Getting PLA to Stick!

Hey all!

I've just made my first prusa, I'm using PLA and I'm struggling to get it to stick! It works until a centimeter or two high then it just lifts slightly and pushes off

Settings are as follows (inc all attempts at getting it to stick!):

170 .5 j-head
60 hot bed
sand blasted glass (cleaned with acetone)
largest first layer height allowed
very slow speed...
large brim and connecting skirt to hold it down! (this just comes loose too )


Any recommendations much appreciated! Thanks, flemish4

How does the layer look as it goes down?
The height of the first layer is somewhat critical
If the cross section looks round, adjust the height down slightly.
If it looks very flat and it peels off then you need to move the height up slightly.

1) Boost your heated bed temp a little. PLAs' general range for glass temp is 60-65C. May even be higher if filament isn't pure or for some other reason doesn't fall exactly within the characteristics of idealized PLA.

2) Consider using a dilute mix of PVA (white glue) and water, or a similar applied adhesive, to increase surface tack. (you indicate that you have a heated glass bed, which is why I won't bring up specious answers like "use painters tape" or "dude, I get like great results with Kapton tape", since it's clear from your system description (or should be) that your intention is to solve the problems of printing to glass, not to get recommendations for alternative paradigms.

3) Reduce air currents at the bed (make sure fans aren't blowing across the bed during initial adhesion of the extrusion, try to block natural drafts that flow across the bed, etc.)

4) (optional) insulate your bed to ensure a more uniform thermal profile in the bed. (the temperature profile will tend to droop as the distance from the center of the board increases)

Try to raise your hotend end temperature a bit too for the first layer, 180 should be safe.
Make sure it is degreased really well, I have prints coming off when the glass gets slightly smudged with fingerprints when printing pla.

Put some tape on the bed if all else fails..

Groeten,
Wauter

Just curious, I've been having a similar problem. I have blue painter's tape without a heated bed, but I can't seem to get it to stick. Should I get the bed heated?

@psktam

Heated bed helps.

You could also try Kapton tape instead of blue painters tape

@flemish4

I had similar issues due to air currents cooling the edges of the print, but they were being caused by a fan on my hot end. I used Kaptop tape to stop these air currents getting down onto the side of the print.

On glass alone, a perfectly clean one is enough. None of the Elmer glue, hairspray or sugar ever worked for me.
Beer goes in my glass, not printer's one.

with heated bed at 70°C, kapton tape is the best thing I've found. works well and last. I'm often forced to put the plate in freezer to get parts pop without damage.
To replace easily, I use a narrow tape (1/2") so i can change only damaged bands and use alcool for acurate positioning.
Vinyl (Tesa brand) white tape works also in the 50-60° range but is less durable. Need to lower extrusion temp too.
Without heated bed 3M blue tape is perfect. If you heat that, it will never go off.

In any case there is 4 things which are critical for first level :

- perfectly leveled bed. If it lift always in the same corner probably the culprit.
- use a fatter deposit for first one (advanced setting in slic3r) and verify the shape. should be round, only slightly flattened, over crushed wont stick.
- go slow (i use 25%-30%) for fisrt level, and slightly hotter than for the rest (current PLA 195°C for 185 for rest).
- If not in chamber, the bed should be insulated on backside. I use cork. If not, movements alone are enough to cause temp variations that are detrimental to sticking

I have fans always on. fans starting later cause more problems than they solve.

there is many proper suggestions, but simply you can also suspect the quality of your PLA

Are you sure that your nozzle height is correct? I use a 100um feeler gauge to set the height between the bed and the nozzle. Too low and my nozzle drags through the print and my second layer doesn't go well, too high and the part pops off the bed in the middle of the print or I get curling. I use blue painter's tape, cleaned well with acetone, and no heat. It's what I started with and I've never had a problem with it so have never tried the various other ideas that are floating around.

KDog

I only print with PLA,.. on to Kapton Tape.

no 1 for me is "no grease", I clean the bed about every 3 or 4 prints with some acetone wipes I got from the chemist.
Then I rub it over with a bit of toiler tissue to dry it.

I second all of the above as well. Have never used hairspray, glue, etc etc.

Level the bed, and when you home "Z", Z should be *just* and I mean *just* touching the bed.
Home Z, send a command
G1 Z8 F400
Use an 8mm drill to check it your nozzle is exactly 8mm off the bed.
If it passes under, it's too high. If it doesn't pass under, it's too low.

iterate:
Adjust the Z endstop
Home Z
send G1 Z8 F400
try again.

See my thread called "By Jove I think I've sussed it" I'm about to post about PLA sticking to the bed, I think first layer fill direction has a LOT to do with it too.

cheers

Dave