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geert_2

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Everything posted by geert_2

  1. Looks like a leaking nozzle, maybe not tightened enough? Or maybe there was some debris on the thread when it was tightened? I think they need to be tightened when warm, so any filament-remains on the thread would be molten. If fastened cold, it could leak. But I am not familiar with an UMO, so it is best if you google for a manual how to disassemble the UMO-nozzle.
  2. I like the conceptual idea of "drying on the fly" very much, but I have the same doubts as Ishy. Normally people recommend to dry plastic for at least *several hours*, preferably in the presence of desiccant (to remove the dislodged moisture). My printer usually consumes about 1m of filament per hour. So a heater would have to be 2 to 3 meters long to meet that spec, and it would need to have escape-routes for the moisture. So I am not saying this can't work, I hope it does, but I do have doubts. Also, this seems to be only for 1.75mm. Along the same line of thinking: in the chemical industry they have heater systems for heating thin pipes and sensor lines with fluids, so they do not freeze in winter. These sort of "socks" do encapsulate the pipes. Maybe you could have a look into such systems, and try to adapt one? Maybe then you could make a longer one? And at places cut holes to allow moist air out and fresh air in? Not sure if that would work either, but it could be an interesting experiment?
  3. In the past I have seen people doing this by just watching the printer, and when it reaches the desired layer, manually pause it, and manually change filament. Then continue. This may not be the most convenient method, but if it works to get the job done... :-)
  4. Does this also happen with a slightly larger block with *plain* walls (=without any text or indents)? Just a clean cube? In my UM2 printers, when printing small objects with very sudden changes in layer area, that also shows up as "horizontal lines" in the print, due to the differences in layer cooling time. See the images below. For me, printing slower and cooler helps, or for small objects, printing a dummy "cooling tower" next to the real model. But this will only work for you if this is the cause, of course. I could imagine that an irregular feed also would cause this problem: changes in flow rate, filament diameter, kinks in filament,... Or irregularities in nozzle temperature, or air flow around the printer. Or vibrations in the X, Y and/or Z-axis? Sift for the laboratory sink: Tiny part (see the irregularities in the side-wall in front); the ruler is in mm/cm:
  5. I thought all countries world-wide had switched to the metric system? The UK has switched gradually, with the latest units changed around the year 2000, I think? Today in the UK the old imperial units are only allowed for "drinking and driving", as one Englishman said on another forum. (=for road signs and beer bottle labels). But correct me if this info is incorrect. :-) The USA has officially adopted the metric system in 1875 (yes, 18..., not 19...), although most politicians, government officials, and press people are not aware of this. So they keep converting these metric units back to imperail units for "convenience", although it is very inconvenient for them, and it slows down conversion in everyday life. This causes big headaches for US-technicians, engineers, industry, and all other internationally oriented businesses. I thought the handfull remaining countries in Africa and Asia, previous English colonies, had also switched recently, except maybe Burma/Myanmar? Although in daily life people tend to keep using their old habits of course, just like we still use horse-power for cars instead of kilowatt. I guess because the number in horse-power is 1.3x higher than in kilowatt, so it sounds more impressive. :-)
  6. Did you print this with an enclosed front? If not, I could imagine that too much cold ambient airflow would cause this? Or maybe too much cooling fan? I have no experience with this material, but generally high-temp materials need an enclosed front and little or no cooling fan for good layer-adhesion. Otherwise the new layer won't melt into the previous layer.
  7. Originally I also used a piece of plain paper, but now I just do it visually: I print a border of 15cm x 15cm, one layer thick, with a skirt of 10 lines, and then adjust on the fly while it is printing this skirt. This works well for my UM2; I don't know if this is recommended for later printers like UM3 or 5.
  8. Yes, that is how I understood it. :-) To be totally sure I just tried it on my old Cura 14.09, and there the function is named "Split object into parts". It works, and you can indeed delete each of the parts separately afterwards. So, you could save the remaining as gcode, and print them one by one in this way. However, it does have side-effects: if there are hollows in an object, like my watermark text, these will also be extracted as separate objects... Lol. Which should have been this:
  9. This is a good idea. Even though I printed so many "dummy cooling towers" next to my models, this has never occured to me. I am going to borrow this idea. :-)
  10. I think in older Cura versions it was possible to "split object in parts" or something similar? This would split a model into all its parts, and these would all be distributed on the build plate separately. Then you could delete the unwanted parts one by one, and only keep the desired ones. You would have to redo this whole sequence of splitting and deleting for every part, so it is a bit cumbersome, but it could be a temporary workaround to get a job done. I don't know if this is still possible in the newest versions of Cura (I haven't tried)?
