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geert_2

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Everything posted by geert_2

  1. This is what I would rather expect from an atomic pull: see the nice orange one at the bottom. It has still a little bit of white, since I was changing colors from orange to white and back. This is from an UM2 (non-plus) with standard 0.4mm nozzle, 2.85mm filament. On an UM2+ with removable nozzle you might see some additional lines, but the general shape should be similar:
  2. If your model and function allow it (we can't see the inside here), another option might be to cut it in parts, and glue them back together again after printing. Or design some holes for hex nuts and screws, and mount it with screws. This might go a lot faster than other post processing, and might be good enough.
  3. I was about to say that neotko *does* promote hair spray and has a video of it. But he was faster. I use the "salt method": after cleaning the glass plate with water, gently wipe it with a tissue moistened with salt water. Gently keep wiping while it dries into a thin, almost invisible mist of salt stuck to the plate. For me, this gives excellent bonding of colorFabb and Ultimaker PLA, and still good but not perfect bonding of ICE PLA. When hot, it bonds like cyanoacrylate. But when cold, the models come off by themselves and are sitting totally loose on the plate. For the full manua
  4. For some unknown reason, my reply was eaten up by the system and didn't show up on the page. So, let's try again. I use silicon mould release oil: spray it on a tissue and wipe the nozzle. This reduces build-up of molten filament on the outside, but does *not* eliminate it. It depends on the material: it works less or more for PLA, but does not work well for PET, which is much more sticky and "rubbery" when molten. I also tried PTFE oil, which also helps a bit, but less than silicon oil. I haven't tried any other oils. Some time ago, there was a thread in which this was discussed, if
  5. I think it is a good idea to restart from fresh, in case of hard to solve problems. To me, this looks like underextrusion. If the filament is rather hard, as in the case of PLA, and it is bent into a tight corner on the end of the spool, try to manually straighten it. This will give far less friction in the nozzle and coupler. I usually wind it in the opposite direction around a skater wheel of 7cm diameter. Also, I would try the following things: First remove filament and do an atomic pull to clean the path. Then manually insert a piece of filament (with cold nozzle) to see if it slides
  6. XTC-3D is a chemical too. So it may also have health-risks, similar to any other chemical. About XTC-3d, from the Smooth-On website: "Avoid eye and skin contact. Avoid breathing fumes - use in a well ventilated area. NIOSH approved respirator is recommended. Wear safety glasses, long sleeves and rubber gloves to minimize skin contact. This material has a high exotherm (generates heat). Do not mix components in glass or foam containers." The MSDS also mentions that it could cause skin burns. Whatever chemical you use, you need to inform yourself of the risks, and then take proper precausions
  7. In my experience, if the spots are dark brown or black flakes with sharply defined edges, they come from the inside of the nozzle: burnt material from the inner edges of the nozzle, or from around the area where teflon-coupler and nozzle meet. Solution is atomic pulls, and if necessary replace burnt and deformed teflon coupler. If they are bigger and lighter brown spots, without sharply defined edges (more looking like dark honey), they come from the outside of the nozzle: material that has built up around the nozzle, and then slowly burns and leaks down on the print. Especially if you have a
  8. Have you tried a new SD card, or at least cleaned the contacts (blown out with compressed air)? This seems the most logical cause to me. Else, try if all electrical connections on all boards are still okay, not loose. Also those of the mains power supply. Wiggle them. Or maybe spikes in your 230V supply? Flikkering of lamps, motors nearby switching on or off? Electrostatic discharge could also cause stops: I have had that a few times in freezing cold weather: I got shocks whenever I touched anything: doors, lamps, iron tables, lift, just about anything... Also when touching the printer, and
