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Everything posted by geert_2

  1. @thorsenrune: I don't know what this "@-thing" does, other than drawing visual attention, so I rarely use it. :-) And yes, you can quote me on the Onshape phylosophy. I am used to very wel organised graphic design packages, with easy navigating through logical menus and toolbars. Functions should be where you expect them to be. But in Onshape all functions seem to be randomly splattered all over the screen, and often hidden, without any logic (or at least I can't find it). I had to consult the manual *every time*, again and again, even for the simplest functions like saving or expo
  2. I have tried Onshape, in the beginning when you could still have 10 private models (all above 10 would become public, accessible to the whole world). But I don't think you can still have 10 private models? Maybe 4? Unless you pay big money per month. Anyway, I could not find my way around in its user-interface: I can't find anything and can't get anything done. Its phylosophy seems to be incompatible with mine, so I stopped using it. This could be my problem of course, since some other people *can* make great designs in Onshape. :-) I have a very different graphics background tha
  3. In my experience, *random* crashes usually indicate a hardware problem. Often memory modules that got defect, or contact pins that got dirty or oxidated. If the driver update would not help, and if you can access the memory modules, try gently (!) wiggling them a couple of times. This has often worked well in my PCs (I don't know for a Mac). Maybe try a night-long RAM memory test? Memory-problems often show up only on memory-intensive software that occupies nearly all of the RAM: 3D-software, browsers with a ton of open tabs all playing videos, etc.
  4. To me your samples look pretty decent. This is what I would expect. Infill is not meant to be visually perfect: its purpose is to add strength in *invisible* areas. And to reduce material consumption and printing time in invisible insides, where a solid body is not required. So its purpose is a good balance between strength, printing time, and material use. Although today there are a couple of really beautifull infills indeed. If you want nice looking spokes, and you want more control over how they look, I would suggest you design them in CAD. See the model
  5. On my UM2, the tube is also worn-out, but it keeps clamping well. If the nozzle is not blocked, and there are no temperature problems (printing too cold, so it does not melt), the tubing is the correct diameter, and the filament is not too thick, or any other things that block feeding, then I keep thinking that you might not be inserting the tube well enough? It is not sufficient to just push-in the tube all the way down. At the same time, you also need to lift the white ring as high as possible by pulling hard: this lifting is what will cause the locking afterwards. Could you veri
  6. For the future, get your staff and students to use other software than SketchUp for 3D-printing, or you will keep running into problems and keep repairing errors. SketchUp was designed for visual models only, not for 3D-printing. It produces sort of "cardboard" models where the edges do not fit together and are not watertight, not solid. It is excellent if you want a quick idea on-screen for an architectural concept, as long as you are not going to print it. Students and educators can often get free or cheap educational versions of professional 3D-CAD software. Otherwis
  7. I wonder how this would reduce stress? Wouldn't most of the stress be caused by adding hot new layers to a colder base, causing an *upwards* pulling force due to shrinking? Further, I think this might cause more ugly corners: now the ringing effects are on only one side of a corner, and they are the same for each layer. When alternating, these effects would alternate too. This might cause the same combing effects as on interlaced videos?
  8. I just printed a filter for my vacuum pump, to prevent it from sucking up big particles when suddenly applying vacuum. The filter was printed on an UM2, thus in a single material, no supports. I printed the first model at 0.3mm layer height, 25mm/s. This was *not* airtight: when I put tap water on it, maybe 10 tiny jets spurted out of the shell, through tiny holes. The holes were where the layer-changes and take-offs and landings from traveling had occured. The second model was printed at 0.06mm layer height, and 50mm/s. This model is *absolutely watertight*. Yes it too
  9. I think the basic idea is excellent, and worth trying out. But maybe an optical sensor or mechanical switch might be more reliable? I would fear that a thermal switch could cause false alarms, e.g. when printing hot and slow without cooling fan, so there is no airflow. Then it might get too hot and trip. Or it might miss real leaks when printing fast, cool and with full cooling fan, if the air blows directly on the sensor, and it cools the outer shell of the leaking plastic too fast. Such a sensor should never give false alarms and abort a good print, nor miss real events: that will be the mos
  10. I never used sprays for 3D-print adhesion. But years ago I did use a lot of silicone anti-stick sprays for moulding and casting models. I had built a special cardboard box with fume extraction at the back, to take away the spray mist. And I only sprayed deep into that box. But even then the whole area outside of that cardboard box got slippery with silicone oil too, after some time. I have seen similar setups where people used spray paints, and there too the whole environment got colored. Even though they had fume extraction in their cardboard box, just like me!
  11. If it is a lab with normal ventilation, and you did not sit with your nose directly above the printer all day, and if you only printed PET or PLA, it probably will not have done any damage. Seems very unlikely to me. I don't know where you live, but here in Belgium the laws require that the air in a lab is renewed several times per hour (was it 6x or 10x? I don't remember). So you should get plenty of fresh air in the lab anyway. In a research lab, most other products you use will probably be more dangerous: solvents, biochemicals, composites,... Things woul
  12. Steep overhangs tend to curl up. Maybe that might cause this deformation? Watch closely while it is printing, then you can see if this is the cause indeed. If you can't get it to print well, another thing you could do is make an undeep thread, so the overhangs are not so steep. And then using a standard thread cutter, cut the final thread. When cutting threads in PLA, go very slow, and with lots of cooling. Otherwise everything will just melt. Don't ask how I know... :-)
  13. I have silica gel with a moisture indicator, which turns from dark blue when dry, into pink when moist. To the Ultimaker-developers: maybe you could try adding this moisture-sensitive pigment to the PVA? Then people can see at a glance if their PVA is still dry enough? I don't need it, since I only have single nozzle UM2-printers. But moist PVA seems to come up again and again here on the forums.
