Jump to content
Ultimaker Community of 3D Printing Experts

geert_2

Ambassador
  • Posts

    1,941
  • Joined

  • Last visited

  • Days Won

    28

Everything posted by geert_2

  1. Not an official answer, but based on common sense, I think the problems are not going to be the plastics. Kids wear plastic rings and armbands all the time, and most clothing is from plastic these days. But it will rather be the tiny openings in which bacteria and dirt can get a grip. So you would want to make your prints as smooth as possible, with as little tiny openings and layer lines as possible. PLA is bio-degradable, so theoretically bacteria could eat it. But I have printed PLA sifts for the sink in my laboratory, and after years of use in the wet and dirt, they don't seem to be affected too much. So, unless a person is very sensitive and has contact allergies, I wouldn't expect problems from the plastic. But maybe from dirt/bacteria in the layer-lines.
  2. Another thing I forgot: smooth the mould prior to casting the silicone. Every detail will be replicated, so layer lines will be visible in the silicone too. This will make removal of the part from the mould more difficult, and it will make it more difficult to clean. So, sand, polish, chemically smooth ("acetoning"), or paint the mould. This is well spent time.
  3. Yes, if you have the tools, I can imagine that heatsinking-in real knurled inserts is the best. Probably the strongest also, less likely to go rotating. For completeness, if the design allows it, and if forces are low, inserting the nut via side-openings might also be an option. See the pic below. I use this for light clamps. Advantage is that this is very easy.
  4. This is a good This is a good idea, worth remembering. This concept could be usefull for lots of other models too.
  5. One extra note: if you use a thin, slow-curing silicone for casting, be sure that the lower half of the mould is absolutely water-tight. Silicone slowly creeps into the tiniest openings, even only microns wide, and would leak away. With thick, fast curing silicones, this is less of a problem, as they are already cured before they have time to leak away. If there are non-watertight seams, you can close them with plasticine or wax. Another option is to make the whole mould out of plasticine. Be sure to use non-sulphur plasticine, as sulphur inhibits curing of silicone. I have used both 3D-printed moulds, and plasticine moulds, and combinations. Obviously, you need non-stick silicones for mould-making, not the sticky sanitary or construction silicones.
  6. The little rear fan (nozzle-cooling) should always be on when printing (when the nozzle is above 40°C). If not, check if there are no hairs and strings of filament or dust stuck in it. Check the connections and wires. If the bearings would be worn-out, or the wires broken, replace.
  7. If you say the fan is "making noises", it could be: - There are filament hairs and strings stuck into it, hindering the rotation. - Or the fan bearings are worn-out. This was very common on similar CPU-fans in older computers (286-386-etc.). If you don't have a replacement yet, you can extend the life of the fan a little bit by lubricating the bearings: using a needle, cut through the silver label covering the bearing, and then inject a drop of bearing oil into it. This is obviously not a permanent solution, but I did use this quite often on computer fans in the old days, and it can extend fan life for a couple of months. Enough to keep working and meanwhile find a replacement fan (and time to install it).
  8. Good. And yes, this technology will come with its own new learning curve. I also like the fine details. I can imagine that for juwelry or very small railroad models, etc., this is fantastic. In the beginning such resins tended to get brittle after exposure to the sun, because it was UV- or light-cured, and it kept curing further. Also in the beginning, freshly printed parts were subject to creep deformation on heavy loads. You had to let them post-cure first. This was years ago, and I don't know how things evolved since then. But it might be a good idea to test this on a couple of prints, before using parts in a critical design.
  9. Have you checked if the nozzle cooling fan is working? If not, this would give this phenomena. On an UM2 this is the little fan behind the nozzles; but I am not sure where it is on an UM3. Occasionally this fan may suck up hairs and strings of filament, and get stuck.
