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Everything posted by geert_2

  1. Some of these silk materials are a blend of PLA and other plastics, which causes the silk-effect. Although I don't know for this particular type. If there ar no nozzle clogs and no overheating, have you tried how hard it is to unwind the spool? PLA is already stiff by itself, and gets even stiffer after time, which may make it very hard to unwind. It acts like a spring, trying to wind up again. Especially near the end of the spool where the bending radius is very thight. It might be just on the edge of what your printer can feed. If it is a bowden-tube printer, a tight radius also
  2. Exporting to STL converts circles - thus curved lines - into polygons with straight segments. So if your wall thickness is exactly 0.4mm in the design, upon converting to STL-segments it may vary between 0.39mm and 0.41mm for example, depending on the chosen accuracy. The 0.41mm walls print fine, but the 0.39mm wide walls are dropped, leaving holes. That is why I often use 0.5mm for thin walls and tiny text legs, which prints well. I never tried changing nozzle-width to 0.39 or 0.38mm, because I am prone to forget that later on, messing up later prints. :-)
  3. Hello, I am considering using Breakaway to make casting moulds that can not easily be made from simple two-part moulds. Normally I would use the traditional method of two mould-halves that are clamped together using alignment-keys. But this may not work for complex shapes with lots of undercuts, or shapes where I don't want parting lines in the model. Then Breakaway might be an option? This would require printing a new mould for every cast, but for special items like machine parts it might be worth it. Question: can Breakaway be acetone-smoothed, similar to
  4. I think if the model does not stick to the bed very well, then it is not going to stick to the PVA-interface as well. Raft isn't used very much anymore, and I have even never tried it. I would suggest you try brim, which generally works good and is easy to remove. Or if you have a really special model, you could design your own brim-features in CAD. Automated functions are good for general items. But for very specific and unusual things, you as designer are best suited to design custom brims. For example I used them here to prevent the little red and orange things from
  5. Printing slow, cool and in thin layers reduces the effect for PET (I have no experience with nylon), but does not eliminate it. One cause is the internal pressure of molten material in the nozzle, which then leaks a little bit while traveling. So, less speed = less pressure = less leaking. That droplet is deposited on the next wall the nozzle encounters after traveling through air. On the next pass, the droplet is deposited on the previous droplet, and so on, causing these nice "insect antennas". Watch closely and you see them growing. Another cause can be material accumulating on the outside
  6. Can you make a few close-ups of the bottom of that part? At first glance it looks like the first layer did not stick to the glass, sort of lifted, and created gaps. That would be my first guess. But we need to see the bottom. If yes, then thoroughly clean your build-plate, first with isopropyl alcohol, then a couple of times with pure warm tap water only. No soaps, as they reduce bonding. Then apply a bonding method suitable for your model and material. If using the glue stick, do a thin layer and spread and wipe it smooth with a wet tissue afterwards. For the later lay
  7. I am not familiar with Fusion 360, but in most other CAD-software there is a Structure-Tree, listing all components. Maybe you can find the superfluous surfaces or parts in that list, and delete or hide them? Then they shouldn't interfere with the model anymore. If you hide them (if possible), they are still available for editing later on if necessary. I sometimes use this in DesignSpark Mechanical, to keep the basic shapes before I merge them into complexer models. Note: according to that Australian guy Angus (he makes Youtube videos on 3D-printing, but I don't remember his channe
  8. Some materials are very sticky like hotglue. The PET that I have also has this tendency. Hot PLA is more like yoghurt and doesn't accumulate so much. No experience with TPU though. Immediately after a print completes, I wipe off the nozzle with a strong thick paper tissue, while it is still hot and the goo still soft. Use thick or folded paper tissue, to not burn your fingers. If the goo is too much burnt-in, I remove it with a long brass M3 bolt or threaded rod. This works as a gentle file. Of course, never use steel or sandpaper or so, as that would destroy the nozzle
  9. Have you made the wall thickness an exact multiple of the nozzle diameter? Then export to STL using a fine-setting, so the segments are not too long and don't cut corners too much. But even then there will be places where total thickness is slightly more and where it is slightly less than in your design, due to the straigth lines of the segments. Not sure how the slicer will handle this. And then print rather slow (and cool to prevent overheating the filament in the nozzle), so there is no underextrusion. Before printing the whole model, try cutting out the most critical part and try to optimi
  10. I am not using the latest Cura-versions, so I don't know if this is possible in Cura. (We will leave that question for others to answer.) But a trick you could always try, is to put some tiny dummy objects left and right of the real object, but a bit lower. Then those dummies touch the glass, and your real object is floating a bit higher. Like these two tiny strips: Ps: how does this filament compare with real metal (machined)? What post-processing is required, and how do dimensions change (any shrinking, bending, or non at all)? If possible, co
  11. I don't know your printer, but if it was an Ultimaker 2, I would guess: or the nozzle is too far away from the build plate, or the flow is far too low, e.g. 50% instead of 100%.
