PLA to ABS

Discussion in 'Digital Design and Fabrication' started by tgalx3, Jul 31, 2023.

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  1. tgalx3

    tgalx3 Well-Known Member

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    I have an Ender 3 printer with an encloser. I tried printing a small test cube today and I have zero bed adhesion. I increased all of the temperatures to match ABS. I adjusted the bed height that has worked in the past.

    YouTube just prints ABS out with the settings that I have changed with no problems with bed adhesion.

    Can you think of something that I am doing wrong to not have the prints adhere to the bed?
     
  2. Iunnrais

    Iunnrais Active Member

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  3. tgalx3

    tgalx3 Well-Known Member

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    Disregard...

    Apparently I forgot how to level the print bed properly. Quite embarrassing.

    First test print has adhered to the bed successfully. Crossing my fingers to see how the rest of the print goes.
     
  4. tgalx3

    tgalx3 Well-Known Member

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  5. Kotori87

    Kotori87 Well-Known Member

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    What is your print bed made from? How flat is it? How clean is it? How close is your nozzle to the bed during the 1st layer, and how much over-extrusion (if any) do you have?
    For example, I use a PEI surface. I also do my prints on top of a few raft layers. These are basically extra-sticky layers that are spread out and heavily over-extruded to ensure the part sticks to the bed. I don't think of it as wasted material, since it saves me from a LOT of bad/warped/failed prints. Very useful when printing hulls, cannons, and other big parts.
     
  6. tgalx3

    tgalx3 Well-Known Member

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    Uhhhh. Everything on the printer is stock. I use a piece paper to set the bed height. But what I have not been doing is doing test prints to get the height dialed in after that.

    I did a successful print of a calibration cube. It was stuck on there really hard. There was no layer separation. I think I’m back on the right track.
     
  7. bsgkid117

    bsgkid117 Vendor

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    You poor souls and your manually leveled printers.

    No joke, I would not even use a manually leveled printer in 2023. Couldn't pay me to, it's so amazingly annoying.

    There are probably 58 different write-ups and walk-throughs on how to add a BL touch and auto bed leveling to Ender printers, I cannot recommend the modification enough.
     
  8. Iunnrais

    Iunnrais Active Member

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    The BL Touch certainly does help :) The only 'leveling' that I need to generally do is adjust the z height offset if I change the pei sheet or the nozzle. Occasionally an adjustment to the flow modifier if a particular spool is showing over/under extrusion (thank you amazon).
     
  9. tgalx3

    tgalx3 Well-Known Member

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    I was watching YouTube on the Ender 3 BL device. I haven't received it yet. But how do I know which z height offset to set it at?
     
  10. bsgkid117

    bsgkid117 Vendor

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    When you install the sensor, you will need to calibrate the printer with the X/Y/Z offset of the probe tip vs the nozzle. So, if the sensor hangs off the toolhead in front and to the left of the nozzle, you'll need to let the printer know that the probe offset is +25mm X, - 12.7mm Y, etc.

    When you home the printer, the probe becomes your z endstop. When it triggers, the printer will stop at N mm above the build plate. From there you jog it down to the print bed using your traditional piece of paper manual level method. That's your Z offset, how many mm on Z axis it needs to go "down" from where Z home is. Then you save that offset and don't need to do it again.

    From there you can live adjust Z offset by "babystepping" the printer up or down in .01 mm increments to get a perfect first layer.

    ABL, auto bed leveling, mesh bed leveling, etc, works by taking the probe and creating a grid of references on the print bed and live-adjusting the Z axis to compensate for any imperfections in the build surface.
     
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  11. darkapollo

    darkapollo Well-Known Member

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    Start with -3 and move it down.
    My Ender3 with BL ranged from -2.4 to -2.8 depending on how much first layer squish I wanted.
    The firmware was also REALLY hit or miss. It would do 8 points, fail the 9th and just start printing. I lost so many probe tips because of that. But maybe they fixed that in the past 4 years.
     
  12. NavyShooter

    NavyShooter Member

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    I've had very little success in 3D printing with anything but PLA. I've got a Prusa Mk3S+ and it does amazing work...with PLA. Getting ABS or PETG to stick to the bed has been an absolute nightmare.

    I really don't know what I'm doing wrong either...so my answer has been to stick with mostly PLA for what I make.
     
    Last edited: Aug 2, 2023
  13. tgalx3

    tgalx3 Well-Known Member

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    I’m sure there is a better way. But I have been getting great results by making sure the bed level is perfect and using an elementary school glue stick. It’s water soluble. After the print it washes off.

    I have beautiful ABS Bismarck barbets now.
     
    Last edited: Aug 1, 2023
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  14. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    Don't forget to clean your table... If I run pla and immediately run abs afterwards, it won't stick till the table is well cleaned.
     
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  15. tgalx3

    tgalx3 Well-Known Member

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    I’m getting some minor layer separation on the corners of my ABS prints. I’ve read that is common but can’t seem to find a good solution.

    I’ve tried slowing the print speed to 35 m/s and increase their nozzle temp to 255.

    does anyone have any other good solutions?
     
  16. bsgkid117

    bsgkid117 Vendor

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    Like it's pulling the corners up off the plate?
     
  17. darkapollo

    darkapollo Well-Known Member

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    Layer separation is never normal.
    Corner lift can be normal. Usually that is a sign of inconsistent chamber temps or too high of infill causing a lot of internal stress.
     
  18. tgalx3

    tgalx3 Well-Known Member

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    Yea it’s mostly the corner lifting.
     
  19. tgalx3

    tgalx3 Well-Known Member

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    I have noticed that when I dropped the infill down to 20% that it is happening more.
     
  20. Kotori87

    Kotori87 Well-Known Member

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    Corner lift is annoyingly common on ABS since it concentrates the effects of ABS shrinkage. I also found that the effect was more pronounced at faster print speeds, lower infill%, etc. I reduced the effect by raising enclosure temperature and reducing/eliminating drafts. I switched over to Raft type bed adhesion. I don't think of the raft as wasted plastic, since it prevents me from tossing parts. Lastly, I also changed my design process to reduce/eliminate the sort of sharp corners that are particularly vulnerable to it. For parts that simply must be sharp and pointy, a breakaway disk on the bottom provides much more gripping surface with less stress than a straight corner does. On particularly large prints, I even put thin relief cuts in the print to limit the stress. A perfect example of these design features is Greg's Deutschland class 3d-printed hull. You can clearly see how disks were used around the corners, casemates, and (especially) bilge keels, and the hull segments are absolutely covered in stress relief cuts.