  10. Maybe from another computer you could recover a dedicated graphics card, and put that into your computer? Or use older Cura versions? Depending on what you want to print, on which machine (e.g. on older UM-printers), this might be sufficient?
  11. I have heard that there should be absolutely no broken-off bits and pieces of previous models left in the vat, because that would ruin the next prints. Maybe that is why they empty and clean the vat? And sift the resin? But I have no personal experience, except for seeing it once. And yes, the "mess" and chemicals were some of the main reasons why we chose for FDM back then... But I think you would best search a dedicated resin-printing forum for this, they are going to have way more experience and tips.
  12. Looks good. The "cold" metal suits this model. Instead of plating, have you ever tried automobile "chrome" painting sprays? Not the "metalic" sort with little flakes, but the real "chrome" look spray-cans? The sort that is used on car bumpers, wheels, and decorative chrome stripings? I have seen it on model cars, but I have never used it myself, so I don't know what preparation is required, nor how well it withstands bending, temperature, weather, etc. Migth be worth trying on a scrap piece.
  13. Als de "verbrande stukjes" eruit zien als kleine zwarte schilfertjes, dan komen ze wellicht uit de nozzle: dan is die van binnen aangekoekt en moet je die reinigen met "atomic pulls". Zoek hier ergens op de Ultimaker-site. Of kijk even naar mijn soortgelijke maar veel zachtere methode hier (en dan een beetje omlaag scrollen): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Als de verbrande dingen eruit zien als lichtbruine smurrie, in een blob op de print, dan komt dat waarschijnlijk van de buitenkant van de nozzle: soms blijft daar materiaal tegenaan kleven, en na een tijdje gaat dat verbranden en zakt het af, tot het op de print valt. Die blob wordt dan door de nozzle een beetje uitgesmeerd bij volgende passages. Vooral bij kleverige materialen zoals PET gebeurt dit gemakkelijker. In mijn UM2 (non-plus) heb ik dit verminderd door de nozzle te behandelen met teflon-olie en siliconen-olie. De nozzle opwarmen tot 200°C (zonder filament erin!), en dan een beetje van die olie op een stukje zeemvel spuiten, en dat zeemvel tegen de nozzle drukken. Zodat de olie en teflon tegen die nozzle gebakken worden. Dit elimineert het probleem niet, maar het wordt wel minder. Dit zijn geen officiële methodes, ik ben geen Ultimaker-personeelslid, maar voor mij werken ze wel.
  14. Or maybe try the opposite, reduce the current to let's say 900mA? Then the problem should get way worse if friction is the cause. But I think this would give less risk of damaging the electronics? But anyway, if it is friction, you should be able to feel it by hand, by moving around the head manually with the printer off. Further, if I remember well, there was an old UM2-series that had wrong resistors, causing a too high current, which in turn caused the drivers to get too hot, and temporarily shutting the chip down? I had this effect a couple of times on the Z-axis of one of my UM2: the driver would shut down, the bed would drop about 5mm, but it would keep printing. After the Z-chip cooling down the bed would continue moving down normally as if nothing had happened. Except for the 5mm-gap in the print, of course. After reducing the current to 900mA this never occured again. I am still not totally sure this was the cause, and if reducing the current did solve it, or if there was something else going on in parallel.
  15. I don't have dual-nozzle printers, so I can't help with your question. However, another thing: if you want the vase to be water-tight, be sure to print it slow and in very thin layers. In thick layers of 0.3mm this filter housing had lots of tiny holes, through which the water jetted out. In 0.06mm layers, it was perfectly water-tight. I printed this in a single material (PLA); but dual materials is even more difficult to get watertight.
  16. Thanks. Yes, this already gives a good understanding of the orientation.
  17. Thanks, this is a good idea. My current activator is not a spray, but a pen with felt tip, like a fluo marker pen. But I could probably apply it to the outer edge only, where glue would ooze out indeed, to get the same effect. I will try next time.
