New diy printer, help choosing mechanical design

Hi
Sorry if I'm posting in the wrong place.

My goal was always to learn how 3d printers worked and then build a better one.
I started with a very flawed e-waste cd-rom based small printer, it worked (sometimes).
Then I searched for a proper 3d printer kit and found a Graber i3 kit, it's based on the Prusa i3.
In this printer, I spend more time upgrading and fixing then properly printing. That's what I like to do anyway...

Now I want a new challenge, and I will "design" (a.k.a. copypaste) and build a new printer all by myself (with your help).
I'm thinking on building a Ultimaker clone, with aluminum frame and fully enclosed.
What are the main disadvantages of this design when compared with a CoreXY? And the main advantages?

My main goals on the new printer are to be silent and fast. By fast I mean printing at 80mm/s without too many issues.
Frame will be aluminum extrusions, and I want it to have something like 250x250x400mm of build volume.
Will use 8mm aluminum rods, maybe carbon-fiber ones, and Igus bearings for the silence.
What about those 3dprinted "bearings", are they good?

Also would like to use some kind of water cooled hotend, to get a smaller tool head.
Another thing I'm inclined to use is a remote direct extruder, something like the Zesty ones, but in a DIY fashion. I will build one for my current printer and then decide if will use it on the new printer too.
Maybe developing a tool changer in the future isn't a bad idea too...

Anyway, cost will be a main issue here, I don't want to expend too much on this machine. It's a hobby and I don't make too much money for that...
Also, I'm Brazilian so basically you could take the price you think of, multiply by 5 and that's what I may pay for that parts...! Not kidding, I bought a Raspberry Pi Zero W for roughly US$50 here... The same ones that you can get for US$10...

Any links to actual build/guides will be very appreciated!

Thanks!

CoreXY is fun, but honestly, the best fun I had was with a Delta. Steep learning curve, many things that can go wrong, many variables that you need to keep track of. And everything has to be perfect. But once you get it down, boy is it a fun printer to print with!

---

http://www.marinusdebeer.nl/

... a parallel SCARA is pretty much fun too

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
VDX
... a parallel SCARA is pretty much fun too

Ha, I was looking into this machine earlier today:
[www.youtube.com]

---

http://www.marinusdebeer.nl/

... your's is a "standard" Serial SCARA -- "parallel" means some decades more precision/accuracy over the complete working range!

[www.youtube.com]

[www.youtube.com]

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

SCARA and other cantilevered arm mechanisms all share the same fatal flaw for amateur builders- they wobble. When have you ever seen an amateur built cantilevered arm mechanism that doesn't? You have to keep the arm masses very low, use extremely rigid materials, and make very high quality joints that are beyond the fabrication capabilities and budgets of most builders. If you can see it wobbling, it's going to make very bad prints. Even if you can't see it wobbling, it will probably make bad prints because it only takes a tiny amount of wobble to ruin a print. You might be able to make it work if you print very slowly, but who wants to do that?

If you want a printer that makes high quality prints at reasonable speeds, you'll end up with one of the few proven architectures. Any of them will work fine for 250x250 build area.

Quality linear guides (not HiWin knockoffs) are silent and have the best quality bearings you'll find. Plastic bearings sliding on metal is OK, but they have to be loose enough to slide and that often means they will wobble. Microscopic amounts of wobble will create print surface defects. Carbon fiber rods/tubes are not made for use as linear guides so the surface finish and material cannot be relied on to achieve smooth linear motion.

Water cooling the hot end is a sort of crossover fad among the computer nerds who have gotten into 3D printing. They water cool their CPUs, so it must be good for 3D printers too, amiright bro? Don't forget the multicolor, individually addressable blinkenlites! Water cooling the hot end is unnecessary unless you'll be enclosing the printer and heating the chamber to very high temperatures. It adds unnecessary complication and an extra potential disaster failure mode. A small, yet adequate, cheap fan will never leak and destroy your controller board and power supply. The OP said cost is the main issue. Why would anyone concerned about cost waste money on unnecessary water cooling when the money could be put into better bearings, a more rigid frame structure, a better controller board, or a more reliable power supply?

Edited 1 time(s). Last edit at 08/20/2020 10:34PM by the_digital_dentist.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks for the replies!
SCARA printers do seem cool and fun to make, but at the same time seems to need high precision to make work reliably, even more if I want to print at higher then normal speeds...

I though about the carbon fiber rods just because they are lighter, and I saw someone using them as rods with bronze bushings so I thought it would work.

About the water cooling, the main purpose was to have a smaller hotend assembly, using a small water block instead of the long heatsinks, but after looking for it I see they are all the same size of the V6.
I also think watercoolers are overrated in PCs, I use a huge air cooler, it's even more silent then a similar priced AIO kit, and much more simple to maintain.

... look at the difference between "SCARA" and "parallel SCARA"!! -- it's a complete different world in respect of speed, accuracy and precision

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
VDX
... look at the difference between "SCARA" and "parallel SCARA"!! -- it's a complete different world in respect of speed, accuracy and precision

Check this cool one:
[forum.duet3d.com]

---

http://www.marinusdebeer.nl/

I bought a Scara from a University Surplus Auction without a controller and am just getting it moving. I just recorded a quick video for this post. (It is not production quality) Scara from Surplus Auction

Edited 1 time(s). Last edit at 11/21/2020 02:06AM by Phearl3ss1.