Extruder Head Upgrade – Second attempt

Today I am going to upgrade my extruder head… again. My last attempt looked great, but was a prime example of why you should research a little more before you print a bunch of parts. So, now I am planning to install the original extruder head upgrade that I had chosen, before I talked myself into trying the one that didn’t work.

Extruder head upgrade parts

Parts for extruder head upgrade second tryI have decided to create a direct drive extruder head instead of adding a Bowden drive and extruder head at this time. I have already printed all the parts I need for the Proto-Plastik extruder head I found on thingiverse.

As I mentioned above, this was the part I originally planned to create, but I talked myself into trying the Laird V11 extruder head. The V11 extruder head provides vents to cool your prints, but it turns out they are about 2-3mm too tall for the hot end that came with my TwoUp.

Assembling the Extruder Head Upgrade

This extruder head upgrade is very straight-forward to assemble.

As the purpose of my upgrades are to create better 3D prints, it is not surprising that there are often inconsistencies in my prints.  When necessary I use a sharp blade to smooth parts, make coarse “adjustments” to parts and to clean up ooze, strings and etc. Frequently I use a drill bit to clean up and round screw holes. To improve my grip I wrap the shank of the drill bits with a length of blue painters tape.

Step 1

Put a 624ZZ bearing in the direct drive tightener then pass a M3-16mm screw through the larger hole in the tightener and the bearing. Tighten the screw but be careful not to over-tighten it or you will strip it out.

You probably noticed in the picture that the bearing is barely visible, I assume this is because of my printer’s poor bridging and not Proto-Plastik’s design. I disassembled the tightener and thinned down the upper part of the arch to about 1mm from the screw hole with a sharp blade.

Step 2

Insert the hot end into the inner plate for the Direct Drive Extruder Head, then place the hot end retainer over the hot end. Insert two M3-16mm screws into the holes in the retainer and tighten them, once again being careful not to over-tighten.

When I finished tightening down the hot-end retainer, I noticed there was too much play (I could easily turn the hot-end). I tightened things up with a little excess PTFE I found lying on my desk in the groove and re-tightened everything.

Step 3

Although not pictured above, I also printed an extruder mount which turns the extruder head 90°, so it lies on the same plane as the X-Axis Gantry.  Proto-Plastik claims this reduces the extruder heads inertia. I am just concerned that without the anti-sag truss, it also moves the motor further down the arm so causes greater sag when fully extended.

To install the extruder mount fasten it to the X-Axis bearing mount using four M3-16mm screws. If you don’t have a one piece bearing mount you really should print one. The screws are held in place with M3 nuts, and it is kind of tricky keeping them in place to start them.  I tried several things, including a magnet, but had my best luck sticking the nut to a piece of blue painters tape and basically taping the nut into the hole to start it.

Step 4

Insert an M3-16mm through the bottom left NEMA motor hole and mount the NEMA-17 motor into the extruder mount. You may have to slightly loosen the hot-end retainer if there is not enough space to slip the screw past the retainer, mine slipped past it easily enough. By the way, I first tried an M3-16mm which when fully tightened down did not secure the NEMA-17 motor. I then tried a M3-12mm and it couldn’t reach the motor face through the extruder mount. My final compromise was to put a washer on the screw and tighten it down. This prevented the socket head from going in to the recess and made everything nice and snug.

Put the tensioner in the extruder head and check the depth of the filament drive gear. You want the center of the knurl under the filament hole in the top of the extruder head. I had to remove my drive gear and turn it around to get the groove centered under the hole. Screw the tensioner knob into the tensioner and pass your filament down through the cool end and test the fit. You don’t want to have to disassemble the head and fiddle with the centering too many times.

Step 5

new-extruder-headFinally, put the outer shell of the extruder head upgrade in place and fasten it in place with three M3-35mm screws. I also added a small length of cable guard to make sure the wires did not get down on the hot-end. I then finished putting tension on the filament and printed a calibration cube.

 

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