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geert_2

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geert_2 last won the day on October 18 2023

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  1. Could it be that the nozzle-cooling fan is not working, and the heat creeps up into and above the nozzles, weakening the filament and thus blocking further feeding? That could produce similar effects. Those fans could suck-up debris and hairs of filament, and get stuck.
  2. I think you will need to provide more specific info: which printer and model, which exact material, which settings (e.g. nozzle and bed temp, and all the rest, project file), bonding methods you tried, and especially close-up photos and maybe videos.
  3. In case of a cube, you could think of "watertight" as it being one chunk of solid metal. However, if that cube is made of six cardboard sheets glued together, with seems and gaps between the edges, then it is "not watertight". In old computer games you often see such gaps between walls, where the edges do not lign-up correctly, so these models are not watertight. Models made with SketchUp usually are not watertight either, because that program was originally made to design visual 3D-buildings for Google Earth, not for 3D-printing. For 3D-printing you need a true solids modeler.
  4. Polycarbonate is known for stress-cracking. Car headlights in PC also get dull from microcracks, so manufactureres tend to go back to plexiglass (PMMA) now. If you can find PET or PETG that can handle 100°C, it might not be the worst choice. PET should be food-safe, as it is used in all sorts of bottles and other food packages. And it prints reasonable well with decent layer adhesion and not too much warping. If the available space allows it, design the part way sturdier and fatter than the original part. Make it more "flintstone-like". And print slow, without cooling fan (if there are no overhangs), and in thin layers for best form fit, best layer-adhesion and minimal air-entrapment in the model. I never tried annealing PET, so I don't know if that is possible. PLA can be annealed, but it deforms so much, and in different ways for different brands, that it is not worth trying in my eyes. It is probably not going to fit anyway, unless you do a lot of testruns. Another solution could be: print the part as accurately as possible in PLA. Post-process for a perfect fit (but don't use it, just test-fit). Then make a silicone mould around that part. Spray the mould with silicone release-spray generously, so it is totally soaked in silicone oil, and let it dry well. And then cast some very strong filled epoxy into that silicone mould, e.g. sand-filled, metal filled or glassfiber-filled epoxy. That should give very strong parts. Chances are that your original part was glass-filled nylon or ABS too. Try to find a food-safe epoxy, or at least a not-too-smelly one, and let it cure well, preferably at somewhat elevated temperature, and clean thoroughly.
  5. Why single layer? That is going to be very fragile and might break up in steep turns or rough landings?
  6. I think you should ask that on a Bambu forum. People here are using Ultimaker and Ender printers and probably don't have any Bambus.
  7. Wow, 96-98% is pretty good. Thanks for the info. You know, in the back of my head, I still had the idea that 3D-printed metal parts were rather like sugar cubes for the coffee, sort of, but then in metal... 🙂
  8. I often find that each model needs its own settings, depending on the geometry and purpose. Some need combing, some can't have it. Some need a lot of cooling, some can't have it. Some need thick layers (e.g. for overhangs), some can't have it (e.g. for fine quality and watertight objects). Some can print fast, some can't. Some need a brim or custom skirt, some not. It all depends on the geometry, purpose, materials, fitting- and quality requirements. Even different colors of the same material might need different settings, because some flow less good than others: e.g. high-filled colors like white, yellow, lightgreen often flow less than others. If you are going to sell things, I think you should offer the STL-model (for people who do the printing themself). Or if you are doing the printing yourself, slice each model individually according to its needs, and to the customer's wishes. This for optimal quality and customer satisfaction. Otherwise they are not going to come back. Building a good customer base requires a lot of effort, it can't be done on a quicky. (That was one of the reasons back in 2014 why we bought our own 3D-printers: the parts we had printed externally, were soooo badly printed, that we could easily do better, and it was worth investing in our printers.)
