Ender 3 pro, printermods direct drive kit, skr mini e3 v2, bltouch abl, creality glass bed, and silicone bed mounts.  Bed is manually leveled and BLtouch works fine.

So after moving my printer around last week and getting it in to a new enclosure I started having issues with layers getting pulled out of place, zits/blobs, nozzle not raising high enough when passing over the print leaving drag marks or tiny zits along its path, etc.  I had just switched from hatchbox pla to 3d solutech pla because I ran out of HB and they're sold out on amazon, so I figured that was the issue but no matter what settings I used in Cura the issues remained.  I pulled apart the hot end assembly and found that the short section of bowden tube I was using wasn't all the way down in to the hot end so I cut a new piece to fix that, cleaned out the hot end, replaced the 0.4 nozzle, re-assembled everything, and calibrated my z-offset to just gripping a sheet of printer paper(-50).

Since then the only issue I have now is the very first line not adhering to the bed.  The printer makes its purge pass on the left side of the bed and then when it goes to start printing the melted plastic just sort of balls up at the nozzle instead of sticking.  Sometimes it starts to stick after a few seconds but that ball clinging to the nozzle ends up being a problem later, or I catch it and try to knock that tiny ball off the nozzle so the print can continue without obstacles, or I just cancel the print from Octoprint.  I've printed four 20x20 hollow test cubes w/ skirts since the above work was done and it happened on each one, so it's a consistent issue.  If I can catch it, or it sorts itself out, the rest of the first layer lines for the skirt and the print itself look amazing.

I've manually leveled the bed again, I made sure the ABL is mounted securely and working/reporting back info to the abl plugin in Octoprint, and I've run a z-offset calibration 3 times now and it's currently at -60.  The threaded z-rod doesn't have debris and doesn't feel like it's hanging up at all.  Belts and v-rollers are fine.  Is there anything else I should be checking, or do I just need to keep dropping that z-offset until it hurts my first layer quality then back it up a point or two?

I'm currently using a 2mm plate from thingiverse to calibrate my z-offset assuming that's the issue, but not making any progress here.

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Started with a z-offset of -60.  When it started to print it looked like it was under-extruding/pulsing, kind of hard to see in this photo but it's the bottom left of the skirt.  It then starts to stick, makes several good looking passes on the outside of the skirt, then starts to create those wavy/pulsing lines on the inside of the skirt.  I increased z-offset to lower the nozzle, kept getting worse and too close to bed as you can see in the bottom right corner of the diagonal lines.  I slowly adjusted the z-offset back to -60 which cleared it up before I cancelled the print.

I'm not sure what issue I'm chasing here but it's terribly frustrating and has me wondering if I just need to pull all the mods and upgrades off of this printer and go back to stock which printed fine.

could be as simple as cleaning your glass bed, I had this problem the raft stuck fine but the skirt or brim would not, so I heated the bed up a bit and rubbed it down with denatured alcohol and then with a damp cloth to get rid of the residue from the DA and everything sticks fine now


Disclaimer:

I'm only a week in on my first printer and don't really know anything

I wipe it down with 91% alcohol at least once a week, and cleaned it yesterday/today to rule that out.

Just ran an e-steps test and I'm only under-extruding a hair less than 1mm so that's not the issue and it's not off enough to recalibrate.

I'm probably going to pull the printer out of its enclosure tonight and clean the z-rod, re-tighten all the belts, etc but I'm pretty confident those aren't the issue.

I was doing the same with no luck then I read the alcohol leaves a thin residue after it drys I could see a white residue smear and to follow with water moistened towel to get rid of the residue worked like a charm everything sticks and almost too good gotta work at releasing the print from the glass, i'd try doing that first only takes a few seconds and run a quick test print vs tearing down the machine and starting over

Are you trying to print on clean glass?  I know it can be done, but your printer will have to be dialed in perfectly to do that.  I've been printing for years and would highly recommend using either Aquanet hairspray or Elmers purple gluestick on the bed as a binder.  I started with the gluestick method and have gone 100% Aquanet extra super hold (purple can) hairspray.  A quick spritz on the area where it's going to print before heating and the parts will stick like crazy until the bed cools down.  I clean the bed every once and a while when the hairspray builds up too much or I just run the putty knife over it to knock down the high points between prints.

