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geert_2

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Everything posted by geert_2

  1. Yes, I have seen it, good. Reachability is key. :-)
  2. At thicker layer heights, and at higher speeds, you have to extrude a lot more material in the same time, so internal nozzle pressure will be a lot higher. So there will be a lot more "overpressure" stored in the feeding traject that has to be released when the printer slows down. When printing slow and in thin layers, there is very little pressure build-up in the nozzle. I guess...
  3. I have tried annealing PLA (Ultimaker) and PLA/PHA (colorFabb), by very gradually increasing temperature during the course of several hours: 50...60...70°C in my laboratory oven (=Binder: incubator with range up to 99°C). Especially the Ultimaker Pearl filament gets clearly harder and stiffer, and the sound when dropping it changes in pitch: it gets a higher and less dull pitch. This gave maximum 10°C higher temperature resistance, thus still not enough for use in the car, nor for letting it sit in the car in hot weather. That is why I tried it, to see if PLA prints and demo-models
  4. My personal viewpoint on software - any software - is to keep using it as long as it is stable and I am happy with it. I can do everything I want with an old MS Office 2000, so if I wouldn't need to be compatible with others, I would still be using that since I like that way more than the horrible "Ribbon" mess from Office 2007 onwards. Idem for a very old image editing program and a couple of others. I keep using old hammers and screwdrivers too. :-) Only things like VLC and browsers need to be updated to get the best performance (video formats) and best page display and security
  5. This is fairly common with polyesters (PET, CPE,...). Some people advise to use glue, in the hope that the glue layer will break instead of the glass. But for me that didn't help, my glue was too good. So, just like you, I also heard the glass cracking while it was still cooling down. Now I use my "salt method": wipe the glass with a tissue moistened with salt water prior to printing, which leaves a thin almost invisible layer of salt stuck to the glass. For PLA the salt method greatly increases bonding (compared to printing on bare glass) when the glass is hot, but there is no bon
  6. I don't know your printer, but this looks like too much mechanical play in the system? Things wobbling around? But I would rather guess the X or Y-axis.
  7. If you want very accurate temperature control, you might want to go to laboratory equipment: there do exist lots of ovens and incubators (=breeding machines) in several temperature ranges. I have one that goes up to 99°C, and one that goes up to 200°C. The point is that they shouldn't have a too big overshoot, which would melt the model. Some models have computer control, where you can set desired curing times and temperatures in stages. Also, dental lab equipment might work, such as the ovens used to cure prostheses which can be pressurised. But I don't know how stable control is.
  8. I do have experience with moulds for silicone printed in PLA, but not in PVA or breakaway. The biggest problem, even with "correct" moulds with slanted sidewalls and no undercuts, are the layer lines. The silicone gets stuck into these, causing a very firm grip, which makes it hard to remove the model from the mould. You might also have this problem with breakaway. Most silicone can withstand 250°C for a while, so another option would be to use PLA, and then heat it up and peel away or melt away the PLA at around 100...150°C? If you would use PLA, "smoothing" i
  9. I haven't used TPU yet, but I vaguely remember others saying that soft plastics are hard to print, because they tend to get compressed and stuck in the bowden tube. Some say you need to print it *very* slow (to not compress it), and some oil the filament (to reduce friction). But I don't know the details, so try searching on the forum. Also, a nozzle temp of 135°C seems very low? Could that be a typo, and should have been 235°C? If you would really print at 135°C, that of course would cause underextrusion.
  10. Actually, I sanded a standard injection needle of 0.41mm diameter down to 0.39mm, so I could use it to poke into the nozzle from the bottom, to clean it. That was its original purpose. After sanding, that needle's diameter gradually transited from 0.39 to 0.41mm. Measured with a good quality Mitutoyo digital calipers, +-0.01mm. Also I cut off and rounded the sharp tip, to prevent damaging the brass nozzle (see photo below). Even the soft steel of this injection needle is much harder than a brass nozzle, so you could easily damage it. The ability to measure the nozzle-di
  11. @yellowshark: You can overcool by blowing compressed air directly on the nozzle tip. This cools down the nozzle too much so it can not keep up heating, and generates a "temperature error" (I don't remember the exact description). I had that once in my overhang-tests, where I was testing the effect of additional cooling on the quality of bridges and overhangs. This was on a standard UM2 (non-plus). I think layer-bonding could also suffer, similar to printing with ABS without front door and too much fan, but I haven't tested bonding strength, so this is a bit guessing. Ho
  12. While there could still be underextrusion (hard to see), that alone would not cause the rounded corners, I think. Too much cooling would rather cause no layer bonding, and thus splitting layers. But the shape would more accurately follow the nozzle-path. Yes, putting a desktop fan in front of the printer at its lowest speed, and maybe 1m away, is worth trying. That would give a nice gentle flow.
