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geert_2

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Everything posted by geert_2

  1. Actually I have no idea of the percent: I take an old glass bottle, fill it half with water, and just pour in quite a bit of salt. Enough to make it taste really salt, but not so much that it does not dissolve anymore. It is not critical. And if kept in the fridge, it stays good for months. Concerning the rest of the settings: this is hard to say, since it is influenced by materials, model, circumstances and personal preferences. For me the standard settings work pretty well: 0.1mm layers, 60°C bed, 200...210°C nozzle, 50mm/s. For very small objects that need better quality, I prin
  2. If it is just a cap, why not leave out all internal extension and pin holes? So you only have the outside? But I think you would best print this in a softer material. An alternative might be to print a small cup, sacrifice a real connector and clamp it in that cup, and then pour silicone moulds (non-stick model-making silicone) of this? Then the silicone plug will have the correct dimensions, and it is flexible.
  3. The first layer may be too cold. Hotter gives better bonding. Also, it needs to be squished well into the glass, thus into very thin flat layers, not round sausages. You did not mention if you used any bonding agent, so I guess not? Some people have excellent results with 10% dilluted wood glue in water (user gr5's method), some with the standard stick (sometimes with spreading the glue with a wet tissue), some with hairspray (user neotko). I prefer my "salt method": after cleaning the glass, then clean again with pure warm tap water only. And then wipe it w
  4. Recently I tried glueing PP-straps back together after cutting them. It were injection moulded parts, not printed. You can bond them with cyanoacrylate, after roughening up the surface by sanding, and after using an "activator". These activators come in little tubes similar to a fluo pen marker with felt tip, except that the liquid is not ink but a chemical that partially dissolves the plastic (at least I think so, but I am not sure how it works chemically). Then apply the cyanoacrylate and *immediately* press parts together. The activator makes the bonding stronger and also speeds
  5. What I was thinking about, is to design and print a small item like this (the square baseplate is 50mm x 50mm). The 45° overhanging edges are likely to curl up (at least with PLA, at 100% infill, and on my printers), and cause the nozzle to bump into them violently, creating a hard test. Then dial up printing speed until it starts causing trouble and skipping steps. And then dial down until these go away. That will give you an idea of how fast you can maximally go. And then reduce further for a safety margin. Maybe that could work as a test?
  6. If your printer has a front panel, then maybe you could change the speed while it is printing, without having to go into the gcode? Like we can do on our Ultimakers? But I don't know your printer, so I don't know if it has this functionality?
  7. I don't know the cause of the slicing problem, so I will leave that to others. But even if you could get it to slice correctly, the 6 tiny holes will be way too small to print, I think: they will get closed down. Also the circular gap around the holes will become too narrow to be functional, if it has to be functional and not only visual. (It looks like a cap for a DIN-connector or something similar?) Unless you would use a 0.25mm nozzle at low speed, temp and layer heights, then you might have a chance.
  8. Have you tried designing a custom brim in the CAD file itself, and maybe some sort of tree-like or inverse-tree supports? Just to add more stability? I guess it now starts wobbling around due to the brim or supports not being stiff enough? An added issue could be not enough cooling, due to the hot nozzle sitting continuously on a small area, which tends to increase this sort of effects. So, adding a dummy cooling tower or printing multiple at once might improve this. But it might also worsen the situation if during traveling around, the nozzle would hit the legs...
  9. If you are printing near your printers maximum, then the slightest bump can cause skipping steps. Overhangs often tend to curl up, so that can be enough to trigger it. At slow speeds the force required to accelerate and move is far less, so the printer has more margin before it skips steps. Maybe try a small test print with overhangs and other difficult stuff, and on the fly change settings up to the point where it starts skipping (or underextruding or whatever else problem comes first)?
  10. That is very severe underextrusion, which can have a ton of causes: partially blocked nozzle, worn-out teflon coupler, bad little nozzle fan, dirty feeder, too wide filament, friction in feeding traject, printing too cold, too fast, etc... Search for the whole list made by user gr5 on this forum (I don't know it by head), which has excellent info.
  11. Yes, I have seen it, good. Reachability is key. :-)
  12. At thicker layer heights, and at higher speeds, you have to extrude a lot more material in the same time, so internal nozzle pressure will be a lot higher. So there will be a lot more "overpressure" stored in the feeding traject that has to be released when the printer slows down. When printing slow and in thin layers, there is very little pressure build-up in the nozzle. I guess...
