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geert_2

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Everything posted by geert_2

  1. Can't you tighten the clips carefully with a plier? But I agree, a sort of quick lock mechanism like in camera-equipment would be good, similar to this (the one on top). Although I don't know how well this holds under repeated vibrations for days, which we have in 3D-printing. At least, it would require a strong spring, not just mechanical friction, to hold the lock.
  2. I print most models in PLA (95%), and they are functional: good enough for use in the hospital, and good enough for mould making. But they can't stand the heat of a car interior, even not in mild spring or autumn weather: then they will deform. And of course desinfection has to be done chemically, not by autoclave. Also, PLA is very hard to drill into, or tap threads into, because it melts. Functional items that need flexing, like carabiners or snap-fit locks, will break over time: PLA is not flexible enough, and it hardens over time. Creep is also a factor in PLA: if tightened fast, it will permanently deform over time. This is also why threads in PLA don't work well: they tend to dislodge. Now I use nylon nuts and screws, or glue, to fix PLA models. If more flexibility is required (e.g. for snap-fit locks or carabiners), or for in the car, I use PET. I haven't tried nylon, PU, or PC yet. The cream carabiners below are PLA/PHA (colorFabb) after some time of daily use and flexing. You see where they crack and deform. The green one is PET, which is flexible enough for this application. However, when pulling very hard, the PET snaps before the PLA. So it all depends on the exact application.
  3. Yes, then he would better concentrate on studying the methods to grow his plants well, how to prune (trim) the leaves and bunches of grapes, how to making the grapes taste well, make the wine taste well, and make it conserve well without turning into vinegar. This is not simple and there is a lot of knowledge involved: grapes need special soil, climate, and treatment. The wine-production itself requires even more knowledge, to prevent it from rotting. Making vinegar or rotten fruit juice is easy, making good wine is not. :-) We had grapes, although we never made wine. But in our neighborhood a couple of guys started wine-production from scratch, from bare soil. If I remember well they had to follow specialised evening courses for a couple of years to get the knowledge to make it really good and to cover all aspects. But they made it, so it is definitely possible; a beautiful hobby.
  4. It does exist: in my old Cura that function is called "Print one at a time" (versus the standard "Print all at once"). I don't know the name in newer Cura-versions. However: this needs more room around the piece, to prevent the print head from crashing into already printed items. And if the models are very small, you will run into cooling problems: the nozzle staying on top of the model at +200°C, radiating heat, prevents the model from solidifying and cooling down. Increasing minimum layer time does not help in this case, since the nozzle just stays on top of the print. Moving it away is explicitly what you wanted to avoid. You might get this effect: the left models are printed without dummy cooling tower; the right are printed with dummy cooling tower. That dummy is only to allow the cone to cool down. But even in the white dummy tower, you can see that it had not enough cooling at the top.
  5. For PET from the brand ICE, I usually print between 215°C and 225°C, slow at 25...30mm/s, and with a bed temperature of 80...90°C. No fan if the model allows it. If I need to use a fan for overhangs, then a higher nozzle temp works better. If I need a fan, then I need to use glue to prevent warping, otherwise I print on bare glass. Most of the time I use the "salt method" (=wiping the glass with salt water, and let that dry into an almost invisible mist of salt stuck to the glass), which slightly reduces bonding for PET, but it makes it much easier to remove the models afterwards, with less risk of chipping the glass. (While for PLA, the salt method increases bonding.) PET goo accumulating around the nozzle, and then sagging and leaving brown blobs on the print, is something I also see. The effect lessens when printing slower and cooler.
  6. Depending on the software you used to design the tubes, "deleting" the hollow insides (thus making them solid) might be as simple as just clicking the inside area once, and then press the delete button. Takes a few seconds per tube. In some programs you might even be able to select "all similar hollows" (or something equivalent) after clicking the first inside, and delete all in one shot. It might be worth looking into that?
  7. Wow, that red one looks really smooth, with absolutely no layer lines visible. Did you sand it prior to acetoning, or was it straigth out of the printer?
  8. You could try printing a short, straight section of a round tube sideways, for test. Print rather cold, and with max fan, or even with an additional desktop fan in front for fast cooling. The roof-section of the inside might look a bit like it has grapes hanging from the ceiling, but the canals should stay open. Try the concept on a short straight test piece first, to see how much the inner roof sags, and if this is still acceptable for you. PLA can usually bridge gaps quite well. This is a test of a table model, with custom support structure. At the underside of the support structure, you see how much it sagged. The middle section overhang is 30mm long. But you can do better by printing colder. So, if such an amount of sagging would still be acceptable to you, you can print it without internal supports. The external part will need supports and good brim, otherwise it will fall over while printing. So you might consider some support structure similar to the pink support in the blue spring, and then cut that out later.
