I know I know, it's a old model, but still VERY popular model for it's cost.
Tho it didn't use to be cheap.
I spent literally thousands in this machine, building began something more than 2 years ago! But only finished it a year ago as i were being busy with other stuff.
I bought the best parts available, sourcing everything individually. All metal hotends were a really new thing back when i began this build, people were still using PLA bushings, and generally people had really bad print quality and slow speeds (80mm/s was top of the range).
People were just starting to test Nylon and other materials at this time too! PC filament was not available etc.
So i went with LM8UU, 608ZZ all around, hotbed, glass printing surface, actual precision linear axle smooth rods, highest quality print PLA printed parts i could find, Mega1280 (no mega2560 back then) + RAMPS i had to solder myself (No readily assembled was yet available). GT2 Belts + HQ Pulleys. Brass extruder small gear. Arcol.hu hotend, aluminium bed carrier etc. the list just goes on.
Before i proceed, a little bit of background:
I'm an entrepreneur and IT professional, who's hobby is rally/drift cars with which i tend to go to the extreme. Flawless rust repairs with no visible weld marks and exact to original shapes to within under 1mm: No problem. Complete different type engine swap from different era (15+ years newer engine to older car): Not a problem. Building custom suspension parts? No problem. Building complete suspension including design, acquiring parts and setting it up for motorsports in a week? Just let me clear my calendar, not a problem (and results are actually very good). Installing, setting up and tuning a aftermarket programmable ECU? Not a problem. Building all car electricals from scratch? Just give me a week or two.
I also code, and used to work as a coder. I like to tinker and build things, but i also like to build hosting services etc.
BUILD & INSTRUCTIONS:
Parts were outright WRONG, carrier dimensions were all wrong and no real info on how to build the carrier, since never saw an machine live had really no idea what kind it's supposed to be, so couple plywood errors later i bought a aluminium water jet cut one.
JIG -> There was exact mm measurements for these, sounding like it's extremely important. So i made a jig within 0.1mm. All for nothing, later on it turned out those JIG measurements were wrong to begin with, and it would have been just OK to be within reasonable tolerance. One of the measurements actually did not MATTER at all as long as it was exact (distance of vertices from each other), and the number was actually *WRONG* in the documentation, you need something like 15-25mm wider than specification say to even use the full bed, but best to make like +50mm wider for extruder stepper to clear.
m3 screws, bolts & nuts all around: What an moronic idea. Normal hardware stores don't carry these, and since they are different lengths etc. needs to be allen key etc. you can't just buy them from anywhere. End result -> Expensive and fiddly to use with. I bought a vitamin kit for this reason, i think from ultimachine which was missing a few ones, but fortunately had some extras also!
Better idea: Use all around M4 or M5 which are readily available in many forms from ANY hardware store. The cost SIMPLY does not matter, and for 99.9% of the parts weight neither. Only where the weight matters is the carriers either X or Y (Bed).
Snap-On bearing fittings: Some broke already on initially assemble. Not really good. Zip tie fixing: These tend to remain every so slightly loose causing play.
Z rod printed couplings: Shitty Shitty Shitty. Never got them to work properly for prolonged periods of time.
Smooth rod couplings: Stuff which is supposed to bend from PLA? Bad idea. Secondly the design is ever so slightly wrong.
End stop mounts: And these are supposed to work? Yeaaaah right, if you don't mind loosing half of your build space. Lots of fiddling later found acceptable solution which just worked.
Printed parts from PLA: Pretty much only the big parts have survived to this day, vertice triangle, mostly Z motor mounts. Everything else, including X motor carrier are broken. Extruder base block is insanely enough still i nuse today and has not broken!
Vertice design: VERY VERY strong ... But to the wrong direction, duh! There's no sideways support, so it's fiddly on X axis. Y axis is extremely strong tho as a result but X axis is garbage.
Z axis: Wow, are those threaded rods curvy from get-go! Banding etc. issues, can be hacked to be better. But the whole design commits to the X axis wobbly issues.
Z axis motors: Mounted to the top? Really? REAAAALLY?? Never heard of center of mass?!
Belts: Really, this is supposed to keep them tight? Yeaaah riiight. You need some kind of manual tensioning system, just clamping them on there is not sufficient. Many issues with the clamps breaking or simply not gripping to the belts. Eventually some of them i just used super epoxy (JB Weld kind of stuff) to make them stay there, and made custom tensioner for Y axis.
