Reasons for a PLA print not sticking to bed all the sudden?

    • Plastic: Same Matterhacker PLA (filament I use every day)

    • Printer: Anycubic i3 Mega (the one I use every day)

    • Slicer: Ultimaker Cura 4.2.1

    I don't know what's causing it, I haven't changed any slicer settings to my knowledge, I haven't changed anything on the printers end, and I'm using the same filament I've always used. But for some reason, the first layer is simply not sticking. At first I noticed when doing a print the nozzle seemed a little higher than normal for the first layer, but then it started having problems where 0 % of the filament would stick to the bed and it would all just come off and turn into a mess. I've checked and checked, but I see no reason the printer would just start doing this now all the sudden when it's worked perfectly for a year now.

    EDIT: Something I've noticed since posting this is that older sliced models seem to print just fine, which means there's something about the newser slicer settings that's causing it. I don't know what I would have changed though and/or how to restore to my original settings.

    Did you re-level your bed?

    Sure sounds like the nozzle height has been increased a little, or the bed has lowered a little.

    @Pᴀᴜʟsᴛᴇʀ2 I did not, however after trying to do so I found lowering it made things worse, and lifting it up had no effect until it got high enough to where the extruder just knocked the filament off the bed.

    @CrossRoads I didn't change anything, I don't know how that would have happened, but after trying to re-align the bed to a better position it did not help (See my response to Pᴀᴜʟsᴛᴇʀ2 for more information on that). I don't know how my nozzle height would have changed, but if it did how do I re-calibrate that?

    Please add an image and optionally a link to a video recording for us to see what is actually happening. Is this a nozzle to bed distance problem, or an adhesion problem. Do you use an adhesive agent between bed and filament?

    I added a WhamBam system to my printer. Magnet goes on the aluminum (or glass in your case?) bed. Flex steel plate plops down on that, PEX material get stuck to the flex plate. PLA sticks to it great, but releases with just a simple flex of the plate. Leaves nice smooth bottom surface on prints. Glass & hairspray & gluesticks, fuhgetabout it! I've posted some videos of it in use in this forum before.

    @0scar I can look into it, but it's not something I can highly well film

    @TomasBy I've looked at other acetone type chemicals before and they seem to have no effect on the filament, any suggestions on what type of acetone and/or how to apply it?

    @CrossRoads It's been fine up till now though, what could have happened since then that would have gone from nice sturdy prints to non of it sticking to the bed whatsoever?

    Now that you have added more information that older sliced models do print correctly, you should look into your slicer. Have you upgraded the software (considering the version number you did) since last sliced models, have you accidentally changed a parameter, can you revert all changes, reslice and compare to older sliced models? Best start is to download a calibration cube and slice and print it. Post the settings as text or an image for people to help you solve this problem! Hope it can be fixed soon!

    @0scar I've just tried resetting all settings on the slicer, even installed an older version in a VM for good measure, no change, yet the older models still work. I don't everything that's been stated so far defies logic, but do you have any idea what's happening?

    I'm really sorry, I'm out of ideas. I think you researched the problem systematically, only thing you could try is re-slice an older model and compare G-code or use a different slicer, e.g. Slic3r. Note I use different slicers for different machines too. :)

    Please don't edit the question to include "EDIT:" this is unnecessary, the question is good as it was, we'll revert the question for you. Note that the text under the line already explains that this is added later "...I've noticed since posting..." Your question is perfectly fine! Hope you get it solved soon! My best bet would be to try a different slicer and compare G-codes. Or G-code comparison of files that print well and newly sliced of the same model.

    I have this strange behaviour too. Since Cura 3.2.1 I cannot print any good models any more. Looks like there is not enough filament coming out of the extruder. Going back to 3.2.1 solves the problem. My printer is a Wanhao Duplicator i3 plus. Hope that this helps a bit.

  • There are 3 general factors about print adhesion you always have to keep in mind:

    • Have a sufficient surface for the print to stick. A pyramid printed on the tip can't print properly.

    • Check the leveling of your bed occasionally and relevel the bed. By removing prints, one can easily unlevel it over time without noticing it.

    • Clean your print bed from fingerprints and grease every so often. Fats are good separators between the print and the bed. Getting them off with Isopropyl alcohol or other solvents can restore print surfaces in an instant.

    In this specific case, there are some hints that make the general things less of an issue though: Old sliced items print fine, newer not. This hints that you changed something in the print settings. Among the settings that are good for adhesion, check your old G-code for the following three:

    • Bed temperature. I use 60 °C bed temperature for PLA and have good results on bed adhesion. Others print with 50 °C. However, going too low can make the plastic not stick well anymore.

    • Extrusion temperature. When the plastic extrudes, it has to be molten enough to push out enough and cold enough to solidify within moments and stick to the surface of the bed. If it is too hot, it would be dragged along, if it's too cold it doesn't get to stick either. I use 190-200 °C for PLA.

    • The first layer height might be different. I usually use 0.2 mm for this setting, no matter what the actual layer height is, and get good adhesion and not too much trouble with tiny unevenness.

    • The reason might be a mechanical issue, in that the Z-endstops (in an Anycubic i3, there are two, hidden in the frame sides) might have bent, moved or misaligned over time. Check its positioning. If the mount is broken, there are replacement part designs.

    1. This is nothing new, I follow that all the time and I guarantee that's not the problem. 2. I've tried that already as noted in my original post 3. Ok, I can try that, I don't think it would happen so suddenly and everywhere on the bed at once though. These are good general tips, and I will be looking into them more to see the cause but I'm 99% sure that's not the problem due to it being so sudden, what other reasons do you know of?

    @UltraGamer With painters tape, it can be a problem that the tape is slick.The last addition makes me thinkng though...

    I'm not using painters tape though, because the bed is glass, usually, there are no problems with it sticking to the bed at all. You did add another 3 reasons though, I've checked the first 2 and they are fine, I don't think I changed any slicer settings but I am going to try to reset it to see if that improves it. What is Z-endstop though and how can I re-position it?

    @UltraGamer the z endstop is the physical limit switch that triggers "here is Z=0"

    Where is that located on the printer?

    @UltraGamer the left gantry carries a little trigger switch around - That's it.

    I don't see it, could you link a picture to where it would be on a standard printer?

    @UltraGamer it's hidden in the frame, and there are two.

  • This seems like a long-shot, but I've noticed at this time of year many 3D prints fail. We noticed 4 printers all went dead and had massive non-stick issues last year about this time. Turns out it was mostly around changes in temperature and humidity - the outside temperature changed inside AC settings/wind-flow, etc.

    So, you might think through some of the meta-causes of where the printer is, and if temp/air/humidity might be just enough chaos to not make the material stick. Right in September, I start putting a light layer of glue down on the glass bed under each print or increasing the use of rafts...

    Ok, That could be it considering it is in the garage, Do you have any idea why most of the older sliced models work though?

    I’ve found that when it’s colder outside I slow down my print speed, especially on the first few layers. Maybe those older slicers had lower speeds?

    After looking at the gcode, nothing appears to have changed on the speed side, anything else?

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Content dated before 7/24/2021 11:53 AM