FalmouthLouis

I've just had the same problem. It was an overnight print. Something slipped on the plate,with the result that I have this badly bunged up print core. I had this happen once before, some six months back, and that involved nylon so all I could do was get it repaired by Ultimaker/3DGBIRE. This time around, the blockage is PLA. I did a bit of work with a heat gun, and started to be able to strip away bits on the congealed mess. Clearly, it will take hours to clear the major blob, but is it worth it because, the closer I get to the actual print core, surely my heat gun will be damaging the electronics and producing subtle distortions. Has anyone successfully cleaned up one of these messes? If so, how did you do it?

I collaborated with an Exeter University researcher who ran tensile tests on 15 variants of the same design. There was clear evidence that the tetrahedral pattern was seriously stronger than the grid pattern. So I remain interested in the extent to which the Ultimaker design team have evidence about the relative performance of the varied infill patterns

Thanks GR5. What you say about retraction intensity and print core reliability is very interesting. I'll do some thinking and checking.

Every so often I have a long print fail because the drivers at the back of my UM3s stop feeding the filament through - instead they just eat into the filament so that all forward movement stops. This has just happened to me about 75% of the way through a 2 day print. This was despite the fact that I had been checking every couple of hours that the filament was hanging loosely on the spools at the back. I put prints on hold over night, and that was not an issue. There was no sign of a filament tangle. Since I didn't spot that something was going wrong until several hours after the breakdown (breakaway scaffolding was still printing happily), I can't totally guarantee that the PLA reel had not been offering too much resistance at the point of the failure. I have a sense that having two spools running simultaneously at the back of UM3s causes problems because (i) there's a fair amount of resistance as the spools rotate and (ii) the far spool is being pulled forward as well as rotated. So, if I want to improve the reliability of long prints, will I need to think about one of those systems whereby the filament is fed upwards from below? If so, what is the most cost effective recommendation>

Just for information, using my UM3, I've had decent results for Bronzefill and Copperfill, using fairly simple 90 minute designs. I used the PLA defaults with slight tweaks. Brassfill was unfriendly. I almost had to use a hammer to get the print off the printbase. In the course of doing this, the print fractured in several places.Then the unused filament refused to unload itself, and snapped when I used pliers to try pulling it out of the Bowden tube, so I was left with a totally blocked tube. To be fair to Colorfabb, they do indicate that Brassfill is a work in progress, which has particular problems with the wider Ultimaker filament standards.

I've got test lengths of Colorfabb's ###fill series - bronze, copper, steel, wood, cork, brass and glow. I know thay some of these are very tricky to print with, but I just want to print out small test items to allow clients to get a sense of what the different surface finishes are like. I could print on either a UM2 or UM3. I have found the basic print settings which are advised for each of these. Cura doesn't seem to offer specific profiles for these filaments, but do these exist in a form which could be imported into Cura? If not, what's the best way forward? Currently, I.m thinking of creating individual material profiles for each filament within Preferences, then using Print Setup to create profiles with more subtle settings such as print flow rates. Does that make sense? Or am I missing something in Cura where all this can be setup more simply? Finally, if I go with my UM3, I will be very careful to keep the printcore clean. Do any of you have any wider advice based on experience of printing with these filaments?

Using Cura 3.4.1 I seem to have lost the ability to show quite a number of items in preferencies. Specifically, I want to be more precise on Retraction distances but, in the information in Configure/Preferences I am told that it can't be shown because of the vlues in my G-Code Flavor. I am asked to change values in this flavour, but I can't find any sign of where I do this. The reason I'm asking is that I seem to be stuck with a Retraction default of 4.5 mm on my UM2 which seems to be producing some unwanted stringing. I want to experiment with some different retraction differences.

