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Everything posted by geert_2

  1. The thing is that a lot of spools are not transparent. They only have a small window, and they *do rotate*, and so does that window. So you can not see nor measure from the axial side how much filament there is still left on the spool. You would have to measure radially, thus from the top (sort of), and then calculated differences in distance by means of the reflected light, similar to a radar. And then calculate radiusses and circumferences for each winding, and the amount of windings. And then things soon start to get very complex. When you have spools that are very loosely wound, or materia
  2. I guess redesigning it to make it smaller is not an option, as probably some elektronics have to fit in? I would consider printing it in two parts, flat on the glass. But then it might be a good idea to have some overlapping areas in the side walls, if the design allows for it, so you can glue it better. See the pic below for the concept. Another option might be to print it diagonally on its side, from front left to back right, instead of slanted vertically? Then you only have to provide supports the top edge that is overhanging, and the bosses. To mi
  3. Multiple lines of skirt (=an outline around the model, but a few mm away from it) do solve the underextrusion due to the oozing before printing. I usually do between 3 and 10 lines of skirt, depending on the size of the prints: the most for small prints, the least for larger prints. I don't have problems getting them to stick, even if the beginning stutters a bit. Also, it gives you the opportunity to check if your bed leveling is okay, and it purges the nozzle and removes some of the dirt in the nozzle that often comes loose when starting a new print (=tiny black flakes in the mel
  4. Have you tried blowing the readers out with compressed air? Quite often there are dust and hairs accumulated in the slots, causing bad contacts between the cards and slot. This has helped several times for me. Do the printers fail on all cards, or on only one or two cards (but in all printers)? You could also have a bad SD-card, or a bad batch of SD-cards. Or you could have a program that has corrupted the cards. Or accidental corruption due to power loss or removing the card while writing to it. That sort of things. I am not saying these are the solutions (you may have
  5. I think so, otherwise the problem should have moved with the glass. So it must be or a bent bed, or incorrect leveling, or both? If you would have a steel ruler or a steel bar that is totally straight, maybe you can put that on the bed, and see if it gives perfect contact everywhere? Or does light shine under it in certain areas?
  6. What if you rotate the glass 180° (=front right becomes left back)? If the cause would be uneven thickness of the glass, the problem should move too. If the aluminum plate is bent, or leveling is the problem, then the problem should stay in place.
  7. When reading my text again, I see that it could be interpreted in multiple ways, and it was not clear enough. I was not trying to convince you to switch to PET. :-) But I was wondering if the same principle that I use for PET (=printing very slow, very thin layers, very cool) would also work for your ASA materials, if you have tried that?
  8. These photos show the effect of acetone on a part that I left on purpose in acetone for way too long (more than an hour), just to try what would happen. It got weak, lost its spring-effect, and cracked. Its strenght recovered somewhat in the next months when drying, but not fully. Now I broke it. So you can see how deep the acetone penetrated and cracked the model. The inside seems to be still chemically affected, as it broke in a weird way, with very different inner and outer fracture surfaces. This is yellow PLA/PHA from colorFabb. The fracture surface is ca. 6mm x 4mm.
  9. I don't have this material, but my experience with PET is just the opposite. On my UM2-printers, I achieve the best bonding and best fill rate (=least amount of unwanted voids inbetween extruded sausages) at very low speeds, thin layers, and low temperatures. Typically 20...30mm/s; 0.06...0.1mm layer height; 210...215°C nozzle temp; and no fan (!). Due to this slow speed the material has plenty of time to melt and bond with the previous layer. Due to the thin layer, the heat from the nozzle is transferred well onto the previous layer. And due to the low temperature, even 5...10°C b
  10. Thanks for showing the idea. I have seen this concept for embedding nuts, but I hadn't seen it for other stuff like reed relays, sensors and magnets.
  11. I don't know what printer that is, but to me it looks like or bed adhesion is not good enough, or the nozzle is too far away from the bed. Then for small circles it tends to pull the printed string off sideways. Just watch closely what happens when printing.
  12. Whether you use a prime blob or not, I think it is a good idea to use a few lines of skirt anyway. This gives an indication if your bed is calibrated at the correct distance, and you have time to manually adjust it if desired (at least on UM2 printers, I don't know about others). You also have an indication if bonding is okay: if the skirt would already fail to stick, the rest will too. And finally, if the nozzle is getting dirty, tiny flakes are often released in the very beginning, showing up in the skirt. Also, for my UM2 printers I added a wire to catch the priming
  13. The problem is that systems with sensors and wires on rotating stuff are prone to all sorts of errors: false positives, and not correctly detecting real amounts, due to the spool rotating and the "sensor window" being covered by that rotating spool. These things will complicate the situation. But recently there was a post of a guy who printed labels with a measuring scale showing the remaining amount. Then he glued the labels to his spools. The idea was similar to the scales on glass bottles and measuring jars in the kitchen. This actually is a nice and simple solution, I think. It
  14. Interesting. And how is layer adhesion? Can you pull layers apart, or is it melted into one solid block? PS: I think the word for half-transparent is "translucent": when some light is still shining through, but it's not water-clear. Like the model below (this is colorFabb PLA/PHA, "natural"), which looks like uncooked spaghetti.