  9. Could something like this be caused by a worn-out nozzle cooling fan? So it doesn't cool enough and filament gets heated too much upwards and gets stuck? Or by a worn-out feeder-wheel, so it doesn't bite enough? Or a combination of one of these, with filament near the end of the spool, so it is wound-up too strong? If you cleaned the nozzle, did you carefully (!) poke through it with a 0.39mm needle? If burnt residus would be accumulated, it might reduce the opening from 0.4mm to 0.3mm or so? (I have sand down a standard 0.5mm needle to 0.39mm and used that.) Or the nozzle touching the aluminu
  10. I took a look at these videos. Very interesting project, but with the naked eye you can already see some diameter variations and deformations in the extruded filament. So I think it could give poor results in a 3D-printer when using standard nozzles of 0.4mm. Might be okay for 0.8mm, on a direct drive printer (without bowden tube), and if you accept lower quality prints. In Europe good quality filaments are available from around 20 euro/spool, which sounds reasonable to me (from a European perspective at least). However, to produce art and as a toy in school to promote recycling of plast
  11. When the traveling speed through the air is high, this easier breaks strings, and creates less chance of oozing and blobs when landing on the next part of the print. But when traveling over "land" (thus over the already printed model parts), this causes ugly dull lines, or even causes the printer to leave behind a sort of "morse code". On the next pass, the head crashes into this morse code, and it accumulates on the nozzle, and then leaks and causes hairs. When the traveling speed is identical to the printing speed, e.g. 30 or 50 mm/s, traveling over land gives a much smoother surface, witho
  12. An easy way around is to make a JPEG-image of every model you design, with the exact same name. Thus the corresponding 3D-model, STL, gcode and JPG-file all have the same name. By browsing through the JPG-files with an image viewer (e.g. IrfanView on a Windows system), you can easily find which file is which. It doesn't work on the printer itself of course, but at least you can easily see which gcode-files to copy to SD-card. In addition you could add the main parameters in the filename of the gcode (max 20 characters before the extension). For example: - model_v33.rsdoc (native DesignSpar
  13. I think it might be a good idea to google the BC817 specs, and test things out with a separate transistor and a test board. If it would go wrong, that is a lot cheaper than a new controller. The very limited specs I found (but I only did a quick search), do list a VCEsat of 700mV at 500mA, which is surprisingly high. I would have expected 300...400mV. And a Ptot of 250mW at 25°C ambient temp. So, at a load of 300mA you could still go over the max power rating in a closed environment with limited airflow and cooling (thus probably 50 to 60°C in summer). So you need to find specs that show all
  14. ABS warps a lot and does not easily stick to a glass build plate. And its smell is toxic. There are materials that are as heat-resistant and strong, but that do warp far less, stick better, and are not toxic: PET, more and more polyesters, high-temp PLA, nylon, PC,... And there will be more developed in the next years. So more and more people seem to move away from ABS. An UM2 has the advantage that you can print all sorts of materials from all a lot of different manufacturers, as long as it is 2.85mm diameter, and not too flexible (as it is hard to push an elastic rubber band through a bowd
  15. In addition to what Labern said: I found that blobs, ringing effects around corners, calibration of the first layer ("elephant feet") and similar deformations also affect accuracy on an UM2. So they may exist also on an UM3 to some degree. Speed and temp have a visible big influence: print a 10mm x 10mm x 10mm test block and manually change speed or temp half way. You will clearly see the difference with the naked eye. If the layer height is 0.1mm, then there are already layer lines, thus ripples of about 0.05mm, in the Z-direction. Blobs and these layer lines generally cause a part to be 0.