I've now had a bad experience with Breakaway supporting a relatively delicate structure. The item below was printed in Polycarbonate, but had relatively thin walls. I was probably too cautious and printed this with scaffolding both inside and outside the structure. As a result the final print was pretty well enclosed with Breakaway. I left if for a week before I started the clean up, which may have allowed the Breakaway to harden more than if I had tried this right after printing. On the right below, you will see the damage I did as I tore Breakaway off the print. if you compare the picture on the right with the picture on the left, where I was more successful, you can see how the dividing columns between the circular openings got broken away. What you also don't see from these pictures is that the structure ultimately sheared horizontally along a mid line, as a result of some of the force I had to use. Towards the last third of this tidy-up I was starting to refine my techniques, and could probably have reduced the damage I did. However, this has just convinced me that soluble PVA may still have its uses when I need to support relatively fragile structures.

This problem has gone away, and, after rebooting my laptop, the installation went OK. Having said that, the problem showed itself on Friday and, again, this evening (Sunday). I'm pretty experienced in handling these downloads, and something had me beaten,

I've tried downloading Cura 3.4.1 a number of times and, after it has unstalled the earlier version of 3.4, I get the following If I press Ignore, I get the same message regarding the cura.exe file. Any suggestions as to what may be wrong?

In the academic literature about the strength of 3D prints, there is some debate about the importance of narrowing the air gap between the lines of filament. I can't see anything in Cura's preferences which would allow me to control this. Am I missing something? As a matter of interest, if one takes the default settings for printing with a .4mm nozzle, what kind of gap is there between the lines? If I reduce the width of lines, which does seem to be permitted, the gap between lines will presumably increase. What would happen if I increase the line width from the .35mm default setting nearer to .4mm? Can I assume that any air gap will be reduced? (This is for a project, which I've mentioned elsewhere, where we will be doing tensile testing on 12-14 variants of a standardised test specimen. I'll report back on the findings when they come in)

Thanks for the various comments. I'll do some servicing on the Z screw out of interest. I suspect this is mostly an infill issue, so I will experiment with gr5's advice. What's with your point about the variable infill feature?

As my PLA prints grow in height, the nozzle increasingly seems to drag across the print surface, making enough physical contact that I can see the print plate actually vibrating. I know this happens with my UM2s, but I think it also happens with my UM3s. Last night, I observed this phenomenon on the print job photoed below. I was using a UM2 and PLA, with a .8 nozzle, printing a .2 layer height. It prints the wall OK. It seemed to print the structure of the infill OK. However, whenever it did one of those rapid repositioning moves, the vibration and sound of contact were very notiecable. I was observing this around hour 5 of this particular job. What's happening here? Is the print somehow expanding in size as the job continues? Are there any settings which I should be tweaking to get the nozzle to give the print surface a bit more leeway? Do infill patternshave any bearing on this?

I would like to add to this. I have a UM3 and UM3E in a workshop about half a mile from my home. What would I have to do to be able to monitor them at this kind of distance?

Thanks to you both. I understand about pause-at-height, but all I wanted to do was schedule my time so that I could observe these transition points as the printing went through them. Without knowing what layer the printer has got to, I may find myself taking on confllicting tasks around the time the printer is due to pause. @Y: that idea of estimating the print times sounds manageable. Knowing that a key point is likely to come, say, around 2 hours 10 minutes into a print, would satisfy my needs on this occasion. Incidentally, PVA on PLA worked fine on this occasion.

There are two distinct issues in this posting: I've got a 24 hour print coming up, with a tricky interior structure, which will twice require PVA to be deposited on PLA. In Cura's layer view, I can see the layers when this PVA-on-PLA action will take place, and I would like to be there to monitor these two stages particularly closely. Is there a way with a UM3 to keep a check on what line number one has got to? I realise I could get the print to pause at the relevant levels. Alternatively, can I monitor the height of the printed structure in mm? Am I right in assuming that PVA does not always deposit reliably on a PLA base? If this is true, what precautions can I take?

