Custom Large Format CoreXY 3D Printer Build

A few people wanted to see a build log of this printer after I posted the frame and CAD model on the “Pictures and Nothing Else!” thread, so here it is. I will keep it pretty detailed, and also I only get to work about 1 hour on it per day, so expect it taking a long time until it is finished.

This printer had a few requirements from the start:

  • 400*400mm bed. Height is not really important, as I don’t think I’ve ever printed anything taller than about 20 cm.
  • No traditional cartesian design. The bed is too heavy to be moved in the Y axis, and it is definitely the limiting feature in the quality of my CR-10 prints.
  • Completely enclosed with a HEPA filter. I want to be able to print ABS, Nylon and anything else that might require an enclosure. Enclosing my CR-10 was not really an option as it would waste a lot of space and also it would be hard to make it look nice.
  • Direct Drive with BMG Clone. After using it on my CR-10 I can never go back as I have been getting flawless results with it.

I decided going with a Hypercube Evolution (Hevo) design and modifying it more than I initially expected. Here is what a standard Hevo build looks like:


By default, it can’t be enclosed because of the X carriage cables at the top, so I added extra extrusions to have space them. Also by default it does not have any neat place for electronics, so I will add a box at the bottom for them. Here is the current CAD model, that still requires quite a lot of work:

The stock Hevo uses 8mm rods for the X axis. That is a bit thin for 400mm, so I ended up deciding to use 10mm rods instead. This means that I have to rework the whole X and Y carriage. Also I ended up ordering the stock lengths for 400mm build for the bed 2020 extrusion, but this made it interfere with the bed bolts. I was thinking of maybe keeping these bolts angled like below, but I ended up deciding that it will be just much better to just cut the extrusions to have the bed mounted properly.

I currently have pretty much all the parts for this build, except the acrylic for the enclosure, but I will get it only once everything else is up and running


Awesome! Look forward to seeing your progress!

I saw this the other day and was immediately interested. I have a bunch of 15 series 8020 at my house, do you think this could be adapted to that profile? (1.5” thick)

Just to check, they’re just square 1.5" extrusions? As 8020 usually means 80*20 mm extrusions. If so, then it would be pretty easy to convert it to use them, as they’re about 38mm instead of 30mm, so not a big difference.


8020 is just a name.

Do you have links/names for the hepa filter, motor drivers, controller board, etc.

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So far I have assembled the frame for the printer. It is much bigger than I thought it would be, and the 3030 extrusions are overkill. I can literally fit inside the frame, and it can easily hold my body weight if I stand on it.

My CR-10 looks tiny next to it.

Just realised I haven’t mentioned the actual specs yet:

  • 400 * 400 * 400 mm Printing Area
  • 24V Heated Bed, with high temp magnetic PEI sheet
  • Duet 2 Wifi Clone with a touch screen (forgot what size I got as I ordered it ages ago)
  • Trianglelab BMG, E3D V6 All metal with hardened steel nozzle, BL Touch
  • 500W 24V PSU

I think that’s it, might have forgotten something as it is 2 am when I’m typing this. I got most of the components from “Components Explorers” shop on Aliexpress, I sent them a Custom BOM and they agreed to sell it. However I would not recommend buying from them. They are pretty well known in the custom 3D printer groups, since a guy named Lin used to work there and they were great. He left recently, and it became pretty bad. The seller only answered my messages before I paid, and stopped afterwards. I did not get a tracking number until 2 days after i received my package, which was already almost a month late. My package was missing the corner brackets that I paid for, and they said the only way they can do anything is if I post the whole package (which is extremely heavy) back to China and they would refund original cost. So yeah, don’t order from them.


I haven’t decided on what filter I will use yet. I am going to do that once the printer is up and running, and I will be ready to work on the enclosure. I will probably adapt one of the common filters meant for vacuum cleaners as they’re super cheap.

The Duet clone I will be using is made by “fysetc”, hope that it will be good, as it is supposed to be completely identical, and also saved me quite a bit of money.

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Just saw this on reddit. I don’t know what I am going to use it for, but building this would be crazy.

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Dang, that’s a BIG printer.

Following along because at some point when I’m less broke I want to build a similar printer - probably 300x300x400 ish. One of my big ticket features I want to incorporate is a tool changing system ala e3d, so I can do fancy stuff like multimaterial/multicolor/dissolvable supports. I print nylon and I love the parts I can make, but supports are horrible because the layer adhesion is so strong and it’s not brittle - Nearly impossible to remove them without a knife. A single layer of dissolvable support at the interface between part and support would be fantastic for complex prints.

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Printing something on it that gets anywhere close to the full bed size is going to take months haha.

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That’s true, but I am assuming they would be using a largest heaterblock out there and the biggest nozzle it can support. At that scale, vertical resolution won’t be important either, so you save time there too.

Another way to deal with it would be to use multiple extruders working together. Sure the slicer will have to deal with that, but there shouldn’t be any problem mechanically, right?

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yep, they are 1.5"

What he said! lol

Thanks for the explanation!

Can’t wait to see this come together, I have wanted to do a corexy build for quite some time now.

I will be using 10mm rods for X axis instead of the stock 8mm to prevent gantry sag, and also I am not planning to print too fast so the extra weight will not affect me too much. I had to modify the Y carriages to make them hold the 10mm rods. I also started designing my own X carriage and extruder mount, but I ended up finding ready made ones which would work perfectly for me. I will be using the following:

Here is how the X axis looks currently:

The 5015 part cooling fan is nicely hidden at the back:


This looks awesome

Do you plan to have any sort of enclosure heater? Or the bed will be enough? Also, how rigid it’s the bed frame? Since it’s only supported in the center in my head it could twist a bit

I think the bed should be enough, but I can always add an additional heater afterwards if I need to.

I have thought about the possibility that the bed might twist, but I was not able to find any reports of anyone having problems with it, and there are plenty of people who used it with 500mm+ build platforms.

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I added the slide joints to the components to check the clearances. Because of the stepper motor interfering with the belt, I will lose about 1 cm of the bed. I could redesign the X Carriage and fan duct from scratch to get that space back. I could also get a smaller pancake stepper, but I want to be able to get in the future a Volcano hotend with large nozzle, and it might not be enough. At the end of the day, 39*40 cm is still huge and I don’t think I will ever print anything that uses the whole build platform

I have removed a bit of the right Y carriage to increase the distance between it and the stepper. I do not have the belt modelled in here, but it will be about 1mm to the right of the stepper.

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Added the feet, Z & Y linear rods, and the build platform. So far looking great, but the bearings are pretty low quality. Going to replace them eventually, just want to get the printer running first.

When moving the bed platform up and down slowly, it is “cogging” a bit, not sure how to better explain it. It requires varying amount of force to move it. When moving it fast, it is pretty smooth. I think the bearings are binding slightly which causes that. Will try fix that some other time. Aligning everything and making sure it is square is an absolute nightmare on this printer.

Any reason you decided to go for rods and not rails with linear bearings.

Yeah that binding is probably the linear bearings. The IGUS plastic ones are a great alternative, no binding and almost no resistance. Lulzbot uses them in their printers

I think the cogging is inconsistencies in the bearing ball size within the channels of the LM8UU or whatever you selected.

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