  18. Long ago I made a font for my 3D-texts. But this was in DesignSpark Mechanical's RSDOC-format only, as I didn't know how to make a real font-file. Recently a guy by the name Jason Chall has turned part of this character set into *real font-files*. Thanks! See here on Github or Thingiverse: - https://github.com/pbz/geert-font - https://www.thingiverse.com/thing:4160261/files My originals in DesignSpark Mechanical format "RSDOC" are still here (sroll down a bit): - https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ I have looked at his version of the font in Windows' font viewer, and the characters seem very close to the original. But I haven't tried it in a 3D-editor yet, so I can't comment on stability, character spacing, or bugfree-ness. Feel free to use this font. It can be helpfull if you use another 3D-editor than DesignSpark Mechanical. You may also modify it, as long as you keep it free when reposting it (Creative Commens - Attribution - Share-Alike License; CC BY-SA). Originally I designed it on a 0.25mm grid, fontsize 3.5mm caps height, and 0.5mm wide legs, thus well suited for a standard 0.4mm nozzle. Don't go too much smaller than 3.5mm, because then the slicer might drop legs that become thinner than 0.4mm. Unless you use a smaller nozzle. This pic shows the original set (not all characters and images are converted into the font-file): Printed as watermark text (=hollow) in transparent PET: Screendump showing the real font TTF-font file in Windows font viewer: PS: in older versions of DesignSpark Mechanical there is no real text function. But you can insert text by abusing the Dimensioning tool. Place dimensioning arrows and text on a model, and then edit that text: delete the measurement numbers (e.g.: "<-- 5.23 mm -->") and replace them by your own text (e.g.: "Copyright Geert"). This text is now still floating text in a black font. It is not yet 3D. Now select that text, move it to the desired place, and *project it down onto a model surface*, using the "Projection" tool. This projecting creates editable outlines onto that model. Now you can select and raise or lower these outlines into real 3D text. This method was originally developed by a user named "Jacant" on the DesignSpark Mechanical forum.
  19. Could it be that you selected the wrong printer in Cura, or whatever slicer you used? Or its bed dimensions in Cura got corrupted? Or else: defective SD-card, corrupt gcode files, hairs or dust in the SD-slot causing bad contacts (try blowing it out with compressed air)? Or something else along this line...?
  20. Yes, I would welcome videos on your techniques. Thanks.
  21. You would need to sit next to the printer and keep watching. My guess is that the bed is not perfectly clean, and/or the glue (if you use glue for bonding) is not spread equally. So the printed sausage does not stick perfectly. In such cases, I have seen these printed lines lifting a little bit on the outer edge. And then, on the next pass of the nozzle in the opposite direction, they would be melted again and be pushed against the bed again. If the bed-adhesion is not identical everywhere, this could cause similar irregular patterns. Filament with silver or glossy particles makes this much more visible, since the orientation of the filler particles changes, and thus their reflection. Mostly the fillers are flakes, little mirrors. Printing thinner first layer lines might help. But then your bed leveling and bed flatness need to be very good. You can see this effect to some degree in these photos too:
  22. Wow, print quality and smoothness is impressive, especially the teeth. Did you use supports for the fins? I was trying to see in which orientation you printed it, but I can't see the layer lines. :-) The color, is that colorFabb's translucent orange?
  23. Is this also present Cura's layer view? If yes, it is most likely a Cura software-issue. If no, it is most likely a printer hardware-issue (which I think it is): or the motor is missing steps due to too much friction, or some pulley is sliding over its shaft instead of gripping it, as gr5 said. The "too much friction" can be identified by moving the head with your hands: this should go smoothly and evenly in both directions. If you almost can't move it by hand in one direction, then the motors can't either. I had this once when a new oil I used for lubricating the rods, dried into a sticky, thick gum in a couple of days. For a pulley sliding over its drive shaft: also check the ones on the stepper motor: they see twice as much load as the others. Further, I have no idea how likely a dying stepper motor or printed circuit board are?
  24. Hoi Sander, a question: what are the "cover photo" and "member title" fields in our profile? Is that the profile photo or avatar on each post? Or where do these show up if we add them?
×
×
  • Create New...