  16. Another method that just crosses my mind: you could 3D-print the model, make a silicon mould of it, and then fill the mould with a fiber reinforced composite. Whatever fibers you like. Then you might get something that has the correct shape, but with physical properties closer to the real thing. Or first stuff the mould with fibers, and then pour a very thin liquid composite or polyurethane in it. These methods overcome the layer- and infill-problems of 3D-printing. (Note: concerning my idea of "steel wire" above: if you ever do that, make sure it can not cause amputations if some body part g
  17. Wow, this is a brilliant idea, both the dropping in of supports, and of the pre-printed plate of peggyb. Concerning the use of release sprays: most dental release sprays are based on silicon oil. Some other release methods are water soluble, I think (but I am not sure) they are based on alginate dissolved in water? The problem is that the release method should not bond when trying to remove the support, but it should bond very well when printing, otherwise the next layer won't stick. Contradictory things. So, if you would want to drop in a support block, maybe covering the support with a lay
  18. For the bonding, have you tried the "salt method"? First, thoroughly clean the glass plate with warm water (without soap, this reduces bonding). Then wipe the plate with a tissue moistened with salt water. Gently keep wiping while it dries, so it leaves a very thin, almost invisible mist of salt stuck to the glass plate. For me this greatly increases bonding, and it works even for difficult models (e.g. thick 100% filled). I never use brim or raft for my models, the salt method works well enough. For a full description and photos, see the manual: https://www.uantwerpen.be/nl/personeel/geert-
  19. Regardless of the material, try to print it as hot as reasonably possible, but without burning the material in the nozzle. Also try to minimise cooling as much as possible, but without the model sagging and deforming. And try to print rather slow, so the new layer has enough time to melt well with the previous layer. This will give the best layer bonding. This in addition to (depending on your printer) increasing the flow a little bit, so you have a little bit of overextrusion, as said above by the others. So that all tiny holes in the print are filled well. When I print in Cura and use 100%
  20. The problem with Creative Commons licences is that they basically only apply to creative artwork. It is a sort of copyright protection. So it has to be *art*. Copyright does not apply to technical stuff. Although a lot of people do attach a CC-licence to their technical designs. But this has very little legal value: it can only serve as an indication that your invention existed at that time. If I understood things well... The only way to protect technical inventions, is by a patent. And if you don't protect your own invention, then a competitor can. Then the cost is on you to prove that th
  21. What I usually do with PLA filament is manually unwind a bit of filament and straighten it: I roll about 10cm of filament in the opposite direction around a 7cm skater wheel, thus bending it in the opposite direction, then the next 10cm, next 10cm, etc., until I have done about 1 or 2 meters, enough for the print to come. This takes only a few minutes. Then I wind it up again on the spool. But now it is sitting very loose. This gives far less friction in the bowden tube and nozzle, improves print quality and eliminates underextrusion. Maybe you could try that? I guess in your case it is the
  22. In my experience, white PLA is often easier to sand than other colors. I am not sure why, maybe because it requires a lot of filler particles to get a really white and opaque look? ColorFabb filament is a bit more fibrous (if that is an existing word? - showing more fibres when sanding). On the other hand, ICE filament (distributed by Trideus in Belgium) is a bit more brittle and sands more into fine powder. When printed fresh, both have a satin gloss look, but after sanding of course, it gets as matte as you want. Disadvantage of white is that you see every spec of dirt on it. Especially w
  23. I haven't tried clear PLA yet. But for PET I found that printing slow helps best: 20mm/s for a somewhat clear result. Temperature plays a lesser role at that slow speed: just don't print too hot (bubbles, fog), and not too cold (doesn't flow well into corners and thus leaves unfilled areas). A little bit of overextrusion also helps to push the melt into all holes, and to avoid voids. Try 105 or 110%. When the model is only a few layers thick, underlaying text shines through nicely. But the diagonal infill lines stay visible. Thicker models always get a "frosted glass" appearance. So you can
  24. I just realised that my text above could be interpreted in different ways. So I would like to make clear that up till now we are very happy with our two Ultimaker printers, with the service, and with the openness on the forum and in the documentation (e.g. the technical drawings). According to my collegues, they don't find such openness in some companies with huge +100.000 euro 3D-printers. It's just that I want to make sure that your management is fully aware of the importance of this currently good and open atmosphere, and that they need to make sure it stays so in the future, for all the
  25. One more comment: I do understand the Ultimaker fear that some people may abuse the printer or materials in an attempt to sue and to get a huge damage payments. Like those idiots who wash their pets (pet animals, not PET plastic) in a dish-washer, and then dry them in the microwave. And next, of course, they sue the manufacturers and demand 100 billion dollar. Criminal lawyers working on a 25% margin of these wins, and idiot judges, are often all too happy to join in. This tendency is now coming to Europe too. So I do understand that any company should legally avoid that huge risk. But the w
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