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geert_2

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Everything posted by geert_2

  1. I have two UM2 (non-plus, thus the version before the UM2+) printers and they are still fine for what I need them for, mostly long flat models that need no support. So if you only need one color and no dissolvable support, it should be okay. But I would suggest that you make a testprint first, to see if everything still works fine, and the printer isn't abused or damaged (e.g. by dropping, printing abrasive materials, things burned out, damaging mods,...). This is usually repairable, but then the costs might no longer make it the best choice.
  2. No, I didn't change the flowrate, so it was the standard for PET on my UM2, and I left it at 100% on the machine. I had to look up temperatures for these test blocks (I had written it down somewhere): - all were 215°C, except: - 0.06mm layers at 10mm/s (unpolished block) = 210°C - 0.06mm layers at 10mm/s (polished block) = 200°C - 0.4mm and 0.3mm layers at 50mm/s = 225°C due to the much higher extruded volume The recommended temp range by the manufacturer is: 215...250°C, so I am at the lower edge. I once tried higher temps too, but that gave more bu
  3. On my UM2 (=single nozzle) I get watertight PET parts by printing at low speed, low temp, thin layers, no fan. Usually 25...30mm/s, 215°C, 0.1mm layers, bed 80...90°C, 0.4mm nozzle. But 0.06mm layers are even better. At slow speed, print cool to prevent the PET from decomposing and getting brown. Layer bonding is excellent: when overloaded, fractures run diagonally through parts, disregarding layers. Main disadvantage of no fan, is that overhangs and bridges are terrible since the material won't bridge well. But for my long flat models, this usually is no problem.
  4. Ik denk dat niemand nog een raft gebruikt. Maar waarom zou je niet gelijk op de glasplaat printen, dat werkt prima? Als je perse een soort raft-achtig ding wil, kan je misschien een dunne plaat ontwerpen in CAD, en die printen met beperkte infill (ca. 50%? - Probeer op kleine teststukjes), en zonder top layers?
  5. Maybe move your bed closer to the nozzle, or make your first layer thinner, 0.1 or 0.2mm? I get really glossy bottom layers with both PET and PLA. Print on a glass bed, not on tape or some other rough surface. Hard to see in the photos below, because the reflection is out of focus, but these bottom surfaces are high-gloss and do reflect like shiny injection moulded parts. The "copyright design ..." watermark text is hollow and sitting 0.5mm below this glossy bottom surface. For reference: text caps height is 3.5mm, character legs are 0.5mm wide. High-g
  6. I don't know your printer, so this is guessing. To me this looks like a hardware issue. Maybe some connectors that are not seated well or are oxidated? Or electromagnetic noise on the power line or environment? Motors starting or stopping causing pulses, or sparks you get in cold dry winter weather? Or a cell phone going off nearby? This sort of things can easily lock up electronics. (Cell phone often locks up my USB-keyboard and mouse.)
  7. If you want to examine a 3D-print in detail, but you don't have a microscope or good macro lens. Try using your webcam or smartphone, and add a close-up lens in front of it. Then watch the picture in full size on your computer screen. You could use any old camera lens as close-up lens, provided that it is concave and does not cause too much distortion. Or buy a dedicated smartphone adapter with close-up lens. Magnification will differ depending on its focal length. If required, design and 3D-print a lens holder for mounting the lens onto your camera. The results are not
  8. I don't know your printer, so just guessing... Maybe a blocked nozzle, and then the filament cooked, burned, and spilled all over, due to sitting too long in the hot nozzle? Or something along that line, where the filament got stuck? Some materials burn away rather cleanly or leave black coal dust (like the PLA that I have), but some burn into a sort of glossy varnish that is hard to remove (like the PET that I have).
  9. In the beginning I also had this problem. But now it is extremely rare, even though I have lots of models with small openings. Maybe you can solve it by adjusting nozzle height a bit closer, or changing temp or speed of the first layer? Or improving your bonding method? Also, a thinner first layer gives better bonding and less risk of the first outline being ripped off, on my printers. A 0.2mm layer sticks *much* better than a 0.3mm for PET and PLA: this is just my observation, but I am not sure why.
  10. The whole world has switched to the metric system officially, so I think we should stay with the metric system. And not go back to medieval units that don't work well in high-tech environments, no matter how much sentiment there is in it. I grew up with "horsepower" for car engines, which now has changed to kilowatt. I regret this, because the horsepower-number is higher and thus more impressive than kW, and because I grew up with it, but kW makes calculations sooooo much easier. No more weird random conversion factors. The USA has switched to metric in 1875 (yes, 18...
  11. I don't have resonance problems (2x UM2 non-plus), so I can't test this. But I think this is an interesting approach. The only question is: if people notice resonance, how are they going to find out which frequency it is exactly? If I feel a vibration, I can't tell if it is 5Hz, 7Hz, 10Hz,...? At least not without a known reference next to it. Further, it is very hard to feel/hear whether there are lower or higher harmonics on it, which could also trigger the resonance. Maybe you could find a printing test pattern that "resonates well"? Or a printing pattern that causes
  12. A few years ago I lubricated the edges of the belts with hard silicone grease, with the same effect: sound gone. It seems to be the edges running agains the flanges that cause it. Only lubricate the edge, not the belt tracks, otherwise they might jump teeth. And don't use petroleum or plant or animal oils or fats: these might damage the rubber. Hard silicone grease is chemically almost inert, and it does not leak away. It is the same sticky stuff used to lubricate movements of binoculars and microscopes, in which you can't have oil leaking onto the lenses.