  13. I have tried annealing PLA (Ultimaker) and PLA/PHA (colorFabb), by very gradually increasing temperature during the course of several hours: 50...60...70°C in my laboratory oven (=Binder: incubator with range up to 99°C). Especially the Ultimaker Pearl filament gets clearly harder and stiffer, and the sound when dropping it changes in pitch: it gets a higher and less dull pitch. This gave maximum 10°C higher temperature resistance, thus still not enough for use in the car, nor for letting it sit in the car in hot weather. That is why I tried it, to see if PLA prints and demo-models
  14. My personal viewpoint on software - any software - is to keep using it as long as it is stable and I am happy with it. I can do everything I want with an old MS Office 2000, so if I wouldn't need to be compatible with others, I would still be using that since I like that way more than the horrible "Ribbon" mess from Office 2007 onwards. Idem for a very old image editing program and a couple of others. I keep using old hammers and screwdrivers too. :-) Only things like VLC and browsers need to be updated to get the best performance (video formats) and best page display and security
  15. This is fairly common with polyesters (PET, CPE,...). Some people advise to use glue, in the hope that the glue layer will break instead of the glass. But for me that didn't help, my glue was too good. So, just like you, I also heard the glass cracking while it was still cooling down. Now I use my "salt method": wipe the glass with a tissue moistened with salt water prior to printing, which leaves a thin almost invisible layer of salt stuck to the glass. For PLA the salt method greatly increases bonding (compared to printing on bare glass) when the glass is hot, but there is no bon
  16. I don't know your printer, but this looks like too much mechanical play in the system? Things wobbling around? But I would rather guess the X or Y-axis.
  17. If you want very accurate temperature control, you might want to go to laboratory equipment: there do exist lots of ovens and incubators (=breeding machines) in several temperature ranges. I have one that goes up to 99°C, and one that goes up to 200°C. The point is that they shouldn't have a too big overshoot, which would melt the model. Some models have computer control, where you can set desired curing times and temperatures in stages. Also, dental lab equipment might work, such as the ovens used to cure prostheses which can be pressurised. But I don't know how stable control is.
  18. I do have experience with moulds for silicone printed in PLA, but not in PVA or breakaway. The biggest problem, even with "correct" moulds with slanted sidewalls and no undercuts, are the layer lines. The silicone gets stuck into these, causing a very firm grip, which makes it hard to remove the model from the mould. You might also have this problem with breakaway. Most silicone can withstand 250°C for a while, so another option would be to use PLA, and then heat it up and peel away or melt away the PLA at around 100...150°C? If you would use PLA, "smoothing" i
  19. I haven't used TPU yet, but I vaguely remember others saying that soft plastics are hard to print, because they tend to get compressed and stuck in the bowden tube. Some say you need to print it *very* slow (to not compress it), and some oil the filament (to reduce friction). But I don't know the details, so try searching on the forum. Also, a nozzle temp of 135°C seems very low? Could that be a typo, and should have been 235°C? If you would really print at 135°C, that of course would cause underextrusion.
  20. Actually, I sanded a standard injection needle of 0.41mm diameter down to 0.39mm, so I could use it to poke into the nozzle from the bottom, to clean it. That was its original purpose. After sanding, that needle's diameter gradually transited from 0.39 to 0.41mm. Measured with a good quality Mitutoyo digital calipers, +-0.01mm. Also I cut off and rounded the sharp tip, to prevent damaging the brass nozzle (see photo below). Even the soft steel of this injection needle is much harder than a brass nozzle, so you could easily damage it. The ability to measure the nozzle-di
  21. @yellowshark: You can overcool by blowing compressed air directly on the nozzle tip. This cools down the nozzle too much so it can not keep up heating, and generates a "temperature error" (I don't remember the exact description). I had that once in my overhang-tests, where I was testing the effect of additional cooling on the quality of bridges and overhangs. This was on a standard UM2 (non-plus). I think layer-bonding could also suffer, similar to printing with ABS without front door and too much fan, but I haven't tested bonding strength, so this is a bit guessing. Ho
  22. While there could still be underextrusion (hard to see), that alone would not cause the rounded corners, I think. Too much cooling would rather cause no layer bonding, and thus splitting layers. But the shape would more accurately follow the nozzle-path. Yes, putting a desktop fan in front of the printer at its lowest speed, and maybe 1m away, is worth trying. That would give a nice gentle flow.
  23. I made a quick drawing to illustrate how I understood it ("a picture says more than..."): 🙂 It does not really matter what the diameter of the nozzle is: it just has to be able to fill the gap with molten plastic. And that gap is: line-width x layer-height x line-length (=red bar in the drawing). Although of course a 1.0mm nozzle can't draw a line of 0.4mm wide, and neither can a 0.1mm nozzle. So nozzle-diameter and line-width should be about the same, both about 0.4mm, to get decent results. The extruder has to push that volume of filament through the nozzle. In calc
  24. I have done line-heigths of 0.4mm with a 0.4mm nozzle (=the only nozzle-size on my UM2), just for experimenting, and I started to see a bit similar deformations. Corners got rounded more than at lower heights, and it didn't cool well and deformed. From left to right: layer-height = 0.4mm, 0.3mm, 0.2mm, 0.1mm, 0.06mm. Top row = 50mm/s, bottom row = 10mm/s if I remember well. Each block is 20mm x 10mm x 10mm. This one is printed at 0.4mm layer height, 0.4mm nozzle: The next one is 0.06mm. (Also, you see it starts to discolor due to sitting too long
  25. Two top layers is not enough to fill the roof smoothly. You probably need 4. Further, on such a small object, I think it is not getting enough cooling: these thick sausages don't cool down and stay molten for too long, so they get dragged along and get deformed. Plus there is the hot nozzle sitting on top of this, radiating heat and preventing solidifying. You will need to print multiple models at the same time, and bigger models. For a 1mm or 1.2mm nozzle, it will be hard to print details finer than ca. 1.5mm. This is a guess, but it won't be far off, I thi
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