Off Center shifts mid print

[semtex95]

Hi, I was printing a Samsung Galaxy S5 phone case straight off of thingiverse but it messed up. I think it was a problem with the slicing program but could also be with the filament or hardware. The phone case printed the raft just fine, but it looks like right after the raft was formed, the entire print shifted lengthwise of the phone case by 1 cm, and continued printing for several layers, then shifted another cm and printed several more layers. The strange thing was that it was almost perfectly aligned widthwise, and each shift printed accurate layers to the extent that its recognizable as a phone case. That leads me to assume that it was a systematic problem with the slicing program or maybe something with the printers programming.

My University uses Flashforge Creators mainly and they have had great results. However, it may be a source of error as a ton of our printers break down and this print was from the 3rd printer I tried because the first 2 had problems.
I used Makerbot Desktop to export the Thingiverse STL straight from the site, so it's probably not a problem with the file as it looked like a proven build. My settings were 20% infill, 0.1 mm layer height, device setting as single extruder, and standard quality with 3 shells.
This was the first print for a new roll of PLA I got off of eBay for $19/1kg. It was produced by some company called WyzWorks, but is probably an American rebranding of chinese products. The filament was a lot stiffer and brittle than the ones we used at the makerspace, but the print quality was okay for the most part, except maybe some problems due to the material constituents. I need to further test that to make sure.

A noted problem was that as it started printing, the edges and sides of the raft had parts curling up in some places, but my guess is that is from the filament being too hot and being pulled up alongside the extruder as it moved. 230C was the standard setting here, but that may have been too high for this filament. Some broken pieces were scattered around the raft, which I think were from the extruder hitting the upraised curled edges and breaking them off. This doesn't seem like a problem for the print as it was only the edges of the raft, and the print itself had layers beneath it to firmly stick to.

What do you think is the problem?
WIN_20160227_23_21_17_Pro.jpg

[LambdaFF]

Hi,
This is most probably a mechanical failure, not software related.

What you need to do is the following :
1/ Check that the belt on this axis is tight. This is most probably due to a skipped tooth while moving.
2/ Next check your speed. Try much slower and see if it works. This is still a high probability.
3/ On some cases, where the head bumps into the print and the print stays on the bed (very low probability), the belt skips a tooth. In that case, look whether you are over extruding or if the print has good adhesion. Looking at the print while it's done could give you a hint.
If it's none of the above :
4/ Finally, on some badly designed printers, it can be due to heat creeping on the belts. You don't specify the make of your printer so... can't help you. But if the above points don't solve your problem, you should see if other owners experienced the same and what they did about it, might be a mod somewhere that solves this.

A few general remarks :
1/ PLA should not be printed at 230°C. Try 210°C. If you have a heat bed put it at 60°C.
2/ If the corners don't adhere, use paper glue on the bed to help adhesion, avoid sharp corners in your design, add adhesion "DAVO" pads.