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geert_2

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Everything posted by geert_2

  1. Although this is not an answer to your question, it might also improve the situation: the cause of warping might also be because of the way you clean your glass plate, the bonding method you use (or lack of), the distance between nozzle and bed, and the environmental situation (air moisture, temp). Since I started using the "salt method" for bonding, I don't have Ultimaker PLA warping anymore. I use their nice "Pearl" color; I don't know about other colors. The "salt method" = first clean the glass with whatever means you want, e.g. isopropyl alcohol, acetone,... (but no soaps or oils). Then clean with pure warm tap water only. Then wipe the glass plate with a tissue moistened with salt water. Or put a few drops of salt water on the glass and wipe them dry with the tissue. Very gently (!!!) keep wiping until this dries in a thin almost invisible mist of salt stuck to the glass. Especially in moist weather this gives me a much improved bonding when the glass is hot (60°C). When cold, there is no bonding at all, so the models come off by themself after finishing and cooling down. The ease of applying and ease of model removal makes this method attractive for me. This works very well for low and flat models. My models are usually 12 to 15 cm long and 100% filled. But I don't recommend it for narrow and high models (e.g. lantern poles) or models with huge overhangs, because the salt can not absorb much shocks when the nozzle bangs into edges of a model (overhangs tend to curl up). An original model (bottom), perfectly flat after printing. And one that sat in a laboratory oven (top) at an elevated temperature of 70°C for a couple of hours, to see how it would react and warp due to its internal molded-in stresses, as a result of the 3D-printing process. Other people are very successfully using other bonding methods: hairspray, dilluted wood glue, glue stick (some wipe it with water afterwards), 3D-LAC, and other means. Each method may have its advantages and disadvantages. So it might be worth sorting out the basic cause of the warping and remedy that, instead of trying to find a workaround.
  2. Yes, I do fully understand that concern. I am feeling the same about post-processing work; I don't like it. :-) But printing vertically with lots of retractions, and the nozzle moving through the air a lot, also takes time, in addition to creating the imperfections you have seen. Depending on your designs and your printer, there might come a point where printing flat goes faster, and requires less post-processing than smoothing out these imperfections. So you could get more done with less effort. Maybe... If you plan on doing lots of prints, I think it might be a good idea to print a small representative test in both ways, and compare the time, quality and required post-processing? Or even not print them, but just slice them in Cura, and compare the predicted printing times?
  3. This looks like a fun project for kids. Did you print each cutter-blade assembly in one piece, or print each blade separately and then mount them on a rod?
  4. Maybe printing the walls flat on their back, and then glueing the pieces together, might give better results? Similar to the HO-model railroad houses we had as kids from Faller, Vollmer, Kibri, etc... Then the material flow is more constant and the print head does not need to travel through air as much. Or maybe you could print the main wall vertically, just like you did now, but print only the windows flat on their back, and then assemble? That might give a better layer line pattern? Also, using sand- and stone-colors (beige, warm grey, light grey, cream) could also help to hide artifacts, and they are very well suited for architectural work. White is often a difficult color to print, and it shows defects quite hard. ColorFabb has a lot of custom sand- and stone-colors. (I am talking about the non-filled, plain PLA colors.)
  5. I hope you speak a bit of English. As far as I know, almost all magnets lose their magnetic characteristics at elevated temperatures, because the iron (or other) magnetic particles become looser and their alignment changes into random. For neodymium this is around 80...90°C if I remember well (but verify it, as I could be wrong). 3D-printing is done above 200°C... So, I think you would need to print a magnetisable material, and then later turn that into a permanent magnet by exposing it to a very strong magnetic field. I don't know how that is done exactly, maybe at somewhat elevated temperature? Probably you can Google how permanent magnets are made? Or maybe you could use a magnetisable material, for example iron-filled filament, and then put some very strong permanent magnets close to the nozzle (but out of the heat), so they align the freshly printed particles while still molten, during the printing? So that when cooled, they keep that orientation? Not sure if this would work, but it might be the easiest method to try. Use an abrasive-resistant nozzle for this.
  6. To me this seems reasonably okay, it looks like what you could expect at 0.3mm layer height. Although there seems to be a bit of "elephant feet" at the first layers (=thick bottom). There may be other reasons, but often this is caused by a bed temperature that is a little bit too high for the material, so the first layers sag a bit. Maybe you could try to lower your bed temperature by 5°C and test if the model still sticks well? Stay with the print, in case the model would come off, so you can abort. When printing on a glass bed (I don't know what bed your printer has), we often have to find a balance between bed temp and good bonding. A too low temperature reduces bonding, and the model may suddenly pop off while printing. A too high temperature also reduces bonding: the model stays too weak, and warping forces tend to peel off the model gradually, in my tests. In both my UM2, and for PLA, the best bed temperature was the default indeed, 60°C. Although 55°C also worked usually. At 45...50°C the models would suddenly pop off. At 65...70°C they would get severe elephant feet and would be peeled off. This will differ from material to material, and printer to printer, so I recommend doing test prints at various bed temps, and definitely stay with the printer!
