Adhesion with PLA

I just started having this problem. When I print with PLA it gets the first Layer down nice, but midway through the second layer it lifys and gets dragged by the tool head. Im sure its an easy fix but I just can’t figure it out. Any suggestions??

Mark

Have you been printing any other filament than PLA? If you have printed ABS or have just had your hands touching the print surface too much, you may need to clean the print surface. I use acetone. Others use alcohol.

Have you double checked the Z axis home? Too high and the first layer will not stick to the print surface well.

I use acetone. Others use alcohol.

I use alcohol to clean my bed and I have the oppsite problem. It is so very hard to get the PLA off the bed after the printing is done. I have tried a range of removal temps. I am worried that I may end up pulling the PEI off the bed.

Jato3d - I had the same problems. Turns out there were several causes, corrected with the help and advice of those here on this forum.

I was over-extruding. I needed to put in a more accurate diameter for the filament, and recalibrate the extruder using 40mm/min speed, rather than the 100mm/min recommended in the calibration guide (the lower speed corresponds more closely to the actual extrusion speed during printing). Fixing the overextrusion helped the prints release a little easier, and also cleaned up the surface and corners of my prints.

What does the surface of your first layer look like? Mine was a bit rough. There were “fins” of excess filament poking up parallel to the lines of print (where one line adjoined the next). Basically, I was dragging the nozzle through the extruded filament and smushing it down onto the print bed. Resetting the Z offset up a bit smoothed out the surface of the first layer dramatically, and also helped with part removal. It took a few tries to figure out how high to raise it, but for me, 0.1mm seemed to do it.

Thanks for the info John i’ll give your suggestions a try. The first layer looks good have never noticed any evidence of dragging the nozzles but i’ll take another look. Thanks again.

Jato3D - There are other signs of over-extruding. I just mentioned it as a possibility. Some of the folks on here could tell you from a picture of some of your prints. One of the signs is that parts tend to come out oversize in the X and Y dimensions, and interior holes tend to come out smaller (I tend to ignore the little lip which shows up on the first layer of some of my prints when checking dimensions. It has gotten smaller as I’ve tuned things in better, but it’s still there.)

The biggest difference for me came when I increased the z offset a bit - and it didn’t take much movement to make a change in adhesion to the bed.

Many of the other folks on here are much more knowledgeable than I am, so they may have better suggestions.