Kossel Mini top mounted spool tensioner magnetic

thingiverse

I assembled a kossel mini from think3dprint3d and I'm completely thrilled with it.... except for the top mounted spool holder, which moves too smoothly on a bearing. Consequently, the spools tend to unwind, and at times this has caused a loop to fall underneath the spool, tighten, and jam up, resulting in the extruder halting and the print failing. This tensioner achieves exactly what I needed - it places just enough tension on the spool to prevent unraveling yet still permits smooth filament movement. Additionally, it allows for unobstructed movement while maintaining constant pressure when the spool is slightly misaligned or not perfectly circular. There's even micro-adjustment possible by adjusting the small tensioner slightly. Print Settings Printer Brand: Deltaprintr Printer: Deltaprintr Kit Rafts: No Supports: No Resolution: 0.2 Infill: 20% Notes: the large plate is printed upside down to ensure a smooth surface, which allows the long tensioner to move freely. At 50mm/s this entire plate prints in 1 hour and 16 minutes. Post-Printing images will follow soon. Bill of Materials 6x M3 x 20 socket cap screw 4x M3 x 8 socket cap screw 6x M3 nut 2 pieces 3mm diameter x 3mm neodymium magnets. http://www.first4magnets.com/circular-disc-rod-magnets-c34/3mm-dia-x-3mm-thick-n42-neodymium-magnet-0-29kg-pull-p3328 Drill all holes with a 3mm drill bit. Long screws pass through the posts, attaching them to the top frame (Picture 1). The plate is then placed over these screws (Picture 2). The long tensioner is attached with a magnet in a small hole (Picture 3), followed by the short tensioner with a magnet in the final hole, ensuring opposing directions are observed (Picture 4). Knobs are added, making the long tensioner free to rotate and the short one tight (Picture 5). A spool is placed over these settings, and posts are adjusted so there's a small air gap of 2-3mm for fine-tuning tension on the spool (Picture 6). attach posts to the frame using long screws that pass through the posts. then place the plate over these screws add the long tensioner with a magnet in a small hole add the short tensioner, making sure it's positioned opposite to the other one. knobs are added next, ensuring the long tensioner can rotate freely and the short one is tight. add spool. adjust posts so there's a 2-3mm air gap between them to fine-tune the tension on the spool. How I Created This theory my intention was to achieve sufficient tension on the spool to prevent unwinding without restricting filament movement too much. After several unsuccessful attempts using springs and elastic bands, I decided to use two opposing magnets. currently printing this design; more images will follow tomorrow. custom section Final version: V4 correcting a basic error with the knobs – now they can have their nuts dropped in from above, enabling easy tightening. this design functions perfectly now. Once the post positions are set to allow for small gaps between the magnets, full pressure is applied when these two magnets are opposite each other. The adjustment is made by turning the small tensioner clockwise or anticlockwise.