This semester, I am taking a CAD/CAM course and one of our homework assignments was to make a chess piece. The end goal being to 3D print, mold, and then cast it. In one of the first weeks of class, we learned about using the Loft tool in SolidWorks, and when I saw it was capable of doing twists along the loft, I instantly had the idea for my chess piece. Modeling just one chess piece on this theme seemed a bit too easy though, so naturally I made a whole set for it!
The parameters for the chess piece assignment was that it had to fit within a 1″x 1″x 2.5″ bounding box, and be *possible* to print and mold. I liked a hexagons as the base shape, so I decided to go with a .875″ (inscribed diameter) hexagon for the base of each base. All of the pieces have this same size base for uniformity. Another, smaller hexagon offset an inch or so off of the base is used to make the top faces. These two hexagons were then lofted from one to another, applying a 1/3 twist to it, to make a solid.
Every piece follows the theme of hexagonal twisted bases, and then hexagon based features for everything else. The knight was a particularly difficult one to come up with, as a typical horse type piece would be a little odd in hexagon form. Instead, I chose to go with a knight type helmet to represent the knight piece. It is still unique enough of not to get confused with any other piece.
Also, here is a thingiverse link to the design files: http://www.thingiverse.com/thing:680373
After designing all the parts, I saved them off as .STL’s, ran them through Slic3r and got to printing. The first one I printed was the rook, as it was the first one I designed, but I followed that up by printing one of each piece to see how they would each turn out.
Things I noticed right away: The knight’s head was too small, the queen’s crown points were sloppy, and the rook’s merlons were not looking so great. Luckily, all of these were easy fixes. I bumped up the size of the knight’s head, and increased the size of the queen’s crown points and the rook’s merlons. Fairly confident in these changes, I organized all the pieces of one side together and decided to print them all at once.
Everything printed out great. I usually try to avoid long prints like this because it just increases the risk of a mid-print failure, but my Prusa i3 performed like a champ. It took about 4.5 hours for everything to print, and there were surprisingly few stringers between parts (which is quite lucky, as I haven’t done much in the way of retraction calibration).
I am fairly pleased with the appearance of these pieces. Twisting shapes are one of those cool things that’s hard to do on anything but a 3D printer. They feel pretty good in hand, if a bit light. The weird, translucent yellow PLA that I used to print them out is not really my favorite, but it’s all I had on hand, and not what I plan to use for the final product. The bases of the pieces look a bit weird, since they are solid and darker in color than the layers above.
The next step with this project is to get some black and white PLA so that the pieces are the proper colors! I’m also thinking of a design for the chess board itself, which I will likely mill out on my shapeoko. Part II will hopefully be not too long in the making!