White Board Magnetic Marble Track

thingiverse

The grand kids are getting bored during these COVID-19 restrictions, so we decided to do something fun. I removed the work in progress flag since the V4 design is pretty much complete and working well. Any modifications will probably be cosmetic, but the new design will still work with the old. I'll still be adding to it as we come up with new ideas. I'm also in the process of posting separate things for a powered "screw" or auger lift for marbles. It uses a combination of printing and Lego building. Check it out at: https://www.thingiverse.com/thing:4318613 What I've made are tracks that magnetically stick to whiteboards, refrigerators, or any other magnetic panel for marbles to run down. There are different lengths and shapes of track available. You or the kids can rearrange them all you want. It's all designed for a 14mm marble, which seems to be a common size, and is available on Amazon (Amazon link below). The magnets I'm using are 15mm x 2mm fridge magnets (Amazon link below). The idea is pretty simple and straightforward, so I won't spend any time explaining how to use it. Instead, I'll just use a build notes section below to try to explain the how and why I did things the way I did and my results in different printing methods. Build Notes: Materials: * Marbles: 14mm dia., https://www.amazon.com/gp/product/B07WP8JZSK/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 * Magnets: 15mm x 2 mm, https://www.amazon.com/gp/product/B07G48647D/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 Design: 1. Joining holes in the end. There are three holes in the end of each piece to aid in joining multiple pieces together. I just use a short length of PLA filament for that. Depending on your printer and settings, you may have to ream them out with a drill bit. 2. Number of magnets required to make good sticking power. I think I have extra holes in each section. For instance, the 100 mm straight piece has holes for three sets of magnets. I actually only use two holes with one magnet in each hole and it seems to work well, but... it hasn't been thoroughly kid-tested at this point. In those three holes, you can use up to six magnets total (maybe even nine) to increase the sticking power. 3. The spiral piece(s), front and back will have to be glued together. 4. Some of the pieces are made to go on the right of a run or to travel to the right. If you want the other direction, just mirror the piece in the slicer. Even the free Cura has a mirror capability. Printing: 1. I tried printing on end and with the backs of the tracks to the plate. Printing with the backs to the plate worked best for me, so I optimized the design for that. Printing on end makes for a little bumpier track, and the supports you need for the magnet holes can be a little messy. 2. Supports are not needed for most parts. Printing these pieces on their backs as they are oriented works well for the track pieces. The buckets do require supports when printing on their back. The switchback and loopback pieces may need supports. I was able to print them without supports, but you decide for your printer. 3. I use PLA at 210 degrees for the print head and 60 degrees for the bed. Post Print: 1. To put the magnets in, I just made a little ring of CA in the bottom of the magnet holes around the edges, dropped the magnet in, put it up against a piece of metal to pull the magnets tight, let it sit till the CA cured. It seems to work well. If you decide to use a second magnet, it will hold quite well against the first one without any additional glue. Glue if you want. 2. One problem I ran into was the PLA slides easily against a whiteboard. This can be helped a lot by putting a layer of electrical tape on the back of each piece. I found that Scotch 33+ worked well. Some electrical tape is fairly thick. The thicker the tape, the farther the magnets will be from the board resulting in a weaker grab. The 33+ is 7 mils. If you want more grab, a second magnet can be dropped into each hole. That helps a little.