Somewhere early in this thread, someone mentioned that they would be interested to see what my thoughts were after a significant amount of time with the printer. So far, I think it has been generally positive. While I had may share of issues to address, and it is certainly not a put it together and go type situation, since I have addressed those issues, the printer has worked without issue. I have run into one longer term problem. The linear bearings for the Y axis have started to score the Y axis rods. Early in the Mk3 life, Prusa shipped a number of printers with un-hardened rods. You can find several discussions in the Prusa forums. The unhardened rods would get scored rapidly. My printer has the proper hardened steel rods, and still, one of the two (left looking at the front) is showing signs of scoring. The design of the linear bearing attachment to the print bed makes it very easy to deform the linear bearing casing and cause one or more of the ball bearings to seize. Over time, this will score the rod. The bearing attachment is just a U bolt through the print be frame and if you over tighten, the U bolt puts pressure on the bearing case in a very small area. So, the scoring is likely an assembly problem on my part, but its a weak design that allows it in the first place. The spring kit will uses bearing attachment parts for Thingiverse (something like this: https://www.thingiverse.com/thing:3214732
). In the mean time, I rotate the Y axis rod about 15 degrees so that the bearings will wear on a different part of the rod.
Now, I still have print problems from time to time, but they are all of the type that are common to all 3d-printers. Occasionally I'll get bed adhesion issues. Most of the time, print problems are because I screwed up a slicer setting and asked the printer to do something silly, or beyond its capability.
I haven't actually been printing a lot since Thanksgiving due to my lack of time to do things. I decided it would be good to print some things from Thingiverse since the printer wasn't doing much else.
This is a model of an automatic transmission. Its a fully operational 6 speed transmission, plus reverse. Fully printed, no external parts. You can just barely make it out in the picture, but the brakes used to hold the sun gears in place are actually printed as integral parts of the frame. They just snap loose after printing. Their pivots are printed in place. Was actually pretty impressive.
Yesterday afternoon, I stumbled across this Christmas tree. You can only slice it with a slicer that lets you assign different print processes to different parts. I used Simplify3d, since I have it.
Once I printed it, I decided it needed a "tree topper", so I went and found a star and scaled it down to a size that worked with the tree.
Last night, I decided to print a DNA desk tchotsky as it is rather appropriate because of where I currently work.
The first image really is the print sitting on the buidl plate as it finished. No supports. For size context, its about 6" tall and the runs are about 2" in length. If you look very closely, you can see a slight convex shape to the bottom of the rungs due to sagging, but there is no layer separation and the whole thing is quite smooth, even at 0.2mm layer hight. I started the print right before I went to bed and I was a bit nervous about what I was going to find when I got up. I was pleasantly surprised, to say the least.
I'm traveling with work next week, and if I can get time to take some measurements this weekend, before I leave, I'm going to try and use my evenings to do some CAD work on an enclosure for a project I'm working on. I will, of course, post an update when I finally get it done and try and print it.