Surcouf Guns

Discussion in 'Weapons & Pneumatics' started by JustinScott, Oct 26, 2022.

  1. darkapollo

    darkapollo Well-Known Member

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    I went down that road because I couldnt print ABS reliably. I tried all sorts of things to seal PETG and nothing fused the layers like acetone and abs.
     
  2. JustinScott

    JustinScott Well-Known Member

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    Update - printer has its heated enclosure and is starting to print ABS.

    I’ve decided to send a few Deutschland hulls through the machine first, to work on the machine’s print quality.

    After a bit of struggle, it’s starting to yield good prints. Probably a new ABS Surcouf cannon will happen this weekend.
     
  3. Kotori87

    Kotori87 Well-Known Member

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    Is your enclosure actively heated and temperature-controlled, or does it just retain heat from the nozzle and bed? For very large ABS prints, you really want active heating with temperature control. That's your real big league ABS setup. Active heating introduces its own problems, though. The heater has a fan to circulate air, and that air circulation can cause uneven cooling, which warps large parts and causes bed separation- exactly the thing you're trying to prevent. The trick is to get lots of heat into the enclosure while minimizing airflow near the print bed. I use a diffuser (basically a flat wall) to slow down and redirect the air from the heater, significantly reducing the problem. For best results, you want to insulate the walls, seal any openings, and allow the enclosure time to reach uniform temperature. This reduces run-time on the heater. The less the heater runs, the less you have to worry about air circulation. My enclosure runs at 120F. I would run it hotter, but the on-time gets too long.
    If you still have issues with warping and bed separation, consider some stress-relief slots in the hull. These slots can easily be filled in later with ABS slurry or a 3d print pen. I couldn't have printed my Mikasa hull without stress-relief slots.
     
  4. JustinScott

    JustinScott Well-Known Member

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    It’s actively heated & temp controlled.

    81F9F3CE-86DD-44A9-8781-B61F7F152AE4.jpeg



    I’ve been keeping it at 95F. See the chart from last nights print.

    50B5DECB-7E4A-4BE5-9796-0E3277E94583.jpeg


    The prints are coming out good. No issue with plate separation so far.

    I have some boogers on the print, and some layer separations in my first print, but found the nozzle wasn’t tightened. Last nights print is looking better so far, but I’ll come to know today what issues remain.

    E54E66EC-F096-48A5-ABB4-C165AD98C815.jpeg
     
  5. bsgkid117

    bsgkid117 Vendor

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    So build plate separation isn't a symptom of chamber temperature being low. The bed being hot will give you a good first few layers even without an enclosure. AMHIK.

    Chamber temp being low will result in large cracks in the print once you're 5-6" above the plate. Like the crack you circled. And the similar cracks that appear (at least look like cracks) at regular intervals up the sides of the print. The cracks will be concentrated on the largest mass areas of the print, as you are putting more hot ABS in those areas that then is going to cool and contract. For me this is traditionally the subdeck areas, as you've got "exterior walls" on all sides of a relatively small area...they almost print solid for me depending on my set wall thickness.

    I dont design "stress reliefs" in my prints. I don't have issues. I have at least 10 3d printed hulls in my garage (6~ Suffrens, a VDT, a Jean Bart, a Malaya, an I boat) and each of them is made of chunks at minimum 320mm tall.

    My previously actively heated printer cabinet would get air temp up to 120F. It was aimed so the air blew at the back of the cabinet, not at the printers, to keep any direct drafts down. On my 3DP bart you could actually see waves in the print which matched the dwell time of the heater. Cabinet temp would rise to 120F, the heater would kick off, as the air temp cooled to 100F the whole print would contract slightly until the heater kicked back on and the print would relax. This resulted in me changing the on/off temps to a much tighter tolerance, on @ 120 off @ 118.

    Also, plexiglass may be neat because you can see whats going on....but its not very insulative. If it was me, I'd at least get some self-adhesive automotive insulation with the foil face and put it on your plexi panels. Everywhere except for maybe a 6" x 6" viewing window. Tape off any holes/cracks etc in the enclosure...anywhere cold air can enter is not good. You're not just worried about average ambient, you're worried about the death star laser of 32F air that comes in through a screw hole.
     
  6. JustinScott

    JustinScott Well-Known Member

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    Update -

    Enclosure can now do 110F and stay there with a tolerance of 1F. Layer separation seems to be fixed. I will need to add insulation later, since it can’t keep up with the garage door open.

    I called this good enough for now & I tried printing the cannon for the first time, on my own printer with ABS.

    I found the bridging is terrible & my threads are junk as a result…. So that’s my next issue to solve.
     
  7. Kotori87

    Kotori87 Well-Known Member

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    Off to a great start, then. I never got good bridging on my horizontal threads, so I separated them from the rest of the cannon and printed them vertically. No bridging required, and I can use much nicer threads. That said, it may be worth printing multiple cannons in one print, so there is a little more delay between layers to allow them to cool. I got much nicer results when I print several cannons at once.
     
  8. darkapollo

    darkapollo Well-Known Member

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    I do the same. My threads are made into an insert which is printed vertically. I can then weld it in place.
     
  9. bsgkid117

    bsgkid117 Vendor

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    In most slicers there is a "minimum layer time" setting that accomplishes the same thing :woot:

    I wonder if you could get a heat-set insert of sufficient size to eliminate the plastic threads all together....just thinking out loud...err...thinking....on keyboard?
     
  10. darkapollo

    darkapollo Well-Known Member

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    Ive looked. I couldnt find any in the 7/16-24 thread that I use.

    Yet another reason I want a lathe.. custom heat set inset threads.
     
  11. JustinScott

    JustinScott Well-Known Member

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    but i've had good results from the polyprinter at makerspace, which is a crappier printer than my new one.

    SO it's possible using my current STL model with the same brand of filament. The only thing that's change is the printer and slicer... :(