I would like to amplify this query. Every so often, I have had filament snap around the entry to the feeder. Sometimes the cause will be clear, in that the filament has become tangled. On occasions, though, I get a sense that the friction involved in turning a full reel of filament may be enough to trigger a snap. I particularly feel this with the outer reels on UM3s - those which feed into Printcore 1. I've recently had this happen with loose filament which hangs loosly round an empty reel. On a recent long print, I loaded 50 coils (say 40+ metres) of new PLA, taking great care to ensure that the coils would not get tangled. It snapped after using less than 10 of those coils. When I re-inserted the remaining 40 coils, the print ran totally smoothly, so tangling was not an issue. I'm pretty sure I've never had a simple break like these when I've printed using 10-20 metres of loosely hanging filament, draped round a reel. Is friction a serious issue when one is dealing with longer runs of filament?

gr5 - that's very helpful. I never thought about how the collet actually worked. I shall look for those blades tomorrow.

I've been doing some 10 hour prints on a UM2, using a .8mm nozzle and printing layers of .2mm. Jobs have failed twice with the bowden tube becoming disconnected from the print head, with the result that filament has just been pushed through into empty space. I've been printing for 3 years and this is the first time this has ever happened to me. The tube was fed into the print core in the normal way, with the little blue clip holding the white bit up and seeming locking the tube in place. Before the second print, I specifically checked the tube and I confirmed that it could not be pulled out. I'm also pretty sure that it had been pushed right down. Certainly, there had been no problems when I reloaded filament at the stat of the job. I was checking these jobs about every four hours, so I did not pick up any advance notice that this was going to happen. So what on earth might have caused the bowden tube to pull out of the print core in the middle of printing something which should just have involved continuous printing? Could it be something to do with the volume of filament that I was printing - wide nozzle, thick layers? I was using one of the 3D infill patterns, so might they be posing issues? It's a machine which I've had for three years, and I can't remember if I've ever changed the Bowden tube so, might the age of the tube be an issue?

This issue matters to me as I'm trying to test the impact of assorted print variants. One variation we want to test is on differing infill patters. As far as I can see the most recent details of what the various infill patterns consist of is on https://ultimaker.com/en/resources/20416-infill . These are now outdated, The options in 3.3.1. are more numerous and at least one of the older names (tetrahedral) has disappeared. Where can I find an updated explanation of the various infill patterns? ..... and which of these patterns should give strongest tensile strength?

Brulti: This dragging noise is something I've had using both UM2s and UM3s. I work with an open front, which might be a factor. I take your point about perhaps not needing a priming tower at all. My experience of an 80 hour print involving PLA and Breakaway left me feeling that I would trust Breakaway to behave itself. I've done a separate report on my experiences on this print, which you can find elsewhere on this site. Just search on "Breakaway"

I thought that that was what I was doing when I went into the maintenance directory. I probably won't be able to have another go at the log for a couple of days (traveling)

Over the last six months, I've sometimes blocked a nozzle when under pressure and it has made more sense to quickly change the nozzle than to go through the whole Atomic clean process. I also have one BB print core where the PVA has just refused to flow however many hot or cold cleans I do. I now have a heat gun and an assortment of fine needles and probes. My machines are busy enough that I would like to clean these nozzles without being dependent on finding gaps in print schedules. At what temperature do brass nozzles get damaged? Same question for the BB print core, though this also has electronics inside which I assume could be damaged. Any advice out there?

It's saved as one of those gz files which isn't accepted in this system.

(I had versions of this problem last week) This morning, I started a new print. Automatic Leveling activated and decided the print cores were not alighed. Before I took any further steps, it tried to start the print again, going into automatic leveling, with the same result. Even when I switched the machine off and on again, it immeidately tried to start printing with the same Leveling failure. I must have had five levelling failures in a row without my being able to pause things to assess what to do next. In between all this, I cleaned the print bed and the tip of the print cores and it eventually decided to print. The point about this is that the machine/software takes on a mind of its own. I downloaded the relevant coding dump. How do I get that to you?