let you know I have the exact same issue. See these pictures below from my flow rate calibrations.
I’m having what I think is a related issue with nozzle bulldozing, leading to buildup, leading to shedding clumps onto my build plate, leading to failed prints. (see here)
At this point, I’m guessing this is a bug somehow present in the K2’s firmware or in CP, although I (obviously) haven’t figured out the mechanism/exact issue. If you make any progress, I’d be interested to hear what you find!
Try stepping through the gcode preview in CP, looking for exactly what is happening during this time - is the bed supposed to lower 0,1mm (all other layers) but does not (only on these layers)?
Hi
Only a thought here but have you checked the hotend securing screws, they have a habit of coming loose. This can cause nozzle drag and inaccurate Z offset.
. I have a few prints in my backlog that I will use to test some different increments (perhaps 5c at a time?). I will relay my feedback. Maybe just some further info, this happens with PLA, PLA+, EN-PLA and CR-PLA at roughly 60c.
