Jump to content
Ultimaker Community of 3D Printing Experts

geert_2

Ambassador
  • Content Count

    1,894
  • Joined

  • Last visited

  • Days Won

    24

Everything posted by geert_2

  1. I am not sure, but can't you do without spring? And replace it with a piece of metal of fixed length and suitable design? So that you can still finely adjust the position of the pressure wheel, to get the desired bite-depth of the teeth into the filament? I have always wondered why there are springs in the feeders of almost all printer brands? Yes of course, officially they are needed to push the filament against the knurled feeder wheel, so it gets a good grip. But does it? If the spring tension is too high, it flattens the filament into a plate, instead of a round. Then the filament gets
  2. What happens on the next layers if you continue printing? Does it keep extruding so irregularly, or does it level out nicely? I sometimes see a bit of irregular extrusion too in one of my printers, but only on the first layer, although far less than yours. Then it smooths out. So I don't really care, as it is only one layer. In some brands or colors of filament, this effect is much stronger than in others. Also, when the nozzle is leveled rather close to the bed, to get a smoother bottom layer, the effect is stronger. I am not sure what causes it, but I guess that in the beginning the te
  3. Normally nylon can easily be dried in an oven. But I have the impression (this is a guess, not necessarily correct!) that nylon for 3D-printing sometimes contains modifiers to reduce moisture absorption, or to chemically bond it, or to mechanically bond it in the molecular structure (like the gels in pampers)? Maybe this could cause this? Anyway, store all filament in a closed box, with a huge bag of disseccant (the sort with color indicator: blue=dry, pink=moist) that is also used to dry car interiors, and that can be dried in a microwave. For really sensitive materials, keep them in such a
  4. I don't know Tinkercad, so I can't say anything about it. If the purpose is for 3D-printing, I would suggest that you try DesignSpark Mechanical. This is a free but limited version of SpaceClaim. It is very easy to learn, and there do exist a lot of good tutorial videos. The basics can be learned in a few hours. Intermediate level stuff takes a few more days. It is distributed by the big RS-components electronics company. It does require registration, but if you want to do a whole classroom, maybe you could find a solution with RS to make that easier? If the purpose is only modeling, but not
  5. Excellent! You can't start early enough to get kids interested in technology. In traditional education it is sometimes forgotten that the purpose of studying is to be able to actually use that knowledge. The only real knowledge is being able to do things, thus "active knowledge". So-called "passive knowledge" - thus recognising that someone else can do something, but you can't - is no knowledge; it is only the first step towards knowledge. I believe that all education (math, physics, chemistry, language, whatever), should be given with practical goals in mind. If students understand what t
  6. Have a look at the nozzle while printing. It could also be that molten material accumulated on the outside of the nozzle, especially on small objects, or when you have a bit of overextrusion. And then that starts to burn, sinks, and gets deposited at random spots on the print. In my experience, thick light-brown blobs usually come from the outside of the nozzle, while thin black flakes usually come from the inside, with PLA and PET. But this may be different for other materials of course. Anyway, regularly doing an atomic pull never hurts. And you should definitely do one whenever changing f
  7. I don't know the size of this car. But if it would be rather large, it might be cheaper, easier and safer to buy a completely new toy? It might take days to get a few wheels 3D-printed, and cost a lot in shipping. And they are likely to be less strong than injection moulded wheels. To estimate the costs, you could have a look at pricing at specialised 3D-printing services, like Shapeways (UK), Materialise (Leuven, Belgium), or 3D-hubs. They give quotes based on dimensions, material, size and volume. I guess you should expect a few hundred euro? Another solution, which you can easily do you
  8. An idea that just occured to me: what about making the prime-method adjustable in Cura? For example let people choose between: - Prime as extra skirt lines around model (same thickness as first layer). - Prime as spiral (same thickness as first layer). - Prime as blob. - Prime in the air. In the last three cases, with additional parameters to specify the location where priming has to occur: x=..., y=..., z=... (height above glass plate only for priming in the air) All with the same material-volume of priming as now. For each printer, you could set the defaults that work
  9. And how does plaTec behave over a longer time? Normal PLA gets harder and more brittle: after a year or so, it may snap easily when stressed (like you would do with hooks, keychains, etc.). And it may lose its shine and get duller. Does this also happen with plaTec?
  10. If you measure on a modern power supply ("switched mode"), then make sure it sees some load: use a lamp or a suitable power resistor (heater) as load. Most modern power supplies do not work or do not work correctly without load: they may output nothing at all; or a far too high voltage. For a correct measurement, it would be best to use a load similar to the real load it will see when in use in the printer. Connecting a few car lamps might do. And then at least you have some visual feedback too.
  11. I guess you are always going to have a temperature difference in the plates. A huge temp difference between glass (+60°C, here almost 100°C) and room air (~20°C) causes a strong upwards draft: it will pull in cold air from the sides, and blow off hot air upwards in the middle of the plate. Like the "thermals" outside in nature, in which glider planes keep circling: they can be strong enough to lift a plane from 500m to 1000m in a few minutes. So that will cool down the sides much more than the middle. But the distribution is pretty nice and even, I think. If this ceramic glass would cause le