  12. Printing 4h/day is not that exceptional. Here on the forum I have seen people who print almost continuously. If you do regular maintenance on your printer, it should be fine: nozzle cleaning with atomic puls, cleaning and lubricating rods, removing dust and hairs from the fans, cleaning feeder wheel,... Or you could try moulding and casting: 3D-print a master-object and a shell, carefully post-process these (=sand, smooth,...) and use these to cast a silicone mould. Then use that mould to cast plastic items. On Youtube you find a lot of good tutorials on moulding and casting. Then
  13. Sometimes (1) filament hairs and strings get sucked-up and block that little fan. And (2) the bearings wear out: if the fan made a sort of "rheu-rheu-rheu..." sound prior to your problem, it is probably the bearings. I have often successfully extended the life of such little fans by a month or so (this was back in the days of old 80286-computers), by lubricating worn-out bearings with bearing oil. I have also done this on an UM2 fan once, and it worked well. This gives you time to buy new fans. The oil should not be too thin, because then it does not lubricate enough: it should be
  14. Some laserprinters (=paper-printers) have an auto-retry function if the print fails due to errors like paper jam, out-of-paper, door-open, etc... Then the print is automatically redone. Some printers can also receive jobs when the printer is offline or asleep, because the network card and electronics keep their power and the job is somehow buffered (I guess...). Also, in Windows a print job may get stuck in the print queue when Windows has problems connecting to a network printer. When you then switch-on the printer, or set it online, or restore the network, it may print those old jobs.
  15. In DesignSpark Mechanical there are 3 standard quality-options for export to STL: coarse, medium, fine. I use the fine, which gives about 2x to 3x more triangles than in your image (which corresponds to about medium). Custom quality allows for even better, but that is overkill: the printer can't follow too fine details anyway. But there can be lots of other reasons why accuracy is not great: extruded flow too much or not enough, nozzle too hot or too cold, blobs, incorrectly callibrated X- or Y-steps per mm, printing fast so corners get too thick when it has to slow down suddenly a
  16. There is no official text feature, at least not in the version I have (maybe in the newest or beta-versions?). DesignSpark Mechanical is a free but limited version of the commercial and expensive SpaceClaim. But there are 3 ways around it: 1. Use the Dimensioning tool. This is the tool which draws measuring lines and arrows and dimensions like this: <-- 3.0mm --> Measure a dimension where you want text. So, now you have this: <-- 3.0mm -->. Then delete the numbers and arrows, and replace them with your custom text, in a font you want. This text is still sit
  17. In your CAD-software, can you hide parts of a complex model? For example in DesignSpark Mechanical (=free but requiring registration, and only suitable for geometric models, not for organic life-forms): as long as the parts are not merged, I can simply hide each by unchecking it. And then make it visible again. This allows exporting each part separately. Let's say you have a cookie-cutter mould, named: "cookie", and the kid's name written on it: "kidname". Then I could hide "cookie", and save "kidname" separately as a model, or export to STL. And then I would make "cook
  18. What about modeling custom supports in CAD? In that way you can make a wide and stable support in the same material as your model. And only a thin dissolvable support-layer in-between the support and model. Not sure if this would work, I have never tried it yet, but it might be worth experimenting on a small test-object? To make the dissolvable support material stick better to the custom support structure, you could add sort of dovetail ribs on top of it, so both interlock. See this concept-pic:
  19. Forgot to say in the above post: that method is only good if the load is directed inwards, obviously. I used it to clamp two mould-halves together. For a load in both directions, or outwards, I use side-openings for inserting the nut afterwards. Sort of slots where the nut slides-in. This too can be with or without retention ridges, to prevent the nut from falling-out if the screw is removed. It is not suitable for every model and every print-orientation, but if it is, it works very well. Here too, I can use cheap standard nuts. See these real models:
  20. Indeed, PLA parts do deform quickly, even here in Europe in mild spring and autumn weather. Not only on top of the dashboard in direct sunlight, but even in the dark in the trunk, the coolest place. Now I make parts for my car in PET or in colorFabb NGEN (which I think is similar?), both of which are still easy to print. Since then I haven't had parts warping. But these materials are harder to glue. While cyanoacrylate works very well for PLA, bonding is only mediocre for PET and NGEN, and tends to break suddenly under load, or due to temperature related expansion/shrinking. So I a
  21. Are you sure a single layer is enough for strength? I think that might fracture or split soon due to baked-in stresses from the printing, or later due to loads in flying. I had single layer rods split, even when under moderate load, especially if the load was for a longer time (days, weeks). Test strength on test pieces first, before taking the plane into the air.
  22. Generally, my experience is: print slow, cool, and in thin layers, with a material that does not cause too much blobs and strings (but that still fullfills your other wishes concerning temperature resistance and strength of course).
  23. I don't know for your printer. You have to search for that in its manual, or a forum for that specific printer. For my Ultimaker 2 printers, there are the X- and Y rods (=with the drive belts and sliders), and the rods where the head hangs on. These require thin oil. Plus the Z-axis worm, but this requires grease. All have to be cleaned first, and then lubricated. But for other brands and models it may be completely different. And some may have sort of internal movements, slots, or sliding mechanisms (I don't know the correct English terminology), where pieces of dirt c
  24. What you could also do, is make a hex cage with a protruding ridge at the bottom, for retention. And then using brute force, push the nut through the opening past the ridge. Then it can't fall out. It will take a bit of trial and error to get your tolerances right, but then it should work fine. If you use a conic top surface of the cage, you need no supports. Also use a conic chamfer at the bottom, to make sliding the nut in easier, and to remove elephant feet due to printing. I find it easiest to design the nut separately, then move a copy into the model and subtract i
  25. I don't know your printer, so I have to do a bit of general guessing. I think it could be the printer missing steps, but it could also be the object becoming a bit loose and wiggling? Or a defect in the model or slicer-bug? First, in Cura (or other slicer) always check the model in Layer-View, to see if this defect is there or not. Check if the printer head moves smooth in X- and Y-direction. Movement could be blocked by debris, or lack of lubrication. Then, while printing, keep watching closely what happens. You should be able to see the differe
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