It's the Creality textured glass bed, so no glue or spray needed.  It's almost like there isn't enough filament primed in the nozzle for the print to start even though it just did a prime/purge pass on the left side of the bed.

This issue also didn't start until after I disassembled/reassembled my hot end in order to fix the bowden tube between the dd kit and hotend and replace the nozzle.  All that should have done is alter my z-offset, which I recalibrated half a dozen times since then in an attempt to fix this.

I backed off the z-offset to around -54 and it appeared to lay down the skirt without issue, but the first layer of the part ended up warping/peeling up and had gaps between lines due to the nozzle being too far from the bed.

I put the z-offset back to -60, restarted the print, and the first 20-30mm of the skirt didn't adhere to the bed and instead created a small spaghetti ball at the nozzle.  I caught it and knocked that off with my knife as the first line finally started to adhere to the bed.

I'm completely lost on this one.  I've never had this issue before and I don't know what's causing it, but I don't think it's the z-offset.  I've adjusted it at least a dozen times today.

ETA:  The small part I'm printing is about halfway done, at 0.16 quality and it looks great.  That's the most frustrating part.  That stupid first line has to be babysat or it takes out the rest of the job, but if I catch it after that it's damn near perfect print quality.

It looks like initial layer speed is already 20mm/s by default, and I have my print speed set to 60mm/s.

With the nozzle higher the first line doesn't stick, just balls on the nozzle, unless I lightly lift up on the bed which tells me the z-offset is too low.  If I increase the z-offset then overall first layer quality drops because the nozzle is too close to the bed.  It almost acts like the glass bed is warped in certain areas but I did not have this issue at all before taking apart my hot end assembly to fix the DD kit bowden tube and replace my nozzle.

I'm running an skr mini e3 v2 motherboard and bltouch auto bed level sensor that does a 25point bed level measurement before each print.

I check every new nozzle before installing with my 0.4mm needle, this one didn't feel any different than other nozzles.

I changed filament and have the same issue.  Completely different brand.  So it's not the filament, or a spool/feeding issue.

I'm 99.9% sure it's not a z-offset issue.  I've spent far too much time adjusting it back and forth and it doesn't seem to do anything but affect the rest of the print quality as I'd expect.

It's only the first inch or so of the first line, and it doesn't matter how big or small the print is(which starts the print in different areas of the bed) which indicates that it's not a bad spot in the bed or a bad reading for that spot of the bed from my ABL.

The rest of the skirt, brim, or the print itself has good adhesion which indicates that it isn't the bed.

The rest of the skirt, brim, or print has great print quality.

My e-steps are dialed in and I'm under-extruding by less than 1mm, so that's not it.

It does the back and forth purge pass along the left side of the bed and that seems to be fine.

This makes absolutely no sense and I'm at my wits end trying to figure it out.  All I can come up with is that it's not extruding/priming the nozzle with enough filament to start the print, but I don't understand why that would happen after removing/reinstalling the hot-end so I could replace that dd kit bowden tube.  I guess I can pull that hot end assembly back apart and re-check everything/reassemble, but that's pretty much the last idea I have.

I'm dis-assembling the hot end and DD kit to clean and re-assemble everything.  Also switched nozzles again.  My hope is that the issue disappears as mysteriously as it showed up and I can go back to printing all my HeroMe Gen5 parts.

the CR 10 v3 I just bought came with the creality textured glass bed and did have adhesion issues as op described a good cleaning with denatured alcohol followed up with water wipe down solved my problem and everything sticks very well  I heat bed to 60

I tore apart the hot end, extruder, etc.  Cleaned and checked everything, re-assembled, installed a new nozzle, ran a z-offstep calibration, printed a test cube and the entire first line failed to adhere to the bed at z-offset -54 and I had line separation in the rest of the brim.

