PLA not sticking

[Explorer71]

My M2 worked perfectly out of the box. I printed a few projects, and during one the factory filament bound up on the reel. That build was ruined of course, but I've been having problems ever since. When the project starts the PLA doesn't stick. It just comes out a trails and builds up. I have adjusted the leveling of the bed. I have checked the top end spacing. I have tried bare glass, glass after cleaning, glass with glue stick. It all does the same thing. I don't know if I screwed up the settings, or if there is something wrong with the feed, or some other stupid newbie mistake. Can anyone help me? I am getting rather frustrated with this expensive machine.

[jimc]

99% guess i would say your printing 1st layer with too big a gap between the bed and nozzle. you need to adjust your z-stop bolt to raise the bed up. check with a feeler gauge. you should have about .006" space.

[Levi8than]

Jimc is correct. Sounds like too big of a gap, or printing on unheated kapton tape.

Share some more information. Are you printing with the open source chain (slic3r and pronterface) or s3d?
And what are you printing on? Blue tape with an unheated bed? or kapton tape heated to 70 degrees? I'd recommend starting with virgin blue tape on an unheated bed. You can apply it right over the kapton if it's already there.
And what temperature is your hot end? 215 is good. If you don't mind some oozing, for your first few prints it's often easier to let it go a little hot: 220 or 225. But I wouldn't go any hotter with PLA. Once hte head heats up, let it settle and extrude some extra filament into the trash first to make sure it's running smoothly.
Finally bed leveling. You may not actually be close enough in your bed leveling. I like a single sheet of paper moving freely between the nozzle and the blue tape/glass. You want the nozzle to be close enough that the first layer sort of smooshes out to be wider than the nozzle size itself. But not by much.

Then try the bigfoot.g print from the included sd card.

If all else fails, take a video with your phone and post the video of what is going on. Be sure to catch the pronterface or s3d window showing your settings and what is going on.

[Explorer71]

I am printing on bare glass, but I've also tried glue stick. I use a print head temp of 215 and heated bed at 70. I tried blue painters tape, but I couldn't get the model off the tape. I wound up breaking the model, and gouging the glass. I flipped the glass over, assuming the two sides are the same. Also on the tape I had a lot of support structures and the tape had some give in it and about 2" up one of the supports flexed a little and broke off. I will check the head gap again. I have been using two sheets of printer paper to gauge the gap.

[Levi8than]

So it sounds like your pla certainly does stick.

Worst case with blue painters tape is it should peel off of the glass along with your print and just remain stuck to the bottom of your printout. Then you can work on peeling it off from there. A little warm water goes a long way.
Also, for removing PLA, I've found a spritz from an upside down can of compressed air works great. Just be careful. You are shooting the liquid compressant, which is very cold and can cause frost bite and very bad eye damage if care is not taken. You'll hear some crackling followed by the part just lifting.

I've never had luck with printing directly on the glass. Always some sort of tape and maybe an adhesive above that. Kapton tape coated in hair spray as the bed heats up to 70 degrees has been working well for me, with the upside down spray can release. Also hair spray dissolves in soapy water, so if all else fails just soak the whole piece of glass in a baking pan.

[Explorer71]

The one try with the blue tape was a fairly large piece, in the neighborhood of 4" across. When I tried to peel up the tape .. it just tore around the base of the model. I tried putting it in the freezer, but finally had to pry it off the glass/tape. That is how I gouged the glass.

[Dave K]

The glass is not perfectly flat. I always print on the same side of the glass because I noticed, when I flipped it over, that the gap changed. The glass on mine is bowed enough that I have to readjust the z axis if I print on the other side. I also recommend using a feeler gauge instead of paper. They are cheap. When I started using the gauge instead of paper, my z axis adjustments became a lot more consistent.

It's funny how different techniques work fine for some but not for others. For me, glue stick on bare glass has worked great with PLA. Almost too good. The only thing that gives me fits sometimes is nylon. I still haven't hit on a method that gets it to stick consistenty.

[Levi8than]

The glass is not perfectly flat. I always print on the same side of the glass because I noticed, when I flipped it over, that the gap changed. The glass on mine is bowed enough that I have to readjust the z axis if I print on the other side. I also recommend using a feeler gauge instead of paper. They are cheap. When I started using the gauge instead of paper, my z axis adjustments became a lot more consistent.

It's funny how different techniques work fine for some but not for others. For me, glue stick on bare glass has worked great with PLA. Almost too good. The only thing that gives me fits sometimes is nylon. I still haven't hit on a method that gets it to stick consistenty.

Thanks. I'll try my feeler gauges. I hadn't really considered it being that important previously.
But I also leave ripped up tape on my bed and just make up for it with a thicker coat of hairspray. I'm bad.

Have you tried hairspray with nylon? I'd imagine it's more of a physical connection than an actual bond. The other thing to try would be to get the dual extruder setup and actually sandwich the nylon in pla for the first layer to make a physical connection. Worth a try I'd think.

[Dave K]

I used to use hairspray exclusively, then tried using a glue stick. I wasn't a fan at first because sometimes it bonded too well. But it made some problematic prints turn out better. And I found if I let cool tap water run down the back of the plate while it's still warm, the parts will often start to release on their own because of the glass contraction (I assume). That was with PLA. With nylon, I never did get good results with hairspray, but usually got decent results with the glue stick.

[Explorer71]

OK, I leveled the glass, and checked the gap between the head and glass at .006". I cleaned the glass thoroughly and applied a coat of glue stick. Tried a print at 215 for the print head and 70 for the bed, and it would NOT stick. Could I be having a feed problem or a clogged nozzle? I had the filament bind up on the reel just before all this started. It tried to run for 15 or 20 minutes with the filament bound so it wouldn't feed. Could this have caused a problem?