  9. In my opinion, although I don't drink wine: wine does not need fancy bottles. It needs to taste well, conserve well, and be resealable after opening. There are already a lot of beautiful standard glass bottles for wine, so it is best to stick to proven quality standards, I think. If he wants the bottle to be eye-catching, which of course I understand, maybe he could design a really beautifyl label with some gold-lined edges and logos? And have that printed professionally in a label-printing factory? These companies are used to do gold-lining, relief-printing, self-adhesive labels, custom cutting, barcodes, and all such stuff. This would give a much higher impression of quality than a 3D-printed bottle, which will always look somewhat poor and amateuristic, sort of "stuck in the prototyping phase".
  10. Keep in mind that the salt method works for PLA and PLA/PHA only. It does *not* improve bonding for ABS, PET, and probably most other materials. Even for PLA, use it for low and wide models: this works very well for me. But not for high models like towers and lantern poles: they tend to be knocked off: the salt-bonding obviously can not absorb repeated shocks very well (e.g. the nozzle banging into curled-up overhanging parts, especially on tall models).
  11. I do this manually, for example: "model_v1234_pet.gcode". But on my UM2 the name can be maximum 20 characters; the rest is cut off on the little display. So I often have to abbreviate the model name and version number. Depending on the priority, and if space allows it, sometimes I also include other specs such as layer height (if deviating from my normal 0.1mm), or the amount of models on the build-plate (if more than one). E.g.: "mod1234_02mm_3x_pet.gcode". This comes in handy after a couple of weeks, if I have to print the same model again.
  12. Does it have to be a circular tube? Or would a pentagon-shape also be okay? Or a triangle on top of a square, like a house-symbol? In that case, you could print it sideways, with the flat area towards the bottom, and the "roof" on top. I will try to insert a unicode symbol here, if the system allows it: ⌂
  13. Doesn't coldspray risk fracturing the glass due to thermal shock, or fracturing layer-bondings in the model?
  14. If you want dampers, I would recommend using professional and tested damper mats, of which the damping specs are listed. Each material has a resonance frequency, also dampers, in which they absorb less energy. A wrong "damper" could cause the opposite effect: the thing getting into resonance, like on a spring. So I wouldn't trust a spring-like design like that. Such damping mats should also be antislip, as gr5 says, so the printer can not vibrate off the table (we have seen a couple of these here on the forum...) In the early days of harddisks (late 1980's) I have seen harddisks crash *because* they were mounted on dampers: the at that time very heavy heads swinging around caused resonance. We had to mount the disks directly and firmly on the metal frame. If the effect you notice is "ringing" after a 90° corner in a print, this is due to the head changing direction suddenly. It won't help putting a damper under the printer. Then a solution could be to tighten the mechanical tolerances of the rods and bearings, and mounting the steppers directly on the driving rods, instead of via belts, I think?
  15. For steep overhangs you need to use supports, or redesign the part so it has no steep overhangs. Or split it and glue both halves together, or print it in such a way that there are no overhangs while printing (if the design allows this; probably not here). I don't know your printer, so if it is a single nozzle printer, you would need supports in the same material as the print, and cut them out later. In dual nozzle printers, you can use one nozzle for the support material, and the other for the print, and dissolve the support later. You could design your own custom supports, if the model has special requirements, like I did in the test below. Or use the standard Cura-supports for general models, which is far easier. Try this on small test pieces first, before doing a big print. An example of custom supports, in order to not destroy the text below the bridge (standard supports would go all the way down). For reference: the main plates of this bridge are 1mm thick; text caps height is 3.5mm.
  16. Does this effect also happen when you print a simple square tower, without any details, and without curves? In single-wall shels, and double wall shells? If yes, that would definitely rule-out model-geometry specific causes. I have no explanation for this effect, since normally PLA is supposed to print better when cool? At least in my experience... Or are there strong and variable air flows in the environment of your printer? Which would cause sudden temp changes of the nozzle? What if you put a desktop fan in front of the printer, to provide plenty of cooling air: does it get worse, or better? Or vibrations that only occur when the nozzle is printing in front?
