I FINALLY CAVED, COREXY - GIANT 3D PRINTER BUILD PT. 4

First print will be a corner piece to an even larger printer. 😁

Here’s the CoreXY explainer comment! The primary goal, as Ivan said, is to reduce the moving weight of the system. By keeping the motors stationary, you accomplish this. Unfortunately, it becomes difficult to isolate the movement of the motors into the two separate X and Y axes, so they end up getting combined like he demonstrated. Previously, in industrial machinery with very stiff gantries, you could accomplish this with a kinematic system called an H-bot (called this because the belt forms an H shape), which was very simple and didn’t involve any belt crossing. It does however, REQUIRE the gantry to be very stiff, as X direction moves applied force to only one side of the gantry, exerting a twisting force on it. With the advent of 3D printers, pretty much the first consumer-tier high speed cartesian robots, a new system was needed, in order to not require a super stiff (and therefore heavy and expensive) gantry. CoreXY had been used throughout history, most notably in computerized drafting tables, but didn’t see it’s big moment until people realized it’s perfect for fast (or in this case very large) 3D printers. As for how each system actually works: here’s a quick explainer: - H-bot kinematics use one very long belt, which wraps around each motor with both ends at the carriage. This means that there is only one way to pull the carriage in each direction. Since each end comes from a different side of the gantry, those same forces are applied to only one side of the gantry, causing it to twist. - CoreXY kinematics essentially just double up the H-bot design, adding a second belt, running in the opposite direction to the first (with one motor per belt) so that each carriage move produces two equal and opposite forces on the gantry, cancelling out the twisting forces.

I'm pretty sure that Polymaker has a dedicated factory just for the red filament.

Our pleasure to help you fab these parts out and most importantly, nice content as always, Ivan 👍

For folks building their own printer: When tensioning the belts on coreXY, you need to keep the Y-gantry square with the frame. The easiest way to do that is to move it to one end of the printer and tie it down there temporarily while you tension the belts. When you pull on one belt, it will want to move the gantry out of square, and this is normally held in check by the tension from the other belt. This is why both belts need to have the same tension, and why you need the gantry held square while the belt tensions are uneven while being adjusted.

foam filling will reduce noise or stick some rubber sheet in different locations to stop reverberations and hollow tubes that are magnifying the sound. awesome built Ivan. Well done

Aw man I love this kind of engineering, everything is so modular and well planned/fitting. Bolts everywhere, no destructive connection. It's like a giant toy lol

change the idles with puly's so the ribs of the belt doesnt slide over the idlers -> makes it more silence and less vibrations.

Definitely one of my favorite video in a while. I really enjoy when you talk about the process along the way

00:34 Fantastic explanation. You made it simple to understand the Core-XY system of movement.

your videos are truely inspirational, youve given me the belief I can make things myself, I am currently making a 3D printed CNC router that can cut a full sheet of plywood. I am 1 week of continual printing into printing out the parts. hopefully in the near future I will say I have made something!!!!!

Bravo, excellent design, Ivan. All of those long-length belts and frame stability are a big challenge. I can't wait to see the printing quality of this machine. Keep going

Seriously amazing. It seems straight forward but CoreXY is still a mystery to me. Hey, thanks for the constant encouragement at the end of your videos. I'm finally back working on one of my project while watching this.

super awesome work Ivan! congrats on the first try success! :P i think a large part of the sound and belt vibrations are coming from the belt teeth running over smooth idlers(/bearings). i'm pretty sure you can buy appropriate idlers and it not get PCBway to hook you up. the pallet of polymaker filament is pretty sweet, but maybe ask them for pellets and a pellet extruder. alternatively, a multi-input hotend like the diamond, modded with multiple heat zones and drilled out to 1mm+ will let you push lots of filament and multiple spools at the same time.

Love the last shot with the camera on the gantry 😁 this project is amazing!

Your wire management is really nice. I wish I had the patience to do that.

Hey Ivan, please check out vzbot AWD for example adding 2 more motors on top :) shorter paths realy would help this build ! the shorter the paths the less problem with torque cause of the heavy belts adding 2 more motors on the top would realy make a big difference a specialy for a printer this size :)

Very nice looking printer. If you are looking to make it even more insane, you could upgrade to a CoreXY AWD by adding 2 more steppers at the idlers. It would give you greater stiffness in the belts thanks to shorter paths between motors and gantry as well as more acceleration. If you want to lighten up your X axis, machining pockets in the aluminium extrusion is a known way to do it as long as you don't remove too much metal. Or straight up use a square carbon fiber extrusion. That way you lower the moving mass. The frame itself already seems very stiff, using steel instead of aluminium could improve that. Since it is immobile, that added mass is no big problem and will help damp gantry induced vibrations. Sand filling could also work. Don't know what kind of hotend you plan to use (maybe even a custom one?), but with this size it better be a very high flow one to take advantage of such a large print volume.

Each video makes me more proud of being one of your subs. Thanks for leting me know you with these videos! Keep up the amazing and inspiring work!!

Ivan, thank you for your video series. In industrial robotics what you have made is called an H-bot. They are perfect for this type of application where the Z height of the end effector (print nozzle in this case) remains constant. The sound you are is a byproduct of the resonant frequency of the components connected to the source (motors). Adding mass or dampeners at the right locations will reduce the amplitude of the transmitted sound. This could be a block of rubber next to the motors inside the hollow aluminum tube or filling the tubes with sand or other material.