peristaltic pump

thingiverse

A peristaltic pump which works best with the red thera tube or similar silicone tubing. It can be used to pump liquids and does also transport gases (blow bubbles). The NEMA17 stepper motor which rotates the rollers is driven by a 555 timer IC and an A4988 driver module on a little pcb (see schematic). The rotor is attached to the stepper motor with a spiraled lock that has recesses for a wrenchlike tool. That locking mechanism proofed to be appropriate with a reasonable runout and clamping force. Before tightning, a spacer tool is inserted between the base and the rotor_base so there is 2 mm clearance. The gap between the runway and the rotorcircle, where the tube is seated, can be adjusted and easily tightened with a wingnut. That is necessary to get a good sealing of the tube. In- and outlet have clamps in order to prevent the tube from slipping. I used a stepper motor model 17HS4401, available at our local electronic store, that has a rated current of 1,7 A and phase resistance of 1,5 Ohm. It shows that the current is on the edge of what the driver module can deliver. It would be better to get one with higher phase resistance. The parts picture shows them in printing orientation. The posts for the ballbearings probably need to be sanded down a bit for proper seating. No supports needed. Printed with PETG, 0,3 mm nozzle, 0,15 mm layer hight. parts list: printed parts: 2x foot 1x base 1x rotor_base 4x roller_sleeve 1x lock 1x rotor_top 1x rotor_lid 1x runway 1x fulcrum_knob 1x tubeclamp_lid 1x mirrored_tubeclamp_lid 3x spacer_pcb 1x cover_pcb 1x spacer_tool 1x wrench tool purchased items: 3x flat head M3x40 for the wrenchlike tool 4x countersunk M3x10 and nuts for the feet 3x flat head M3x16 and nuts for the pcb 4x countersunk M3x10 for the stepper motor 1x hex M5x40 plus 3 nuts and a wingnut for the runway 4x ballbearing 608-2z 1x stepper motor 1x thera tube red (ID 5 mm, OD 8 mm) 1x populated pcb ps: replaced the stepper motor with one rated at 1A, called 17HS3410-02 by ACT motors. Also replaced the green driver module with a red one because I killed it. Runs much smoother now. Adjusted the lock because the flat area on the shaft is higher now.