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Everything posted by geert_2

  1. Gradual differences: 1) Maybe a different airflow, different air-temperature, different bed-temperature from left to right? If you would have an IR-thermometer gun available, try measuring the bed temp at several spots. I found that in my old UM2, at 100% fan speed, the bed-temp could drop by 10-15°C locally, when printing small objects in PET, so the fans were always blowing hard on a small area. To compensate for this, I did increase bed temp by 10°C for PET. 2) Differences in cleanness? 3) Differences in bonding layer thickness, or method of applying?
  2. Have you tried measuring if the X- and Y-axis of the printer are perfectly perpendicular? Maybe they are around 89° or 91°, instead of 90.0°?
  3. In the very beginning, on one of my UM2 printers, I had the Z-axis moving down a couple of times during long prints, due to overheating and temporarilty shutting down of the drivers. In mid-print it would fall down 5mm, and then continue printing as if nothing had happened. This was only on long prints, or very intensive use all day. I never had it on the X- or Y-axis, but I can imagine that it is possible too. In my case the solution was to reduce current through the stepper motors. Since then, it never happened again in all those years. If I remember well this was done on the pri
  4. Yes, I can see your viewpoint now. To be honest, I hadn't even thought about existing models from others, it simply didn't cross my mind. 🙂 I design mostly for internal laboratory or hospital use, and 95% of the models don't need supports anyway. So I can design towards easy printability, and I wrote the above from that perspective. Also, I am not using the latest Cura version: for my older UM2 machines, the older versions still work fine, so I can't say much about the latest settings.
  5. In short: - a "CAD-program" is for designing *new* 3D-models, or for modifying existing models. Most CAD-programs create vector drawings, sort of, but then in 3D with solid models. CAD-programs are only for modeling, not for printing. - a "slicer" is for cutting an existing model into thin layers and for generating traveling-paths ("toolpaths") for the nozzle, so that this existing model can be printed layer by layer by the printer nozzle. Slicers are *not* for modeling, only for printing. Cura is a slicer, not a CAD-program. - a slicer may allow you to resc
  6. I think you would best use the "shelling" commands in a CAD program. Or delete the top- or bottom surface in CAD, so you end up with a non-solid surface-only model, which has zero wall-thickness and is unprintable at that moment. And then thicken that surface *outwards* until it is 2x nozzle width, so it becomes a printable solid again. And then design some supports, so that the print can stand upwards or upside down, whatever is required for casting, without toppling over. And if required: add pouring canals, venting canals, cut the mould in two halves, make flanges at the seams,
  7. As I just said in another post. I don't have dual nozzle machines, but due to the lots of reports about PVA-problems, if I had dual nozzles, I would custom design and print most of the support in PLA. And only do a small interface in PVA in-between. And I would use a dovetail to let the PVA grip well into the PLA-support. Like this concept. Then you can design the PLA support structure economically but still very stable. Test this concept on a small test piece first, before doing a large model. And stay with the printer to see what happens during the first attempts.
  8. Yes, that could work. But it could also fuse the support into the model, making it very hard to remove the support without extensive cutting and damaging the model. You have to test this first on a small test-model with variations. If I would have dual nozzle machines, I would use PVA-support in this case. However, to minimise PVA consumption and to maximise stability, I might custom design most of the supports to be printed in PLA, and only do a small PVA interface in-between. And I would use a sort of dovetail to make the PVA- and PLA-supports grip well onto each other. I can't t
  9. As gr5 already mentioned: don't use ordinary PLA: it may work a couple of times, but after a while it gets harder and tends to break. Even when printed in the "right direction". And it has too much permanent creep-deformation under continuous load. I use PET now for snap-fit lockings and keychains. It has enough flexibility to survive, and is still easy enough to print. Haven't tried tough-PLA yet, it's on my to-do list. And indeed, do small test pieces first, until you get them right. I would also recommend that you make keychains, carabiner hooks, cloth hangers, and s
  10. Most consumer electronic components are designed for a long-term maximum operating temperature that you can still touch, although barely, about 60°C. This is heat due to power dissipation in an environment of 25°C. Especially electrolytic capacitors, diodes, small transistors, chips, LEDs,... are sensitive. Power transistors and -amplifiers, and resistors, can usually withstand a lot more. Above that temperature the components usually don't die immediately, but their life shortens a lot. And power drivers need to be able to release their heat. I don't know about Ultimaker electronics, but I do
  11. Glad you found a solution. I like the idea of printing topographical maps. Where did you find good quality images? Another question: do I understand it correctly that the main purpose of this procedure is to round the 4 corners of the image (but not the mountains themself)? Like a plastic bank card? And to "drill" a hole in it? If so, couldn't the same be achieved in Photoshop by changing the black and white levels of the image, and adding a black or white border around it? (Depending on whether black or white is zero height?) And then import it in Cura and
  12. As far as I understood, slicers don't do boolean math on the STL-files. They rather "count walls", sort of. The first wall it encounters, it switches material on. The second wall = material off. Third wall = material on, fourth wall = off, etc... So any objects totally enclosed by another, will automatically be subtracted and become hollow upon slicing and printing. (But correct me if I am wrong on this.) At least, this is how I make hollow watermarks. In the beginning, I made complex subtract-operations in DesignSpark Mechanical on my CAD models, to get these hollows. But this mad
  13. The old Cura versions (14.xx) did something like this: it started at the shortest distance away from the current nozzle position, to minimise travel. However, this causes weird infill behaviour in that it starts filling halfway a surface, for example it starts at infill-line nr. 50 and fills-in to line 100, and then jumps back to line 50 and fills up to line nr. 0. This causes weird travel lines in the infill. And in the end it causes more travel instead of less, because of all the required jumps halfway the infill. Instead of nicely filling from line 0 to 100. Maybe you can also r
  14. Probably not the answer you are looking for, but what about making a human part of the art installation? And let him/her do that? Put him/her on a marble base plate, attach a nice brass label similar to those on stone statues, and shine a spotlight on him/her? That "human piece of art" can handle things like parts stuck to the build plate, or parts falling off prematurely, or cleaning a blocked nozzle. An automaton can't, or not that easy. Further, a human seems way more artfull to me than a silly automaton, and probably way more beautiful too (depending on who you c
  15. Maybe you could try cutting out critical parts or features from the design, and assemble them in a small test piece? Then try printing this until you get it optimised.
