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geert_2

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Everything posted by geert_2

  1. If you are printing near your printers maximum, then the slightest bump can cause skipping steps. Overhangs often tend to curl up, so that can be enough to trigger it. At slow speeds the force required to accelerate and move is far less, so the printer has more margin before it skips steps. Maybe try a small test print with overhangs and other difficult stuff, and on the fly change settings up to the point where it starts skipping (or underextruding or whatever else problem comes first)?
  2. That is very severe underextrusion, which can have a ton of causes: partially blocked nozzle, worn-out teflon coupler, bad little nozzle fan, dirty feeder, too wide filament, friction in feeding traject, printing too cold, too fast, etc... Search for the whole list made by user gr5 on this forum (I don't know it by head), which has excellent info.
  3. Yes, I have seen it, good. Reachability is key. :-)
  4. 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...
  5. 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 would survive transport and storage in a car in summer. Not. Also, during heat treatment, the models tend to warp, and shrink in length. So they need to be clamped down. And mating parts will no longer fit. It might be usefull for artwork to releave some of the internal stresses, but not for mechanical objects with precise dimensions. So for PLA it isn't worth the effort for me. Printing in PET is a better option. I have no experience with nylon or high-temp materials. Light-curing 3D-printing materials used in optical printers (with lasers or beamers) get a lot stiffer after post-treatment. During the initial curing phase in the printer, only a portion of the material reacts to the light and cures. During the post-curing treatment (sometimes heat, sometimes UV-light) a lot of the remaining uncured resin also gets cured. The result is that it is far less susceptible to creep deformation under load, but it can get very brittle. If you do not have an oven, you can use your 3D-printer for annealing by putting the model under a cover, and let it sit overnight with the bed at elevated temperature. If you are not sure if annealing works for you, it might be a good idea to try it in this way first, before investing in an oven. If not done very carefully and slowly, or if going over the limit, the models will soon warp (the top one was at 80°C, PLA, just for testing). Sometimes they first warp upwards, and then after a couple of hours start warping in the other direction (second one). Weird, and I have no idea why. This sort of models will no longer fit and slide well after annealing: the stem of the spoon shrinks in length, but expands slightly in width and height. Also, the ruler in mm is no longer correct. The Binder oven I use:
  6. 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 (browsers). Concerning slicers, it might be a good idea to keep a couple of stable old versions on your computer, and install a newer version parallel to it, if you need some of the latest features for some prints. Then you have the latest stuff, plus a fallback. Especially if you have a printer with dual nozzle, the area where the most progress is. But that is just my personal preference, based on my needs. Feel free to see things differently.
  7. 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 bonding at all when cold. But for PET the salt method slightly reduces bonding, so the glass doesn't crack anymore. Now the model separates from the glass in the salt layer, as desired. Disadvantage is a bit more risk of warping, so I print with no cooling fans. I only use glue now if I need a lot of cooling fan for printing overhangs.
  8. 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.
  9. 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. But these are all expensive. Maybe there do exist hobby ovens for moulding and casting too? Try googling for that? If have seen big vacuum equipment and mixers for hobby use, so it would surprise me if ovens would not exist. Some silicones, epoxies and poly-urethanes need heat to cure.
  10. 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" is highly recommended. This reduces the undercuts in the layer lines, and tends to fill and close tiny gaps. See the thread of user cloakfiend on this forum, where he has done an enormous amount of tests, with excellent results. I don't know if breakaway can be smoothed. If using PVA, smoothing should be possible with water, so you might want to try that on a test piece: it will probably be required to close the gaps and remove irregularities, because PVA seems to print less smooth than PLA. Further, there do exist dedicated mould-making filaments, but I have no experience with them. This you will already know, but I add it for other people not familiar with mould making or silicones: if you make a mould from multiple parts (the A and B side of the mould), make sure to seal all gaps, because the silicone will leak away through the tiniest openings, even if only microns. And provide a way to let air escape while pouring or injecting the silicone. Entrapped bubbles are another common problem.
  11. 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.
