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geert_2

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Everything posted by geert_2

  1. On Youtube you can find videos, if I remember well on channels of "CNC-kitchen", and "Maker's Muse", and others (I don't remember the names). These are indepentdent people (not company related) who have done lots of reviews of different products. These printers are getting a lot cheaper and more reliable now. The biggest drawback is that it is a huge mess: prints come out of sticky liquid, and they need to be rinsed in alcohol or similar solvents. This is messy, and creates chemical waste. Also, tiny supports need to be removed, but this should go easy. I do
  2. Before doing a whole mask, I would suggest to do a test model first. Start with default settings or proven settings from other people, and then on the fly change temperature and speed, and see what effects that has on your model. Different brands, material compositions and colors may all have an effect, as well as environmental circumstances (e.g. moisture).
  3. I have come across this terminology in manuals of power supplies, especially high-power units with separate sense-lines. If the ground-wire is too long or too thin, you can get a significant voltage drop across this line. Let's say the ground line has a resistance of 0.1ohm, and the current is 10A. Then you get a voltage of 1V across the ground-line. So the "ground" at the electronics board is 1V higher than at the supply. This was the definition of "ground level shifting". Hense the sense-lines in the power supply, which needed to be connected as close to the board as possible. Th
  4. Long ago there has been a discussion if the heated bed could be the cause? If it would draw so much power that the ground-level (zero volt) would shift up, and if the temperature sensor would use that same ground wiring, this could cause errors in the temperature the main board "sees". And then it would adjust incorrectly. But I don't remember exactly on what printer models this was (maybe UM2?), and what the conclusions or solutions were. Maybe you can find that again. It was several years ago. If you could print the same object on a cold bed, using glue, maybe you cou
  5. Yes sure, anything according to that concept. As long as it separates your hands from the door handle, and it doesn't contaminate your pockets! This is why I wanted a cylindrical object, not an open flat one like most others, so the inside would not touch your pocket lining. My first idea was using left-over pieces of copper tubing, rain/drain-pipe, aquarium-tubing,... Copper tubing would have the advantage of being self-desinfecting: its oxide outer layer is poisonous and soon kills germs; it is sturdy, easy to machine, and can easily be further desinfected or autoclav
  6. I designed a cover that separates care givers from contaminated door handles. The idea is that you carry this cover with you all the time, and slide it over a door handle to open the door without touching it. It protects you from contamination by dirty door handles, and vice-versa. You only touch the outside of this cover, and the door handles only touch the inside of this cover. There do exist lots of other means, but this one provides the best separation, as far as I have seen. And it can stand up vertically (it has to be printed this way), and can be re-used as a little vase, wh
  7. She looks like sun-burnt now. :-) I was thinking, for simple models you could make an inverse as mould, and pour gypsum into it. Gypsum is a lot easier to sand than plastic, and its stone-like structure hides small defects and layer lines. Then you would have a solid heavy-weight gypsum girl. But that method won't work for this model, because she has way too much undercuts in the hair, and in her fine hands and arms: even with a complex multi-part mould, it wouldn't go. PS: I didn't do any "heat-acetoning" myself. I had considered it, but I didn't want to explod
  8. I think effects like this might also be caused by fluctuating temperature, because that changes viscosity and flow-rate (=less back-pressure when more liquid). And maybe also by a worn-out white teflon coupler? But I don't know a good means to reliably measure the temperature from the outside? A thin and heat-resistant sensor that you could move into the nozzle from above might be best? (Of course after removing filament, removing bowden tube, and cleaning the nozzle.) And then let the printer run, "printing" this same object. Thus it goes through the same moves, same temperatures,
  9. I would suggest: cut out a small part of this model with some text for testing purposes only, so you don't waste time and material doing the whole thing. Try printing at 25mm/s, cool (but without underextrusion), and in thin layers (0.08mm...0.12mm). See what that gives? 3D-printing is always searching for a balance between quality and speed, but often they don't go together. So you will have to chose your priorities... In my experience (with UM2) such text on the sides always comes out poor, due to ringing effects and widening in corners when slowing down.
  10. I like the girl model. Have you ever tried painting such models in a gentle sort of "marble" technique? So it looks like stone or marble? I think that might work for this girl, and it might conceal layer lines and defects. I once knew an artiste who turned lightweight wooden crates into "heavyweight marble" bases for displaying sculptures. These bases were hard to distinguish from real marble. But I don't know how she did it, I only saw the results, not while applying it. Might be worth trying that? I also like the "old" look of the partially painted and sanded model. M
  11. I think it will be hard to find something that has the flexibility, chemical inertness, long life, temperature resistance, stickyness and grip of silicone. What you could do, is print a mould in PLA (or whatever), and pour your own silicone sleeves in it. Then you still need silicone of course, but at least you have the design flexibility you want, that off-the-shelf part can not give.
  12. I would suggest you embed the pictures in your message, instead of using external links. Then you are more likely to get answers. While writing your text, place the cursor in the desired spot, and drag and drop the picture from Windows Explorer into your message. I guess this should also work on a Mac or Linux. Due to the enormously increased phishing and hacking since the corona-crisis, people are less and less willing to click on links from unknown sources.
