That last one is mechanical. 
Your head got caught on something and slipped the X axis by a bunch, then continued as if nothing had happened.
Give us pictures of your print head and extruder from as many angles as you can. There’s got to be something going on there that shows as under extrusion.
OK, here are some pictures: https://imgur.com/a/9hxP8l8
I took some other photos of the fan/heat sink if there are some other issues, but I think they are clean enough. The hot end looks pretty gross from underneath, but I assure you that the photos make it look worse 
I’ve now printed two larger parts after reducing my PLA temperature without the under-extrusion problem (one being this XY_C_Burly piece). I’m fairly confident that it’s solved, but now this new issue has popped up :\
I see two things. Your heater cartridge seems to be hanging out really far, make sure it is centered and in there snug. Your nozzle is out really far.You should only have about a credit card gap from the nozzle shoulder to the block, for there the throat should be tight against the nozzle. That might give you a tiny bit more room to give the heat break a better chance.
Thanks! I will attempt those fixes tonight.
Am I correct to guess that these are both fixes that will help with the temperature and reliability of printing, but not really combat the extreme layer shift that I experienced? I’m hoping that was just a bit of bad luck, as I’ve never had anything like that happen on one of my prints.
Yep, those fixes deal with the heat/cool characteristics of your hot end. The fan is constantly blowing on the heat sink, which cools the mounting block that the hot end throat is screwed through. If you have any gap between the nozzle and the throat you will clog due to plastic oozing into that gap. If the nozzle is too far from the heat block as Ryan suggests the nozzle tip will be cooler than the heat block and the tip will tend to clog. Any clog shows as under extrusion.
It’s a bit of a challenge to get everything just right. Screw the throat into the mounting block as far as it will go without hitting anything in the feed mechanism and lock it in place with a thin nut. Next screw a nozzle into the heat block so only a millimeter or less is away from the block surface. Then screw the heat block/nozzle onto the throat until the throat seats with the nozzle. Finally take the system up to temperature and reach in with a wrench and tighten the nozzle. When everything heats up things will expand enough that you’ll get another rotation or two on the nozzle to get it seated again. Once it’s fully seated it can still cool down without causing issues and won’t generate a gap when heated again.
You can still end up non-optimal if your throat is too long or too short for your hot end design, but they usually come shipped setup with the right length. Measure your old one before buying a replacement though! It’s easy to get them the wrong length…
OK, I just disassembled the extruder and I’m not sure about the results.
You’re fine without then kapton. Your hotend temp might oscillate a bit more because the PID loop is not as well tuned, but you should be fine.
You’ll have to adjust you Z0 down a little bit because you shortened things up (not sure the procedure for your printer).
OK, some better results with printing.
No under-extrusion and no layer shift!
Despite taping down all of the external brims, the edges lifted up somewhat.
Is this good enough to use? Should I maybe try a raft for my next print?
Thanks again! This is frustrating but rewarding whenever something works
Compare the horizontal hole locations against another part that didn’t lift. If the bearing will be in the correct spot the part should work fine.
What are you using for a build-plate? What (if anything) are you putting on the build plate to help with adhesion? What bed temperature are you using? How level is your bed? What layer height are you using for the first layer?
If all the above is in order something else you may try is to delay the part-cooling fan a little longer. My fan speed is 0, 33,67, and 100% on the first four layers (vs. the standard 0, 100%). I also use a pretty warm bed (60-65C), print on glass and use hairspray to help with adhesion.
I tried posting this earlier but it wasn’t showing up. Spam filter maybe?
The build surface has a sheet of 3D printing surface from Buildtak.
I am printing with 9 external brims and after the printer has completed the the first layer, I’m putting blue tape down to help it stay down (which I guess didn’t work very well on my last print).
The filament is PLA without a heated bed and I level the bed after 1-2 prints.
“Floor solid thickness” is 0.05mm and “Floor surface thickness” is 0.25mm.
I have the fan at 0% for the first layer with the print speed of 12mm/s
I might try printing with a raft tomorrow with a 5mm margin.
I do 60c for the bed on buildtak.
I’ve been using 70° under 3mm glass with painters tape. 195° extruder… 105% extrusion on the first layer, no fan until layer 3.
I don’t have a heated bed and the Makerbot print software is missing some of those settings (I can only make changes to general and first layer printing).
I’m a few minutes away from starting a new print with a raft. Maybe I’ll put down some painters tape before it starts.
The filament I was using before seemed to have some serious shrinkage issues. Those long arms on the XY part would crumple and lift off the plate. The stuff I have now seems much better, and the fit is a lot better, too.
Try printing on blue painter’s tape. Get the wide stuff and put a layer down so the edges just touch. Then wipe it down with some isopropyl alcohol to remove finger oils, and rough it up a touch. Printing without heat is a pain in the ass.
Try a smallish part with just the tape. Personally, I loathe brims because I usually end up pulling off the outermost wall (or two) when I remove the brim. Especially when there’s a chamfer on the bottom of the part. If you have better experiences with them, feel free to ignore my commentary. That’s just my experiences.
[quote="kvcummins,post:36,topic:11426"] Try a smallish part with just the tape. Personally, I loathe brims because I usually end up pulling off the outermost wall (or two) when I remove the brim. Especially when there’s a chamfer on the bottom of the part. If you have better experiences with them, feel free to ignore my commentary. That’s just my experiences. ?
[/quote]
Same problem here. All of my MPCNC parts are missing the outer wall on the bottom of the print. Oh well
All I have left are the XY_C parts and Tool mount.
Here is my latest successful print!
This time I used “IPG ProMask Blue Painter’s Tape”. Laid it out diagonally across my print bed and cleaned the surface with alcohol. I tested a couple other tapes but the adhesion wasn’t as good.
I encounterd one issue while printing but I was lucky enough to catch it about 1 minute before absolute failure. My printer was running out of filament and for whatever reason, when I pause a print or try to change filament it will cancel the entire build. It was difficult, but I had to hand feed the new filament into the motor while it was in the middle of printing…I had some trouble getting the motor to grab the filament, so there’s one layer missing about half of its infill. Good enough for me!
Thanks again for the help everyone.
I’ve run into this issue after I’ve built an enclosure for my printer. The extruder motor would slowly heat up over time, and eventually put enough heat into the extruder gears to soften PLA filament. This resulted in severe under extrusion very similar to what I see in your pictures. Sometimes it would recover for some layers and then go back into under extrusion. It does look suspiciously similar to your second picture.
