The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • Smashed Glass Coasters: Chipboard Variation

    The summer season brings iced drinks with condensation trickling down the mug and, alas, running off the smashed glass coasters:

    Printed Coaster - Set C - oblique
    Printed Coaster – Set C – oblique

    The hard parts of making those coasters involved converting the glass fragment outlines into vectors and arranging them in interesting patterns. However, with those files already in hand, making a similar coaster with chipboard “fragments” was straightforward:

    Chipboard Fragment Coaster - detail
    Chipboard Fragment Coaster – detail

    Slightly modify the OpenSCAD code to suit thinner chipboard:

    include <BOSL2/std.scad>
    
    fn = "Printed Fragment Coaster - 5 in Set B - Inkscape paths.svg";
    
    FragmentThick = 0.8;
    
    BaseThick = 2.0;
    RimHeight = 0.4;
    
    union() {
    
    
      linear_extrude(h=BaseThick)
        import(fn,id="Perimeter");
    
      color("Green")
        up(BaseThick)
          linear_extrude(h=FragmentThick)
            difference() {
              import(fn,id="Perimeter");
              import(fn,id="Recesses");
            }
    
      color("Red")
        up(BaseThick + FragmentThick)
        linear_extrude(h=RimHeight)
          difference() {
            import(fn,id="LipOut");
            import(fn,id="LipIn");
            import(fn,id="Island");
          }
    
    }
    

    Run the solid model through PrusaSlicer:

    Chipboard Fragment Coaster B - slicer preview
    Chipboard Fragment Coaster B – slicer preview

    And have a baseplate an hour later:

    Coaster Printing - in progress
    Coaster Printing – in progress

    While that’s buzzing away, tell LightBurn to cut chipboard instead of metallized paper, stick some craft adhesive sheet on the chipboard, and Fire The Laser:

    Chipboard Fragment Coaster - chipboard cutting
    Chipboard Fragment Coaster – chipboard cutting

    Remember to mirror the fragments, because you’re cutting them bottom-up.

    Do the same for the cork sheet going on the bottom, which does not require mirroring.

    I tossed the cardboard alignment fixtures I used to stick the cork onto the 3D printed baseplate, so make another one for each coaster.

    The top layer holds the baseplate:

    Chipboard Fragment Coaster - cork fixture - top
    Chipboard Fragment Coaster – cork fixture – top

    The cork + adhesive sheet is inset 0.5 mm from the edge of the baseplate, so the outline cut in the bottom layer of cardboard is just that much smaller:

    Chipboard Fragment Coaster - cork fixture - bottom
    Chipboard Fragment Coaster – cork fixture – bottom

    Although the time used to make a fixture isn’t deducted from your allotment, I’m not sure about making two identical fixtures, so I’m saving these for the next time.

    Then peel-n-stick the chipboard fragments in their recesses:

    Chipboard Fragment Coaster - variety
    Chipboard Fragment Coaster – variety

    The first baseplate didn’t have raised rims around the fragments (because there’s no need to retain any epoxy), but the result looked kinda … flat:

    Chipboard Fragment Coaster - flat top
    Chipboard Fragment Coaster – flat top

    Fixing that was a matter of not setting the rim height to zero in the OpenSCAD code.

    It’s perfectly functional even without a rim:

    Printed Coaster - chipboard inserts - sweaty mug
    Printed Coaster – chipboard inserts – sweaty mug

    Protip: White chipboard is a Terrible Idea™ in a quick-n-easy laser cuttery project. All the rest have only red or blue fragments for a good reason.

    Conversely, white PETG makes a nice contrast to the deep red and blue.

    Prosit!