CR-10 mini looses bed adhesion and warps at the bottom egdes

  • We got a CR 10 mini setup and I have been trying to configure it as best as I can, the prints come out great, but the bottom layer starts to loose adhesion on the outer corners after printing for a while, causing slight warping on smaller prints (30-60mins) and on larger prints the printed item comes loose fully.

    I have experimented with different temps on the bed and nozzle, but can't get it to adhere well over time. first layers prints great at 200C/50C.
    I first thought it was the bed that was too hot (50C) causing it to warp, but setting it lower then 40-50, the first layer is not sticking.
    (I relevel at each different temp test)

    Any good suggestions on how to proceed? Eager to try to print something larger. 🙂

  • I tend to start the print with bed at 60 to get good adhesion, then drop the bed temp to 55 or 50 after the first few layers. If the room temp is low there will be more tendancy for the upper part of the print to contract further and faster so pulling up the bottom edges of the print. Helps to have room temp above 30C , or an enclosure,. As best as possible be sure you have no room fans or draughts.

    If you want to drop more than 5c on the plate, you will most likely cause loss of adhesion due to sudden large change in temperature. You will need to go in steps, so after layer 3 drop to 55, after layer 20 drop to 50. mostly once you are a 10 - 20mm into the print then you are good to the end of the print as long as no large sudden changes in temperature cause loss of bed adhesion.

    I nice big brim should help some. there are some custom brims you can find in the plugins or 'Market' in some slicers. Big round ones that sit at the corners, have not tried them but I cured mine a long time ago without. I do use an 8mm brim but if something happens and sudden draughts of cold air before it gets 10 or 20mm into the print then nothing will stop it.

    If you can manage to control the difference in temperature from upper layers to lower layers and thus cooling rate, and use high bed temps in the first 2 or 3 layers, adhesion will be fine. Warping at the corners should completely vanish. Another thing is to try to keep the part cooling fan as low as needed, even off during first 2 or 3 layers. Not so low during the rest of the print as it makes a bad print obviously but full on 100% will more likely hinder than help.

    High build plate temp for the entire print may not help, and likely make it worse in the case of cold rooms and draughts. Also likely cause elephants foot. Worth a try, but I find the opposite to be very effective.

    As mentioned by @SteveDee also try totate the model 45 degrees, your corners may be on the bed hot spots. Moving them off the hotspots will help a lot. We want cooler, not hotter.

  • A few more things you could try;

    • increase the width of the brim
    • move the object to a different part of the build plate in the slicer software
    • assuming you are printing PLA, raise the bed temp to 60'C
    • clean the bed with Isopropyl Alcohol (99.9%) and then keep your fingers off the bed surface

    I don't think all beds are uniformly heated, that's why I suggest printing on a different part of the bed.

    Oh, and here is a really crazy idea; It might also be interesting to rotate the base of the object through (say) 45 degrees.

  • @SteveDee
    Ah yes I tried with brim thinking the same thing. the brim sticks well, but the edge of the print still have a small tendency to lift a bit slightly breaking of from the brim 😕

  • The corners of a 3D printed object cool faster than the edges, which can cause warping/lifting at the corners.

    Try printing with a "Brim".

  • Update:

    Tried with 60C on the bed and it sticks much better, but still slight warping at the edges of the print.
    Using PLA I should have told in the first post.
    Maybe try to go even higher up on the bedheat?
    From what I read PLA shouldnt need a heated bed at all? Or is that just nonsense?


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