  13. I made a quick drawing to illustrate how I understood it ("a picture says more than..."): 🙂 It does not really matter what the diameter of the nozzle is: it just has to be able to fill the gap with molten plastic. And that gap is: line-width x layer-height x line-length (=red bar in the drawing). Although of course a 1.0mm nozzle can't draw a line of 0.4mm wide, and neither can a 0.1mm nozzle. So nozzle-diameter and line-width should be about the same, both about 0.4mm, to get decent results. The extruder has to push that volume of filament through the nozzle. In calc
  14. I have done line-heigths of 0.4mm with a 0.4mm nozzle (=the only nozzle-size on my UM2), just for experimenting, and I started to see a bit similar deformations. Corners got rounded more than at lower heights, and it didn't cool well and deformed. From left to right: layer-height = 0.4mm, 0.3mm, 0.2mm, 0.1mm, 0.06mm. Top row = 50mm/s, bottom row = 10mm/s if I remember well. Each block is 20mm x 10mm x 10mm. This one is printed at 0.4mm layer height, 0.4mm nozzle: The next one is 0.06mm. (Also, you see it starts to discolor due to sitting too long
  15. Two top layers is not enough to fill the roof smoothly. You probably need 4. Further, on such a small object, I think it is not getting enough cooling: these thick sausages don't cool down and stay molten for too long, so they get dragged along and get deformed. Plus there is the hot nozzle sitting on top of this, radiating heat and preventing solidifying. You will need to print multiple models at the same time, and bigger models. For a 1mm or 1.2mm nozzle, it will be hard to print details finer than ca. 1.5mm. This is a guess, but it won't be far off, I thi
  16. This took me some time to understand, but as I see it now, it is the *printed* sausage that counts, not the nozzle. The extruded amount has to fill the printed sausage. So, ideally if there would be no air trapped between the sausages, and at 100% infill, it would print perfectly *rectangular bars* with dimensions: line-width x line-height x traveled distance. I guess that is where this calculation comes from? The nozzle-opening limits accuracy: too wide, and it can't print fine lines; too narrow, and it can't extrude enough material. Is this correct?
  17. Since today there is no link to the forum ("Community") anymore on the Ultimaker website. So, for people who don't have the sublink "https://community.ultimaker.com", from which the forum is still reachable, it seems to have completely disappeared. Probably just a glitch that has been overlooked? Could you have a look at that and repair the link? Thanks. PS: my browser is a standard Pale Moon, which is a Firefox split-off that has kept the traditional menu-structure and status bar, like in the good old days before Firefox went evil à la Google. Pale Moon is a very stan
  18. The overshoot on the corners is most likely mechanical: oscillations and vibrations because the printer head can not immediately stop and change direction. Plus it will extrude a bit more material per mm while the head is slowing down, compared to printing straight lines. This effect can be reduced by printing slower, and by changing some settings, although I don't know which ones (never experimented with that). I have no idea about the shift. Can you see that shift in the layer preview in the slicer, when zooming in a lot? I guess if you move that transition from strai
  19. In future posts, it is best if you place the pictures directly in your message: you can drag and drop image-files (JPG, PNG) from the Windows Explorer directly into this message-board. Not everyone is willing to follow unknown links. I believe your intensions are good, but we all get too many spam mails with links to virusses, and fishing mails, so people tend to become cautious. That said, I am not using the same Cura version, and I always design my custom supports in CAD too, so I can't answer this question.
  20. Controleer ook eens of de printkop nog soepel beweegt, door hem manueel over en weer te schuiven (met de printer uit natuurlijk)? Dit voor het geval één van de lagers geblokkeerd zou zitten door vuil, of er iets tussen de riemen zou zitten.
  21. Did you clean and oil the X and Y rods, so they move very smoothly? More friction could also lead to more noise. On one of my UM2, I once had a belt rubbing against the flange of a pulley, but that made a squeeking sound. After I carefully wiped the edge (only the edge!) of the belt with chemically inert silicone grease, the noise went away. Don't use petroleum oils or grease on rubber, this may damage it. Only use inert lubricants. And don't get it on the teeth: it could make them slip.
  22. This is severe underextrusion, caused by not enough material flow. But there can be a lot of reasons: blocked nozzle due to burnt residu, dirt particles in the nozzle, kinks in the filament which prevent it from moving well through the feeding traject, spool not willing to unwind for whatever reason, printing too fast, too cold, and probably many many others. User gr5 has a good video and info on this, search for it. I guess the flow in your model is only ca. 30 to 50% of what it should be, once the problem occurs. See the photos of the tests I did a couple of months ago (flow-rate
  23. If it is only in the back corner, and it was not earlier, maybe you could have a look into these: 1) Is there something stuck under the glass, so it bends upwards? Sand, dust, a burr around one of the holes in the aluminum plate, or so...? 2) Or did the glass itself deform over time? Try rotating it 180° clockwise and see if and in which corner the problem remains? 3) In the left back corner, the filament has to make a very tight bending to get through the bowden tube. This may cause a lot of additional friction in the bowden tube. But it may also cause extr
  24. Probably not the answer you are looking for, but an option you always have is to design any supports directly in your CAD model, and switch the auto-generation off. Then you can customise it to your specific needs and design-in all stability and other features you need. For example in these tiny models, I can not get in with a knife to cut the supports loose, so I need them (=orange and red parts) to extend from the model to grip them with pliers. And due to the relatively large overhang and tiny ground-surface of the supports, I wanted to give them some custom brim for more stabil
  25. For an immediate solution, yes. For a long term solution, I think it might be worth looking further into the idea of drying on the fly, but then over a much longer path, and with a means of evacuating the released moisture. And with a means to cool the filament down again after dry-heating, before it enters the feeder. If PLA would enter the feeder at 50 or 60°C, it would get totally deformed by the feeder wheel pressure, and would cause grinding and/or blocking in the bowden tube. So, after the heating and drying cycle, there needs to be a cooling cycle too (without moisture enter
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