Filament Diameter (thickness) Measurement (sensor) for DIY Extruder, Dial indicator mount

thingiverse

This dial indicator mount allows simple measurement of the diameter of the filament that your DIY filament extruder is producing. It is shown with a normal dial indicator, but it is designed to accept any dial indicator. I have updated the design once again as of Dec 1, 2020. One change is that I have moved the dial indicator measurement point to be directly over the point where the bearing contact. This makes the measurement simpler. The reading of the dial is what the filament diameter is. I have also included a more substantial mount that is thicker and may be mounted either vertically, or horizontally. The horizontal position seems to work better, but it a bit harder to read the dial. I also mounted the digital dial indicator little more firmly, and made subtle improvements in the guides for the filament, etc. One of the major differences is in how the bearings are mounted. In the latset design, I opted for a 1/4 inch through bolt to hold two of the bearings, instead of the fragile 3D printed spindles. The 1/4 bolts holes are tapped into the thicker back plate. Much more stable and substantial. I would suggest the fine thread 1/4 - 28 with an unthreaded section to fit the bearing a bit more tightly. 1/4 - 20 will work, of course. (So to speak. :-) ) It is a simple design that uses three 1/4" ID, 11/16" OD, 5/16" width sealed bearings, one in the pivot point of the horizontal arm, a second one on the other end of the arm to touch the top of the filament, and the third stationary one to hold the bottom of the filament. The arm rests on the filament, and the tip of the dial indicator rests near the bearing on the top of the arm. Bearing link: https://www.mcmaster.com/2780T51/ When it finally arrives, I will install a digital dial indicator with digital output that I will plug into the Arduino that is controlling my DIY filament extruder. I can combine this sensor with the other electronic sensor (that I have posted previously) to provide the feedback signal to control how quickly the pull rollers will draw the filament out of the extruder. One sensor will measure the side-to-side width, this sensor will measure the thickness top-to-bottom. Here is my connector design to connect the dial indicator to an Arduino: https://www.thingiverse.com/thing:4605457 The dial indicator sends a measurement about ten times per second. The pivot bearing and the stationary bearing are held in place with M4 screws and washers. You need to _carefully_ thread the back plate mounts for these M4 screws. If you are not very careful, and don't continuously back out and clean the tap, you will break off the hubs that hold the bearings. The arm halves snap together over the two bearings. You can hold these two haves together with two M3 button head screws. You will need to print both the front arm, which has the platform for the dial indicator proble, and the rear arm which has no platform. I have included the Inventor 2018 files if you wish to make any changes. Please post your remixes! Bill D.