  9. This is probably not the answer you want to hear, but *almost all* plastics come from biomaterial. Although some of that is a bit older, maybe a few million years... Wood and leaves fall to the ground, get covered under sand, and become coal, which can then be used to make gas and plastics. In the sea, fish and plants die and sink to the bottom, decomposing into a thick smelly goo, called fossile oil. Than is pumped up, refined, and turned into all sorts of fuels and plastics. All this carbon that was once alive on the surface of the earth, when the whole planet was green and covered in forest, has gotten stuck under the ground in the form of coal, oil and gas. Thus it is now dead carbon. So, to save the earth, we need to dig up all this dead carbon, burn it so it becomes CO2, which is then food for plants on land, and algae in the sea. Both CO2 and H2O are the most important life gasses on earth, without which there would be no life at all. Currently there is a lack of CO2, so plants are now starving from hunger. Optimally, we would need 10x more CO2 (more, not less!!!) for optimal plant growth: then plants would grow 6x to 7x faster, and all current deserts would become green again, just like in prehistory, when there was 10x more CO2 indeed. The formula: CO2 + H2O + fertilisers + sunlight ---> C-H-O-chains + O2 In words: carbondioxide + water + fertilisers + energy from the sun ---> gives plants, wood, juices + free oxygen Wood is stored solar energy. That is why it gives so much heat when burned: the solar energy is then released again. Only plants can convert solar energy into food, and convert CO2 into free oxygen. These plants are what we eat, and the oxygen is what we breathe-in. By burning the food in our body, we again release the stored solar energy in our bodies, so we get warm and we can move. We are living on solar energy, via food. In thick forests it is much cooler than on bare rock in the summer: this proves that plants do absorb the solar energy and convert it into wood. Thus more forest = cooling down. And more forest also means more food, more habitat for animals and people. The reason why forest is cooler than bare rock in hot summer, is because almost all the solar energy is captured by the trees, and converted into wood, green, and juices. So that solar energy can no longer heat up the earth, because it is no longer there, it is eaten up by the trees. That is why CO2 is a cooling gas, not a warming gas, contrary to popular belief in brainwashed people that have no clue about science, chemics and biology. They should go to school and study these sciences, and do field experiments, and open their eyes. So, to cool down the earth, we need more forest to "eat up" all the solar energy, and to convert it into wood, leaves, and juices. So we need more trees. And to get more trees, we need way more CO2, preferably 10x more. The above formula only works when there are enough ingredients to the left of the arrow. Without plenty of water, carbondioxide, fertilisers or sunlight, there is no reaction, and thus no wood, no green, and no free oxygen. Today we are at the absolute lowest level of CO2 that plants can barely live: 0.03%. Below 0.02% most plants will die soon. We are dramatically low today. So, to save the earth, to cool down climate, and to make the whole earth green again with plenty of space and food for everyone and every animal, we need to dig up and burn as much fossile fuels as possible, to pump as much CO2 into the air as possible. So we should go drive with big V8-engines that drink fuel like mad. This is pure proven science. Even drug dealers know this: that is why they add huge amounts of CO2 into their green houses, to get way more drugs. Only some politicians and some unschooled people do not want to know the facts. So I see nothing wrong in using plastics: it helps making the earth greener, producing more trees, more food, and more habitat for animals and people, and it helps cooling down the earth. So don't feel bad about it. As I said, probably not the answer you were looking for. But it is the proven scientific thruth.
  10. I think you need to keep your nozzle cleaner. I always wipe it immediately after a print completes. If there is stuck residu, I gently (always very gently!!!) scrape that residu off with a very soft brass screw thread, whereby the treads act like a soft file. Never use steel or hardened things, that could damage the nozzle. Sometimes I oil the nozzles when hot, with PTFE oil. This reduces the amount of material sticking and accumulating onto it, but it does not totally eliminate the effect. What can also help against edges or corners lifting, is using a brim. Or use a skirt that is very close to the model, e.g. with 0.1 to 0.3mm separation: that separates easier than a brim, but still helps in keeping corners down. Or for stubborn cases, design a custom brim into your model in CAD, in such a way that it is very stable, but still easy to remove. This may require quite a bit of trial and error, on small test pieces, just to find the optimal concept. Apart from this, I have no experience with your material. Maybe try different glues or adhesion-sheets (like wiping dissolved wood glue onto the bed, tape,...). For my PLA and PET prints, I just *never* use glue..., so I have no idea about your material.