  12. I haven't printed with flexible material yet. But have you tried removing the bowden tube, and feed some filament manually into the nozzle? And then see if it flows through easily? This would make sure there are no blockings, no old material stuck somewhere, no nozzle-clogs.
  13. You need to adjust the temperature to the material you are trying to remove and to the material that you use for pushing/pulling. I usually do the cold-pull / atomic-method a little bit different: - place nozzle in front corner, - remove bowden tube and filament, - heat the nozzle, insert a piece of filament and push through some material by hand, - dial down temp to zero, - gently push a few more seconds, - do a small manual retract of a few mm (this prevents a big blob from forming in worn-out couplers on the UM2, which would make pulling it out impossible or very difficult),
  14. I don't have an UM3 and haven't printed with CPE, so the following is from experience with PLA and PET. Usually this sort of defects comes from overextrusion. Or, if it is on the first layer only, it comes from the glass being a bit too close to the nozzle: the advantage is that the layer is squeezed well into the glass, usually with better bonding as result. I also see brown spots on the print. So I would guess that the blobs come from molten material that is accumulated on the outside of the nozzle while printing (thus due to overextrusion or the nozzle being too close to the glass), and t
  15. Exactly. I knew I had seen it somewhere...
  16. Each method seems to work in a lot of cases, but not work in some others. Maybe a combination of all good ideas would work? The area above the metal bed clips can not be used for printing anyway. So maybe it could be used for priming? What about making a small trashbin in silicone (=heat resistant) that can be clipped onto this metal clip? A size of 10 x 15mm and 10mm high might do. Then prime in this bin, and wipe the nozzle against the edge of the bin, so the nozzle is clean and does not drag anything into the print? After completion, the primed stuff can easily be taken out of the little
  17. If you haven't done so yet, I would suggest you try DesignSpark Mechanical for 3D-design and editing. This is freeware from RS-Components (big electronics supplier), and is a limited version of SpaceClaim. It is very good for geometric shapes (not for organic shapes). It only requires registration on their site, which seems an acceptable price to me, regarding the quality of the software. It is very easy to learn: it works similar to SketchUp but produces much better quality 3D-models. On Youtube you also find a lot of good manuals and modeling tips. Have a look there to see if the DSM-workf
  18. Placing a thin anti-slip rubber mat under the printer might also help a bit. Well, at least it helps for washing machines, and for all sorts of laboratory stuff like stirrers...
  19. If moisture is the problem, then consider making a box with disseccant where you can put the spool *while printing*. Find a sealed food box of suitable size, a bit bigger than a spool, make a spool holder in the center, drill a small (3.5mm?) hole for the filament to exit, and put a big bag of silica gel in it. Then place that sealed box with PVA-spool behind your printer while printing. I haven't tried it myself (no need to), but I have seen people using this for printing nylon, which is also very sensitive for moisture. Silica gel with color indicator can be found in car shops: these bag
  20. Yes, I also prefer compact, separate, dedicated programs for each function. It is better that a program can do one thing excellent, than 100 things half-way. Because in the latter case, you have a bunch of bloatware, but you can't use it for anything. For example, Microsoft Word got such a nightmare, compared to the old versions '97 and 2000, that it takes me five times more clicking and searching through the mess of ribbons than before. It really decreases my productivity. And to prevent it from destroying my layout, I have to disable every automatic function (which I also did in Office '97
  21. Yes indeed, that was where my version was based on. Being of spring steel (I am not sure if that is a correct English word, meaning: "steel for making springs"), the wire easily moves down when the nozzle passes it. So I deliberately placed it a few mm too high, to get a sort of wiping action. I only need to make sure that I do not position my models in that corner. But even then, it would probably do no damage, or not much (although I am not gonna try it): most likely the build plate will be pushed down when the nozzle tries to put down the first layers, similar to what you have when corners
  22. If you try to avoid standard glass from warping, don't forget the effect of the print cooling fans. Some time ago I bought an infrared thermometer, and to my surprise the glass plate temp was *very* uneven: on a small print, in some areas it was 15°C cooler than in others. So I tried heating the glass without printing, and then the temp was very nice and even, except at the last centimeter at the edges, but that is okay. Only then it occured to me that the cooling fans blowing at 100% made all the difference. Their job is to cool whatever is in their path, so that is what they do. .. :-)
  23. If this is a common problem, wouldn't it be a good idea to machine a flat area in the rods, where that screw has to sit? This would give the screw a much better grip on the rods, and it can not rotate anyway. Or would this have other side-effects?
  24. For PLA, try putting a desktop fan (ca. 30cm diameter) at a distance of 3m in front of the printer, and let it blow at lowest speed towards the printer. It should not create a storm wind, but just a nice breeze. This extra air circulation prevents/reduces local heat build-up: it helps a lot for me.
  25. At the very beginning, I also noticed that in dry weather (freezing cold, blue sky) bonding to the untreated glass was reasonable. But on warm, rainy weather, it was almost non-existent. Putting down a straight line of filament on the glass is one thing, but I have models with lots of tiny circles, which are much more difficult to make stick. With Ultimaker and colorFabb PLA now I get a very good bonding with my "salt method": first clean the glass with isopropyl alcohol and then with warm water. No soap, no detergents, no window cleaners, as they all reduce bonding (nothing sticks to soap).
×
×
  • Create New...