Tetsuobot (mag + Traxxas connectors)

thingiverse

A delta bot built with MakerSlide(Wolfstock thing:124929) and magnetic carriages and effector (Berrybot thing:132463) with some modifications from absolute failure. I commissioned the parts for the frame and carriages from someone who has a 3D printer. I got the frame built (part Makerslide, part 80x20 '20mmx20mm'). Then when I went to mount the magnets for the carriage and effector, it was a total failure (not enough pull). Instead of recommissioning and waiting for the parts that might fail again, I built my own using my laser cutter (dur). I also realized that I needed more parts than I originally planned for (idler, end stop holds, etc). These are those parts. You'll see some pictures of the failed berrybot carriage and effector. That was a failure for me because I used the wrong magnets. They didn't have enough pull. There's a picture of the right ones. I had to remake the whole thing with a laser cutter so why not also make it capable of handling Traxxas joints?!? REMEMBER: the stance (width) between the connections on the effector MUST be EXACTLY the same as the stance of the carriage! So if you use these plans, make absolutely certain that your carriage matches. The side effect is obvious: tilted effector when moved towards the edges of the bed. Instructions UPDATE!(1/13/15) a year later... I just converted from a bowden extruder to an airstruder (suspended by bungee) and on wide prints I started to hear 'clicking'. I realized that the clicking was the balls coming out of their joints when I came back to a birds nest of a print a few hours in. This is temporarily 'solved' by adding a 1/4" cube magnet to each of the chrome balls, which just increases the magnetism to the effector (and carriage's) magnets. I just ordered a few dozen n48 and n52 magnets from amazon to sturdy it up properly. TLDR: if you go with a mag effector like this, double-down on magnets. I would look for 8+ lbs of force per socket to be completely safe. The magnets are supposed to be magnetized for life, so I think it's just the added torque from the shorter airstruder connection and nema 17 motor flopping around above. There was no problem like this before the airstruder conversion. One way you could do this is to cut out 2 tops from my design and use a thinner acrylic for the bottom or no bottom cut at all and just use epoxy. Use the socketed magnets on top and a solid 1/2" round magnet beneath that. They also sell some crazy strong (52lbs+) 1/2" x 1" cylinder n52 magnets. Total overkill, but with some engineering, you could have an effector capable of holding a router. I couldn't find 1/2" x 1/2" in n52 grade. n48 grade is 8lbs each. UPDATE!(1/12/14) I found that my effector is tilted when I extend outwards and couldn't figure out why until now. I think that the distance between the rods at the carriage has to equal the distance at the effector. This design definitely is not! I'm going to fix the magnetic sockets and redo the effector to match the carriage first. If I'm right, I'll try and rework the Traxxas holes too. UPDATE2!(1/12/14) I just uploaded effector.v2 which has the same spacing as the carriage. Still haven't tested it though... I use Illustrator for my laser plans. My laser cutter reads Illustrator 8 files, which is what I uploaded (at the time of first post). All parts, except for the "Top Corner" are 2 parts of acrylic laser cut and welded together with Weld-On SCIGRIP #3. The end stops take 2 #4-40 x 3/8" bolts (actually just 1/2" dremel cut to fit) and a single M5 to mount to the Makerslide. The carriage parts use #4-40 x .5" bolts. There's two sets of mounts there; one for magnets and another set of holes above to tap out #6 for Traxxas mounts (YES! 2 MOUNT OPTIONS!) You can also use 4 v-groove bearings (2 eccentric spacers) or 3 v-groove bearings (1 eccentric spacer) to save cash. The effector is like the carriage in that there's 2 mounting options. One requires the magnets, the other needs to be tapped for #6 mounts into Traxxas. The hot end plate I made to mount the PTFE tube holder. You can see that in the image. The balls are pachinko balls I bought in bulk from ebay I had lying around (make sure to get smooth ones). They're JB-Quik welded to carbon rod (what a PitA to cut).