  7. I usually print my medical models with 100% infill, which by nature very much reduces the possibilities of holes and leaks, althoug of course there are always thin "canals" of entrapped air in-between the extruded sausages, that are not filled. You can not avoid this. Printing slow also helps, and with enough extrusion: better a little bit over- than underextrusion. Also, user cloakfiend's acetone smoothing works very well: this tends to fill tiny gaps. Search for acetone smoothing on this forum. Further options: spraying a thick varnisch? Or dipping the model in it? However, for cell cultures, I would rather try to find commercial injection moulded containers in PP or PE (polypropylene, polyethylene): these repell water, and are chemically quite resistant. Or some other injection moulded containers that can be autoclaved. I wouldn't like the idea of cells, bacteria and chemicals getting into the little holes in the plastic of 3D-printed models, and contaminating everything. If not commercially available, and you need enough copies of the exact same part (let's say a few thousand), it is worth looking into custom small-scale injection moulding via prototyping companies like Shapeways. They can make injection moulds in aluminum, for up to 10 000 pieces, and run the production. Might be way cheaper than 3D-printing. You make the design (according to injection moulding rules, thus with draft and equal wall thicknesses), you make a few 3D-prints to verify if it works well (very important), and then send the design online to them and they do the rest.
  8. No shame on you. We do not always have the time to fully explain things. Further, I am working in an educational institution (university), where we are by law required to: "provide education, research and service to the community". Often I also have to provide explanations and guidance to collegues and PhD students about computers, software, and laboratory equipment. So I am used to it, and it fits within my job. Also, I enjoy sharing knowledge, so I don't mind doing this at all. :-)
  9. If you use a 9V battery, and you put the LEDs in series, it will work with the same resistor value, but just give a bit less light. But usually I would prefer to recalculate the resistor: voltage over resistor = battery voltage minus first LED voltage minus second LED voltage. Vr = Vs - Vled1 - Vled2 For an educated guess, that would be: 9V - 2V - 2V = 5V over the resistor (as a crude order of magnitude). Use two identical LEDs. And then calculate the resistor, based on the recommended current through the LED. If it is a high-efficiency LED with low power-consumption, the current could be 1mA. Then the resistor would be: R = Vr / I = 5V / 1mA = 5KOhm If it is a medium efficiency LED, with a current of 5mA, it would be: R = 5V / 5mA = 1KOhm For a LED of 10mA: R = 5V / 10mA = 0.5KOhm = 500 Ohm. This value does not exist, so we take a nearby very common existing value: 470 Ohm, or 510 Ohm. For a very old LED, or a brighter LED that requires a bit more current of 20mA: R = 5V / 20mA = 0.25 KOhm = 250 Ohm. This does not exist, so we would take 240 Ohm or 270 Ohm. For the existing resistor values, Google for: E24 resistor series Among the images in Google, you will then also find the color codes. If you are not familiar with electronics, avoid very high power LEDs like those used in spots or in traffic- or billboard signs. These may get very hot and require special cooling and mounting features. Tiny low power LEDs like in keyboards, stereos, etc..., don't get warm if a correct resistor is used to limit the current to the recommended value. If you want to buy new LEDs, search for low power high efficiency LEDs, because: 10x less current = 10x longer battery life. Search for 1mA or 2mA LEDs, provided they give enough light for your purpose. This may sometimes be very hard to guestimate from the specs, so you may want to try various types. It is a long time ago since I bought LEDs myself, so I can't say what is on the market today. About 20 years ago a typical low power high efficiency LED of 3mm diameter consumed ca. 2mA, but that is 20 years ago... And LED-voltage was 1.65V for red LEDs, 1.9V for yellow, 2.2V for green. Hence my 2V guestimate, which is usually okay for red, orange, yellow, yellowish-green. However, blue, white, and "traffic green" LEDs (=blue chip with phospor on top) usually are around 3...3.5V. But different values exist. Look them up in specs of distributers like RS-components, Farnell, etc... Mr. Google is very helpfull today (credits to the original photographers): However, solder the wires, instead of wrapping. Or try these boards for experimenting: they are very handy, but watch out for short-circuiting wires: With this board you can try lots of different resistor values and LEDs in a short time. I used them a lot. Note: LEDs have virtually no internal current-limiting features: if you apply a too high voltage without external resistor, or if you short-circuit the resistor by accident, the current can get very high and immediately burn out the LED. Don't ask how I know... :-) So, *always* use a separate resistor for current limiting, and never rely on the very unpredictable internal resistance of batteries, power supplies, or LEDs. Further, when plying the leads, use a plier to grip the wire close to the LED, and bend it around the plier, on the side away from the LED. So don't put too much mechanical stress on the plastic housing of the LED. Pulling hard on the leads of tiny 1mm LEDs could cause them to break, since the plastic is not very strong. Here too, don't ask how I know... :-) These are a couple of very good educational Youtube videos on this subject: - https://www.youtube.com/watch?v=Bozb8t6d1Xk - https://www.youtube.com/watch?v=Yo6JI_bzUzo - https://www.youtube.com/watch?v=NfcgA1axPLo - https://www.youtube.com/watch?v=VSpB3HivkhY This reply is a bit longer than I intended, but fortunately I can type very fast. Also, I realise this is a bit off-topic concerning 3D-printing, but I think it is close enough. It may also be usefull for people who want to modify their 3D-printers to mount some indicator LEDs in it. For example you could mount a LED on the bed heater or on the (cold side of) the print head and nozzle, to see when it is on. Carefully calculate resistor-values (Ohms) and power-ratings (Watt).