Second test cube z-offset was set to -56 and first line failed again, during the rest of the brim I upped z-offset to -58 and then -60 and the brim cleaned up.

Third test cube the z-offset was still at -60, first line failed again.

Fourth test cube at -62, first line failed.  Brim still looks good after I pull away the loose melted plastic so it can print without obstacles.

Might run more tests later at higher z-offsets, but I'm pretty agitated with this printer and probably need to walk away from it for a day or two.

Just ran two tests at -64 z-offset.  Both only had first line adhesion issues within the first maybe 5mm, then they stuck and the prints continued.  However, halfway through the brim the lines started to look like the nozzle was too close(too high z-offset).  So whatever I'm fighting here isn't a z-offset issue, it's something else.  At this point I'm giving up and going to order one of those removable PEI sheets and seeing if changing the bed surface does anything.

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So I realized I still had the magetic bed surface that the printer came with, swapped out the glass bed for that.  Recalibrated z-offset, landed at -54 again with the sheet of printer paper(which I've always used and never had issues).  Ran the test cube print, the entire first line of the brim failed and got dragged around clumped to the nozzle until I knocked it loose and it printed fine after that.  Tried again but with -56 z-offset, same issue.

So it's not the z-offset, that's right where it needs to be.

It isn't the bed, I changed to a completely different and barely used surface.

It's not the nozzle, replaced that.

It's not the filament, changed to a different brand.

I don't think it's the BLtouch ABL...but I did have to unmount it the other night and that's when this issue started.  I'll run an ABL in the bed level plugin in Octoprint to see if my bed terrain has changed or looks odd.

Nothing seemed out of the ordinary when I dis-assembled the hot-end and dd kit/extruder assembly again earlier, and I carefully re-assembled everything just like I did the other night when this issue started.

The night this issue started I had replaced the little 2" section of PTFE tube between the hot end and the extruder because the one I had was too short and not inserted all the way in to the hot end which was causing print quality issues.  I can't imagine that tiny section of tube is a problem, especially when 99% of the print comes out great.  I would be seeing issues throughout the print if the tube was bad, same for the extruder.

Pretty sure it's not the BLTouch or a warped bed.

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Do you have a link for that plate? I find myself in a similar situation needing to calibrate the z offset and unable to judge if the first layer is "squished" enough (I suspect over squished, but old eyes have trouble seeing those little bitty lines).

https://www.thingiverse.com/thing:3013740

You can use any print with a big enough first layer to give you time to watch it and adjust your z-offset on the fly.  This one is meant to print as-is and then adjust your z-offset based on how thick it is, should be 2mm.  I didn't use it for that.

Normally for z-offset I use the following method that I pieced together from various sources based on what works for me(ender 3 pro, bl touch abl sensor).  You'll need to use Octoprint terminal or similar to send the commands to your printer.


I do this every time I work on anything that could alter the height difference between by BL Touch and nozzle, so pretty much anything on the hot end assembly.

Is there anyway to confirm the hotend temperature? My prints started getting stringy and not laminating

im replacing the hot end as a test

Is very interesting stuff but I think I walked into a graduate level class with a f’ing pencil.
Would like to learn if this 3D printing is possible for a newb or better to go to an dedicated CNC just for Ramesh.
I know making small parts via copying with the result as a MIM would be the bomb but think baby steps is the way to go for a Fudd.

I bought one not knowing anything about them at least you have a pencil I had a broken crayon but I push a button and it prints are my prints factory quality no, but I think they turned out pretty good for my skill level and I'm happy with the results,  this is mostly a toy for me and the grandkids to mess around with they are young and can figure out all the techy stuff for me as they get older, being able to make gun parts is a bonus

My issue was caused by routine maintenance and persists regardless of the bed surface, z-offset, bed level, filament, temp, bed adhesion options, etc and it only affects the first inch or so of line laid down.  It has to be a priming issue or something, but I don't see how maintenance on the hot-end would have caused that.  All I did was replace the short section of bowden tube because it was too short and not inserted down in to the hot end far enough, causing filament to pool between it and the nozzle in there which was resulting in print quality issues like blobs and zits.

