gr5

The "shrinkage" is caused by the heated bed. The pla is not cooling enough there and it's still soft when the next layer goes on top. The outer layer is going down as a liquid rubber band (like snot) pulling inward but the lower layers are too warm to resist the pulling inward because you are still close to the bed. Maybe get the fan up to speed sooner or lower the heated bed (and/or the nozzle) by another 5C.

In addition it's common for that back right corner to be lower on the glass - the glass or the aluminum under it can be warped down. So before you start another print check your glass with a straight edge or ruler and if the back right corner is lower then try removing the glass and bending up the aluminum bed or move the prime tower to the rear center.

Well I recommend adding your own prime towers before adding your model (so they print before the model) to help hold it together and you can make the bottom wider and stronger and the top smaller/skinier. I added 2 towers - one of PLA and one of PVA:

In the photo of the side of the blue part some layers look overextruded and some look underextruded. This is most common if the Z axis is moving strange distances which is most common if it is very dirty. Try Pushing the bed down and then cleaning the Z screw a bit with some tissues. You can twist the screw with one hand while letting the axis pull the tissue up or down the threads. Repeat a few times over 5 minutes and then reapply grease. Just concentrate no the top 1/3 of the z screw as that is what you will use the most and where you will see a difference right away.

I find at every speed change you get over or underextrusion. So when you go from fast infill to slow shell for example you can get overextrusion for a few millimeters. Until things stabilize again. Creating an annoying bump on the wall somewhere.

Ah. Good point. There are over 100 settings in the "per model settings" but layer height isn't one of them. Too bad. Well I believe S3D lets you do that (Simplify 3D) but it's not free.

cura 2.X or cura 15.X? What version cura are we talking about. And which side is it printing towards - the right side?

I have no idea if .25mm nozzle strings more. White filament definitely strings more. I would do a few things. UM2 can travel up to 300mm/sec. Try at least 200mm/sec. This helps to break the strings. I'm pretty sure .06mm is worse for stringing. Try .15mm for .25mm nozzle or .2mm layers for .4mm nozzle. There is a setting in cura - horizontal expansion? Something like that. It can compensate for all wall thicknesses without you having to modify your STL. It can make all walls thicker. You might have to enter a negative number. I forget what it's called but it's a fun parameter to play with. Do not use any support. Make sure fan is at 100%. Cooler is better. 195C was smart. 180C smarter. But that might underextrude. You can play with temperature a bit. Make sure retractions are at max - there is something like "minimum gap for retraction". Set that to 1mm - if the gap to traverse is less than this it won't retract. Also there is something like "minimum extrusion between retractions". If this is too low you can grind the filament but you should be okay. The default retraction is 4.5mm and if you set this to .45mm you will get no more than 10 retractions for every spot of filament. Maybe set this to .1mm so there are more retractions on your model. Turn off infill. You don't need it and it just makes for more retractions.

Yes. You can do all that with Cura. S3D also supports that. You need Cura 2.3 or newer to do that. It's not super simple - if it's not your model the first step is the trickiest. Roughly: 1) Split your model into multiple STL files. For example if you wanted different slicing parameters at the core of a cylinder you could cut the cylinder into an outer cylinder and an inner cylinder -each a whole, solid, manifold STL model. 2) Place all the STL files on the bed in cura. They will be in separate locations - don't worry. At this point you can set differe slicing parameters for each or you can do that later. 3) select all the models and merge them into one with right click features. 4) On the left side of cura display there is an icon - select *part* of your merged model and with that icon (left side of screen) you can change slicing for that region. By default there are only a few choices of parameters to override but you can enable hundreds more.

Can you move them with power off? You have to push pretty hard. Don't worry about damaging the steppers as they are extemely strong and you can overpower them without damaging the steppers. You might damage the wood frame or benda metal rod but you won't hurt the steppers. The Bed is the most difficult to move with power off. The extruder is easiest. It sounds like something is wrong.

If your filament is brittle - don't throw away the whole spool. Usually only the meter or so that was straightened for several hours in the bowden is bad.

There's lots more details about this problem and slow motion video of it happening and ways to reduce the problem and why it happens: http://umforum.ultimaker.com/index.php?/topic/4094-raised-edges/ Look at the first picture in the first post to see if this is the same problem you have. Then skip right to "page 2" and look at foehnstrum's video and read all the posts after that possibly. It's not until around post #39 and later that we really begin to understand what causes the issue. That video was important and looking with "reading" glasses.

