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I happened on this post as I was planning to undertake my first "shell" print with the vase / spiralize mode. After reading up on this thread and deciding it would be a lot of trouble to figure out how to deal with the issue, I did the print anyway using an older version of CURA, specifically 3.6.0 (running on Linux) and it printed without this seam business. So if anybody is trying to see when this corruption got into the GCODE generator, it had to be after that. Now another setting in CURE strikes me as possibly implicated here, and that is the setting to hide the z-seam. Ironically that setting is supposed to work by moving the shifting the start of each layer a bit so they don't all line up. It's just a shot in the dark, but I could suppose a situation where that seam correction is making trouble by overseeing the the spiralize algorithm and inserting in little "hop backs" when the z-height increases by 1 layer. In the case of a spiralized object, that would happen around the same place every time, so you would actually cause a seam to be produced. Just an idea...

I am asking for an acquaintance who has a UM3 Extended. The issue is that when printing lines that are parallel to the x or y axis, the printer is making a grinding noise. I am told that re-orienting the print in Cura so that the walls are at an angle (i.e., both x and y motors would be running to print a 45-degree line across the print bed) the grinding goes away. This makes no sense to me. I hope to get to check it out personally, but figured someone here might know what could cause such a condition. Thanks in advance for any help! UPDATE: I went to see the machine in action. Indeed with even a small change in the alignment of the model the machine prints as smooth and quiet as the day it came out of the box. Examining and thinking about it a bit more, my current idea is that as the slicer sets (and the hardware attempts to maintain) a print speed, when nozzle is moving strictly parallel to either x or y axis, the respective motor must move the gantry at the desired speed on it's own. When, however, the head is moving in both x and y axis, each motor can contribute a lower component velocity according to angle and the "hypotenuse" vector of print head speed. Therefor the motor has less friction to overcome and would possibly not be as noisy. The owner of the machine said she contacted Ultimakers support people and they suggest that she disassemble the machine and lubricate the motors. So that would fit with this assessment that the motors are not able to function at their peak speeds anymore. The test will be to make a print job that forces slower print speeds but maintains the orientation that is normal to the x-y axis.

I had a reasonably good improvement changing the infill from "line" to "gyroid", which basically adds some linear distance to each infill extrusion. Not perfect, but acceptable. I also reversed the orientation based on the fact that all the problem seemed to be on one side of the print. In the reversed orientation, the issues were mostly on the opposite side of the print this time, meaning it might have something to do with the fan being over one side of the print more than the other.... and as I paid a bit more attention, is seems like maybe the "globs" weren't from end-of-line over extrusion, but in fact from a bit of layer that wasn't getting good adhesion to the layer below it and stuck to the nozzle instead, smudged around, and deposited somewhere else, then repeated again the next time the print head passed over. If anything it seemed like some of the over-deposits were at the start of each line, possibly due to the prime-after-retract setting being too high?

A key observation that would help explain why a choice of a different infill could change the amount of "blobs" as some other sources suggest... because if it is making triangles or hex, it doesn't need to stop at the end of the grid "lines" and travel to the next line, it just keep printing a complex shape.

Got to looking through Cura very carefully on this issue. Seems like the "Retraction Extra Prime Amount" might be something related to the linear advance stuff, except for the fact that it's only applicable to the points where the filament retracts. Which isn't at the end of an infill line that then travels over the wall to the next infill line. But then I also saw a setting "Infill Wipe Distance", which also looks promising. In my settings it is .0875mm, which seems like it might be on the low side is there is overextrusion at the end of these infill lines. Anyone have thoughts on these ideas?

Well that is disappointing to hear. It seems like something is very helpful. Going back to look at what I thought were search results suggesting it was supported, it turns out they only talk about "Ultimaker Cura" and not the actual Ultimaker printers. I guess that makes sense why it was a 3rd party plug-in. Which brings up the question: what to do to fix this problem? I can try lowering the infill print speed, but since the longer infill lines on the other side of the model print fine, I'm not so sure. If I had to speculate about what's going on, the issue could be that the end-of-line over-extrusion is happening everywhere but with lower fan speeds, on longer lines, when the nozzle passes over the blob, it's bonded enough to the layer below not to stick and drag away with the nozzle. But on the short infill line, the mass of goo is too sticky and gets mopped around by the nozzle, making a mess of clumps. I suppose maybe I will try a different infill pattern before doing anything else, or maybe us the "avoid printed areas when traveling" setting.