I'm not chasing perfect quality here, I'm trying to resolve a 50%~ print failure rate.  When that first inch or so of line forms a blob on the nozzle or gets dragged around, half the time it gets sucked in to the print job and screws everything up.  Half the time it gets push outward or I catch it and use my knife to pull it away from the print and the rest of the print comes out perfect.

I haven't printed anything in a week or so because I got so pissed at this thing.  Probably going to switch back to the oem extruder setup to see if that makes a difference, once I can find some authentic capricorn tubing.

Printed the last two parts of the Hero Me Gen 5 cooling system, used regular aquanet on the bed for both.  First part was the main gantry plate and the first inch or so of line failed like usual.  Second part, below, was a tiny clip and the line tried its best to hold but as you can see it pulsed.  This is definitely not a bed adhesion issue.

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I completely tore apart the hot-end, even took the DD plate and rollers apart.  Then rebuilt everything with the Hero Me kit making sure the ducts were positioned right and not sitting lower than the nozzle, etc.  I still need to tidy up all the wiring and get a new cable cover that isn't as bulky as the one I had previously, make the x/y offset changes in the firmware, and recalibrate z-offset.  Dual 5015 24v fans, 24v LED light bar to light up the print area.

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The part cooling airflow is ridiculous, and where the air streams hit each other is right under the nozzle.

Maybe after all this work that first line issue will disappear as mysteriously as it showed up.

ETA:  Also, no gcode or firmware changes were made before or since the issue started.  All I did to cause the issue was disassemble the hot-end to replace the short section of bowden tube that goes between the hotend and DD kit.

I won't know if the issue is still there until this weekend when I have the time to finish cleaning up the wiring and making the necessary adjustments/calibrations for the Hero Me setup.

Not sure how to do that, but it does affect all prints that I've been grabbing off thingiverse.

I pulled this from that little clip I printed and posted above.  This is right after the cura start gcode and 6 lines in to the G1 X??? code which I assume is the actual printing process.


Here is the last chunk of code at the end of the file.

Already have a 2x purge line built in to my start gcode.  I can see it struggle to put out plastic on the first line as it recovers from all that retraction from the last print, and on the way back/2nd pass it lays down a full line, does the blob at the end, raises Z, moves over to start print.

Is that "G1 F2400 E-1" being generated in the .gcode file because I have my Cura retraction setting at 1.0mm?  Or was it built in by the author of the file?  My cura retraction settings are 1mm and 40mm/s, that seemed like a common combo for ender 3 with DD kit, and I haven't had the time to run the retraction tests to fine tune it.

Tonight I'll run to autozone or walmart and pick up a pack of small zip ties so I can get the wiring bundled up a bit and maybe try a small print, like the 20x20x20 hollow test cube, to see how she does with the new Hero Me system.  I'm really hoping this issue just randomly disappears after all that work yesterday.

I think traced my adhesion issue to 100 percent fan power setting

pulled it down to 75 and my prints are much better

I just get STLs from thingiverse and slice them myself in Cura.  I am on the latest version of Cura, 4.7.

I did find this - https://community.ultimaker.com/topic/33965-cura-471-under-extruding/

I went in to the printer settings > extruder 1 and it is set to 1.75mm so that's not the issue, and those folks are experiencing constant under extrusion and I don't think I am.  I could try going back to Cura 4.6.1 like some of those users to see if that does the trick.

Without hairspray that dotted line ends up being an unstuck line or blob of filament stuck to the nozzle and eventually the line starts to stick and the unstuck line/block falls away or gets sucked in to the print causing more issues.  The rest of the lines in that photo look fine, and the adhesion is good with or without hairspray.  In fact, adhesion is too good with hairspray and it's a bigger pain in the ass removing the print from the bed.

I'll comment out the 1mm retraction at the start of the print and see if that helps any.  If it does, I'll change retraction distance up or down and generate a new .gcode file to see if that E-1 shows up again or follows the number I set in Cura.