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Everything posted by geert_2

  1. The strings might be caused by retraction being switched off, so that the nozzle leaks while traveling. Have you checked that? The thick line at the height of the top of the big part, might be caused by the sudden change in area of the part. This suddenly gives a different cooling time of the next layer (actually less time to cool), which often shows up in my prints too. Try printing cooler or print two or three parts at the same time, and see if that helps. The thinner part halfway seems like: or underextrusion, or there is something wrong with the Z-movement (which you already addressed).
  2. I sort my designs first by directory, with an appropriate directoryname for each project. Then within each directory I usually use a syntax similar to this: "modelname_yyyymmdd.extension" to differentiate between versions. For example, a cable clamp in the shape of a snake (a "snakeclamp"), would sit in the directory "clamps", and its name could be: "snake_v20160912.rsdoc". In which "rsdoc" is the native file format extension of my DesignSpark Mechanical 3D-editor (on Windows). Often I have more than one version a day, so I add "a", "b", "c", etc... to the version. Then I always save a JPG
  3. When I want models to sit closer together than Cura allows me to do, I multiply them in my 3D-editor (DesignSpark Mechanical) in the desired amount and positions. And then I export that combination as STL. Now Cura recognises this as only one object. In this way you can put things as close together as you want. But then they will always be printed all together of course, and not one by one, since Cura thinks it is only one object. Have you tried this approach?
  4. It appears that your mould has vertical side walls? To make removal of the casts easier, I would recommend that you use slanted walls where possible, if the model and its function allow it. For injection moulding a few degrees would do, but for 3d-printing (with rougher side walls) I would recommend more, maybe 10° or so. Also, it may be a good idea to design a few holes or extensions in the outsides of your mould, or to make screw threads on places that will not be filled with the casting material, so that you can get a good grip with pliers, hooks, screws, or whatever tools, to get both mou
  5. If you want to make it easier to prove that a design is yours, then I would suggest you print (thus model) your name and logo into several parts of the design. Then at least, if anyone makes a verbatim copy or abuses your original files, it is obvious. Remodeling is still possible, but takes more effort. And since "copiers" are known for not wanting to put too much effort into their work (otherwise they wouldn't be copying in the first place, and they would create original designs), this may discourage them just enough not to do it. Another approach is: just don't care. Make sure that you cr
  6. In films they use very fragile "glass" which scatter without causing wounds. You can hit someone on the head with a bottle of this "glass", shattering it to pieces, without killing him (as we have seen often enough in films). I don't know for sure how this is made, but if I remember well, I once read it is moulded from some sugar-like stuff? So, maybe you could use that, Make a mould, maybe with 3D-printing, and then cast such materials in it?
  7. For PLA and PLA/PHA-blends, do *not* cover the front opening. These need lots of cooling air, so the heat can escape, otherwise the model is likely to warp. Also make sure the fans are on, except for the first layers. Could that be the problem?
  8. Yes, indeed. I also tried lots of different custom support designs for smoothest bottoms. What works best for me is: - A thin but solid bottom layer (e.g. 0.4mm). - Then a sort of tree-like scaffold, which leaves me lots of room to use pliers or hooks later on to pull the support out. - Then I split the tree in thinner branches. - Next again a thin solid layer, just below the bottom of the real model. - And finally small ridges of 0.5mm wide, separated 1mm. - And a gap of 0.2mm (minimum, for very fine models) to 0.5mm (for bigger models) between these ridges and the real model. Then th
  9. I use Cura 14.09 on two computers (haven't found time to try later versions...), and on both retractions were enabled by default. I heard and saw our printers doing retractions even before I knew what retractions were, when I began 3D-printing.
  10. If you want "non-stick" silicone, make sure to use mould-making silicone, but *not* sanitary silicone (which may be very sticky). Silicone for mould making and casting is available from dental laboratory suppliers (dental labs use it to make casts of teeth models), or from special-effects suppliers for the film and theatre industry for their masks and props. There do exist liquid versions, where you have to mix liquid A and B in correct ratios, and versions that you can paste-on, but liquids are better as they give much more detail. But these silicones are not strong: they tear easily. They
  11. For me standard Loctite Cyanoacrylate glue "Super Glue-3" works well. They also sell a special version of this glue with an activator for plastics: wipe over the plastic with the activator (=a sort of felt pen like a fluo-marker, but colorless), let that dry for one minute, then glue as usual and let it cure. But be fast to bring parts together, because the activator also speeds up the curing. I found this in the Delhaize supermarket, among the paper, pens, and other school stuff: "Loctite, super glue-3, All plastics". Of course, grinding may also help, due to the increased contact surface.
  12. Similar visible deformation could also occur when the layer surface to print brutally changes from very big to small. Thus when the part suddenly gets a lot smaller (with a step, not gradually). This gives very different layer cooling times for the big surface and then the small surface. The small surface may not have enough time to cool, and thus deform. This often gives similar lines too in my prints at such changes in print layer area.
