Report on building a MK3S+BEAR clone  

Report on building a MK3S+BEAR clone

First, I'm not trying to convince anyone into anything. I'm just sharing my experience to those, who are considering similar solution. I will provide few facts and also shortly explain reasons, why I decided to do it the way I did.

Intro
I already have original Prusa Mini+ (with Bondtech upgrade) and I am very happy with it. Saying that, if you're looking for your fist printer, I can highly recommend semi-assembled Mini+ option.
Anyway, I realized I need just slightly bigger printer than Mini and MK3S size fits here perfectly. I can't afford original assembled version and if at all, it will be the kit: about 800€ with shipping. And I though, if I need to assemble it from scratch, then I can actually get any other (maybe cheaper) printer. I'm not an engineer, but I can recognize why MK3S has such a good reputation. Is a bit dated, but basic concept still holds with competition. Yes, is the printer I just wish to have. But knowing myself, there's always place for improvements. And so I knew, I woulnd't end at 800€. What about a clone? Yes, I've watched many reviews.. in sense, you never know what you get from China. And it has been proven, that (vital) parts are usually not of the highest quality. But what if I replace those, with better quality parts? Can I get the same quality for less money?

Decission
I decided for MK3S clone with BEAR frame: 403€ (incl.shipping). And here are parts that I decided to change/upgrade:

E3D complete hotend: 65€
Bondtech extruder: 125€
X-carriage for extruder: 40€
Prusa bearing clips: 5€
Prusa Noctua hotend fan: 14€
Prusa SuperPINDA: 26€
Prusa Smooth PEI sheet: 35€

Clone (as shipped) would probably work good enough. Still, I though these parts are just necessary to be replaced, to have a printer, that is comparable with original. Actually, I think it has become even slightly "better" than that (BEAR frame & Bondtech extruder).

713€ in total. Plus, I needed to print parts by myself (about half spool of PETG). It just must be said: not much cheaper!

Clone parts quality
Actually I expected all kind of troubles (bent rods, badly machined parts, missing parts, etc). But it turned out, parts are well made (except hotend) and also alu-profiles (BEAR frame) were cut to very precise dimensions. In short, I had no troubles with assembly. There was more than enough bolts and nuts in package, so I ended up with quite a collection of spares. I hope printer won't fall apart after few days of use 😏. The only thing that was missing, was bowden sleeve for X-axis motor cable (I used the one that was on Mini's filament sensor).

Printed parts
We can get all necessary STL files from GitHub. However, I was quite disappointed by some of these parts. Btw. I downloaded them from BEAR and Prusa GitHub pages. I needed to modify most of important parts, simply because things didn't fit -and I just refuse to use a hammer for assembling 3D printer. Anyway, in case I need them in future, I saved all STL files that I actually used. I have also designed new case for Einsy board -let's be honest, the original one is really too small.

Power on
I forgot what firmware was originally installed on clone, because I needed to install Bondtech firmware as a very first step. I went trough calibration wizard and first layer calibration, and everything seems to be fine. The rest is up to fine tuning, I think.

Conclusion
I can only speak for myself. Yes, I have what I wished for. I can't say I really saved some big money... I "only" got BEAR frame & Bondtech extruder for free. In my eyes, my MK3S+ is original. But truth is, I can't count on any support or warranty -I'm on my own.

Do I recommend it to everyone? No!
First, if you don't already have some 3D printer (capable of printing PETG in high quality), then it can happen you won't be able to assemble it -at least not properly. And second, if you don't know how to modify or create print parts (STL), then you might be in trouble again. Of course, you can also buy printed parts. But that adds to the final price and makes the whole idea questionable.

How about buying only a clone (without "upgrades")? Paying only 403€ (+ about 60€ for printed parts) is still very tempting. I can't really say, because I haven't tried that option. Anyway, from what I could see, there are at least three parts, that scream to be replaced:
1. cloned print sheet just doesn't match original Prusa
2. cloned hotend is not that precisely machined (one can recognize that from a mile away)
3. clone doesn't have SuperPINDA (it has older PINDA v2)

Thank you for reading this -I hope it will help some of you to avoid a mistake. If there's a specific question, I will be happy to answer.