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PLA First Layer Curling off bed when filling...

Posted by jrherita 
PLA First Layer Curling off bed when filling...
December 26, 2012 08:10PM
Hi reprappers!

I need some help. I'm running a Prusa Mendel and am unable to get my first layer to stay on the bed during the initial layer fill process..

The print will start with the outline, initial 'holes', and initial perimeters all going well. However, when the print starts to fill in the other gaps in the first layer, eventually things start lifting from the bed in the center of the print area..

I am printing on a heated build plate with glass on top. I've managed to print a # of other objects with no issue...

I've tried:
- Different color PLAs (sometimes they have different properties)
- Bed temps 60-75C, Extruder temps (180-200C), 60C/185C work well normally for me
- Windex, rubbing alcohol, distilled water, different towels to clean the bed
- Releveled the bed several times
- Tried a couple different first layer fill parameters (seems that Slic3r always mandates 100% fill on first layer?)
- Tried different diameters for filament (slic3r settings)
- Various print speeds
- Tried a fan blowing on the whole thing (nozzle temp consistency?)
- Different z heights for starting print (purposely too high, purposely too low, what appears to be correct)

This is VERY frustrating.

I've searched a bunch of forums and most articles about layers not sticking completely/properly/etc refer to temperature and cleaning the bed, which my hands are now dry as hell from very thorough cleanings smiling smiley

What else can I try?

(The object I'm really frustrated/failing to print is a new x-carriage as I want to build a Prusa i3.. smiling smiley )

Thank you all..
John H
Re: PLA First Layer Curling off bed when filling...
December 26, 2012 08:46PM
I used to have issues with lifting too, but now when I print PLA (which is 99%of the time) I use PVA cement on the glass. This is basically white glue (elmers) and I dilute it 1 part glue to 4 parts water. I wipe it on the glass with a paper towel - it dries in a few seconds if the bed is hot. One coating usually lasts a few prints. One thing - I never put glue on top of glue. I used to, but it builds up too much. Now when I need to refresh the surface I clean it off - I use nail polish remover while the bed is still warm - and then put down a new coat of PVA. I still get occasional lifting, but MUCH less often.
Re: PLA First Layer Curling off bed when filling...
December 27, 2012 10:10AM
I use Swarzkopf┬┤s Got2b glued blasting freeze hair spray on my mirror and I have printed objects filling the entire mirror with only slight lifting in the corners. I clean it up after ca 3-5 prints with window cleaner (ammonia based) and put on a new thin layer.

Prusa with cast PU parts, RAMPS 1.3, Wades extruder, J-Head hot end
Re: PLA First Layer Curling off bed when filling...
December 27, 2012 04:53PM
Hey John,

I print primarily in PLA and I very infrequently have curling issues. When I do it is almost ALWAYS a result of my print surface being dirty. I know you mentioned you cleaned your surface until your fingers were dry smiling smiley, so here's the rest of my setup, which is very similar to yours, but may help.

Heated bed: 60C
Hot end: 185C
First layer height: .25mm
Print Surface: Kapton Tape over glass (good for PLA or ABS)
Cleaning solution: Acetone applied with a paper towel
No Fan for the first 3 layers (configurable in slic3r)

Kapton tape can be expensive, an alternative that I've read has good results (with PLA) is blue painters tape.

Good luck, and when you figure it out, let us know your solution.

Re: PLA First Layer Curling off bed when filling...
February 10, 2013 10:45AM
I actually had this today (and slightly for some time) and I've realised that extrusion width seems to hugely affect first layer infill curling. (probably more accurately 'width over height'. As width approaches height, more curling on the first layer is seen (I was trying to extrude 0.35 / 0.25, on a 0.5mm nozzle confused smiley ), a 2:1 minimum ratio seems to be best, and of course, you shouldn't extrude a width much smaller than the nozzle diameter. smiling smiley

Edited 1 time(s). Last edit at 02/10/2013 10:46AM by Aggresive.
Re: PLA First Layer Curling off bed when filling...
February 11, 2013 06:49AM
If you are printing on glass, try this, it works for me every time.
Get some methylated spirits (alcohol) and add a very small amount of PVA glue to it.
You can also do it by adding a drop of glue to your glass print bed and putting a little metho on and mixing with your fingers spreading out evenly at the same time. Allow it to dry (few minutes) and then make your print.
If you add too much glue then you will need to soak the galls in a tub of water to get your part off, but with practice you will be able to gauge the right amount to use.
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