  10. Now that you say this, I remember: in the beginning I used to wipe the nozzle with a tissue wetted with silicon oil, and PTFE-oil: sometimes the first, sometimes the second. These sprays can be found in car shops. This also reduced accumulation. It seems that after some time the nozzle gets a coating of PTFE and/or silicone, and it gets less sticky. There is still some build-up of goo, but less. So, now I don't need to wipe them with oil anymore; I just clean them immediately after each print.
  11. Google for "simple led circuits" and then select "images". This shows the setup. Always keep in mind: LEDs do need a resistor to limit current, otherwise they burn out! Usually the voltage over a LED is between 1.6V (old red LED) and 2.5...3V (blue and white LEDs). The recommended current for a nice illumination can go from 1mA to 10mA usually, depending on the LED. Don't come near the maximum current through the LED, always stay well below 50% of the maximum. So you need to look up the specs of your LED, or measure them: - normal voltage over the LED= Vled = ? - recommended current through the LED= I = ? What battery or charger are you going to use (I would recommend a 5V or 9V charger): - sourcevoltage = Vs = ? And then calculate the resistor as follows: 1) resistorvoltage = sourcevoltage minus LEDvoltage = Vr = Vs - Vled 2) resistor = resistorvoltage divided by LED current = R = Vr / I 3) power dissipation in the resistor = current multiplied by voltage over resistor = P = Vr x I Example: Imagine this are the specs: - Vled = 2.2V (=voltage over LED, from the specs of the LED) - Vs = 5V (source voltage, as usually found in chargers for charging USB devices or smartphones) - I = 5mA (=recommended current through LED in the specs) Then: 1) Vr = Vs - Vled = 5 V - 2.2 V = 2.8V 2) R = Vr / I = 2.8 V / 5mA = 0.56 kOhm = 560 ohm (take the closest available standard value) 3) P = Vr x I = 2.8 V x 5mA = 14mW (then add some spare: triple this value and take the next higher available resistor series, so it does not get hot: for example take a resistor of 250mW, a very common series) 4) add an on-off switch. That is all. You values may be somewhat different, but this is the principle. Basic scheme But do recalculate the resistor value according to the specs of your LED and your sourcevoltage or battery voltage!!! It may differ. Usually the long pin of the LED is the plus-terminal. And the pin connected to the "dish" inside the bulb is the minus-terminal. Usually, but check it. It only works if you connect the plus-terminal of the LED to the plus-terminal of the battery or source, not vice-versa. Plastic LEDs like these can be grinded or reshaped with a Dremel and cutting disk, as long as you don't hit the wires and chips (also not the very thin wire on top of the chip). But they do get fragile. I used to do that in model trains and cars, to make them fit. But don't cut/drill into modern white LEDs. Typical resistors. The color bands indicate the resistor value. Google for it. That is all there is to it. Use a battery charger with short-circuit protection. And/or add a mini fuse yourself. (All pictures via: "Google --> Images". Credits to the original photographers/designers.)
  12. The PET I used (which I think is a sort of polyester, just like CPE?) has a tendency to accumulate on the nozzle while printing, and then this accumulation discolors into a thick light brown goo, which eventually sags and gets deposited on the print as big brown blobs. Also, while traveling through space, the nozzle has a tendency to leak, and then upon arriving on the next wall, a blob is deposited on the side. Especially when printing fast, due to the nozzle-pressure not reducing immediately. In my UM2, printing slow reduces the effect, but does not eliminate it. I don't know if this is the cause of your phenomena, there could be other reasons, but maybe you could keep watching while printing a test piece? If it would be the above problems, you can easily see it happening.
  13. I don't know about the UMO, but on the UM2 the bushings definitely need oil. Oil does not only reduce friction, thus it prevents metal on metal wear, but it also allows trapped dust to be removed, thereby again reducing wear. Officially the UM2 rods need thin sewing machine oil. But I found that this dries too quickly (may depend on oil brand and composition), so now I use a high grade hydraulic oil, also used in industrial applications like hydraulic test benches, tractors, bulldozers,... This oil does not dry out at all, it lubricates well, and it contains anti-corrosion and anti-foam additives. Not sure if this is the best solution, but it works for me. One of the other reasons why I use this, is because I have a lot of spare of it. Concerning bent rods: maybe you could see if that shows up if you print a thin test layer of 0.1mm? It should cause a wave-pattern in the thickness, of the same distace as the circumference of the rods?
  14. 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.
  15. 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.
  16. 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.
  17. 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.
  18. 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.
  19. 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?
  20. 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?
  21. 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.
  22. 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".
  23. 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).
  24. 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.
  25. 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: ⌂
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