The Hell Ya Beller Fun with hot, pointy, sharp, and caustic stuff.

31Jul/122

Cutting Plastic

I finally started laser cutting the plastic pieces for the chassis.

I happened to have some orange 3mm acrylic and thought it would make a nice accent color.

IMG_0739_modified

Unlike the standard shell, mine is cut in three pieces and glued together.  I had some worries that this wouldn't be very strong but it turns out that the glued joint is extremely tough.  With acrylic, we're basically welding the pieces together.  The solvent cement softens the plastic and the fused joint is incredibly tough.  Even so, I reinforced it with a couple pieces I'd cut to calibrate the laser.  These are just glued in underneath to add some thickness to the glued surface.  I don't know how durable it will be over time, especially flexing it from time to time to assemble, but so far, so good.

IMG_0741_modified

 

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  1. Really nice work on FreeCAD and the openROV project. I use FC for most of my work now too. It’s coming along. Most of the core functionality is there, and its a really capable free cad package.

    I’m quite interested in starting another ROV project (An ROV was my graduate project in college). OpenROV is looking pretty good. Have access to the wonderful FabCafe Laser in Tokyo (http://www.fabcafe.com/blog/category/english/) but not sure I want to build a linear acrylic bender just for this project. Built too many of those in my day (unfortunately all on the other side of the ocean from me now). Really digging your square corner layout. Any idea when you will have a cut sheet layup ready?

  2. Thanks. I still have some concerns about the square corner design. Eric made a comment in a video meetup that they tried similar designs and it ‘was crap’. I don’t know the details on the joints or the adhesive so I might be making a mistake.

    I don’t know how people generally use the cut-sheets. Does the laser just follow the lines cutting directly on them? Particularly because of my joint, I wanted the cuts really tight so I’m compensating for the laser kerf.

    I’ve been individually cutting the pieces with heekscnc rather than a whole sheet at once. My tool chain is to take the solid model exported as a .stp file into heekscnc, select a face and make a sketch from it. Then split the sketches for inside and outside cuts. Then I generate the g-code and cut it.


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