Bed carriage: The instructions were wrong, if you installed it like the instruction your print volume was limited to like 45 x 45mm !
PRINT AREA: 200x200x150 claims are absolute bullshit. Tallest i managed to do was about 115mm but that required special care like manually moving X end stop after print started, and making sure the surface area was small enough that the extruder stepper don't hit the vertice rods, and mounting it sideways to help a bit on that too. I managed however to do some 190mm * 190mm prints successfully, and in Y i think i managed to do 220. But limited height was a real issue!
INITIAL USAGE, THE FIRST MONTH
After battling for weeks to get adhesion, none of the instructions actually worked as supposed to! Found a solution to just use normal dish washing soap to clean the glass. PLA started to stick like mad!
However, once i got it to print the issues jsut kept on coming, getting quality to even somewhere decent took the next 8months - for any material.
This time, with constant breakages.
FIRST 8 MONTHS OR SO:
Part by part i kept on upgrading or ever so slightly changing it to make it work even a few hours at a time. Overtightening the M8s helped a great deal, somethings Super Expoxied in place. Dampers under the machine. Auto belt tensioner.
ABS X carriage. Fan mounts.
And every now and then it would still fail.
Eventually i got the quality way way up, some VERY nice prints, even some VERY hard ones i managed to get done, even some tiny details. The machine would work sometimes weeks at a time without breaking.
I managed to get very nice high quality Nylon prints out of the machine too. ABS no problem. Adherence no problem, actually cracked glasses due to too good adhesion.
Finally i had broken ramps because the connectors on it are not just able to handle the loads of the MK1, but this is prusa unrelated issues.
LAST 4 months:
I'm now on like my 4th all metal hotend, printing like mad. The machine kept on working, hour after hour, and as long as it worked i let it print. Z banding issues keeps plaguing, and the TINY dimensions because of the bad design.
Insanely enough it worked quite nicely for a while.
But last few weeks, everything was just a pain. The Arduino/Ramps kept on resetting without any real reason midprint (again non Prusa related).
Finally X started skipping without a reason what so ever randomly and X stepper carrier broke down and was VERY brittle at this point.
OVERALL:
1 worst, 10 best
Machine design: 3 - Threaded rods are cheap and vertice model is ultra strong, but one should have used M10-M12 and designed in rigidity for X axis too.
Durability: 1 - During the year i only had the single ~2 months period without breakages of the basic mechanical machine. The first 6 months it was almost always broken. First 3 months there was many times more repair hours than print hours.
Print Quality: 6 - Decent quality with A LOT OF upgrades as mentioned, good hotend and carefully calibrated and knowledge of materials. Not top notch, not absolute garbage.
Print Speed: 6 - 100-150mm/s was usual speeds i used. However i'd like to see stable speeds of 300mm/s++
Price: 1 - Because of all the required upgrades + repair work, it's nothing but cheap or inexpensive. Knowing what i know now: Getting a highend commercial printer would have been MUCH cheaper and naturally tons of easier.
Ease of Use: 2 - Some of the build instructions were actually decent, however the incorrect information contained in build instructions and lack of some information, and lack of basic settings etc. to get started with were really bad. You have to jump straight to the deep end (at least at that time) to get started, many things just guesses.
Machine size vs Print volume: 2, it's actually quite large and bulky for the print volume.
Print Volume: 3 - Not the smallest, but almost all commercial solutions offer bigger practical envelope. Without hacks would be the worst volume on market.
Tinkering "Value": 10 - This means how much you get to tinker and wonder. If you want a machine just for tinkering and fiddling, but not actually printing - this is THE perfect solution. Since most likely you need to change it quite a bit to make it actually work!
Hackability: 8+ - Many changes requires redesigning basic machine parts for mounts etc. If there just were more standard mount option for easier hacking... Everything's open so you can change pretty much anything tho
OVERALL
As a 3D Printer: 2
As a tinkering, hacking and fiddling target to spend your time with: 6 - I would actually prefer to it also work at times! Otherwise there's just no worth on all this tinkering!
My recommendation:
STAY THE HELL AWAY, get a MendelMax, Mendel90 or something. I'm wary of even the Prusa i3, if that's such a good design either ...
If you want o tinker or hack away and have a lot of experience with 3d printers: Design your own. New to 3d Printers? Get Mendel90 plans and build your own!