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Everything posted by geert_2

  1. What you could also do to diagnose the problem, is to remove the bowden tube at the feeder end, and manually insert and move filament. Manually dial nozzle temp up to various settings, and extrude some material. Then you might be able to feel where it gets stuck and why?
  2. It could also be that the X and Y stepper motors did miss a few steps, when they hit something. They have no feedback, so they don't know where they are, they just count steps. And thus if they miss a few steps, if they can't move due to too much friction, all the rest of the model will be shifted.
  3. An estimation of the required power could be: power consumption in Watt of your equipment (UM3 + any other equipment that has to stay on) x hours to survive power outage x 3. Thus: Watt x hours x 3. Then this would account for small variations, for degenerating batteries over time, and for all sorts of technical details. But if you only have one power failure in 10 years, it might be cheaper to simply redo the print. UPS batteries don't live forever: expect them to fail in 5 years, probably at the time you need it... And if you calculated the capacity to survive let's say 2 hours, but the
  4. This is caused by drastic changes in layer cooling time, due to changes in layer-area to print. You will notice this especially on small objects, or on objects where the area to print suddenly changes from very large to very small. Exactly like the objects you show. A solution is to place a dummy cube next to the model, and hollow it out at appropriate heights, so that the total cooling time per layer is almost identical for each layer. The simplest method is to put a copy of your model into the dummy cube, and subtract it. However, make sure the dummy has a bottom surface layer covering its
  5. I have never tried this approach via images, so I can't comment on that. But if you want to print 3D-shapes, letters or whatever else, I would suggest you design them in a 3D-editor. Then you can get everything right in the 3D-editor itself. And you can slant the edges, etc. I use DesignSpark Mechanical. This is good freeware by RS Components, and only requires registration. It is a limited version of the commercial SpaceClaim 3D-editor. This has an easy to learn interface, similar to SketchUp. There are lots of good training videos available on Youtube. In a few hours you can design simpl
  6. Do you spray it with an airbrush, or do you use spray cans? In both cases, could it be that the paint is dilluted with solvents, and that these solvents cause the problem? A bit similar to the "acetone smoothing" that cloakfiend uses for his models, which also causes whitening, but then in this case as an undesired side-effect? If so, manually brushing on a varnish might improve things? But these still contain solvents, I think... Anyway, for outdoor use you would definitely need an UV-absorbing and resistant paint or cover. Printing the model in 3D, or printing a mould, and then casting
  7. With that amount of fine details and holes, I would print it slow and as cool as possible. This will also reduce curling up of edges. Maybe 190°C at 25mm/s, if your PLA can handle that? Maybe you could cut out a small part and try that first, and then manually adjust temp, to find the best settings? Also, be sure to have a big thick stable base, otherwise it will be knocked over.
  8. As gr5 said, I also found that printing in the left-back corner is more prone to problems. I am not sure , but I think this might be due to the leveling, to light warping of the glass (even if only 0.05mm), and to the tight bending radius of the bowden tube in that area: this causes much higher friction of the filament in the tube and nozzle, which might lead to slight underextrusion, and thus less good bonding? Anyway, I get best results when printing in the center and front-right areas. This is for my UM2 (non-plus) printers, which are more sensitive to feeding problems than UM2+ and UM3.
  9. As JohnFox already mentioned above, my first idea also was: print only a shell, and fill that with resin? Polyurethane or so? There do exist lots of PU-variations: from hard and brittle, to soft and flexible. Be sure to use a resin that cures slowly, with low shrink, and that does not get too hot, otherwise the shell might melt, or the whole thing might catch fire and/or explode. Or print the shell with very light infill, just enough to make it stable. Post process it (sanding and smoothing), make a silicone mould, including a hard shell around the silicone for stability, and fill that silico
  10. That is a good question, but it may be that the material itself does not actually regain its original composition/qualities once it has aged. I do not know enough about material sciences to answer that. It would be nice if one of the Team Ultimaker guys could give us some feedback on this. When this material is molten, the cracks disappear and it flows smoothly out of the nozzle, like always. So, in my prints there are absolutely no cracks indeed. But as kman says, I also wonder how much strength or flexibility old filament recovers, compared to brand new material? I guess if the materi
  11. Have you checked if all connectors are still well inserted? Just every connector you can find? Gently (!) wiggle it and push it back on. Also visually check if everything is still aligned well and no corners are damaged from rough handling. After moving mainframe computers in the 1980s (they had many 21" racks then, see the photo), it was standard practice for us to open the cabinet, and to reseat all print boards, and all flatcables, from the very first to the last. Because they would shake loose during transport on a truck. This solved 90% of problems caused by moving.