  14. I didn't make a real font-file, since I don't know how to do that. So to set text, you need to copy and pasted each character from the character set, letter by letter. Like in the old days of metal printing. This is good for a short copyright notice, but not very suitable for 3D-printed newspapers, obviously. The character set is in DesignSpark Mechanical's native format, RSDOC; and DesignSpark Mechanical is freeware (requires registration). If you would like to convert these characters to a real font, thus a TTF-file or similar, feel free to do so. Just kee
  15. When mounting the bowden tube, do you push it far enough in, all the way down? Thus: first lift the rentention ring with your finger nails. In my printer this is a white ring on top of the head, where the tube goes in. Then insert the bowden tube all the way down, while you keep the white ring lifted. And then insert the horseshoe clip? If the tube is not inserted deep enough, it may not grip well upon pulling. That could produce the phenomena you see. (But that does not mean there can't be other causes, such as a worn-out tube, or incorrect outer diameter.) For easier
  16. Extruding thin wires of consistent diameter is not easy: try manually extruding a sausage from your printer, by slowly turning the wheel. Through a 0.4mm nozzle, I can get sausages ranging from 0.05mm up to 1.0mm, by varying temperature and pressure alone. The extruded plastic contracts length-wise after coming out of the nozzle, while still molten, as the molecules tend to go back to their usual curled-up shape (instead of being too stretched-out). This makes the diameter very unpredictable, and requires a very constant temperature, pressure, speed, cooling; and constant monitorin
  17. Where did the old printers go? Were they sold, given away, or are they sitting somewhere in the basement, collecting dust? If given away and they still worked, I would suggest you just donate the filament too. If they are sitting in the basement, you could revive them in a separate room, and let students mess around with them for their hobby projects, and let the students take care of them, thus out of the official curriculum.
  18. It looks very similar to the Polyalchemy Elixir filaments, which were the first in this class as far as I know. It seems a lot of companies have jumped on that bandwagon of shiny silky filaments recently. Haven't tried them yet, but I might in the future, I like the metalic aspect. In your experience, how is surface quality? Does the shinyness hide defects, or does it rather make them more pronounced? And how are warping, layer bonding, and temperature, compared to standard PLA?
  19. Would it be an option to hollow-out the model in CAD, instead of in Cura? Let's say we have a solid cube. Then, in DesignSpark Mechanical you can delete one face, and set a wall thickness for the remaining walls (so it is printable). This turns the object from a solid cube into a hollow cup. I don't know if your software has such an option? Also, make sure you have enough contact-area to ensure a good bonding to the glass. This may depend on the bonding method. For my "salt method", a single wall is good for low flat objects, but it is likely to come off for
  20. In PLA-based filament it is known that microcracks can grow if the filament is bent or stretched (thus kept under a load) for a longer period of time. So, don't let material sit still in the feeding-traject after the print is finished, but unload the spool immediately. Some materials also get brittle due to changes in crystal structure, becoming more crystaline (often reversible), and due to moisture absorption and damage (not reversible as far as I know). Both happen in PLA. Keeping it dry obviously helps against hydrolysis. But I am not sure what the best solution is
  21. I was referring to the squishing of the filament indeed. I have two older UM2 printers with manual bed-adjustment, and I adjust it closer, so it is squished more. I prefer a nice glossy bottom, even if that causes a little bit of "elephant feet" sometimes. Not only does that stick better, but it makes watermark text in transparent materials (=inside the model, close to the bottom) easier to read. In Cura, I usually set the first layer to 0.2mm. This too helps in giving a flatter bottom than 0.3mm, and gives better bonding. I have no experience with UM3 or newer, so I ca
  22. If that is the underside, I would level the bed closer to the nozzle. It is hard to see from this angle, but I think it is not flat enough to my taste. :-) I prefer the bottoms of my prints to look more like this, or like the above photos.
  23. Belts are replaceble, and the procedure should be somewhere on the Ultimaker-site. If you are a bit handy, you can do it yourself. Your local dealer should be able to provide the belts. Or you can have him/her do it. While you are at it, I would take the time to have a look at the feeder too: is that clean and in good condition? Also clean the metal rods near the belts, and lubricate them with a thin oil that does not dry out. And also clean the nozzle with cold pulls or "atomic pulls". See the official method on the Ultimaker-site, or use my gentle method h
  24. Just randomly printing Lego pieces doesn't seem like a good idea to me, since: (1) they won't fit, as a 3D-printer doesn't have the required accuracy (microns), and so the pieces would be useless; and (2) you will soon run into copyright claims and huge damage claims, as these are protected models. What you could do however, is go to a local school, and say that you have unused printing capacity. And then let the kids design things themself, so they learn how to do it and they get enthousiastic, and then print those models. Also learn them the possibilities and limitati
  25. Most materials should be reasonably airtight if printed *slow*, in *thin layers*, and with good flowrate. So you get good layerbonding, and absolutely no underextrusion (important). A little bit of overextrusion could also help, but might create blobs. Do not use separate support materials (PVA) that dissolve: if they made strings in a print, these will dissolve and become holes. But all models will have tiny "canals" and pores where bacteria can grip and grow. It's just that the water or air won't blow through. For shell thickness, I would use at least 2 lines (=0.8mm
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