I am dealing with some issues on the infill in a PETG print. I suspect there is over-extrusion at the end of short lines that is getting caught on the nozzle and making a mess. It only seem to happen on the short infill lines for a narrow section of the print (see pic for details). Everything else prints beautifully, so I'm loath to adjust fan / nozzle temps / retraction /etc. anymore. The print looks beautiful on the outside, and only concern is that the integral strength is not what it should be. Anyway, Linear Advance Constant k-value seems like a promising solution... so added the linear advance plugin from the Cura marketplace, but I am looking to do that "k-value test print" to figure out what settings to use. (https://marlinfw.org/tools/lin_advance/k-factor.html) So the question is this: for an Ultimaker 2+, should I select "Line Advance Version" 1.0 (says for Marlin 1.1) or 1.5 (says its for Marlin 1.9/2.0+). I understand that Ultimaker firmware is a fork of Marlin, but nowhere could I find whether it's implementation of linear advance - which appears late to the party - is done according to the older or newer Marlin protocol. Anyone who ran this k-value test on a UM2 / UM2+, what version did you use, and has it given you the information you needed in terms of the Cura plugin to get more uniform lines with less initial under-extrusion as well as less over-extrusion at each line end?

After searching for videos on this issue, I found one where this guy recommended using a heavy, broad chisel. Having worked to refine the method, it is the thickness of the chisel and the angle of the bevel is the key. Rather than trying to slip a thin sharp piece of steel under the object, with the chisel raised at a high angle (bevel angle _should be between 25 & 40 degrees), so that the bevel is flat on the bed and the "bottom" of the chisel blade is facing the part, you work it under the lip and then pry up the edge using the back of the bevel (lowering the handle of the chisel). This leverage will allow you to create a gap where you can then insert your blunt putty knife far enough under the object to pry it without breaking it. I do not recommend the slam-bam method, as I have heard that you can actually shear off small fragments of the glass bed that stay in the print.

Thank you for that insight. Just an aside, because it's kinda interesting to note - for want of available supply, I had been using a creality glass bed that was 235mm x 235mm when I first got this printer. (It also was a lot cheaper at my local Microcenter.) The problem with using that glass is that even though I was careful to put lay out the object in Cura at the center of the print area, the prime blob would land off the left edge of the glass. So it doesn't seem correct that the print head can only reach a 223 x 223 print area. But I am willing to accept it with respect to other considerations, for example, it seems like around the edges there can be adhesion issue and uneven temps, something I came up against when I was doing the multi-object print and posted about separately in another thread.

Hi all - I have a UM2+ and was recently trying to print some dupe objects using the "one after the other" setting in CURA. To do that I had to change some settings like the gantry height in the "machine settings" tab of CURA. I took a screen shot of the original settings not thinking much about it. Now I went back to restore the original settings, and I notice that the X, Y and Z (build volume / bed dimensions) don't look correct to me. They are (and were, at the time I took the screenshot), X=223, Y=223, Z=205. My measurement of the UM2 glass build plate is like 227 x 255, but it is definitely not square. I attempted to get to the default values by adding a "new machine" in CURA, of the UM2 family. It still has those same values as the initial settings (223x223). Tried a search on this issue, got nothing. I don't understand what's going on, so I am wondering if anybody knows whether things will work ok if I change these settings to what my actual measured glass size is... again, for a UM2 family machine, it seems like it could be set to x=227, y=255? Thanks.

Based on how nice the brim looks, I would guess that it's some CURA setting that is messing things up. Also, just gonna guess but when I see a brim like that I think D&D figurine. Don't know why. But if this is a person with a relatively small footprint, then you should focus on the print settings for your supports. Are you using towers for supports? Possibly that might help since the support tower has a bigger footprint and will adhere better in theory. Also there is a setting for "equalize filmament flow" which might be relevant if you have very fine features in your model. I am not exactly an expert, so I'm interested to hear what others here think about these suggestions.

