Uhm Yes..
I dont have a deep set hatred for 'cheap 3D printers' - I just have watched the market develop into a utter crapfest of lowest common denominator behavior, typified by patenting open source ideas, providing subpar equipment, breaking cardinal rules of open source by creating forks only for branding purposes, and so on.
After I ranted above, I did think about the fact UM releases ALL of their materials open source, even for their flagship products. Of course, they have to in most cases, given the licenses of the projects they use. But they do a good version of commercializing open source. I agree.
My real frustration is thus: having been asked by the lab leader to get a 3d printer to make spectrometer component enclosures and mounts, I sighed deeply knowing what was going to happen, all my time would now be spent justifying the inability of a cheap ass 3D printer to make parts. So I convince them to get a UM2 even though it is fairly expensive compared to what they wanted to get based on another lab's "positive" experience with cheap 3d printers. Sigh. I knew what was about to happen though, having been around and used lots of hobby 3d printers.
So we got the UM2 - immediately the Z axis is grinding. So we try it out, it prints ok sometimes, other times appears to be under extruding, except the grinding sound and shuddering z table give away the real issue. The silver fillament we have seems to be somewhat odd, so we try our white stuff, big improvement - except the table is now shuttering and grinding in the downward direction. The rest is history - it is the plight of the owner of a $400 microcenter machine, or a $200 self built machine... Cheap linear motion components and reliability issues.
"This is normal for 3d printers", some say - having a now misplaced pioneering spirit influenced by the early rep rap experience and ethos. It is normal for r&d to go through these troubles, which is what rep rap was doing, iterative self determined improvements and tinkering..
Flash forward 14 full years, and we have proliferation of 3d printer makers - all of them using the same style of low-end parts as the original rep-rap users were using to keep costs of their experimentation down.
I know it is normal for a product to retail for roughly 10x the mfg cost. This is normal, and necessary for a company to survive. But using parts that are not up to the task just because 'it is normal to struggle with these machines' is sad. Maybe I got a bunk bearing by accident.. I suppose it is possible. But the quality of the components belies the real purpose these bearings were manufactured for: non-precision motion in things like food packaging equipment destined for the domestic chinese market.
Ive digressed a lot. Sorry.
I will try to get the reseller to send us replacement bearings and rails. If they cannot or will not, we may purchase appropraite components from sources known for quality. This will cost some $100 or more, and take half a day of my time. Lovely.
"Just send it back" some will say - but we already have invested X time into this. Sending it back for a new machine is a possibility, perhaps, but repackaging and sending back a machine, receiving a new one, and so on... Time consuming.
Sorry for being so ornery. I was just deeply disappointed, like a kid fully realizing his x-ray specs will never see through anything, and barely work as a demonstration of diffraction.