2020 Carriages for Magnetic Arms and Mini V-Wheels

thingiverse

These carriages work for 2020 aluminum extrusions and 15mm diameter V-wheels, such as the ones from OpenBuilds or RobotDigg.com. A horizontal M3x35 screw is used to preload tension on the wheels. You can get ball studs from me for $1 each, and I also precisely build carbon fiber, zero-backlash, magnetic arms at my website http://www.MagBallArms.com. This design works well with my effector which features an LED light ring and 3 PLA cooling fans: http://www.thingiverse.com/thing:1546124. Links to the mini V-wheels from RobotDigg are here: http://www.robotdigg.com/product/519/Delrin-Guide-Bearing-Kit. Links to the mini V-wheels from OpenBuilds are here: http://openbuildspartstore.com/delrin-mini-v-wheel-kit/. Per carriage, you will need three 15mm V-wheels, three M5x25 bolts, three M5 nylock nuts to secure axles, two 3/8" ball studs (from me), two M3 nylock nuts to secure ball studs, two M3x35 SHCS for the belt tightener, two M3 nuts for the belt tightener, one M3x35 SHCS for preloading carriage wheels, one M3 nylock nut for preloading carriage wheels, one M3x20 SHCS for the vertical post for upper G2 belt attachment, one M3 nut to secure vertical post, one M3x10 SHCS to secure lower belt loop, and one M3 nut to secure lower belt loop. You can easily alter the OpenSCAD source to make this work with 2040 or 2060 extrusions by changing the value for extrusionWidth from 20.0mm to 40.0 or 60.0mm. If your belts are farther above carriages, you can easily adapt by using a longer M3 vertical screw. The belt tightener used is very simple and easy to adjust with two M3x35 screws. I found that this delivered better results than using zip ties; my prints got more accurate by about 50 microns. I also have a version for 24mm diameter V-wheels: http://www.thingiverse.com/thing:2183347. Note that there needs to be a tiny shim between the aluminum spacers and the mini V-wheels, otherwise the aluminum spacers rub against bearings. I've designed and tested carriages using both 15mm mini V-wheels and 24mm V-wheels, and I prefer the 24mm versions. Bigger wheels roll better and shims aren't needed. Printer settings: Kossel Plus Rafts: No Supports: No Resolution: 0.5mm Infill: 40%