Yesterday I was attempting to print multiple copies of a 600x600mm bushing plate. I would normally have printed these one at a time in the center of the bed, but I felt like experimenting a bit with cura's "print one-at-a-time" setting. Anyway, I laid them out in a diagonal to print them from the rear-left corner to the front right so that the gantry would clear the completed prints when printing the subsequent one. This is really the first time I've printed anything in that back corner. Anyway, every time I started the print there was an adhesion problem with the back corner of the print. It's possible it is leveling related, but since I had my IR thermometer handy, I check the bed temp and there is a difference from the rear corners to the rest of the bed of about 20-30 degrees (the digital thermometer increments in 5-degrees, so not super precise, but clearly indicating that there is a temperature variation over the bed surface. I am wondering if others have noticed / dealt with anything like this. I read something about screws that might needs some countersinking if the glass bed isn't getting good contract with the heat plate, and I'm going to check that later today, but basically the question is whether a 20-30 degree temperature variation is something to worry about if I'm mostly printing PLA, and maybe rarely going to print with other stuff like PETG. First layer adhesion in the middle of the bed where I usually print has never been an issue for me, but and 600x600 is about the largest base I print, but I would like to be able to use the whole print surface if a bitter project comes up.

I just rebuilt the head / hot end - new block, isolator, teflon thing + nozzle. With that done, attempted to get a test print out. (This machine was a salvage project). The first go was a fail - the material failed to load and instead a very nice crecent was chewed in my filament as soon as it got to the print head. So I'm thinking, "Yeah, that extruder is worn out", but then I inspect and the teeth marks in the strand up to the crecent look Goldilocks, so I try again. This time, I disconnected the gear with the release lever and push manually through the extruder till material was coming out. At that point, I reingage the gear, and it worked fine. Did the mini-cal test print. The bottom layers came out beautifully. But at the first infill stages, it got ugly like blobby and stringy. I ended up slowing down to 50% print speed and it seemed to help. But when I tried to remove from the print bed, the thing broke on those first few infill layers. Good news - the circles and shapes pretty much came out prefect - there was no x-y shift or x/y belt/motor skipping which is what the person who gave away the machine was complaining about. I am going to post some pictures in a bit. I am thinking basically that the failure to load had something to do with the Bowden tube, but I'm not sure. It seems like maybe the filament was getting stuck on the lip of the teflon thingy after exiting the bowden, but I assure you I use all the force appropriate to cram that bowden tube all the way down in the print head. EDIT - ADD PICTURES (1) chewed filament that failed to enter nozzle on "change filament"... got hung up and just litterally chewed a bit out of it in <1 second. (2) MINI-CAL (broken)

Servicing one today that was a mess. It had been serviced before (as the adjustment screw was on top of the housing due to incorrect reassemble) but the fact is it was grinding filament and I expect fixing the tensioner adjustment screw will help but it still seemed to have a lot of slop in the bearing. Like almost 0.5 mm of play side-to-side. EDIT: *** JUST TO ADD, I assume this is the original gear, and the machine has about 2800 print hours on it / 2400 ft of material extruded. So would that be still inside the normal service life on the original extruder assembly? Also, is it possible to save the burred gear and just replace the bearing? It doesn't look particularly serviceable but you never know...

There is a product called "belt dressing" that is used for squeaky automotive belts ... it may be similar to some kind of silicone grease, but that would be my go-to as silicone grease is insanely expensive, although we use it on 3D printer parts thinking that's normal pricing. As for where to get these parts, it seems like most things, the way they are officially sold and supported is in pre-assembled "packs"The "sliding block kit" in this case consists of the belts with the plastic blocks and the springs already assembled. And it's $40 at fbrc8 for a complete set of 4 (elsewhere $11 for 1), not insanely pricey, but more than you should have to pay for two belts that should be about $3-4/each at a hobby shop. Too bad the hobby shops all closed down. For my 2c, I would just get the belt -- I think it's 303 tooth, GT2 6mm width?) If that's the right one, then they are 6 CAD here: https://3dprintingcanada.com/collections/timing-belt-loops/products/gt2-6mm-timing-belt-loop-616mm -- anyway once you find the belt, recycle your bushings, spring and blocks to assemble the loop ( and you'll be all set. As far as buying from Aliexpress, where do you think all the come from anyway? Maybe if they use a belt from China and sell the assemble as a whole and call it made in UK, but it's still just a made-in-china belt. If I'm wrong about that and somebody in the UK is making these belt lay-up's, then I apologize in advance.