Project: FFF 3D Printer “Eta” Part 3

Hello Sunday!

So once again, I’ve been sitting in my little tinderbox workshop, simultaneously juggling designing and building the electronics and mechanics of Eta, in between stretching exercises to retrieve my computer mouse as it frequently makes bids for freedom off my legs where I was balancing it.

I’ve been attempting to video record construction of Eta, but as it turns out, 10hrs of video of me slowly drawing lines on a scrap of wood is hardly inspiring material to view, so instead, here is a visual treat for those who prefer not to stick their heads into the guts of a printer.

So here is a quartet of 4 stepper motors performing “The Imperial March”, a very famous track among geeks. They do this by whirring around at different speeds to produce different tones. You might have to turn up your volume, as the stepper motors I got were really quiet, which is a good thing for a printer, but unfortunate for the purposes of this video. Really, talk about first world problems.

For those who Do prefer to stick their heads into a printer, read on.

So over the past two weeks, I’ve been cutting out many bits of plywood and using them to make the typically 3D printed parts of my printer, such as the carriages, mounts, etc. This is primarily to save cost, and likely I’ll ‘Repstrap’ Eta by upgrading it with parts printed in it.

I’ve drilled and mounted the support biscuits, as well as made a lot more support biscuits… 8 x 5cm biscuits seem to be an integral part of my machine, and my arms are getting tired.

More 5mm plywood is used in making the carriages, like these Y carriages.


Y carriages

Two idler pulleys go in the lower cavity, and two LM8UU linear bearings go just above them, to guide the carriage blocks along the Y axis. The X axis’s smooth rods are mounted perpendicular to the Y rod, more images will follow once I’ve drilled the holes and mounted them.



Back to the electronics division in my head, I’ve installed the driver chips, and jury rigged up a ATX power supply to feel 12v 18a into the RAMPS board, and been using that to run tests.

I’m still doing a lot of research on the heat bed’s electrical bits. I’ve got a couple mosfet heat sinks, which as you can see are second hand. Observe the tempering colours on the heat sink, its previous application clearly generated a LOT of heat. I’d likely use 2 or more mosfets in parallel to switch the heat bed, so I shouldn’t have too much heat being generated. Adding in the large heat bed really complicated the build.

That’s about it for today, and college has reopened for me, so that means a lot less time to spend sawing bits of wood. Until next time,

Signing off,



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