Peristaltic Pump Improved for Nema 17

thingiverse

This is a remix of the outstanding design of Ralf's Peristaltic Pump. I printed his pump and built it according to his specifications, but discovered that the small stepper motors would not operate the pump consistently or provide sufficient power. I decided to modify the pump to accommodate a Nema 17 stepper motor. This upgrade provides PLENTY of power to push any liquid you are trying to circulate. To reinforce this design, I had to beef up the bearing holders slightly. I also added mounting brackets for convenience. A single-pump mount and a four-pump mount are included, with the latter being perfect for my application – adding fertilizers to my aquarium. Despite some modifications, I'm still utilizing the same bearings and screws as Ralf, so you can obtain the necessary parts list from his project. The pump base has countersunk holes to secure the motor in place. If you prefer not to use a motor mount, I've included an extra spacer for this purpose. A washer is inserted between the bearing and the bearing holder assembly on both sides for stability. Metal washers can also be used, but I found that printed washers can be adjusted to achieve a perfect fit. Print Settings Printer Brand: MakerBot Printer: MakerBot Replicator 2X Rafts: Doesn't Matter Supports: Doesn't Matter Resolution: Variable Infill: Variable Notes: For the bearing mounts, use an infill of at least 50% – You need significant strength. I also utilized 60% infill for the pump top, base, and center to ensure durability. The mounting plate and base can be printed with a lower infill percentage if desired, but higher infill percentages mean added strength. I printed the pump housing with four shells, while the bearing holders and mounting plates received two shells each. All parts were printed at 100 microns, although 200 microns should suffice for everything except small components. You may not need support material –I was able to print every component without any issues (I always strive to design items that can be printed without supports). Post-Printing Building the pump I used a 12V 350mA 28oz-in NEMA 17 stepper motor from Robotshop, with part number RB-Ada-138. This motor features a shaft with a flattened side for added stability and to prevent the bearing mount from slipping. For the necessary screws and bearings, refer to thing 254956. Additionally, you will need screws specifically designed for motor use. How I Designed This I generated this project by taking the original files found on thing 254956 and bringing them into Sketchup. Subsequent modifications were made to accommodate a NEMA 17 stepper motor.