After upgrading to the Hemera on my Ender 3, I noticed that the head was wobbly, and noticed ghosting in the print as a result. So I found a 4 wheel mount to replace the default 3 wheels, and set to work adjusting to fit it.

This will probably work with similar 2020 extrusion printers as well. The 4 wheel mount I used was from Amazon.

Required hardware:

4 - M3x10
16-20 - M3 Spacers (Enough to make 4x 2mm stacks)
4 - M3x6
2 - M3x8 (Can use longer)
2 - M3 Nuts

Optional (For the Fan):
1 - M4x20
1 - M4 Nut

Assembly:

Important: Make sure that none of the bolts bottom-out when tightening to the Hemera. They warn that this could break the square nut slots, thus ruining the mounting points. Add washers if this happens.

First prepare the metal mount, I used a drill to remove the standoffs as these are in the way. Then using the included PDF drill guide, drill 4 holes to mount the Hemera. They need to fit a 3mm bolt, I used a 4mm drill bit. Then assemble the metal mount, with the 4 wheels on and tightened. Lossen the adjustable nuts to help put them on the 2020 extrusion later.

Proceed by putting the extruder mount over the Hemera extruder. Route the BLTouch wire through the front slot, and the heat block wires through the side. Then slide on the extruder mount. Ensure that you have the BLTouch wire facing the correct direction to plug into the BLTouch.

Next place the M3x10 bolts through the metal mount. I used tape to hold them in place as it gets turned upside-down. Load about 4-5 washers on the other side. They need to be at minimum 2mm thick stack to ensure the bolts do not go to far into the Hemera and thus damage the mounts!

Place the Hemera onto the bolts, and tighten it down. This requires some patience. If the bolts are not long enough to grab the nuts, remove a washer on each stack and try again.

Now on the front side, use 2 M3x6 bolts on the right side to secure the Hemera mount to the front of the Hemera.

Mount the BLTouch. The upper holder is for the regular V6 Hot-End. The lower is if you are using a Volcano Hot-End (I don't have a fan mount for that currently). The BLTouch goes below the appropriate mount arms. Secure the BLTouch with 2 - M3x8 bolts and 2 - M3 nuts.

To mount the carriage, you will need to remove the right side X Pulley from the machine, and load the carriage onto the 2020 extrusion. Then adjust the 2 adjustable nuts to get a secure, but not overly tightened tension. Replace the X Pulley and re-attach the belt. If you are replacing the old 3-wheel mount, you will have to resize the belt. The mount should come with new crimps to do so.

The fan is a press fit, and fairly tight. First make sure the fan will slide in, then remove it. Mount the plastic fan duct onto the hemera with 2 - M3x6 bolts. There is an hole for the lower bolt on the fan shroud for the Allen wrench. Once attached, insert the fan, and optionally secure it with the M4x20 and M4 nut.

Software Changes:

These are the values I'm using. Of course use caution and watch the machine as it homes and adjust these values for your machine.

#define X_BED_SIZE 220
#define Y_BED_SIZE 228

#define X_MIN_POS -24
#define Y_MIN_POS -14

#define NOZZLE_TO_PROBE_OFFSET { 33.25, -40.55, -2.5 } (My actual Z offset was about -3.8, but this ensures the nozzle doesn't crash into the bed, still use caution)

Print Settings:

I used a .4mm nozzle with .2mm layer height. Some supports are needed on both parts, but some of the areas on the Extruder Mount were designed to use bridging to reduce supports.

Thanks:

I hope you enjoy this. I spent a bunch of time, had to get a second 4-wheel mount, and printed several test parts. I'm really happy with how it turned out, and hope you are as well.

I currently don't have a fan duct for the Volcano hot-end. I went back to the default V6 heat-block because the Volcano caused a lot of stringing, and the overall print quality suffered (I think the part cooling fan couldn't keep up even at slower print speeds). I can't print fast enough to require the Volcano (I prefer quality over speed).

Happy 3-D printing!

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