  17. Okay guys, it's time to get your red/cyan 3D-glasses out! :-) I tried making a few anaglyphs (=red/cyan 3D-pictures) of a 3D-model. These 3D-images were hugely popular in the nineties, but I haven't seen much of them lately. They give a better understanding of the internal structures of a model, like watermarks; and give a better perspective and feel of depth. Also good for microscopy images of cells and fine structures, where the 3D-effect is important for understanding. They are reasonably easy to create in a 3D-editor: - In the 3D-editor, shift the model to the left of the screen, in perspective mode, by using the "Pan" function. This is the view that your right eye would see. Save this view as a picture, and name it "right-eye-view", or so. The 3D-editor should be in a real "architectural perspective" view mode, not a technical "ISO-perspective" with parallel lines but without perspective. It is the real perspective that makes this work. - Shift the model to the right on the screen. This is what your left eye would see. Save this view as picture and name it "left-eye-view". - Do not rotate the picture on-screen, only shift using the Pan-function. - It is best if the background is pure white. - The red glass is on the left, the blue glass is on the right (think of politics: red=left, blue=right). Actually, the "blue" glass should be a intense dark cyan, not real deep blue. And the red glass should be a deep pure red. - Red text or images are invisible through the red glass, because everything is red anyways; you can't see the difference. Only cyan (the opposite color of red on the color circle) is visible as black through the red glass. So, we need the left-eye-view to have a cyan color, to be visible in the red glass. - Idem for cyan: cyan images are invisible through the cyan glass. But red images show up as black. So we need the right-eye-view to be red on the screen, and appear black through the glass. - In an image-editor capable of layer-editing (e.g. Photoshop, GIMP,...), load both images in different layers, in a new picture. - Make the left-eye-view bright cyan, by setting the Green and Blue channel's output levels in the Levels-dialog to maximum, thus: R,G = 255 dec, or FF hex, or 100%, whatever notation your editor uses. Leave the Red channel untouched. - Make the right-eye-view red, by setting the Red channel's output-level to maximum. Leave Green and Blue channels untouched. - Set the top layer of both layers to "Multiply" mode, so the layer below shines through. This gives the composite red/cyan view. - Now shift both images to the center of the picture, and correctly align them for a nice 3D-effect, when seen through the red/cyan glasses. - If the areas that exactly overlap each other are in front of the model, the model will seem to sit behind the screen (see my examples below). - If the areas that exactly overlap are in the back of the picture, the model will appear sit in front of the screen, and you need to focus in front. - So you can move the model from behind the screen to in front of the screen, by shifting the red and cyan layers in respect to each other. - It works best with monochrome images, but it also works with very desaturated colors. Bright colors do also work, but only if they are ca. 90° separated from red and cyan on the color circle, thus yellow-greenisch, and purple-blue. So, landscapes with fresh spring-green and with a desaturated cloudy sky also work. - On a good screen and with good glasses, there should be not too much "halo" images, where the wrong color shines through the glasses. - It works with renderings with and without black edge-lines, and to my surprise it also works in inverse images. - You may need to lean a bit forward or backward (25...40cm?) to get the best effect. See some of the tests: Model behind the screen, opaque. Model in front of the screen. Model behind the screen, transparent. Model behind the screen. This gives a good view of the internal watermarks and rulers, and of other openings. Very pale model, in front of the screen. This works also, to my surprise. Model in front of the screen. Same model, but in inverse colors. This one is more prone to "ghosting". This is just a technical model, a keychain of it. But for really artistic models like statues and buildings the effect should be way more impressive.
  18. What if you print this in PLA? Does it come out right, or does it also have the same visual defect at the same height (although it might not break due to better bonding)? And what if you print this on its side? Does it then have a defect at the same height above the build plate (which could indicate a problem with the Z-axis), or does it have the same defect now running vertically (indicating a model defect)? When moved manually, does the build-plate or Z-axis move smoothly up and down, without hard, stuck points? Is the bottom of this model open, so you can insert the nut from the bottom? Or did you pause the print halfway, move the head away, insert the nut, and then continued printing? If so, I could imagine this has some influence. Do all print-settings (perimeter, infill) have the same speed, temp and other settings? ...Justy trying to narrow-down the cause...
