Fighting with computers

One of the things I did not like about a new printer was that the belt that moved the carriage was not laying parallel to the axis of motion (left) but at an angle, as shown in the picture below (right): Such a belt path is not right as for each inch of motion in the axis a slightly different amount of belt is moved (the hypotenuse of a triangle instead of its long side). Most of the time, the angle is so small the difference is tiny. That is why the arrangement works and printers are printing even though they have this ugly hack. The problem is worse when the carriage is close to any of the two ends, as then one of the angles is not so small and that creates a bigger error. But the question is: how big the error can be? Well, it took me a good part of a weekend to figure that out, among other things because wxMaxima does not like to calculate the intersection of two circles easily . So the first thing I needed was to model the anomalous belt path in a geometric model I co...

Some of my ongoing projects required a larger 3D printer and I saw a good deal on a printer that had good reviews (except for its weird bed leveling system) so I bought one off Anycubic's Aliexpress shop shipped from Germany. I got in in less than a week and putting it together took me a bit more than one hour. It is basically two parts, shipped flat, that you place at a square angle to make a Prusa i3 like configuration. The printer comes with all the tools you need, including the wire cutter to use to remove the zip ties that keep the bed from moving while in transit. The 400x400 mm bed features glass on top with a special texture that does what it promises: good adhesion while hot and easy release of parts when cold. These two brackets will reinforce the vertical axis beams fixed to the horizontal extrusions. Once built, the manual called for a manual or automatic bed leveling. That I did not like as it seems the user has to decide which one is best. Someth...