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geert_2

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Everything posted by geert_2

  1. I don't really see the problem with the head traveling over the infill? This will be closed and become invisible anyway, so why would it matter? Or am I missing something?
  2. I have a spool of Ultimaker nylon, but I haven't printed with it yet. Out of curiosity I cut off 10cm of filament and put that in water for a couple of days. After some time it does get more flexible, and it gets a sort of waxy feel: feels more like low-density polyethylene (LDPE) now than like nylon. A lot of 3D-printing materials are chemically modified for easier printing, to have less warping and better bed adhesion. Maybe one of the modifiers changes properties in water? Maybe one of the UM chemists could shine a light on this? I guess other brands may show similar changes? Since th
  3. I would suggest: if possible, have a small PLA test print made *while attending it*. Watch and listen carefully. Then it will be obvious if everything is okay: bed and nozzle heaters and sensors, display, fans, feeder, stepper motors, all bearings still working, belts,... Even with the original feeder, you can get excellent results, on the condition that you manually unwind and stretch very hard filament (like PLA), so its bending radius is not so tight anymore, and it has less friction in the bowden tube and nozzle. This already allows you to start and get all the rest right (bonding to bed,
  4. Try printing as cool as possible. Also, try putting a table fan in front of the printer, after it has printed the first two layers (do these without fan for good bed adhesion). I found these things help, although they do not totally solve the issue. But too much cooling might cause temp errors, if the bed- and nozzle heater can not keep up with the loss.
  5. Yes, but you can handle that with a bit of chemically inert silicone grease. The sort of thick white or yellowish silicone grease that is also used in binoculars, camera's and microscopes. And this thick grease does not leak and does not splatter around. But do not use petrochemical oils or greases, as they might chemically attack the rubber. Gently wipe the edge of the belt with it.
  6. Nylon absorbs a few percent of water, but then it should stay in a sort of equilibrium. And it definitely should not dissolve or decompose. A lot of clothing is nylon, and you can wash it without it falling apart. Also in industrial all-weather applications, you often find nylon blocks and rods being used for bearings. I have seen them here in automatic bridges from ships to the wall (dutch: "loopbrug"). Are you sure you have real nylon? I seem to vaguely remember that there do also exist some sorts of "biological nylon", based on plants instead of on mineral oil, which might indeed decompo
  7. These photos show what I mean (see my post above). This is a tiny cone: 20mm wide, 20mm high, printed in PLA. With default settings, deformation suddenly occurs when the layers don't get enough cooling anymore. When printing at a lower temp, and with a dummy tower next to it, this deformation occurs much later. But you still can't avoid it.
  8. This seems to be a very tiny model? If so, excess heat might also contribute to the deformation, I think. When I need to print very small models, and when there is a sudden change in surface area to print (from a big surface to a very small), I also see deformations. This seems to have to do with temperature: different cooling times between layers do show up as deformations. And not enough cooling time in very small details shows up as blobs and overextrusion, similar to the one you have here. I am guessing now, but if you print the base at high speed and high temp, and then the printer ha
  9. Maybe you could try non-abrasive kitchen cleaning aids, like those used to remove burnt cooking rests in ovens? They work in a chemical way. Just make sure they do not get into the bearings, as they might be acidic or caustic, which could attack metals if staying on it too long; or they could contain solvents, which might attack the plastics around the bearings. If you want to polish, you could consider using a soft polish for plastic lenses? These should be far less abrasive than metal polishes. Anyway, try them on a small spot in the least used corner first (left back?) Or even better, t
  10. First do cold pulls or atomic pulls as the others said (search for the manuals on this site). Or if you want to do a more gentle pull, try my method. This method does not require brutal pulling, but works by cooling deeper, and by gently wiggling and rotating the filament prior to pulling. See: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Then you should be able to see through the nozzle from above, or from below with a mirror: light must be shining through. Inspect the pulled-out pieces: are there bits of residu or foreign parts in it? I also sanded down a needle (on
  11. Could it be that the nozzle gets blocked, so the melt has no other way to go than upwards?
  12. I don't like the idea of information on one topic being fragmented over lots of sites: that makes it a pain to find anything back later on. So, info on Ultimaker stuff would best sit on the Ultimaker site, especially since they are very open to all sorts of discussions. (It would be different if discussing problems and solutions was not allowed, but this is not the case.) Further, I don't like "Faecesbook". First of all, you can not access the info without logging-in. And if you log in, you make yourself vulnerable to all sorts of data- and identity theft (since that is Faecesbook's business
  13. I like this direct drive concept with the motor separated from the drive gear and print head. This removes a lot of weight and inertia from the system. This should be the direction to go for the factory UM2++ or UM2+++, I think. Have you tried magnesium as the drive shaft? This would weight less, but I do not know if it is strong enough, and if it is safe enough (as magnesium can catch violent fire when hot)? Another question: what is the purpose of the long slider with coupler, connected to the print head? Wouldn't it be possible to connect the square shaft directly to the extruder gear
  14. Yes indeed, you are right; I just tried it now. I had not tried this when writing my previous post, but since you said earlier that it only searched the forum, I had simply *assumed* it would not search the manuals. My bad. So everything is okay for me.
  15. 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".
  16. 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
  17. 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.
  18. 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.
  19. 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
  20. 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
  21. 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...
  22. 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.
  23. 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"):
  24. 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 (
  25. 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
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