  16. If this teflon coupler was on my UM2, I would replace it, if I had printing problems. There seems to be an indent inside the tube, close to the bottom, and the inner diameter seems to have gotten oval instead of round? But this is hard to see for sure on photo, as there could be weird light-effects too. Concerning bonding, I think gr5's method with dilluted white wood glue should also work well. At least it did work well when I tried it for PET some years ago. But my "salt method" will *not* work for ABS.
  17. In addition to the heat-problem described by |Robert|: The resin will most likely glue firmly to the PLA. You would need a very good release coating to prevent that. Test the compatibility of the release sprays or coating with the resin: if incompatible, it might prevent curing, and you would end up with a sticky mess. Release-sprays might make painting difficult; you would need to degrease thoroughly. Concerning heat: in the old days, when mixing epoxy resin in plastic cups, or even in metal (lead) cups, I often saw these melt due to the heat in the left-over resin. So
  18. And try all these things on a *small* test piece first, so you don't waste too much time and material. First inspect in Cura layer-view if the infill pattern does what you want, less or more, and only then print a small test piece. Maybe another option might be: 3D-print a *heavy solid* mould, ply anti-insect mesh over it, and use that mesh as mould for your paper? If you use stable steel or brass mesh, it might be strong enough? Or something else along this line of thinking? You might be able to use gypsym bandage too, like the ones used in hosp
  19. I don't have much experience with it, but ABS is said to decompose fast in the nozzle, if sitting there for too long (=or too hot, or printing too slow), causing clogs. If that is not the case for you, then have you checked that the little fan for cooling the nozzle is working well? On an UM2 this is sitting behind the nozzle, invisible from the front. I don't know where it is on an UMO. This could suck-in hairs and debris, and get stuck. Also on an UM2, a severely worn out white teflon coupler could cause underextrusion after a while. I don't know if an UMO has somethi
  20. Ah, okay, I missed that "straight through" part. I don't dry PLA and PET. Although I do store them in a box with dessiccant. But while printing I just leave them in the printer, sometimes for several days or even weeks. Doesn't seem to make much difference. PET seems to be a bit water-repellent. And PLA seems to get a little bit duller over a couple of years time due to degradation, but I am not sure if that is mainly UV-light, or due to moisture, but it is going *very* slowly over years, not days or weeks. If I would use nylon or ABS, I would dry them thoug
  21. I made a tool to scrape off this primer. It is plied from very tough steel spring (same as used in dental appliances for kids, 1mm thick), so it clamps very well and does not come loose. It hits the nozzle, bends downwards (it's a spring), and scrapes off the blob. Works very well 99% of the time on both of my UM2.
  22. Does it crack along the layer lines, or does it completely ignore layers and go diagonally through them? My experience with PET is that it is less strong than PLA, it will break sooner under high loads, but it can flex more. It will fracture without warning, all of a sudden. Fractures ignore layer lines (indicating good bonding). Also, it has less creep due to permanent loads than PLA. So for keychain mechanisms, carabiner hooks, and snap-fit locks it is better than PLA, since they need to flex to function. However, the PET keychain will break much sooner when it gets stuck in your
  23. The fact that 3D-printing produces smell, means that it produces gasses and/or particles. Composition and long-term effects might not be totally known, in new and rarely used technologies (=rarely used compared to the number of people in general). So I think it would be best to provide some sort of fume extraction anyway, even with the cleaner printing products like PLA and PET/polyesters. Maybe similar to the one in a kitchen? Or a simple pipe with fan that you place close above the printer? If you can not get the exhaust pipe to the outside, you could use a system with active car
  24. That exFAT is probably going to be the problem? I would suggest you buy a couple of thumbnail 8GB or 16GB sticks, and just leave them with the printer. I guess USB2 would be preferable over USB3? Theoretically it should make no difference, since USB3 is downward compatible, but you never know? And speed is obviously of no concern here. :-) They cost less than 10 euro/piece these days. A tiny little thumbnail stick doesn't stick out too far, so less risk of hitting and damaging it. Make sure they are FAT32. I once tried reformatting a 64GB exFAT stick into FAT32 (for another purpose
  25. I never tried it, but I would think the "dot-method" would also work with stacking, on the condition that you merge your model-stack in CAD. And export the whole combination as one STL-file. But obviously you are going to need a lot of support material if the models would be irregular, and I think the risks of something going wrong could increase as you get higher in a stack, e.g. support and model not bonding well, or underextrusion, or running out of filament... So while I do understand the desire to print as much as possible in one batch, especially if you are on tight deadlines or have a h
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