If the cold pull result is in the shape of the tip then that's good. The "long neck" is not an issue. Burnt filament on the OUTSIDE of the nozzle is fine. My nozzles look like that after a while also. The little leaking is normal and is a problem that should be fixed by using the "wipe tower" feature. Or do what I do and design your own custom wipe towers.

I have had zero issues with cores. I have issues with some things but my cores extrude just fine. All the time.

1) Why is the bottom cm or so a lighter shade of red (pink)? 2) Please update your profile to reflect the country you live in because that is important to answering questions more often then you would think! 3) Your parts are small with a somewhat steep overhang. These are tricky to print. You certainly want as much fan as possible. The overhangs will have raised edges on the layer currently printing and the head will hit them and can knock them over. The solution is as much fan as possible and also to make your parts stick so well you can pick up the printer by those little dodecahedrons. Here is advice on that:

In cura 15.X, in expert settings there are more settings for support - something about X/Y distance. Try setting that to zero or playing around with other settings. Or use cura 2.3. But really best is to design your own supports. It will save you filament and printing time.

Wow. Looks like a bug. Which version of cura is this? I'd play with the support features. Actually the crazy thing is every location it put support - it's not needed. The printer can "bridge" just fine from that center "tab" to the two side posts. At least from this angle it looks like it's not a problem. And those 45 degree portions don't need any support either. Just the place where you point with the arrow - that needs support. If you can't figure it out in support settings (set X/Y distance parameters to zero for a test?) then I'd just build support in CAD. Just put one support on each end of that tab before it switches to 45 degrees and turn off cura support.

Squish I talk about here in great detail but I mean flatten the filament more on the bottom layer. Like a pancake shape:

I think you are going to have to put a little support structure in there but I'm not certain you need it. On the slicing issues - somewhere burried in the advanced features is something called "fix horrible A" I believe. Uncheck that - that is party what is causing your "plate". What CAD software are you using? Is this from sketchup? If so you have to make ti manifold (link at the end). Tell me more about the missing layer - look at this area in xray mode. It sounds like your model is not manifold. A manifold model can be filled with water. Your model may have holes in it or may have inner walls. More on sketchup and manifold (if you don't use sketchup skip to #4 and #5 sections of this link): https://i.materialise.com/blog/3d-printing-with-sketchup/

Neotko's method is a little quicker if you've done it 5 times but also more dangerous - you could just melt it in there. Pouring a pot of boiling water into a pyrex or metal pan is the perfect temperature for this: 70-80C (even though boiling water is 100C it will cool very quickly when it hits the pan). It helps to have gloves or tongs. And a friend (4 hands).

I'm not sure what you mean. Do you mean as the filament spool rotates it makes a noise? I always put my filament on the floor so I'm not sure why it would make a loud noise.

Well you can double the feeder pressure with the meduza feeder and you can print most of it. The few, inexpensive parts you need you can get cheaper if you just buy the kit from my store for $19: http://thegr5store.com However I was always happy with my UM2 with no modifications at all. To get it to stop "skipping" you have to print hotter or slower or increase the bottom layer gap (just turn the 3 screws a bit so glass is lower/farther from the nozzle). No need to run the bed calibration - just turn all 3 screws the same amount. Or again - just raise bottom layer temp to 230C and slow it down to 20mm/sec bottom layer speed (the default I think). Or do all 3 of these things. Also your .4mm nozzle may be .35mm due to gunk in there. The newer curas (version 2.X) have default line width of I think .37mm. This also reduces the pressure in the nozzle and reduces feeder skipping.

It's probably the nozzle. It's probably worn. Swap out the nozzle. Let us know if that works. In addition note that white filaments of all brands have something in it (I think talc) that makes it harder to print. Also it looks to me like you don't squish your filament as much as I do and you don't appear to use any kind of PVA. Squish and PVA when done correctly keep the bottom layer from peeling.

PVA burns easily. If it stays hot for just a few minutes it starts to turn brown and can get very difficult to clean out. Also it can eventually create a thin layer inside the tip of the nozzle which slows down the ability for the printer to print at speed.

I haven't opened the feeder in a long time and forget the details but I think you just start removing screws. Before taking the feeder apart, heat the core to 180C ( plenty hot to melt PLA) and push on the filament while holding the release lever on the feeder to make sure there isn't a problem in the head. No need to clean the feeder if the problem is in the head. You have to push quite hard (10 pounds or 5kg force) but you should get some melted ooze if you push. There was another post today I think by iRoberti I think. Or maybe ultiarjan. That linked to how to take the feeder apart.