Pump It Up (Extruder Build Part 1)

For my extruder, I'll be using a 3D printed peristaltic pump extruder found on Thingiverse.  The designer of the pump has an awesome 3D printing blog and his designs are great - probably because he seems to test most of them out on his own RepRap.

That said, this extruder is a work in progress.  There isn't any comprehensive documentation on building it, so I worked from pictures on Thingiverse and the blog post about this design, and asked my ever-helpful Hackerspace colleagues to help me interpret what I was seeing.

To complete the pump I'll need a stepper motor and tubing, which have been ordered but are still on the way.  Here's my step-by-step guide to assembling RichRap's Geared Peristaltic Pump Extruder up to that point:

You'll need the following materials:

• The 3D printed extruder parts
• M3 bolts (3 x 25mm, 1 x 20mm, 2 x 15mm), washers and nuts
• M4 bolts (1 x 50mm, 5 x 20mm), washers and nuts
• 624 bearings (7x)

To build the extruder:

1.  Arrange the 3D printed wheel and large gear with five of the bearings like this:

2.  Screw them together with the 20mm M4 bolts, then insert the 50mm bolt through the centre hole:

3.  Put the main body of the extruder and the cap for the tube housing together.  Attach them using a 25mm bolt on the left side and a 20mm bolt on the right side.  The nuts sit in specially designed slots at the foot of each screw hole.

4.  Attach the nozzle section using the 25mm bolts on the front of the extruder, and one 15mm bolt to secure it on the underside.  Again, there are slots for the nuts to fit into. The other 15mm bolt goes through the bottom of the nozzle and will hold the tubing in place.

5.  Thread two washers and a bearing onto the end of the 50mm bolt and fit them into the bearing-shaped recess in the main body:

6.  Fit another bearing into the recess on the back of the extruder, and secure it with a nut.

And that's the end of part 1 of extruder construction!  I'll post part 2 when the motor and tubing arrive.  Here's what it looks like so far:

One quick note: I modified the nozzle section, cutting off a few millimetres at the edges to make it slightly narrower overall.  This will let it fit neatly into the gap in the ORD Bot's extruder carriage.  This extruder is designed to fit into a 3D printed quick-release carriage, but rather than modifying that to fit the ORD Bot, I'll just drill some extra holes in the extruder and existing carriage.