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Everything posted by geert_2

  1. I have heard about spontaneous unwinding of spools, especially near the end where they are tightly wound-up. Stiff filament acts as a quite strong spring, trying to wind up again. But if there is some sideways twist or rotation force present in the filament, it may jump off sideways. Indeed, anti-unwinding clamps are a good idea.
  2. In winter it might work, in summer I doubt it. And not if in direct sunlight behind a window. Standard PLA will for sure deform in a car left in the sun, even in mild spring or autumn weather. (Don't ask how I know this... :-) So if tough PLA is similar, then that will happen too. Also think about where the lamps will be: on a ceiling is hotter than on the floor, and above a radiator could be quite hot too. Do a few tests, and try them in the worst places, and then add enough margin.
  3. Exactly: print as slow, cool, and thin layers as possible. And, depending on the model, print multiple items at once, so the hot nozzle is moved away and the parts have time too cool down and solidify. Otherwise they stay molten. For more complex models, I also print a dummy tower (with inverted shape) next to the real model, for this cooling, and to make the printing time equal for each layer. Big changes in printing area do produce horizontal lines, due to differences in cooling time. See these: Left: printed without dummy tower, right: with dummy tower. T
  4. On my UM2 (=non-plus) the clicking noise is when the feeder tries to feed more material than the nozzle can eject. This is a sort of protection against overloading, I don't know the official name. Not sure if that is still the same on an UM2+? So, could it be that you are printing too fast, too cold, or in too thick layers? Or a bit of all, so that the nozzle can't melt it in time? Try a small testpiece and print a bit slower, hotter, thinner layers (whatever you think might be the cause)? But apart from the poor layer bonding, it seems the gear
  5. The normal procedure is to print slow, in thin layers, rather cool (because of the thin layers and slow speed), and set all temperatures equal. But it looks like you already did that, so... Maybe check if it is visible in layer-view in Cura, but not in the model in CAD? To see whether it is a printer-issue or a software issue or model issue?
  6. When printing a filter in PLA, I used only one wall of 0.5mm, and very thin layers and slow speed, to get it water-tight. It is mostly the thin layers (0.06mm) and slow speed that does it. When printing at 0.3mm layer-heigth, I got lots of tiny waterjets squirting out, like from a very thin injection needle. But I would recommend multiple nozzle-diameter lines, at least two. But the parts are very likely to warp in the sun, if outdoors. And the material might gradually degrade due to moisture and UV-light, like most plastics. So I would also encapsulate the electronics
  7. For PET, I need to heat the glass bed up to 80...90°C, for best bonding. And turn fan off or very low if you do not have too big overhangs. (You can't turn it off with big overhangs, otherwise they don't print well: the string snaps and curls up into a ball, instead of making a bridge. At least with the PET that I have.) I also had PET tearing a part out of the glass once, when I was using glue. So now I don't use glue anymore, but I wipe the glass with a tissue moistened with salt water prior to printing. For PLA, this greatly increases bonding, but for PET it seems to slightly re
  8. Your idea of using breakaway as raft made me think of this: what about using breakaway to clamp parts down? Like in the picture below. If the design allows it and if it has a sort of flanges at the bottom, or other features that you can grab, maybe you could hold it down like this? I have never tried it, so I have no idea whether it would work or not. But at least, if the breakaway adheres well enough to the glass, it would prevent the nylon model from coming off and sliding around. So it should prevent spaghetti? Theoreticallly and hopefully... Maybe worth trying on a small testpa
  9. In my experience, there are a lot of things that influence accuracy: temperature, speed, flowrate, material, even color (some colors melt better than others, not sure why, maybe due to fillers?), etc. Further there are things like layer-lines (curved edges), blobs, ringing, thickening of corners due to nozzle slowing down,... All these have an effect. The only way to know, is test. Make your typical features in real size in a small test model, and try that. For me, I usually take 0.1 to 0.5mm extra, depending on how tight a fit I want, and whether it are inner openings or outer sid
  10. I think CPE is very similar to PET? Anyway, PET feels totally different from waxy and floppy materials like PP and PE. It can flex a little bit, but definitely not like PP or PE, only rather like ABS. If overloaded it will very suddenly break without warning, almost like plexiglass. I have no experience with printing PP and PE, but I guess also a 3D-printed PP-model would probably feel different from an injection moulded one, due to the layer lines and poorer layer bonding? If I had to do it, I would probably go for what prints the best, the most accurate. And then post
  11. You can always design your own supports in CAD, thus as part of the drawing itself. Then you have total freedom of design. When printing in PLA, you could for example design all supports in PLA too, except for a small interface layer of PVA, so you can wash away that and get nice clean undersides in your model. Automatic tools are great for general use, but for very specific cases, it is best to do it yourself I think. The automatics can't know what you have in mind. See a few examples here: This is how you could make custom supports in PLA, and have only a thin P
  12. Ah, okay, yes I can see the iron/rust concern, if that stuff would get under or into tiny circuits, solderings, and connectors or so. Might also change impedances or resonances at very high frequencies or very low-current circuits. Fortunately iron is not an issue in our tap-water. (Though it could be for people who pump up their own ground-water, which is often brown because of high iron-content.)