  11. I guess that your model has not enough cooling. Print this slow, as cool as possible, and print a dummy model next to the real model. Try a dummy cube, or an inverse of the model. So that the hot nozzle has to spend some time away from the real model, and the real model gets time to cool. But as said, it is a guess. See this conceptual example: Edit: it looks like this effect with and without dummy cooling tower:
  12. geert_2

    line width

    I didn't know I had a photo of the above effect: expansion of the molten filament after exiting the nozzle. But I just stumbled upon it again, so here it is. You can clearly see how the sausage expands immediately after exiting the nozzle, during the first mm. In the zoomed-out image the sideways expansion is from ca. 46 pixels to ca. 51 pixels, thus about 10%, very rough estimation. Nozzle opening is 0.40mm, so that would be from 0.40mm to ca. 0.44mm.
  13. That vertical banding is the "ringing" gr5 referred to: the mechanical oscillations of the print head after taking a sharp corner at high speed, due to its weight, play in the bearings, and the rubber drive belts. So, printing slower reduces this effect. You could also try the opposite: printed a lot faster, and see how the effect changes. For the best settings, you need to ask gr5, as I never experimented with these settings. You can also see the effect in the red print below, due to the light-reflections which exagerrate it. For size-reference: the nylon screw is an M4, and filament is 2.85mm. Printed on an UM2 with factory default settings for this, and 0.4mm nozzle. Instead of printing whole boats, you could also test these effects on small cubes of 15mm, and then change settings (speed, flow, temp) on the fly via the printer knob, to test the effect. That would cost you less time and less filament.
  14. No, it's based on my experience with my own printers. The teflon couplers tended to wear out quite fast if the printer was running on higher temperatures (above 220...230°C). And that resulted in irregular prints and underextrusion. From the outside it can be difficult to see if the coupler is worn out, because that is only at the inside. But there can be other causes of irregularities: irregular friction in the feeding traject also has a lot of influence on these printers. For example, an irregularly wound spool, kinks in the filament, or a spool nearly empty (=bending radius too tight). And also too much play on the Z-axis screw, or dirt. Or a worn out nozzle (=the conic top being grinded off by abrasive filament, or the inner opening got too wide). Further, overhangs often tend to curl up and cause very ugly walls, especially in thin layers. This is far less if you print at 0.2mm or 0.3mm. For me, usually printing slow and cool improves quality, as gr5 also said. This reduces "ringing" and expansion at sharp corners, reduces strings and hairs, reduces the risk of underextrusion. Also, sudden changes in "layer printing time" do often show up as horizontal lines in the side-walls. Maybe this is what you get when it starts printing the deck of the boat? It seems around that height? But in general, although not perfect, your last white boat doesn't look too bad to me.
  15. There is a way to mimick this effect, but it requires changing the CAD model. On top of your model, create these hexagons, and leave a very tiny gap in-between them, for example 0.001mm. This gap will fuse while printed, but the slicer will see it as separate polygons, and slice them accordingly. So it will outline each hexagon separately. Then use multiple outlines for wall thickness. But the problem is that the nozzle has to go from the center to the edge after completing each hexagon, and this may create ugly lines or defects.
  16. Quite some time ago this has been discussed on this forum, with lots of photos. But I don't know the topic name. Maybe you can find it back? They did this by first printing one layer ("the symbol"), in a thin layer height (e.g. 0.1mm). And then, using a thicker layer height (e.g. 0.3mm), they printed the next part over the first, without removing that model from the build plate. But I don't remember the details. Some people got really nice results.
  17. If it is an old standard UM2, chances are that the white teflon coupler on the nozzle is also worn out. If you do a cold pull ("atomic pull"), and it has a huge blob at the seam between nozzle and teflon coupler, it is worn out and needs replacement. See the blob in the white cone below, which shouldn't be there at all. It should look straight like the orange cone at the bottom. Obviously, I did these atomic pulls while changing filament color, so they have both orange and white. Yours should have only one color, and no black dirt. If it has black dirt, do multiple cold pulls until the black is removed. I don't know how familiar you are with nozzle cleaning and cold pulls or "atomic pulls"? If not, first search on the Ultimaker site for more info. Next, you could try the alternative and softer method I use on my machines: this doesn't require hard pulling, but only very gentle handling, but it also works well for me. See the manual here (and then scroll down a bit until you find "atomic pull"): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Also, while on that same page, I would recommend you download and print a couple of these horseshoe clips: they are much easier to handle than the standard clips. These are in PET, but I have also used them in PLA.
  18. For keeping filament dry, I use these bags with desiccant (left=package, right=actual bag), and keep all in a big sealed food box. The blue dot turns pink when moist. These bags can be dried in a microwave, or conventional oven at low temp. They can be found in car-accessory shops as they are used for drying car interiors. For reference: the ruler is in cm. This is good to keep filament dry. But to actually dry already wet filament, it may not be enough: you may need elevated temperatures to first "shake the watermolecules loose" from the plastic, before this bag can absorb them.
