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geert_2

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Everything posted by geert_2

  1. This looks like severe underextrusion, which could be caused by a lot of factors: too low temperature, partially clogged nozzle, worn-out teflon couplers, incorrectly mounted bowden tube, dirty feeder, slipping feeder due to wrong tension, too high speed, wrong filament diameter or setting, too much friction in the whole feeding traject, spool wound too tight (often when almost empty), material decomposing in the nozzle, way too moist, and so on. Somewhere on this forum there is a good list of causes (but I don't remember the name exactly), or google for underextrusion causes on th
  2. The cones can not solidify because the hot nozzle (200°C) is continuously on top of it, and it keeps radiating heat, so the model can't get below 50°C. The "dummy cooling tower" allows the nozzle to be busy for some time, far away from the object, so then it has time to cool down. This greatly reduces this overheating deformation, but it does not totally eliminate it. In very small objects you might still run into it. This is another picture showing the effect: they are 20mm high. The ones printed standing (left, printed in different temperatures and speeds) are deformed due to ins
  3. Even if you could get it to print, you are likely to run into cooling issues, like this below. Unless you would print multiple parts next to each other, or with a dummy cooling tower next to it (=the square blocks in this picture). An option might be to make the walls 0.5mm thick, so they print well on a 0.4mm nozzle, even after converting to STL. And then manually drill out the hole with a separate drill chuck. But it won't have much strenght. I don't have a 0.25mm nozzle, so I can't comment on that. Maybe you might want to search for a totally different so
  4. In my experience, normal PLA gets *much* harder and stiffer after a year, which is a disadvantage if parts need to flex a little bit (like the carabiners above). While PET keeps its original flexibility. How does tough PLA behave in this aspect in the long term, in your experience?
  5. I recommend that you experiment with various concepts on small test models, to see what works for your application. In this spool holder for my UM2 printers, I use several different mechanisms: - Two snap-fits for the main holder (cyan part), where it fits into the printer, just like the original. This snap-fit has long travel-ways, and the openings in the printer have a lot of dimensional tolerance, so it is not likely to break. - The pins (red) are clamped and kept in place by other parts. - The rotating head and bearing are mounted on the main house with a big ino
  6. If you are on Windows, I would suggest you try DesignSpark Mechanical for editing: this is also free (just requires registration) and is much easier and more stable than FreeCAD. There are a lot of good tutorials on Youtube. Have a look at them and see if you like its concept. Or try any of the free online-programs (I have no experience with them). Then for mounting, in my experience: For multiple-part objects, I often mount them with nylon screws and nuts. Provide the holes and hex-indents for the nut and screw in the model, so they sit recessed and are easy to assembl
  7. When giving lessons or presentations in front of a public, or when doing electronic exams, or research projects or production runs, you definitely don't want automatic updates interfering. Stability and predictability are key. So, for me only manual updates, no automatic, even not optional via settings. Very often the default is "yes", and if you forget to reset this after a manual update, next time you're in trouble. I remember the Firefox 29(?) disaster, the Windows 7 to 10 auto-update disaster, Adobe- and Windows-updates in the middle of lessons, updates in the middle of exams o
  8. If you purge more, for example by printing ten lines of skirt, doesn't it come through? Or if you manually purge a bit of material before the print? Or is that blob sitting in the way and somehow blocking the movement of the filament?
  9. I usually use "Fine", which suits 99.5% of my models. Only for big balls or smooth curves this gives a bit of visible segments. If this is a problem, I would take "Custom" and select lower values. In DesignSpark Mechanical, after exporting to STL, you can import that STL again, see the segments, and compare it to your original model. And so finetune your export-settings before beginning the slicing and printing.
  10. Bubbles are caused by gasses, could be water, could be others. Ethylcellulose, does that contain alcohol, or chemically bonded alcohol, ether, or something similar? If so, could it be that the alcohol/ether evaporates, or the compound is broken down into its basic substances (alcohol + cellulose, or whatever the composition is)? That might explain both the bubbles and the poor extrusion / clogging. Maybe you could heat a bit of filament to the same temperature with a soldering iron, or on the outside of the nozzle (not inside, so you don't clog it), and see if and how it decomposes
  11. Yes, the last two ones remind me of the time we lived in Jurassic Park. :-) They could as well be real fossilized dino skulls in a swamp.