  13. Have you tried printing the parts directly on the glass plate, without raft or supports? That should give nice flat bottom layers. If you print on a raft or on supports, the first layer of the model will always look ugly: there has to be a gap between supports or raft, and print, otherwise you can not remove the support from the model. But that makes the first real model layer sag and distort, thus ugly and with holes in it. If you don't mind assembling, try modeling the parts in such a way that every part has one big flat plane on which to print it. Else, it is best to design your own suppo
  14. I hope you didn't leave a 2 meter sized print in your hot car? No, it was an experimental dental appliance, a sort of spoon or fork on which you can put silicone paste and then make an impression of the teeth. About 12cm long, 5 cm wide, and 3 to 6mm thick. But even that warped badly on a mild spring day, not even summer. And then it was in a silver (light reflecting) car, not even a black one... Also a few clamps warped badly. Heat treating these parts in an oven helps a bit, but not enough. So I would be *very* careful when transporting anything bigger, that took weeks or months to ma
  15. If you leave a part printed in PLA in a hot car in the sun, it *will* warp, although some brands warp more than others. Thus PLA is unsuitable for anything that gets hotter than ca. 50°C. If it needs to get *really hot*, as in projectors, you might consider casting: make the mould in PLA, or make the original model in PLA and then cast a silicone mould from it, and then cast the final item in a heat resistant material (clay, gipsum, whatever) in that mould. Plastic in combination with projector lamps that go up to several hundred degrees celcius, doesn't sound like a safe idea to me.
  16. In my experience, if you print too fast, filament has too little time to melt (causing underextrusion), and the printer head's movements overshoot at corners (mechanical vibration), causing visible vertical banding ("ringing"). If you print too slow, the filament has too much time to melt (causing stringing), and the print head stays too long on the same spot and will melt the rest of that area too, causing visible deformation. You often see this when printing very small items (e.g. fine text). So you need to find the optimum inbetween, for each material and each model. Normally I use 50mm/
  17. Just make sure you never leave it sitting in the sun, in a hot car, or in hot studio spot-lights. The model will not time-warp, but it may dimension-warp. (Don't ask me how I know...)
  18. @jamado: if you want to print with very fine details, smooth surfaces, and hard-to-see layer lines, I would suggest that you read the thread by Cloakfind on smoothing PLA with aceton. This thread contains a wealth of good info on temperatures, speed, layer heights, etc. for finest quality. Plus it has a lot of photographs showing each test. It is a lot of reading, but worth it. I think it is this URL: https://ultimaker.com/en/community/10412-acetone-finishing-on-pla
  19. That's what this 15 page topic is all about. There's even videos if you look through it. I think video is better than pdf in this case because people kind of have to see you actually do it and the number of seconds submerged and all that. Yes, a forum like this is perfect indeed to discuss and develop things together, and to show progress and experiences. Or to get help or instructions in case of problems. But after a couple of years, these good posts tend to get hard to find back, as they sort of get "snowed under" all the new stuff. So the same questions keep popping-up over and over a
  20. It took some time and observation to find this method, there was nothing random about it. I often have difficult models: very long, thick, 100% filled, with chamfers at the bottoms. So they exert a lot of warping forces, even for PLA. Printing on bare glass worked only in freezing cold weather when the air was very dry. But even then corners would lift. In moist weather, printing on bare glass did not work at all, and there would be no bonding at all. So, surface tension or surface charge seemed to play a role. Glue stick worked reasonably, but some models got stuck too hard (those that had
  21. Just for your information: my "salt method" to glue models to the glass plate (=by wiping the glass plate with very salt water, and let it dry into a thin mist of salt) does *not* work with ABS+ filament. Even simple models warped and came off, so I had to abort them. I tried it on a spool of ABS+ that I still had laying around, but never used before. (Note: ABS+ is supposed to be an improved ABS, which should have less warping than standard ABS. But I don't know the precise chemical composition. I guess it may have a bit more butadiene than usual, to make it softer and warp less? At least,
  22. I had also stumbled upon this guy and this video, I don't remember how. His filter concept may need a bit of refining, but I like the simplicity of the basic idea. And for sure silicone oil does not get ransic like vegetable oil, which might become a tough mess over time. And it doesn't seem to make the filament slip in the feeder either (which is a bit surprising to me). Off-topic: also have a look at his gaming computer in the background: with four huge screens and 24 CPU-cores, I guess it will make any flight sim, or a GTA V race game, a whole new experience. Slightly above an average s
  23. Regarding the small size of this portrait, only a few fingers, the smoothness is impressive. I think you should write a manual (PDF) with your best techniques. It could become the "standard manual on smoothness" in 3D-printing, or something like that. :-) For this item, let me guess: you have acetoned it, cleaned it a bit, and then polished it with some plastic/acryl polishing paste? But no paint, no varnish, I guess?
  24. Yes, PLA starts deforming slowly around ca. 50°C. I also had that. Never leave it in the sun, behind a window, or in your car (even not in spring, autumn). (I can read Deutsch, but writing is more difficult.)
  25. What I am sometimes missing now, is status info during printing, such as: nozzle temp, bed temp, fan %, speed (actual mm/s, and in flow %), flow %, layer nr. of total layers. This comes in handy when playing around with settings, so that I don't have to open all submenus to find out. Would it be possible to add this, if it would fit on the screen? Probably some parts need to be alternating. For example (I limited each line to 20 characters, like it is now. I don't know if you can put more text per line?): -------------------- file_being_printed time to go 9999 min nozzle 222° bed 100° f
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