  19. Make a small and simple test piece and try to print that with default values: 40...50mm/s, 200...210°C, 0.1...0.2mm layers. Anyway, 240°C is way too hot for PLA: this could easily make the PLA decompose and block the nozzle. So you would first need to check that the nozzle is clean. Then also check if the teflon coupler is not worn-out, if the little fan at the back of the nozzle is working well, if there are no kinks in the filament, if the spool can unwind freely, etc. But definitely start by cleaning the nozzle until you can easily push filament through manually. Search for the how-to guidelines for nozzle-cleaning on the Ultimaker-website (I don't know the link), or try my old manual with a slightly different approach here (scroll down a bit): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ On the Ultimaker website, and sites of Ultimaker distributors, there are also a lot of other good manuals on underextrusion (=no filament coming out, or not enough), and on checking parts. But I don't have the links, so you will need to google a bit.
  20. The little "insect antennas" are when the nozzle leaks a little bit while traveling through the air. Upon arriving at the next wall, that droplet is deposited on the side of the wall. On the next layer, the drop is deposited on the previous drop, since that is now what the nozzle encounters first after flying through the air. And so on..., causing upwards tilted "insect antennas". I haven't printed with nylon yet, so I can't give any recommendations. For PLA, usually printing slow and cool helps, but I don't know how that would work for nylon: it might negatively affect layer-bonding. Increasing retraction also might have other side-effects. I would first try the slow and cool approach on a test-piece, where the "slow" is to prevent excessive pressure in the nozzle, and the "cool" is to make the melt less liquid and thus less likely to leak.
  21. The "0.1mm" should be "1.0mm", to bridge the gap of 1mm between walls and support. Also see the STL-file above, and the picture, where most other major dimensions are 1.0mm also (the width of all plates, and the stair-cases). This is what works for me, but of course, you may want to adapt it to your situation. Different materials, models, and printing circumstances may require different parameters. Before printing big models, I would recommend you design a few small test models with lots of variations, and print these with your typical setup, so you can see what works best for you. For bonding PLA, I use standard Loctite cyanoacrylate glue, after sanding the surface a little bit.
  22. Wasn't that print head the same as the UM2 (non-plus!)? Or have there been different UM2Go versions? In the first case (=like UM2 non-plus), I think you don't need any spacers, because this was with a spring instead of fixed-length metal piece.
  23. It could also be that the little fan on the back of the nozzle is not working. This would cause the filament to heat up too much, and soften before the nozzle, so it gets too thick and gets stuck. Or that there is a kink in the filament, so it can not unwind from the spool, or not pass through the feeder. Or a totally worn-out white teflon coupler (especially on UM2 non-plus). Or any other obstruction along the whole traject. PS: normally you can just drag and drop photos into your post while writing. It should work, I do this all the time.
  24. I have this phenomenon very occasionally in one of my two UM2s, not in the other. There is no clear indication why, although it is most often when playing around with the control-knob a lot. If I don't touch the knob, it doesn't happen. And it gets worse in very dry weather. So I don't know if this is a firmware-bug, electromagnetic spike issue (heater or steppers switching on or off, causing spikes), electrostatic discharge issue (like sparks in freezing weather), communication-issue between knob/display/mainboard, mainboard hardware, or a combination... The randomity makes me think it might be some EMC-issue interfering with the communication between mainboard, knob and display. But this is pure guessing...
  25. Enable the standard supports as Smithy says, or design your own custom supports into the model. Sometimes custom supports may be desirable in special circumstances: for example to make the support stiffer so you can more easily grab and pull it out with pliers, or to make it extend so you can grab it, or to make special holes in it to insert hooks. Usually I prefer to design custom supports into my models, so I have full control. Except for large and easy to reach areas, where the standard supports do a very good job. For example, the red and orange blocks below here are custom supports, to prevent the bridges of the yellow part from sagging too much, since the blue spoon has to slide through that yellow part. This part is too small to get in with a knife, so I need the supports to extend, so I can grab them. The supports also need a little bit of extra brim for stability. For reference: text caps-height is 3.5mm, text legs are 0.5mm. So, all this is very small. Tha same one plus a few other types of supports I tested or used through the years: Another one, if you don't want the support to go all the way down and damage the part below it. Same, now also on the center bridge: the bottom of the support-bridge will sag and produce some "spaghetti", but the real bridge will be reasonably okay after some cleaning up. The above one printed. Keep in mind the small dimensions: the "plates" are 1mm thick, the text is 3.5mm caps-height. Nozzle-diameter is 0.4mm. And another one that could be usefull for springs or cylinders. The red support needs to be cut out later.
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