  12. I haven't printed with ABS and CPE, but I did print several models with PET, which is similar to CPE, I think? If the model allows it and there are not too much overhangs, I always print PET *without any fan*, and slow (25...30mm/s). This gives best bonding to the glass, no warping, and best clarity. Never had any layers splitting. For small models, I print PET on bare glass, or glass wiped with salt water. But for big models, I would rather use dilluted wood glue for PET. I don't know for ABS. If the standard brim does not provide enough force to keep the edges of the
  13. This reminds me somewhat of my cooling-tests (colorFabb PLA/PHA): When printing rather hot and on small areas, the surface does not get enough time to cool down, and the nozzle above it keeps radiating heat. So the model stays molten and it gets this weird overextrusion effect. Adding a dummy cooling tower (right models) reduces the effect, but does not eliminate it. The blobs tend to accumulate more on one side. Another effect that I see on overhangs, is that the overhang curls up, and then the nozzle bangs into it and pushes it down again. This also gives an
  14. Most likely this is a case of two directories having the same name, but sitting in a different location? So Windows Explorer sees one directory, and Cura the other? For example a file downloaded to the folder "downloads" of user Jeff, and Cura searching in the "downloads" folder of user John? Try using old "known-good" files you made yourself. Then try moving the unwilling files to a known-good location, like the desktop, or your own "downloads" or "documents" folder. But occasionally, Windows relocates files behind your back (without telling you) to another directory i
  15. I have printed quite a lot with colorFabb white (and other colors). Last time I ordered, they had two versions: standard white and blueish white: the standard white was a little bit creamy and warm white, definitely not snow white; while the blueish white had a faint shade of blue-grey. I guess this warm shade in the standard white is caused by their base material PLA/PHA ("naturel") also being creamy, like uncooked spaghetti. Both whites print okay, although not as smooth as colorFabb traffic red, dutch orange and naturel. But better than their signal yellow and intense green (spring green).
  16. What you can always do is design all brim (and all other support features) in your CAD design. And switch off any automatically generated brim or support in Cura. Then you have full control over the shape and you can optimise it to your specific needs. For example, sometimes more than one layer of brim might be desirable to prevent the object from coming off the glass, especially if the brim is too flexible and when printing at low layer heights and 100% infill. Or you might want to connect all brim parts into one big plate covering the whole glass for more stability. Or you might want to add
  17. If the model is designed in SketchUp, probably its walls are no solid walls, but rather a sort of "folded paper" models with gaps where the walls are glued together. Just like any paper model we glued as kids. Instead of a solid model, it is a bunch of surfaces that don't fit properly, so it is not a solid, and not watertight. You also see this problem when drawing text in SketchUp: some characters do not close. These gaps may be very hard to see, and you may need to zoom in quite a lot. One solutions is to manually and carefully select each vector and each edge, and carefully alig
  18. Just a question: could an effect as in the man's hair be created if there are too much line-segments in a too short distance? So the printer has to slow down? For example 100 little segments of 0.01mm, instead of 1 segment of 1mm? I vaguely remember reading a post where too much STL-triangles in a model created a similar problem? The indentations in the white boat rather look like a start-stop effect to me, after the nozzle arrives from somewhere else? Maybe you can see in the slicer if they mark the start of a new layer? Also, I noticed that blobs in PET are quite comm
  19. Maybe you could try the "salt method" on a small test piece? Or even better, on the same buildplate, print this test model multiple times using different methods. With a marker, draw lines on the glass, and use a different method in each area: - none at all - salt method - glue stick - dilluted wood glue - PVA-layer - 3D-LAC (spray on tissue and wipe with that, so you don't cover the whole glass) - hairspray - other...? The "salt method" works by first cleaning the glass thoroughly, then clean again with warm tap water only. And t
  20. To me this looks like poor adhesion to the glass plate. I don't know your printer, and I haven't really printed with ABS (apart from small test pieces), but in the very beginning I had a similar problem with PLA when printing on bare glass: if the climate was too moist, I would get this effect, and have poor bonding. The solution was to improve bonding (in my case, by wiping the glass with a tissue moistend with salt water, but that only works for PLA, not for ABS). So I think you might want to search for a better bonding method: ABS-slurry (=ABS dissolved in aceton), dilluted wood
  21. I *do* think it is infill shining through, because the infill pattern in the first pic (of Cura) exactly matches the lines in the second pic (the photo). Maybe too much overlap between infill and walls? Or indeed overextrusion like yellowshark suggests: if the infill overextrudes upon slowing down at the end, causing a sort of blob, then I can imagine that this shows through, since the edge has nowhere to go but outwards. This effect would get worse at higher speeds, since the pressure in the nozzle can not immediately go down to zero when the printer slows down. Printing hotter could also inc
  22. I do not have an answer to your question, but there might be other issues with your approach: - Overhanging edges tend to curl up, which causes the nozzle to bang into these curls, and which might knock the model off the glass. - The support material might not stick very well to the steep slopes of the arches. I think it might be worth trying vertical support columns and then a horizontal dummy bridge. Then you only need support material on top of that bridge, so it would consume even less support material. The bottom of that dummy bridge will of course sag, but th
  23. I don't know the UMO, but on an UM2 there is a little fan at the back of the nozzle, cooling the seam between nozzle, teflon coupler and bowden tube. Probably there is one on the UMO too? Did you check if this little fan is running at full speed? If not running at all, or if too slow, heat would indeed creep up into the filament, melt it above the nozzle, and make feeding and printing impossible. The fan could be worn-out, or it could have sucked-up strings or hairs from prints and gotten stuck, or a cable came off?
  24. Nice. And what method did you use for bonding to the glass?
  25. My models are full of small circles and tiny features, and they print fine, both in PLA and PET. This is a keychain-miniature of dental models used in the hospital. I tend to print these things rather slow (25...30mm/s) and cool (195...200°C for PLA; 210...220°C for PET), bed temp 60°C for PLA, and 80...90°C for PET. Bed is leveled rather close so the first layer is squeezed well (manual leveling on old UM2 printers). Everything else is pretty much default (I am using an older version of Cura). For reference: text caps height = 3.5mm; character legs are 0.5mm wide.
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