  11. If you print them for real use, and not for demo-purposes: aren't they too brittle to screw into wood? I even occasionally snapped standard bolts and screws, before I began to use copper grease on metals, or a drop of oil on woods for lubrication and thread cooling.
  12. I also print PET (or PETG, I don't know) at the lower edge of its temp range, sometimes below its recommended range, and at far lower speeds than PLA. When molten, PLA becomes sort of yoghurt and flows easily, but PET rather stays like soft, rubbery chewing gum, it does not like to flow well. PLA bridges well, but PET tends to snap and fold back onto itself, so instead of a nice bridge I often get a sort of "grapes" accumulating on the edges. And as said before, it tends to accumulate on the nozzle, causing a thick blob that slowly sags onto the print every so many minutes. The blob gets brown due to decomposing, if the temp is too high. I use no cooling fan, and have no problems with warping. I find PET is best for things that need a little bit of flexibility, like snap-fit mechanisms. But it is not stronger than PLA, only more flexible, and has a bit less creep under load. And it can go up to 70°C where PLA can only go to 50°C, and under load even not that. So PET is suitable for use in a car, PLA not (don't ask how I know). When printing without cooling fan, layer adhesion is good, I have no separation. Clarity in transparent PET improves a lot when printing slow and in thin layers, indicating that there is far less air entrapped between the extruded sausages. All bad effects are minimised when printing cooler, slower, and in thinner layers. A few examples: Ruler is in cm an mm: PET can be chemically smoothed with dichloromethane easier than PLA, and it does not seem to dry out in het months after treatment, contrary to PLA that tends to develop microcracks. Both parts are identical, but one is smoothed to remove layer lines: much more hygienic for use in hospitals, easier to clean. Transparent PET printed at different speeds and layer thicknesses: blocks are 20x10x10mm. Printed at 0.4, 0.3, 0.2, 0.1 and 0.06mm layers, top row at 50mm/s, bottom row at 10mm/s if I remember well. The yellowish discoloration is from sitting long in the nozzle at very slow speeds: it begins to decompose. Temp mostly is 215°C, except the thickest layers at 225°C, and the thinnest at 200 or 205°C. The watermark with my name is sitting halfway inside the block, it's hollow text, and only readable at low speeds and thin layers.
  13. Youtube is a good place to find tutorials, especially for very specific objects. Search for "cad how to design a [object] in [3D-program]", and similar. For the free software DesignSpark Mechanical (from RS-components), you can also use the basic manuals of Spaceclaim, since DSM is a limited version of Spaceclaim.
  14. Indeed, as gr5 says, preferably post pictures instead. Most people do not trust zip-files because they could contain virusses or hacking software. That could be done on-purpose by hackers, but also happen by accident without the honest poster knowing. So a lot of people are not going to risk opening a zip-file. I am not saying your files might contain anything irregular, probalby not, but I am not willing to take the risk.
  15. I have seen this occurring when the extruded "sausages" do not bond perfectly to the glass, or when there is a bit of overextrusion, or the nozzle too close to the glass (so the melt spreads out too far). The sausage is layed down but its edge curls up just a tiny bit. On the next infill pass in the opposite direction, these curled-up edges are remelted and pushed down again onto the bed. If only part of it curls up, and part not, then you could get this effect too. Because the originally layed down sausage and the remelted and pushed down again edge spread in a different way, and overlap in a different way. This happens if bonding to the glass is not equal over the surface. But you have to keep watching very closely while printing, to see it happen. You can see the effect to a lesser degree in these two prints: a tiny bit in the first model... ...and a bit more in this model. Note: the vagueness and indents are because of tests with solvents that weakened and deformed the model, making the circular indents on the other side shine through. I am not sure it is the same effect in the topic starter's photos, but it could be?
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