  13. For those who print in PLA: do not leave these masks in your car in the sun, or behind any window. Even not on mild spring days. Because it *will* deform due to the warmth, especially when under mechanical load: PLA starts getting soft from ca. 50...55°C, and that is reached in a car as soon as the sun comes out. Don't ask how I know. :-) For the same reason: Do not clean the masks with hot water or steam jets, and do not dry in hot air. Comfortable handwarm water is the maximum. Also explain this to the people who are going to use those masks, and leave a
  14. Hmm, synthetic plastic food and colorants. Can't be bad. :-)
  15. Another thing that might help, is when you keep sitting next to the printer. Then when it is reaching the top of the models, gently and gradually lower the flow-rate of the extrusion, via the Tune-menu on the printer (name might differ on your printer, depending on the model). Reduce flow-rate very gradually to 95% or 90%, try what works for you. Also, manually reduce temperature as it reaches the top; and here too: try what works for you. The shape will still not be good, but it will overextrude less. My test demos were printed with about standard settings, thus way too fast and t
  16. These "insect antennas" come from the nozzle leaking while traveling through air. Upon arriving at the next wall, it deposits that leak as a drop on the side of the wall. Upon the next layer, the drop is deposited on top of the existing drop. And so on, causing a nice insect antenna. If you watch closely while printing, you can see the antennas growing with each nozzle pass. So you need to tune your settings for less leaking while traveling (print slow, cool, thin layers, enough retraction, travel fast through air), or for not traveling through air at all, if the model
  17. My standard pic to show the effect of a dummy cooling tower (ruler is in mm and cm). In addition to what gr5 said, printing in thin layers, slow and as cool as possible also helps. Also, do not use 100% infill but rather 50% or less. But I could never totally get rid of the effect. At some point the hot nozzle just keeps sitting on top of the tiny model, preventing it from cooling down and solidifying. That is a limitation of this printing method.
  18. A few questions: Are there any soft leather, rubber or cloth straps as interface between the 3D-printed parts and skin, to increase comfort? So that the hard plastic does not continuously rub the skin, causing damage? I have worn safety helmets in the past, and they all had a hard outer shell for protection (obviously), a soft inner plastic frame for good fitting around the head and for shock-absorption, and then a thick, soft leather strap between that soft plastic frame and the skin. Otherwise it was not possible to wear the helmet for a prolonged amount of time, with
  19. At big oil companies, but I don't think it is a good idea to go buying a vat of 160 liter... 🙂 And there are so many different specs for different purposes. I just use hydraulic oil because I had it for my hydraulic machine (and it is on-spec for that hydraulic machine, not necessarily for any other equipment). If I had to buy fresh oil, only for the printer, I would probably go for something close to the official Ultimaker specs: some light machine oil, like used for lubricating bike chains, fine equipment, tools, and similar. You can find that in car-accessories shops, or
  20. I would suggest you add pictures to your post. Then you are more likely to get good answers. You can drag and drop JPG- or PNG-files directly from Windows Explorer into your post while editing. Set the cursor on the desired place, and then drag the picture into there. The reason is that the amount of phishing and hacking has increased a lot since the corona-crisis, so people are less and less willing to open unknown files from people they don't know very well. Without having seen your design (for that reason), my general experience with snap fit things is th
  21. Indeed, I haven't seen this one. :-) Seems like I should bring my knowledge about tools up to date. The inserts I have seen on Youtube videos, but not tried myself yet. If you have used them, do they stick well, and does the molten plastic reflow around the ribs well? I have also seen a similar concept, in which the brass insert had to be screwed into the plastic hole, with a sort of self-tapping one-way screw on its outside, so this would get stuck and stay in there. But again, no personal experience.
  22. I tried tapping too with straight taps (I had never seen those spiraling ones, didn't know they existed), but indeed it didn't work well. Even not when tapping manually and reversing very often: 1/4 turn forward, 1/8 turn backwards. Chips would get stuck and the plastic would melt (even at very low speed, lots of cooling time and lubrication). Also, threads were very weak and got worn-out very soon (M3, M4, M5). So for most of my models, I now use standard nylon M4-screws instead, with a caged nylon nut that can not fall out. This goes a lot faster, and it works better: the thread
  23. Depending on the firmware-version the "Abort" on the UM2 can be plainly visible during printing, or in the "Tune" menu (I have both). In some UM2 there was an issue with driver chips overheating: then they would shut down for a few moments until cooled down, and then continue. Mostly with the Z-axis (up-down). I had this on one printer a few times in hot weather, when doing long print runs. I reduced maximum current a little bit, and since then it never happened again. I am not sure if this could happen to the X- or Y-axis too? But first try the other solutions, and only consider t
  24. I have tried these: - PLA, orange and white: bright colors, printed very nice and smooth, but stuck a little bit less to the glass than Ultimaker or colorFabb PLA when using my "salt method" (=wiping glass with tissue moistened with salt water). Seemed to be slightly less temperature resistant than other PLA. Otherwise no problems. Prints at standard speeds and temps. When burning pieces in a metal spoon on a bunsen-burner, it leaves very little black ash: just a little bit of dry, loose powder that can easily be wiped off. So, the same can be expected in the nozzle.
  25. I think the extra width that you measure might come from ringing- and thickening-effects around corners? When slowing down to take a corner, the nozzle inside pressure does not immediately drop, it lags, so the nozzle extrudes a bit too much compared to the now slower speed. This makes corners thicker. Analog for ringing, sine-wave mechanical oscillations around corners. This could easily explain 0.2mm extra width. Also blobs and overextrusion could explain that, if they would be present. Also, "elephant feet", the sagging of the first layers, could make a model seem wider than it is, if you m
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