Filament Calibration Jig

thingiverse

Every maker has their own unique calibration jig for filament, just as every programming student has their "Hello World" executable. This one belongs to me. This small, simple device is functional and precise. It measures the draw of filament from the extruder inlet using a rigid interface, minimizing hysteresis effects. For accurate results, provide some resistance to the filament coming off the spool, as lash can cause significant errors of up to several millimeters. A light hand on the spool itself is usually sufficient - simply load up the extruder motor slightly to take up all slack. The specifics of this jig include its design to fit perfectly with the effector plate I released alongside the barbell carriages. It may also work with the OEM Ultibots D300VS magball effector plate, but it has not been tested due to potential surface feature interference with the caliper body. Jaw plates have been designed to fit Mitutoyo calipers seamlessly, and should accommodate most other brands as long as the jaw angle is 13.5 degrees. Pictures demonstrate how to secure filament in the clamp and utilize a zip tie for added security if needed. In my case, I found that only the mounting screws were necessary to prevent filament slippage. A minor revision was made to the jig shown in pictures, enhancing strength at the mounting tab and aligning the filament clamp with the extruder inlet for optimal pathing accuracy. On my setup, this resulted in less than 1 degree deflection. Your mileage may vary.