  13. While I don't have much experience with Ultimaker PLA colors, I only used a few, I have seen a similar effect in other brands. It seems the pigments and other additives to create the desired color, such as filler particles for white, gold, silver, glitter, pearl,..., have an effect on viscosity, stickyness, optimal temperature and flow, etc. Some colors tend to give more strings and hairs, some tend to stick more to the nozzle leaving residu, some tend to show layer lines much harder, some tend to create more blobs,... Slightly transparent colors hide the layer lines a bit better, while white
  14. To me it looks like your biggest problem at this moment is basic handling of a Windows computer. Starting with 3D-printing is then like trying to do aerobatic stunts in an airplane, before you can't take fly it safely. I think you would make much faster progress if you would first follow a good course on using computers, just the general principles: how files are handled in Windows, how and where they are stored, zipping and unzipping files, installing programs, etc... Yes, this will take you at least several days, maybe a week. But you will soon win that time back 10 times.
  15. I have had this with PET, when using a bonding of dilluted white wood glue. Bonding was absolutely excellent, too excellent. It chipped while cooling down, even without pulling. Now I wipe the glass with a tissue moistened with salt water, prior to printing. This method slightly reduces bonding for PET, but avoids chipping (contrary to PLA where the salt-method greatly improves bonding). PET models that need lots of cooling now tend to warp slightly, but models that can be printed without any cooling come out fine without warping, and without chipping, such as my typical long flat
  16. Oil *could* be a bad idea, depending on the oil and silicone combination. Some chemicals inhibit curing of silicone, such as sulphur, mint, some oils,... Try compatibility with a little bit of silicone beforehand, or otherwise you might end up with a half-cured mess that is very hard to clean from the mould. Further, make a small test piece first with the same angles of side-walls as the real model, to see if you need smoothing of the walls. Silicone flows into the tiniest pores, so it gets a very strong mechanical grip, even the non-stick mould-making silicones. For complexer mode
  17. Up till now PET has survived undamaged and unwarped in my car, even in our recent very hot summers with Mediteranean weather, quite unusual for Belgium. Contrary to PLA that even did not survive a mild spring or autumn sun. I think PET can have around 80°C? If you would need it for autoclaving and desinfecting at 140°C, that would be a different story.
  18. Excellent info from p-kimberley above. What is said, is absolutely true: any layer lines, blobs or irregularities will show up in the cast, and they will make it *much* more difficult to remove the cast from the mould. I have made silicone moulds from 3D-printed models. It goes as follows: first 3D-print a model, including what will become the filling canals and venting holes. Print in multiple parts and assemble as required. Carefully remove all blobs and irregularities, and smooth the model, as any defects will show up. Stick the model to a plastic base plate, or provide some for
  19. Maybe you could do it with a trick? Put four tiny dots outside of each corner of your models. So that they form an imaginary rectangle that encloses your design. Or draw a custom skirt around your design; just one layer height is sufficient. Then that surrounding skirt or border should always be placed in the same position on an empty bed. Keep that skirt, or those four dots, in place, and then correctly place the rest of your components in this space, and save as separate files. When slicing, the skirt (or the four dots) should determine the position on the glass. At least, that is what I wou
  20. The cones were printed on my UM2 printers (orange on printer nr.1, white on printer nr.2), several years ago. As far as I remember, they all have 0.1mm layer height, but they may have been printed at different speeds, flows and temperatures (I don't remember). The main goal at that time was to see the effect of using a dummy tower (=the square tower) to increase cooling time of fine details. Otherwise the hot nozzle stays on top of the model, so it can not cool down and solidify. I have the other model printed as well, but I don't have photos. I will see next week (too dark here no
  21. How do they handle bending loads, and impacts such as hitting stones on the beach?
  22. Now it looks a bit like those chocolate coins wrapped in silver paper, that we used to get for Santa Claus. Isn't there a way to make the plating chemically bond to the print? Somehow etch and chemically activate the outer layer? Or plate a first layer with a mix of glue and metal, or something along these lines? How do they do this for plastic car "chrome" strips, wheels and radiator covers?
  23. Maybe you could consider this: make a test design that includes all your typical problem areas. For example: long flat bars (do they bend?), thin pilars (smooth, stable?), steep overhangs, small holes (size?), smooth curves (layer lines?), fine text, watermarks, sharp corners (ringing, rounded?), thin plates, or whatever else is typical for your designs. But keep it relatively small so it prints fast enough. And then have that test model printed at: (1) the printers best quality, (2) default quality (well balanced between speed and quality), and (3) fastest draft quality. Of course
  24. To me the second photo looks like overextrusion in general. Then molten material is likely to accumulate on the outside of the nozzle, after some time it gets burned, sags, and then gets deposited on the print in ugly brown blobs. Happens easily with PET, but I have also seen it with PLA. Watch closely while printing: it will be well visible if this is the case indeed. Printing slow and cool generally improves this in my prints (on UM2). But I don't mind some overextrusion in the first layers (=nozzle too close to glass), because that gives shiny flat undersides and good bonding.
  25. I just think about this: if you live in Belgium, the Netherlands or West Germany: we have an independant and quite good distributor of 3D-printers from various brands and various technologies: the company Trideus, in the province of Limburg, Belgium. It might be a good idea to go to such a distributor, have a look at their demo-prints, have a talk and ask prices. Since they have lots of brands, they are likely to give more honest info. For them it is not so much the brand that counts (they have almost all), but if the customer is satisfied enough to come back next time. So you are more likely
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