  12. This is most likely caused by microcracks slowly growing in the material, due to the stress. See these pictures: first one taken with macro-function in daylight, second one taken through a 10x microscope under warm white LED-light. This is colorFabb "natural": due to its translucency the cracks are very visible, but I also see them in other materials. This is fairly old filament, about 1.5 years, although it has been stored dry in a sealed box with desiccant. These pictures were taken after manually straightening this tightly wound filament near the end of the spool, and then relaxing it again
  13. A thought that just occured to me: most plastics do contain additives. For example: plasticizers, pigments, UV-stabilisers, flame-retardants, water-repellants,... I don't know if PLA or PLA/PHA contains any such additives (apart from pigments of course), but it is not unlikely. Could it be that each of your solvents dissolves different parts of this mix? For example, imagine that a plastic blend would consist of a mix of 50% hard plastic, and 50% plasticizer: if one solvent would remove the plasticizer, then the result would be brittle and hard plastic. If another solvent would remove the
  14. Thanks for the very informative videos. Also, the clock is a good idea. I guess the reason why airbrushing did not work very well, might be that the product just evaporates as soon as it comes out of the nozzle, instead of being deposited on the model. To me, an airbrush looks very similar to an injector in a car engine, and the injectors are there to evaporate the fuel as quickly as possible, without depositing it on the cylinder walls... It is not easy to see on the videos, but it appears that the acetone works better in fine details, and the methylene chloride works better on big surfac
  15. You can reduce the ugliness a little bit, but not eliminate it, by designing your own supports. Then you can get them closer to the underside of the design, and still remove them well. There have been a few topics about this recently. Search the forum for: custom supports
  16. A microwave heats molecules by applying a fast changing electric field. Thus the molecules are violently shaken left and right, which causes friction and warms them up, like rubbing. But this only works for molecules which have a polarity, like water, H2O: both H-atoms (hydrogen, positive) are sitting on one side , and the O (oxygen, negative) is on the other side. So, an H2O molecule has a clear polarity, and can be shaken by an alternating electric field. Food also contains a lot of water, so that is why it works. But I don't know if PLA has some polarity? If yes, it might work. If not, it c
  17. Keep in mind that standard breathing masks (fine dust filters, usually white) do *not* eliminate any chemicals from the air. They only filter out dust particles and paint particles. Which is good of course. But toxic gasses go straight through. To filter out toxic gasses too, you need a real gass mask like those used in hazardous environments in chemical plants, plus an appropriate filter for the type of chemicals you are going to use, and for dust. Filters don't filter all: the active chemicals in the filter are designed to trap specific pollutants only. These filters need to be changed whene
  18. If I understood it well, there are two factors that make PLA brittle. But I am no chemist, so my knowledge is limited. One factor is hydrolysis: water is absorbed into the PLA and destroys its molecules. I think it does so by breaking the PLA down into lactic acid first, and then furter into CO2 and H2O? This damage is irreversible. After all, PLA is bio-degradable. And it is used in surgical wires too, where this chemical breakdown is used to make the wires be absorbed by the human body. However, just to try, I made a PLA sift in the sink of my laboratory, thus sitting in dirty water, but t
  19. I don't know if brittle PLA filament breaks at a lower or higher forces than fresh and more flexible PLA. But if you have circumstances where the model has to flex to function, then brittle will break faster. For example: a clamp that has to snap around a tube. Fresh PLA filament will flex enough to snap around the tube smoothly. Brittle filament will no longer flex, so you can't snap it around the tube, and you keep pushing, and then it breaks. This applies to all sorts of snap-fit locking systems. Idem for keychains or card holders in your pocket. If you go sitting, the model may get stuck
  20. Yes, I have used colorFabb PLA/PHA in various colors: white, red, orange, yellow, natural, bluegrey,... It works very well for me. I don't know if there are any other brands that use PLA/PHA. Also Ultimaker PLA works very well, for example Pearl. But I don't think it contains PHA, probably only PLA plus some additives to make it less brittle than pure PLA.
  21. Here you have it, seen from both sides. One is from the first printer, the other from the second. Basically, it is just plied steel wire (inox spring steel, as used in dental appliances), so that it clamps around the edge of the frame. It looks primitive (well, it *is* primitive), but it works fine for me since 1.5 years. At first I also grabbed the priming blob with tweezers. But sometimes I forgot or I was too late, when doing something else inbetween the warming up. The reason why this priming blob does not stick to the glass, is that the purging is done from some height, at
  22. For an UM2 (non-plus) try this: This wipes the nozzle after priming, so it does not drag the priming blob around anymore. I plied it out of inox spring steel wire (1mm), after an idea from another user who made it first in plastic (search for "filcatch" or something). The advantage of metal is that it does not melt, obviously. The spring steel makes that the nozzle easily slides over it, without causing damage. It just gives a nice ping sound. It has been in use succesfully for about 1.5 years I think, I haven't had any problem since. I don't know if you can use the same idea on other m
  23. Hello all, I just put the following designs online: 1) A compact spool holder for the UM2 which takes much less space than the original. Can be handy for narrow cabinets or tables. It has a standard 608 bearing for frictionless movement. My first version (with 4 pins) had been in use succesfully for almost 2 years, this latest one (with 3 pins, handier) for a few months. 2) A clamp to prevent filament from unwinding while in storage, and from falling off the spool sideways while printing (the last function only for colorFabb spools). Has been in use for a few months. 3) A character set
  24. I have no experience with metalfills, so this is all guessing. Copper being one of the best conductors, I could imagine that the heat travels up into the filament really fast, and it gets through the teflon piece designed to act as a heat barrier. So it might weaken the filament before it enters the nozzle, and thus making it expand due to the pressure of the feeder? Like when you try to push a rubber band in a keyhole? Try heating a piece of filament with a soldering iron, or with one end in hot water, to feel how the heat travels? Or remove the bowden tube at the head, and feed a piece o
  25. I clean the glass plate with warm tap water first, with a paper tissue. And then I put a few drops of salt water on the glass, and gently wipe and keep wiping until it dries. The salt should not be visible as such. It should only be a very thin almost invisible mist. Like a wine glass that has been sitting in a cabinet for a year without using: if you look through it to the light, it has some sort of thin grey mist to it. That is how the glass plate should look for best bonding. Also, it does not work equally well with all PLA: the ICE brand still worked, but occasionally corners did lift. U
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