  15. This is what I standardly get by printing on bare glass (0.4mm nozzle). The lines are visible, just like they are visible in injection moulded parts where material flows meet, but the indents are very small. The overall appearance is high-gloss (see the lower half of the first photo: here I focused on the fan cover mesh reflected in the bottom).
  16. If you print slow and with thin layers, so that it flows well into all corners, then density is already quite high with the current 90° alternating strategy. For example with 0.4mm nozzle at 0.06mm layers. I don't think density can be improved very much. However, at high speeds and thick layers, there are a lot more voids. See the test blocks below of 10mm x 10mm x 20mm. The front one is as printed, the back one is polished to remove some of the outer layer lines and show the inside. The clearness indicates that there are not too much voids inside. This is transparent PET.
  17. Yes, I can see what you mean. It is a matter of quantities indeed. I'll mention that aspect in further texts. Maybe I should have said: "CO2 is a life gass, and no poison at all in normal and slightly elevated quantities". About 0.3% (=10x more than the normal 0.03%) is still almost nothing. In poorly ventilated classrooms the concentration can be much higher than 0.3%, and we are all still alive. But in too high quantities it can kill indeed, just like almost anything. Drink 10 liter of water in an hour, and you are dead due to water-poisoning. But water is an essentia
  18. Randen van overhangende delen hebben de neiging om op te krullen, waarna de nozzle daar met geweld tegenaan kan botsen. Deed zich dat hier ook voor? En dunne paaltjes gaan soms wiebelen. Verder: kijk eerst eens in Cura met transparant view en x-ray view of er geen defecten in het model zelf zitten? Indien het okee is, probeer dan eens in een ander materiaal te printen? Gewoon standaard PLA of zo. Dit lijkt een "filled material" te zijn, dus met partikeltjes, en die zijn meestal veel brosser dan gewone materialen. Kan je de afgebroken paaltjes manueel makkelijk verder br
  19. Concerning plastics burning: some burn very dirty indeed, especially ABS and PVC. But some burn very cleanly, like PE, PP and PLA, releasing almost nothing but CO2 and H2O into the atmosphere. Such exhausts can easily be filtered with equipment similar to the filters and catalysers in cars. Concerning the effect of CO2 on plant life: you will find lots of sources if you Google for: - plant growth versus co2 level - real co2 science CO2 is the bubbles in sparkling water, cola and beer. It is the bubbles in bread. It improves the working of our stomach. And it i
  20. Thanks, good idea. I have seen the concept before (metrinch wrenches in shops), but never tried it in 3D-printing. Do you have a rule of thumb, or a formula, for designing the optimal curves? Or do you do it just visually and based on experience? This isn't a standard shape in my 3D-editor DesignSpark Mechanical, so I will have to draw it manually. This concept of "recessed corners" (I don't know a better description) could surely help to reduce the accuracy problems in corners due to ringing, thickening and rounding effects. Also in other designs. Maybe the original po
  21. Something that just occured to me: if you are going to recycle spools by sending them back, it might cause way more harm than it solves. You need to pack them into cardboard boxes, and stuff the box with thick shock-absorbing paper or cardboard. This requires cutting down trees to make cardboard. And it requires a lot of transport: if you are going to have DHL drive 20km to collect your packages, that comes with an environmental cost too. The cleanest option is to re-use them at home, or for your neighbours. Apart from that, I think throwing them in the regular waste co
  22. Layer lines, blobs, strings, hairs, ringing and thickening at corners, always cause inaccuracies. I usually make a couple of small test models to try which tolerances work best for a particular model feature. Depending on the required fit, I usually take between 0.1 and 0.5mm tolerance for my UM2-printers. Printing slow and in thin layers also helps. For example for inserting M4 nuts (which have a diameter of 7.0mm between flats for steel, and 7.2mm for nylon, in my inventory) into a 3D-printed cage, I made this test model with 7.2, 7.3, 7.4 and 7.5mm hex cages. Then I tried what worke
  23. An option you could consider is to design part of the supports in CAD, in the same material as the model. And make these as efficient as possible, and as sturdy as required. But leave a gap between the support structure and the real model, don't connect them. And then let Cura fill-in that gap with its automatic supports. You could design a dove-tail on your own supports, so that Cura's PVA gets a good mechanical grip on your custom support. I am not sure if this would work well (I only have single nozzle UM2-printers), but it might be worth trying? Anyway, I usually de
  24. In moist weather, printing on bare glass didn't work at all for me, in the beginning. Neither did the glue stick (but looking back, I think I used way too much glue). That is why I developed my "salt method": after cleaning (only alcohol, no detergents, no soap!!!), then wipe the glass with a tissue moistened with salt water, so there is an almost invisible mist of salt stuck to the glass plate. For PLA this greatly improves bonding when the glass is hot. But there is no bonding at all when cold, so this makes model-removal easy. For the full manual, see here (and then scroll down
  25. I only have single nozzle UM2 printers, so in my models everything is in the same material anyway. I need to remove these supports manually by cutting or plying. That is why I design-in features to make their removal easier (such as the ribs on top of the support). Everything, also all custom supports, are part of my CAD design, and I switch off any support in Cura. For multiple nozzle printers (UM3, S5), I think in Cura you can assign different nozzles (and thus different materials) to different parts of the model. But I don't know how, so I will leave that to others here. But as
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