As I’ve mentioned above, the published version of robot is really easy to assemble.
#INKSCAPE GCODE MAKELANGELO FULL#
But, for now I think I’ll stick with full gears even if that means using more plastic because it means the final robot will be easier to assemble. I would genuinely enjoy creating a variation with half gears because it would look cool and use less plastic.While it doesn’t matter if a full gear is rotated one tooth one way or the other, a single tooth offset on a half-gear would cause the ‘bot to stop prematurely or cause the gear to hit the ends of the rails. However, if the design required half-gears it would become much more difficult to match the servo’s position with the orientation of the half-gear. As it is, I’m pretty sure a little kid could build this robot with very little direction. My other concern is that incorporating half a gear would make this robot harder to assemble. My concern is that these half-gears will cause a lot of wobble when the ‘bot is operating at higher 4 speed. Why not make these half-gears instead? To be on the safe side, I try these with slightly more than half-gears. Thus, only one-half of the gears actually ever touch the racks. The servos I’m using can only sweep across 180 degrees. There’s one additional way I thought of, but it’s wacky enough that it deserves it’s own first order bullet point… Third, I can try to “hollow” out parts – such as the gears. This probably makes a bit of sense with the gears 3 and the X and Y stages. Since most of the parts were already very thin, I’m not sure how much thinner these parts can get. I figure there are at several ways I can still reduce the plastic used. As it stands, it is already a very minimal design, so there’s not a lot of fat to trim. One of my goals is to make the entire robot use even less plastic.Thus, I’m designing this newest version will be a very little bit larger. The versions published to Thingiverse are able to move in the X and Y axes by about 65mm or so – just shy of my desired goal. Secondly, this is just large enough to draw on three different kinds of common materials – traditional American business cards which measure 74mm x 52mm, and Post-It notes which measure 3″ x 3″ or 76mm x 76mm, and 3″ x 5″ rectangular 2 index cards. Why this size? First, it would be difficult to print the parts much larger than this. I’ve arbitrarily chosen a 75mm x 75mm square 1 as the necessary drawing area.The flip side is that it might make it easier for the ‘bot to accidentally skip a step. I’ve also reduced the size of the teeth used to hopefully get finer control. My script for the rack is so unbelievably “hacky” that I am actually a little ashamed to admit how I cobbled it together. Since I couldn’t find an easily modifiable OpenSCAD script, I had to write a few modules to create herringbone racks and pinions.As a practical matter, it’s not really any more difficult or time consuming for a 3D printer to create a herringbone gear than it is to create a non-herringbone gear of the same size. Fortunately, since this entire design 3D printable, this is not a problem. The downside to herringbone gears is that they’re difficult to produce – except by 3D printing. The reason so many RepRaps use herringbone gears is that they help to reduce backlash, the play between the rack and pinion.Here are some of the things I’m fiddling with so far: There are a number of potential mechanical changes that would very likely help with the accuracy, performance, and even reduce the cost of this little robot. This weekend I’ve been slowly working to improve my Tiny CNC.
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