Filament production is a precise engineering process. Therefore, the production process should be monitored to maintain the filament diameter at a range of +-0.03mm diameter. A feedback loop is therefore necessary to monitor the filament and adjust the speed of the out feed motors accordingly. The industrial diameter sensors are very expensive and are not capable of giving feedback control hence, the need for a diameter sensor
Background[edit | edit source]
Techfortrade has developed a P.E.T bottle waste filament extruder. The extruder runs on an arduino mega which controls the heaters and the auger stepper motor. The auger is sourced form a ship auger designed to bore long holes on wood. The fact that the auger is not designed for extrusion means that it lacks the basic architecture of a compression screw. This in turn leads to irregular extrusion at the least. To solve this a diameter sensor is needed to compensate for the irregular extrusion.
Methodology[edit | edit source]
The diameter sensor has two parts an emitter side and the receiver side. On the emitter side a laser diode produces the laser ray. The ray is then collimated using a by biconvex lens. on the receiver side the light travels through a narrow slight and falls on to a black background. A camera looking at the black screen uses OpenCv to determine the diameter of the filament that would be blocking some of the light from reaching the screen.
Links[edit | edit source]
Results[edit | edit source]
The diameter sensor is able to give a reading with a precision of +-0.08mm. currently I am working on the hardware and software that will enable its integration to the filament extruder.
