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3D Printers - First Layer Adhesion Using PLA

14rhb

I have successfully printed out many things using PLA, including one last night.

 

Today I tried to speed the production up and cloned my article several times but it was soon apparent the first layer had roughed up, the head caught and other layers failed until two of the clones came away completely....I stopped the print.

image

I cleaned the bed, trying several things like pure spirit and washing up detergent. Still the print failed to stick. Bed temperature was 60 degrees C. I tried to slow the initial layer down but again it failed to stick on the initial run leaving a trail that snagged and ruined the later layers.

 

At this point I had a read online and there were solutions and glue sticks suggested. Not wanting to wait I decided to try something different. I taped a piece of plain printer paper to the bed and it appears to have accepted the first layer very well: no snags and the pattern looks great.

image

 

My question for discussion is, what could go wrong with this approach and why is this not a more generally used technique?

  • It has finished printing and I can answer my own question. It looked great at the start and the end of printing:

    image

    But as soon as I started to remove it from the paper I realised it wasn't right. The disc is warped as there is nothing to hold the paper down to the bed and restrain the cooling plastic image. Maybe I need some glue as suggested. I'm going to try a thin layer of PVA/water to see what that achieves.

     

    Actually for the intended purpose it will still be OK to use.

  • in reply to 14rhb

    Painting the bed with PLA glue and water worked really well image and didn't cause lots of noxious evaporation.

  • in reply to dougw

    Hi Douglas,

     

    It's glass with a slightly matt surface finish, and heated if that helps. The Lulzbot Mini from the Sixth Sense Challenge we both participated in image

     

    The watered down PVA (not PLA glue as I incorrectly mentioned above) seems to be working really well as we've been making bits all day here and the initial laydown seems good each time.

     

    Not sure what happened this morning when I posted this blog for help; I probably ended up getting grease on the bed.

  • Hello Rod,

     

    What is the material of the printing bed? Mechanisms for better adhesion will vary depending on it. For example, my Creality's bed is glass, all I need is to clean it up really well and it will work perfectly. As far as I know glue sticks main purpose is to help release the part easier and not to improve adhesion (opposite to what people tend to believe).

     

    Luis

  • I used to have adhesion problems with larger parts with edges lifting off the heated bed.  I solved the problem by using blue painters tape but then it was difficult to remove the part.  I ended up using isopropyl alcohol then the part and tape would come off cleanly.  I got an AnyCubic printer a few months ago and it has an UltraBase bed which works really well.  It has pores that open when heated to help with adhesion and close when cooled to release the part.  Only two issues - 1) the bed has to cool to room temperature before the part will release easily, 2) the base has a stippled pattern which would require some post sanding if you wanted a smooth surface.

     

    I mainly do functional prototypes so I'm willing to accept the issues to get a great adhesion solution.  No more lifted edges or prying to get the part off  image.

  • in reply to luislabmo

    Thanks Luis,

     

    What do you use to clean your print bed? I tried alcohol and later washing up liquid and neither seemed to help.

     

    I'm not entirely sure the bed is glass, it feels like it but does seem to scratch easily when removing suborn parts.

  • in reply to ralphjy

    That sounds really good. Perhaps the Ultrabase is something I can change mine to, as it looks like there are only four corner plates holding my glass bed on.

  • in reply to 14rhb

    Hello Rod,

     

    I use pure Isopropyl alcohol on mine and it works really well (btw, farmacy alcohol is kinda greasy/leaves residue, it doesn't work well). The trick for me is finding good paper napkins that don't leave any residue (I use Bounty and those are good, I even clean my glasses with those, no problems). I believe by judging at the pictures you might own a lulzbot, if that is so then your bed is PEI (I own a lulzbot mini), after some point that material gets spoiled. If cleaning with alcohol doesn't work, chances are you might need the following - it's from Lulzbot support:

     

    "There are a few ways to take care of this. The best way is to get a spray bottle and mix up 10% alcohol and 90% water. Get some 1200 - 2000 grit sandpaper. Get a sanding block.

    Spray some of the 10, 90 mixture on the bed (get it nice and wet). With the sandpaper on the sanding block, wet sand the entire bed until you see a slight whitish film, then stop. Clean the bed good using the same mixture with a clean cloth.

    This process will last a good while. I know this sounds a little strange but it does work really well."

     

    Luis

  • in reply to luislabmo

    Yes, it is a Lulzbot Mini as well. The alcohol I used was called Surgical Spirit bought from the chemist and on closer inspection I think you are right about it being slightly greasy. I'll get some Isopropyl alcohol instead and give that a go (after removing all the dried PVA glue !).

     

    Thank you for confirming the material is not glass, that would be why I managed to put a few scratches into it I guess. It also has some strange flecks in the material which seemed odd for glass. Your last stage sounds similar to when I polished my car's fogged plastic headlamp cover to get it past the annual roadworthy test.

     

    Thank you for all this help, its really appreciated.