  19. On my UM2 I have succesfully printed PET, which I believe is a sort of co-polyester? Its brand was ICE from Trideus in Belgium. I had to download the file "materials.txt" from the UM2-printer to the SD card, and then make a new material-profile in that file, and upload it again to the UM. That profile lists the default temperature and material flow, and fan or no fan, and a chosen name. So I can now select PET from the printer-menu as material. Usually I print PET at 25...35mm/s, and 215...225°C, no fan, bed temp ca. 80...90°C, layer height depending on the model 0.1 or 0.2mm. For me this works well, although most specs list higher nozzle temps. Expect a "frosted glass" look when printing transparent materials. It survives summer days in the car, contrary to PLA. It prints reasonably well, except for overhangs, due to the "no fan": it is very difficult to bridge and fill gaps. PET is more rubbery than PLA: while PLA tends to pull a nice string when bridging, PET rather tends to curl up on the nozzle, like a rubber band snapping back, and that blob gets deposited onto the next wall upon arriving there, instead of making a bridge. I print it on bare glass, cleaned with salt water. If I would print with fan, then I would get better bridges. But then I also would need dilluted wood glue for better bonding, otherwise it warps. But then I risk chipping the glass plate (I had this once), so I don't want that. On the long term PET is more likely to clog up the nozzle: it leaves a thick sort of very hard and glossy "varnish" inside the nozzle: hard to clean with cold pulls. Contrary to PLA that leaves a coating of dry powder-like ashes, which is easier to remove with cold pulls. PET or co-polyester might be a good choice for printing accessories like knobs or enclosure shells. But I would not use it for structural elements: it is a bit flexible (think of PET bottles), so for a CNC machine it will not provide good accuracy. The structural elements should be absolutely rigid, thus made of thick steel, brass or aluminium, depending on the wear and loads they will see. Personally I would also make this consideration: would I print materials unknown to me, for an occasional external customer, and take the risk of damage to the printer? No. I would refer them to services like Shapeways, Materialise, Melotte and various other. Would I take the risk for myself, if there was a need for it in our laboratory, and we needed multiple models? Yes, but then I would invest time to search it out well. The models below are in PET, printed on my UM2: key chains (with hollow watermark text), test blocks in various layer thicknesses (0.06 ... 0.4mm) and in various speeds (10 ... 50mm/s) with a hollow watermark, and carabiners (only the green is PET, the cream are PLA).
  20. There are lots of different formulations, and lots of additives, so I think no one can give good general advice. You will need to look up the specs of each individual filament, or ask the manufacturers. Or do tests yourself: cut off a piece of both filaments and keep them in a flame. And see how it burns and how the fire propagates, or does it extinguish by itself? Also melt it with a very hot soldering iron, and see if it catches flame? Of course do this in a safe environment, e.g. outside, or in a kitchen in a metal sink, with plenty of water available. And with safety glasses.
  21. This sounds like general underextrusion, and may be not related to the type of filament (PCL). I think you would first need to sort this out with a well known standard filament like PLA, until that prints smooth. It could be a (partially) blocked nozzle, incorrect feeder tension, incorrectly mounted bowden tube, worn out teflon in the nozzle (not sure if this also applies to an UM S5?), too much friction somewhere in the feeding traject, etc... Search for "underextrusion". Personally I have no UM S5 and no experience with PCL, so it's hard to give more suggestions.
  22. The printer can bridge quite a lot, but then the first layer over the gap sags a bit. And I need to slide the other part of the keychain into that hole, so I want it to be more accurate. However, I don't want the supports to fuse with the underside of the model. So that is why I use these dimensions: they give reasonable accuracy and not too much fusion. But it differs from model to model, trial and error... So, I would suggest you try the concept on small test plates, to find out what works best for your materials, your printer (and printer settings), and your typical models. Also, bigger models may need different dimensions than small models.
  23. @gr5: thanks for clarifying the degree-thing: although I knew the setting, I didn't know what it refered to in the physical world. I took a look in DesignSpark Mechanical, and indeed, it defaults to 10°, and 0.5mm max deviation for STL-export, in "Fine quality" settings. See the picture below: the carabiner as designed, and as exported to STL (Fine quality, 10°, 0.5mm). For reference: the whole hook is 60mm long x 6mm high, and the text caps height of the watermark is 3.5mm, text legs are 0.5mm. The watermark is present but not visible in the STL-file: I made its color opaque to show the facets better. So, for the rocket-engine, I would rather go a bit more accurate, maybe 5° or 2°? Unless the facets would be no functional problem.
  24. I just stumbled on a photo on my harddisk. This is why some supports have extensions beyond the area to support, so I can grab them and wiggle them loose. This makes support removal very easy. Otherwise it would be a nightmare with these small dimensions (see ruler in mm and cm). Also note the ugly defects in the Z-direction in the print: at that time I did not yet print these models with an extra dummy "cooling tower" to increase printing time per layer for better cooling. Sudden changes in total layer printing time, and thus differences in cooling, show up as ugly horizontal defects in tiny models.
  25. In the beginning when I started 3D-printing, my collegues of the department of Product Development suggested me to keep STL file-sizes below 20MB for normal models, even for their industrial polyjet printers. If you are in doubt which quality of STL export-settings to use, then cut out a small part of this design, export it with various STL-settings, and print these little test pieces next to each other. So you can compare and find the best balance between file-size and quality.
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