  13. Hoi John, Out of curiosity, did you have any specific mineral-related issues in mind? We here in Belgium (near Antwerp, it differs elsewhere) we have very hard water, thus very calcium-rich. It really feels "hard" to the touch, totally different from de-ionized water that feels much softer. If you let a glass full of water dry out, there is a thick layer of calcium-deposit. Also in boilers and kettles. But when cleaning with this water, then rinsing, and wiping things dry, or compressed-air blowing them dry, I have never seen any side-effects. But this could of course be different in
  14. Yes, in my experience cleaning with window-cleaner sprays destroys bonding. Just like any soap would. It seems they all leave traces of soap on the glass. I clean with isopropyl alcohol to remove grease, and then a couple of times with pure warm tap water only.
  15. And check that the rods are totally straight, not bent. Even if they are only 0.1mm bent out of shape, thus almost invisible, that is a full layer-height during printing. Maybe put them on a totally flat table, roll them, and see if light shines through below them. I would also go for window-cleaner, or Mr. Proper or similar, spray bottles to get dirt off. Whatever works in a dirty kitchen, without destroying things, should work here too, I think. And then clean with pure warm tap water, to get the soapy-remains off.
  16. Or leave a gap of 0.01mm between the plate, and the studs, in the same CAD-model. So the plate would print as one block including top layers. And then there would be a 0.01mm vertical gap, after which the studs are printed. Such a tiny gap will obviously be filled, and the studs will fuse to the baseplate as if there was no gap. I don't think this is the optimal way of doing it; too much CAD-work. Beter would be to find the exact right slicer-setting to handle this (if present). But it might be a way around if nothing else works...
  17. Yes, I understood that. But your question has come up here regularly, and I have never seen a good solution yet, except for staying around the printer. That doesn't mean there isn't one, just that I haven't seen it. :-) I am afraid that you have to go to post-processing methods: inserting the nuts or special threaded inserts after printing. Or maybe print it in two parts, insert the nut, and glue them together? Preferably with a sort of dovetail mechanism or similar, to get mechanical retention in addition to the glue? And in such a way that the part does not see too much load in
  18. Yes, I do it similarly: I push in the tube, then while I keep pushing on the tube, I lift the ring of the collet, and slide the horseshoe clip onto it. So it sits all the way down without any play. Never had tubes coming off. To make this easier, I made a custom horseshoe clip, so it doesn't keep falling when I try to handle it: It is old but still on my page (and then scroll down): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/
  19. If I understood it correctly, you mean this: buying a gcode-file from unknown source, with unknown settings, tested on unknown printers with unknown materials all differing from yours, and then hoping it is not going to ruin your printer, crash the nozzle into the glass or the walls, overheat, produce spaghetti and clogs,...? No, I am not going to risk that, no way. Probably not too many other people either. There are just way too many settings that have to be customised to produce the exact results you want, for your purpose, your printer, your filament: speed, layer-h
  20. No experience with this. But a thought: you also need to consider the maximum temp that the printer can deliver (I think 260°C for the UM2?), and the temp required for your material. Some engineering materials need way hotter. I don't know yours. If you already have the hardened nozzle installed, remove the bowden tube, heat up the nozzle, and try to feed some filament directly into the nozzle from above. Just to see if you can melt and extrude it.
  21. Yes, probably the PLA got already soft while still in the feeder or bowden tube? If you want to reduce noise, you could try to put absorbing panels around the printer, but not touching each other, nor the printer. Lets say a panel 30cm away from each side, and with *big* openings in-between each panel and all printer parts. Plus one under the printer. So that air still has plenty of room to pass. This should greatly reduce noise-reflections, echo, and standing waves (and all the other audio-stuff I don't know about). On Youtube, search for "how to build your own noise d
  22. What about staying around and keeping and eye/ear on the printer? Or via a webcam? Me being a simple man, I myself would go for simple solutions... Alternatively, if the design allows it, and depending on the load-direction, you could go for other methods of inserting the nut, for example via side-openings, or by melting-in threads or nuts with a soldering iron. I have successfully used these methods (the cone-shaped opening is only for inwards-directed loads obviously):
  23. I would also check the part and STL for errors, and always inspect the layer view. Maybe design a new "known-good" test part that only has this problem feature. Design from scratch a cube of 10mm x 10mm x 10mm, with such a hole, in a decent editor (definitely not SketchUp). For small holes, you need to calculate-in the narrowing caused by the molten material being pulled inwards. Try pulling a string of honey or yoghurt in a small circle, it's like pulling a rubber band into a circle. Drill-out the holes *by hand*, if necessary. Often I add a rounding at the bottom edge
  24. (I can read German, but not write it, so...) I would say: go to a local distributor, who has a lot of different printer brands and models on display, each with demo-prints made by each printer. Go have a look and inspect all these prints, the printers, and have a chat with that guy. He is most likely to sell you a printer that suits your requirements and budget, and still gives good quality. Because he knows, if he messes up, he will lose you and all your friends forever as customer. For example, here in Belgium we have Trideus, but there will sure be others too.
  25. I have no experience with soft filament myself, but from what I have read here on the forum, very soft materials tend to be very difficult to print. Pushing them through the tube and head is somewhat like pushing a rubber band through a keyhole. Doesn't go very well. Oiling the filament, and printing very slow, and a higher flow-rate, do help a bit. What about printing a mould in standard PLA, sanding and smoothing it, and then casting silicone in it? Then you get the real stuff: chemically inert, temperature resistant, and flexible silicone, but with your own custom design. And yo
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