First layer calibration woes
As embarrassing as this is, could use some help with first layer (or it may just be a symptom of the real problem). So for a while my MK3 was down with an electrical fault and luckily @Joantabb fixed that by guessing correctly my heater wire was cracked (inside the solder blob no-less!). So got it back up and working electrically, but cannot get a first layer calibration to work right. Now the MK3S I have right next to it luckily is working flawlessly, but I have 2 because I need to 2 get jobs done. So I tried a whole bunch of checks. I redid full calibration wizard and it was happy, when I did first layer I had some weird issues, in that the prime strip was split? Never seen that before:
After that figured I had a clog, since when I raised up in Z and just ran 100mm of extruder it gave me a little blob. So I ran some e-sun cleaning filament through and did a cold-pull, and got out a nasty black blob. After that filament extruded in a nice tube like I expected. So then I went to redo first-layer calibration. It was a hot mess (well both literally and figuratively I guess). I tried less z on the live-tune which just resulted in no bed adhesion, and more resulted in extruder skipping. My bed is clean and the filament is dry. The MK3 was my workhorse when the 3S was acting up, because it always "just-worked" so not sure why it's suddenly acting up.
RE: First layer calibration woes
I use this process, for first layer calibration
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
I fid it easier to understand than the prusa method...
the numerical values are unique to my build plate on my printer...
but they give you an indication of how little changed inn values, can make big changes in performance
what do you prepare your build plate with?
I use hot water, dish soap and a sponge, rinse with hot water and dry immediately, then I Do not use any other surface preparation for PLA Prints... I just keep the build surface clean and handle it by the edges to prevent finger prints
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: First layer calibration woes
@joantabb
Thanks. My build plate mostly gets cleaned with dawn dish soap (the one they clean up oil spills with). I’ve found if some saw dust gets on it from my nearby workshop from my x-carve, I will use fresh 99% IPA on a clean paper towel (from my stock for my SLA printer). My 3S works with a beautiful first layer and I have never had a problem getting one to z-level for me. I have had the build plate get contaminated before from something that doesn’t wash off, and that was a nightmare until I figured that out (turned out to be a very fine layer of resin). On my prior printer which had a glass bed and manual mesh leveling I never had problems.
I guess a next troubleshooting step could be to use orange hand cleaner, because that cleaned goo off fantastically (and is a very, very mild abrasive along with strong solvent) and then wash with dawn to get the hand cleaner off.
RE: First layer calibration woes
I'm chiming in because I am having similar problems. I've had my MK3s for several months now. When I first built it in printed Benchy very well. I've done a fair amount with it since and it has gotten touchier and touchier. Now I can't even print with PRUSA's PLA, let alone anyone else's PETG. The problems are generally in the first three layers and it looks like a combination of poor adhesion and blobbing.
I have:
Run self test. All well.
Rerun calibration. It comes up fine.
Repositioned the PINDA sensor.
Tried many live-z changes. The built in test pattern usually prints close to right - sometimes I don't get right angles (poor adhesion) and sometimes the printed pad at the end is uneven. I can't get a z value that's free of problems. Sometimes it looks ok.
I wash the bed in dishwashing soap and hot water. I've also tried washing in 99% IPA and wiping with acetone. I've tried a glue stick (solves adhesion, but I get blobbing that ruins the print, even with PLA).
I've tried rubbing the nozzle with steel wool, and changing filaments several times. Both PLA and PETG fail. I've tried printing at slower speeds. I've tried small variations in temperature.
I don't use abrasive filaments and I haven't printed nearly enough t wear out a nozzle.
All the filament is a few months old, is that a problem?
I am at my wits' end. I'm very frustrated - a print that starts as a simple rectangle generally fails by the second or third layer. What do I try next?
RE: First layer calibration woes
Not sure, but maybe the reason of this issue is partially blocked nozzle. Because of power failure the nozzle was still hot (cooling were not working at that time) and the filament in nozzle got burnt. Just a Idea.
Does filament come out from nozzle straight and clean?
RE: First layer calibration woes
So I wanted to update this, so no one goes through what I went through.
When I originally got the printer built, I had a number of successful prints. Benchy worked first time. I assumed my settings were perfect and it didn't occur to me that I should ever stray far from them.
Then I changed filament types and had to fiddle a bit, but I was still able to print. Until all of a sudden nothing printed at all, things would blob and fail, or fail on the 2nd or third layer because the first layer would pull free. I did a cold pull cleaning (it came out a little dirty), ran first layer calibrations and no matter what I tried, it failed. It looked like the print head was too high. I got down to +0.000 and they still looked too high. I checked the PINDA height, cleaned the print sheet... nothing helped.
Then I ran across the note on the website that suggested a typical z-adjust was -0.400 to -1.500. I been printing around -0.040!
I just tried -0.500, expecting horrible adhesion problems. Instead I got a nearly perfect model and no adhesion problems at all.
My takeaway is this: if first layer calibration draws the initial thin lines but they don't make near right angles, instead bending a bit into and out of turns, and the final square looks something like the picture for "print too high", it's possible that in fact the head is MUCH too low. The nozzle may be dragging just deposited filament around before it sticks, leading to gaps and misplacement, which then invites collisions and blobs.