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geert_2

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Everything posted by geert_2

  1. Hi neotko, This week I first encountered this phenomenon you described, when printing in PLA at a bit higher temperature. Good prediction! So it seems to happen occasionally when the material is quite liquid due to higher temps, and when there is a long travel through air. Never had it with my PET up till now, since that stays more rubbery like chewing gum, and doesn't leak so much. So traveling through air definitely benefits from a fast move. While traveling over land for PET and PLA at low temp, seems to work better with slow traveling speeds, to avoid the "bits of morse code".
  2. Have you measured if the first layer really is 0.1mm thick? In the first photo it looks much thicker, almost 0.3 to 0.5mm. Which could mean that the nozzle is too far away from the glass. (But if you had set the first layer thickness to 0.3mm it could be okay, of course.) Also, did you clean the glass plate with soap, window cleaner, white spirit, thinners, methanol, or other cheap cleaning stuff that might leave a soap- or oil-residu, which could destroy bonding? I think it is best to clean only with isopropyl alcohol and pure warm water. Further, I would rather start from 210 or 215°C fo
  3. I think it would be a good idea to have a test part printed on various machines, via a 3d-hub service, or via hobby clubs in your environment, and see which models deliver the quality you want. Instead of buying a cheap assembled model, you could also consider buying a do-it-yourself kit. This will generally give you a bigger and better printer for the same amount of money. But this only works if you have enough technical insight to assemble it yourself, of course. If you are not confident in assembling such a complex thing, it could become a nightmare.
  4. For me the search works fine now since it is Google-based. But I could imagine that searching through the manuals and help-section too would be useful, not only the forum. For example if someone wants to know how to replace a teflon coupler.
  5. At first I was also confused, since some parts in the original photo seemed okay, some seemed gaps and underextrusion, and some seemed blobs and overextrusion. But when seeing the new photos, and when seeing the original in Photoshop with only the blue color channel (blue is opposite of orange, and shows more contrast), then it is clear that there are lots of gaps. So I guess it is underextrusion. If one layer is underextruded, then of course the next layer will sink into the gaps left by the previous layer, causing an irregular surface. Could it be that printing PLA at 0.2mm layer height an
  6. For nylon and ABS this is a well known problem: in a few hours they may absorb enough moisture from the air to make printing or injection moulding impossible, or with very poor results. But I hadn't heard about this for PLA yet. Although it does degenerate over time (months, years) due to moisture absorption: this breaks down the polymer molecules. I store all my filament in big boxes with a disseccant with color indicator (blue = dry, pink = moist). I found in a car shop: to dry car interiors and to avoid condensation on the windows. So it has a high absorption capacity. There are also
  7. I once made a filament welding tool like this: Procedure to weld: cut off filament ends at 90°. Then put both filament ends in the groves, and hold them down firmly with your fingers. Heat a metal knife in a flame, put the hot knife in-between the filament ends and push them onto it, melting both ends. Remove knife, and slide your fingers towards each other so the molten ends bond. Then wait until cooled down, and with a Dremel tool remove the excess flanges. It worked well, feeds correctly, but still, I didn't like it, so I don't use it anymore...
  8. I don't have a dual extrusion machine, so I can't comment on material (in-)compatibilities. But you could always design mechanically interlocking features into the models, to improve strength of the bonding interface. Then even if it doesn't bond, it can't fall apart. And if the design permits it, provide a few tiny holes at the bottom where you could drip in cyano-acrylate glue along the interface line. It's not optimal of course, but it might be sufficient for showing prototypes.
  9. If I understood things well, this works in a chemical way, very similar to acetone smoothing for ABS, but only with different materials, alcohol soluble? If so, it could be interesting to extrapolate this concept to work with acetone and other materials too. Just make sure the pumps and housings don't melt... However, if you only need to polish objects without fine details, I think a polishing wheel on a drill works a lot faster and gives better results: this takes only a few minutes and gives high gloss. For example, see this video (or google in Youtube for "polishing dental retainer"):
  10. Yes, model engines are fascinating. Sometimes non-functional demo-models, but sometimes also really working models in metal, or metal with glass cylinders. Some of these Youtubers have made fantastic things. Also, I just thought about it: there do exist companies that can 3D-print in metal. Some only for decorative items (thus low dimensional tolerances) such as Shapeways, but some also for industrial applications with higher accuracy. They often use this for injection mould making. So what you could do is design the model, print it in plastic first to test if everything works as desired (
  11. The ICE PET is more flexible than PLA, so in applications where it has to flex a bit, such as keyrings or snap-fit clips, it works better and has a longer life. But thin plates or structures do sometimes fracture indeed. So I don't think it is stronger than PLA, only more flexible. And it is transparant, which may be usefull in some cases, for example to make watermarks, rulers or logos totally inside the model. So I use it mainly for these purposes. In other cases the transparancy may be a disadvantage. I also printed around the same temp and speed: 25 à 30mm/s and 220 à 230°C. Printing a
  12. Any combustion goes way over 1500°C. You could make an educated guess of the temperature, based on the color of the flame: compare it with color temperature charts like those used in photography or interior lighting. Plastics can only handle about 100°C maximum, and PLA even only 50°C. And plastics do burn very well. Further, they don't provide the required cooling. So there is no way you could make a functional combustion engine in plastic. You will have to go for the casting method. You might be able to make an engine running on cold compressed air, provided that it has very good lubricati
  13. I like the "P" and "S" features, for easier alignment and assembly. I have to remember that concept. Are the two middle "vertical colums" separate parts? If so, I would print them in a separate batch. Then, if something would go wrong half way a print, you don't lose everything. And you can already start post-processing the first parts when the next are still printing.
