Filament tension sensor

thingiverse

This is a straightforward design that utilizes a potentiometer, a spring, and two bearings to measure filament tension. The setup is tailored for 1.75mm filament but can be adjusted via the U groove in the bearings. I plan to incorporate this into my upcoming filament extruder project. I've included all necessary files, allowing you to modify them as needed. In the .dwg file, there's a component designed for use when the filament is 45mm above the plate, but it's recommended to use one that accommodates higher heights, such as the 50+mm design available in both .dwg and .stl files. The height can be adjusted using two M3 screws or threaded rods. There are no limits to customization. If you'd like to replicate my custom bearings, I've included a .stl file for printable bearings with U grooves. To assemble these bearings, you'll need 10 pieces of 4.5mm steel balls (BB gun balls work perfectly) and have them available in the market. The ball bearing has an outer diameter of 25mm and an inner diameter of 5mm. For more information about these printed bearings and assembly instructions, refer to my design on Thingiverse: https://www.thingiverse.com/thing:4266295 Required components include: 1x Potentiometer (a resistance value that can be precisely read by Arduino is sufficient; I'm using a 10k one.) 2x short M5 screws (16-18mm, depending on the bearings' height) 2x bearings with an inner diameter of 5mm and preferably a groove on the outer diameter. The outer diameter isn't crucial as you can adjust it using the M5 screw that holds the spring. 1x Spring - designed for a spring with a 5mm diameter and a 15mm height. I'm unsure about the thread diameter, but the spring's height is not critical; 20-30mm would be better than a 15mm one (higher precision). 1x M5 screw to hold the spring - length depends on the bearings used, desired tension range, and more. 4x M5 nuts - two for each bearing and two for the spring-holding screw (one might suffice, but I used two for adjustability). 2x M3 threaded rods or M3 screws. If using threaded rods, attach them to the base plate with two M3 nuts each; if using a screw, you'll need one nut per screw. M3 nuts - depends on how many are needed... 3x 2.5x12mm countersunk wood screws for attaching it to a wooden plate or any surface. Watch the video: https://youtu.be/JOlaAVJPVqc