Giova's Extruder

thingiverse

The objective of this project, initiated in Spring 2015, was to develop a low-cost and lightweight extruder. Initially, the "24BYJ48" stepper motor was chosen but later substituted with the "28BYJ-48" due to its superior strength, affordability, and ease of availability (Fig.1). This unipolar stepper motor requires modification to become bipolar. There are two methods: one involves disassembling the case (Fig.2), while the other is a faster and less invasive approach that entails cutting the plastic casing and PCB (Fig.3). The latter method is recommended. To assemble this extruder, you will need: - 2 x "28BYJ-48" stepper motors - 2 x 40mm fans - 4 x M3 screws and nuts - 4 x M4 30mm screws and nuts - 5 x M4 20mm screws and nuts - 2 x MK8 drive gears for 1.75mm filament - 2 x 605 2RS 5X14X5 bearings - Various M4 washers (quantity unknown) The connection to RAMP 1.4 requires modification (Fig.4). The connector of the second extruder must be inverted connected. Assembly Instructions: (Tolerance is always 0.5mm, excluding Hot-End connectors) Idlers are distinct and marked with L or R letters visible in the model. A washer is used to center the bearing with the drive gear (fig.6). Hot-End connectors dimensions are copied from Greg Wade's extruder. Their distance is 23mm. Usage: This motor operates at a slower pace, is fragile, and weak compared to NEMA17. Plastic gears within it can be easily damaged. As such, the Hot-End temperature must be increased to soften the filament more (in my tests, I use PLA at 210-220°C). The print speed may need to be reduced as well. Another issue with this motor is idler pressure; if too little, the filament isn't pulled into the Hot-End; if too much, the motor stalls. You'll need to find the correct distance (Fig.7). A top fan is required because these motors overheat quickly. Motor drivers' power should be decreased since these motors require less power than NEMA17. Settings: Steps per mm are approximately 1500 Max speed is around 8mm/s Problem/Solution: The motor fails to work: incorrect wiring, excessive filament idler pressure, too high print speed, or insufficient driver power. No filament extrusion: insufficient Hot-End temperature, excessive filament idler pressure. Filament extrusion is unstable or stops after a while: excessive filament idler pressure. Layers appear non-uniform or the object looks bad: try increasing the temperature (Fig.8). Other objects in the photos can be found here: http://www.thingiverse.com/thing:1434161 http://www.thingiverse.com/thing:1407251 http://www.thingiverse.com/thing:1000841 http://www.thingiverse.com/thing:711671 http://www.thingiverse.com/thing:510508 http://www.thingiverse.com/thing:10915 http://www.thingiverse.com/thing:761806 Print Settings: Rafts: No Supports: No