  14. Or you could design the supports yourself, in whatever material you wish. The disadvantage is that it may take more time to design the supports than to design the model. An example of a custom support: at the bottom a thin (0.5mm) flat plate in PLA with large area for good adhesion to the bed. Then a tree-like support structure, also in PLA. Then a roof, still in PLA, with interlocking features on top of it. Then a layer in water-soluble PVA which mechanically locks into these features, so the PVA has good mechanical grip to the rest of the support structure in PLA. And finally the real mo
  15. It is best to clean the nozzle's outside after every print, so that no black residu builds up. I usually do this immediately as soon as the print finishes: just wipe it with a paper cloth, when still hot. But you can do it later too, after warming up the nozzle a bit. Wiping the nozzle with silicon oil prior to starting a print also reduces build-up of residu for some materials (PLA), but less with others (PET), in my experience. Reducing temperature and making sure you have no overextrusion may also help.
  16. I am a bit hesitant to click on non-descriptive short links like these. In this case they may be honest and harmless, but I can not differentiate such links from spam or viruses (like in malicious e-mail links). More and more spam is now custom-made and thus getting harder to recognise, both in mails and on forums. So I am not going to take the risk. I would suggest that you upload pictures to the forum, so that we can always see them immediately, without need to download anything; and that you use long and descriptive links to an HTML-webpage for any downloads, but not directly to the files
  17. I can't help with Blender, as I haven't used that yet. But if the design is an STL-file or STEP-file, you could open it in free editors like DesignSpark Mechanical (requires registration) or FreeCAD, and design the supports there. But expect a serious learning curve and study time. DesignSpark Mechanical can not edit STL-files, but you can edit supports (and other stuff) around it, and save that combination again as an STL. Brim will certainly help the legs to stick better, although I can't say if it is going to be enough, but will not improve the overhangs of course. If the first layer is
  18. I haven't made ABS slurry yet, so I am guessing here. But similar amounts of salt and sugar also do not dissolve in water, unless you stir it very well all the time. Heating usually speeds up any reactions, but for acetone this could be extremely dangerous and cause explosions, so never heat it. I guess you will have to use a stirrer, or keep stirring manually very often. PS: doesn't the plastic lid on the left bottle dissolve?
  19. Just to be clear: my salt method works very well for *PLA* only as far as I know. So for PLA it can replace all other bonding methods for me. But it does not work for ABS. For NGEN it works a little bit. I have no idea what it does for nylon or other materials (let us know if you would ever try it), but I guess you have better chances with dilluted wood glue, glue stick, hair spray, 3D LAC or so. As kmanstudios says, I have also noticed that cheap alcohols and other cleaning aids do leave traces of oils or soaps on the glass, sometimes making things worse. Isopropyl alcohol (as also used in d
  20. Cleaning the glass plate with soap-water or some window cleaners might also destroy bonding. Soap does remove oils, but it itself is anti-stick: you can not glue anything to soap. Could this be a cause? So, after cleaning the glass plate with any method, I always clean it again two times with warm tap water only (pure, untreated, not softened, no additives). As kmanstudios says, the weather can have an influence too. Before discovering the "salt method" (=gently wipe the glass plate with a tissue moistened with salt water) to get my PLA to firmly stick to the build plate, on humid days it wo
  21. If I had to print this for myself, and it was my own design so I could edit the design files, then I would create custom supports as in this quick and dirty Photoshop image: Pink = thin solid layers of 0.5mm height. Blue = support columns. The 0.5mm solid bottom layer (covering the shown area or maybe even the whole area that is now dark grey) is to get a good grip on the glass plate for this high model. When printing overhangs, the molten edges of the print sometimes curl up, causing the print head to hit them hard on the next pass. So you need a very good bonding to the glass to withsta
  22. A similar problem also occurs on an UM2: the priming being pulled onto the printbed, which would sometimes cause problems. Originally I also used tweezers (pincette), to prevent this from happening. Until I found this "filcatch" thing in a post from another user (I don't remember his name). He 3D-printed it, but I made it from inox spring steel, so it lasts forever. This prevents the primed stuff from being dragged around. I don't know if this method for the UM2 could be adapted to work on an UM3 too?
  23. If the print was easy to remove, and the glass at room temp, then I guess it broke already while cooling down. I also had this once, but with PET. The model was difficult to remove, but not exceptionally hard. While cooling, I had already heard some weird cracking sounds, louder than the normal sounds of the print coming loose. So I guess if it cracks, it is while cooling, due to the differences in thermal expansion. Maybe some sort of fatigue in the glass, or just a weak point due to a scratch or so?
  24. All plastics do absorb moisture (water) and oils to some degree. But you can not control that as far as I am aware. Except very crudely by drying a plastic in an oven to remove most moisture. I think you would be better off printing a sort of sponge to mechanically retain the liquid. But that may be hard to model. Or even better: print a shell or container, and fill that with a suitable product, such as a sponge, salts, or the polymers used in sanitary pads. The latter are also used for plants, to regulate water absorption: when giving the plant water, these polymers do absorb all excess at
  25. Dat probleem had ik in het begin ook. Mogelijke oorzaken: te grote afstand tussen glasplaat en nozzle, of slechte hechting aan het bed. Oplossing in het eerste geval voor UM2 (voor UM3 weet ik niet): tijdens het printen van het skirt manueel de hoogte een beetje bijregelen door aan de drie schroefjes te draaien. De eerste laag moet goed aangedrukt zijn, maar ook weer niet extreem. Oplossing in het tweede geval: eerst bed grondig reinigen met isopropyl alcohol of zoiets, dan opnieuw reinigen met alleen water. En dan één van de vele bonding methods toepassen. Voor PLA gebruik ik mijn "salt me
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