  12. 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-diameter was a nice side-effect. :-) First I measure the needle diameter at several spots, and then gently (!!!) push the needle into the nozzle and see how far it gets. At the very beginning, I could only get the nozzle in once it was 0.39mm. Even 0.40mm didn't go (+-0.01mm). Now, a couple of years later, it easily goes in all the way up to 0.41mm. So the nozzle clearly has worn-out a bit, from mainly printing white PLA, which seems slightly more abrasive than other colors, maybe due to filler particles? But it still prints fine. But any thin wire strands, like copper wire, should also work. However, for calibrating the flow, I just dial the flow-rate in until it prints nicely, and that is my setting (e.g. 105% for a certain material). I am not saying this is a good approach, but it works for me. :-) So I don't actually usethe nozzle diameter, nor do any calculations. At the time when I studied electronics (ages ago...), transistor component specs could easily be 100% off, capacitor specs also, and resistor specs were usually 5% or 10% off. So we learned not to care about accuracy while calculating things, it made no sense anyway, but to get the order of magnitude correct. And then we provided good feedback for stabilisation (most important), and a potentiometer for calibration if that would be desired. I still think that is a workable philosophy for subjects with lots of often unknown variables, like 3D-printing. You could calculate flow up to 0.01% accuracy. But then if there is some unknown resistance somewhere in the feeding traject, the indents that the feeder wheel makes into the filament could stretch maybe 20%, from square-shape to diamond-shape, causing an error of 20% in the feed rate. If filament diameter varies with 0.1mm (3.5%), cross-section surface varies with 12%, and so does your feed-rate. So whatever method you use, if it works for you and you are happy with it, I think it is a good method. See the photo for the needle (ruler is in mm and cm): While we are at it: to clean the internals of the brass nozzle, I have a soft brass M3 thread that I use as a file to gently scrape the side-walls. This too has a rounded tip at the bottom to prevent damage. This doesn't really measure anything, but if it has difficulty going through the teflon coupler and/or the brass area of the nozzle, there is accumulated dirt, or a deformed teflon coupler, which could cause extra resistance and negatively affect the flow rate. So this gives a rough indication if the feeding traject in the print head is clear enough to let filament pass easily.
  13. @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. However, putting a 30cm desktop fan (like those used in hot summers) at 2m in front of the printer, at its lowest speed, gave excellent extra cooling without triggering errors for PLA. @paulrhee2002: I do see some horizontal gaps, but I am not sure if this would be underextrusion, or the lower layers sagging due to still not enough cooling? I would guess the last. While it is printing, maybe try poking into the model with a tiny pin or screw driver, to see if it is hard or still weak? Keep watching what happens (don't let this print unattended). I still do think two top layers is not enough, unless you use +70% infill. But then that would greatly increase cooling problems, since all that infill-heat has to be removed too. At such thick layers you are faced with the dilemma that you need lots of heat to get enough plastic molten in time, but at the same time due to the thick layers, you can't remove the heat from the print fast enough. When using only two top layers, the first one is going to sag a bit, and the second one can't fill up all the gaps. I would suggest you try 4 top layers and compare. Since this is an area where we have no experience, you will be pioneering a bit. So keep posting your results, they are very welcome.
  14. 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.
  15. 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 calculating how far to move the filament, it will have to consider the filament diameter 2.85mm, travel distance of the filament (e-steps?), and maybe losses due to "partial slipping" in the feeder. I think...
  16. 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 in the nozzle at elevated temperatures, even though I printed it below the recommended temp range. Material is PET.)
  17. 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 think. :-)
  18. 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?
  19. 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 standard browser that follows the HTML- and CSS-specs as closely as possible, thus any standard compliant website should work. So I don't think this has anything to do with my browser? My operating system is Windows 7, but that shouldn't make any difference for websites either.
  20. 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 straight to rounded corners up and down, the shift also moves? If you look close while printing, does the printer change direction at that point, from clockwise to counter-clockwise, or so? In which case it couls also indicate a mechanical problem such as too much play?
  21. 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.
  22. 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.
  23. 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.
  24. 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 in percent, in black marker on the model). This model is quite small: if I remember well, the left block was 10mm wide and 5mm high. Made on an UM2 (non-plus).
  25. 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 extra friction in the nozzle itself, since the filament enters the nozzle under a different angle, compared to printing in the right-front area (at least on Ultimakers, but this could be different on other brands). When printing hard filaments like PLA, this is an issue on old UM2 printers (non-plus). I don't know if it is also in other models. Disconnect the bowden tube from both ends, and try feeding filament through it *manually*, with the head in various positions (front-left, back-left, center, back-right, front-right), and feel if there is any difference in friction? 4) If it is also on other areas: maybe a bad spool of filament, or different brand? Kinks in the filament? Or any other changes in settings (speed, temp)? Or the spool is nearly empty, which adds a lot of "anti-unwinding resistance" to the feeding traject?
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