From the Loftsmith Workshop

Peristaltic pump for 4 x 6 mm silicone tube (NEMA 17)

Moves liquid through a soft silicone tube without the liquid touching the pump. A three-armed rotor with teal rollers squeezes the tube along a curved track as your NEMA 17 motor turns it. Change the tube size and the squeeze gap to suit your own tubing.

7 parts · 71 g · 85 × 88 × 26 mm

by Loftsmith Workshop

Gray D-shaped pump housing with an orange three-arm rotor and teal rollers, on a square motor mount
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No adjustable sizes

Ask for the sizes you want to tweak, e.g. “make the width adjustable”.

Change it in the Studio

Parts

  • housing · PLA · Floor down

    Press 4 M3 heat-set inserts into the wall top. PETG suggested.

  • rotor-base · PLA · Plate down

    M3 nuts go in the traps underneath.

  • rotor-cap · PLA · Top face down
  • roller-tyre ×3 · PLA · Upright, lip down

    A 608 bearing presses into each tyre until it sits on the lip.

  • lid · PLA · Flat, top face up

Print settings

Layer height
0.2 mm
Walls
3
Infill
15%
Supports
None expected; check the slicer preview.
Notes
PETG is a safer choice for the housing, because a stepper face can run hotter than PLA softens.

Hardware

  • NEMA 17 stepper (42 mm face, 31 mm hole square, 5 mm D-shaft) · 24 mm shaft assumed; a slider covers 18 to 30 mm
  • 3 × 608 bearing (8 x 22 x 7 mm)
  • Silicone tube, 4 mm ID x 6 mm OD · About 250 mm; check its real size and wall
  • 4 × M3 x 8 screw · Housing to the motor face
  • 4 × M3 x 8 countersunk screw · Lid
  • 3 × M3 x 20 screw · Down through the cap and posts into the nuts
  • 3 × M3 nut
  • M3 x 6 grub screw · Cuts its own thread in the hub's 2.6 mm hole, onto the shaft flat
  • 4 × M3 heat-set insert · Lid
  • 1.5 mm hex key, long arm (about 40 mm reach)
  • Stepper driver, controller and power supply · Not part of this design; needs your own code

Assembly

  1. Press the inserts into the housing wall top and bolt the housing to the motor face with four M3 x 8 screws.
  2. Press a 608 bearing into each tyre until it sits on the lip.
  3. Put the M3 nuts into the traps under the rotor base and slide it onto the shaft with the grub screw backed out and the flat facing the access hole, with the tyre tops about 0.4 mm below the housing rim once fitted (check with a straightedge).
  4. Lower the three bearing and tyre assemblies onto the posts, fit the rotor cap and fasten with three M3 x 20 screws.
  5. Feed the tube through the two end-wall holes and around the track. It enters by the right leg and leaves by the left, as the arrow shows.
  6. Tighten the grub screw on the shaft flat through the end-wall hole, then fit the lid.

Good to know

  • Not printed or physically tested yet: every number here comes from the model's checks and estimates. Print one part first and test the fit.
  • The seal is calculated, not measured. Tube hardness changes how much squeeze seals and how hard the motor works, so print one tyre and one roller post and try them with your tube first. The channel is 10.8 mm wide, so the tube can drift and overhang a tyre edge by about 0.4 mm if it wanders.
  • The roller post runs at 3.7 of 5.0 MPa across layers, and the 0.11 N*m drag is an estimate. Flow rate and pressure are not modelled.
  • Silicone tube wears where the rollers run. Check it after the first run and regularly after that. Not for medical or food dosing, and don't leave it running unattended over anything water can damage.
  • The grub screw self-threads into the printed hub, and it is the only drive connection to the shaft. Check it after the first run.
  • Electronics and code are not part of this design.
I printed this Remix

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