geert_2

Sometimes (1) filament hairs and strings get sucked-up and block that little fan. And (2) the bearings wear out: if the fan made a sort of "rheu-rheu-rheu..." sound prior to your problem, it is probably the bearings. I have often successfully extended the life of such little fans by a month or so (this was back in the days of old 80286-computers), by lubricating worn-out bearings with bearing oil. I have also done this on an UM2 fan once, and it worked well. This gives you time to buy new fans. The oil should not be too thin, because then it does not lubricate enough: it should be able to create and keep a nice oil layer between the worn-out parts. Do not use too much oil, and don't spill on the glass, or there will be no bonding of prints. It helps if you have taken apart such fans in the past, so you know how their bearings look and where exactly they are under the silver label. Don't do this on new fans: they come lubricated optimally, and you might shorten their life. Only do it after they start making sounds, but before they lock up. Obviously, this is not an official method, and not a permanent cure, but just a temporary thing.

Some laserprinters (=paper-printers) have an auto-retry function if the print fails due to errors like paper jam, out-of-paper, door-open, etc... Then the print is automatically redone. Some printers can also receive jobs when the printer is offline or asleep, because the network card and electronics keep their power and the job is somehow buffered (I guess...). Also, in Windows a print job may get stuck in the print queue when Windows has problems connecting to a network printer. When you then switch-on the printer, or set it online, or restore the network, it may print those old jobs. Maybe this is something similar? I don't know if Cura has its own queue, or uses the standard Windows/Mac/Linux print queues for sending jobs?

In DesignSpark Mechanical there are 3 standard quality-options for export to STL: coarse, medium, fine. I use the fine, which gives about 2x to 3x more triangles than in your image (which corresponds to about medium). Custom quality allows for even better, but that is overkill: the printer can't follow too fine details anyway. But there can be lots of other reasons why accuracy is not great: extruded flow too much or not enough, nozzle too hot or too cold, blobs, incorrectly callibrated X- or Y-steps per mm, printing fast so corners get too thick when it has to slow down suddenly and creates overextrusion (due to nozzle pressure not immediately releasing), elephant feet, etc. Maybe try printing a square of 100mm x 100mm, 2mm wide, and 1mm high? That should give you an idea if the X- and Y-steps/mm are callibrated well. As for the "snot factor" causing too small inner holes: try drawing a circle with honey dripping from a spoon, or try to make a circle by stretching a rubber band into a circle (without any inner support). Gives a good idea how the thick molten material is pulled inwards.

There is no official text feature, at least not in the version I have (maybe in the newest or beta-versions?). DesignSpark Mechanical is a free but limited version of the commercial and expensive SpaceClaim. But there are 3 ways around it: 1. Use the Dimensioning tool. This is the tool which draws measuring lines and arrows and dimensions like this: <-- 3.0mm --> Measure a dimension where you want text. So, now you have this: <-- 3.0mm -->. Then delete the numbers and arrows, and replace them with your custom text, in a font you want. This text is still sitting in the dimensioning plane, not on the model. Then project the text onto the model, using the project-tool. And extrude as desired. On the DesignSpark Mechanical forum, user Jacant has made a good tutorial of this method with lots of pics: search for it. 2. Set the text in SketchUp. But SketchUp is notorious for geometry problems due to vectors and faces not closing (=they are like poor cartboard models, not solids). Thus repair any open vectors by moving the endpoints until they snap together and can be filled. Export this text. Import in DesignSpark Mechanical. Extrude and move around as desired. 3. Design your own font in vectors, directly in DesignSpark Mechanical, like I did. This is no real font, but just separate character-items. However, they are optimised for 3D-printing small text. Copy and paste them from the font-file to the desired location. This is similar to text-setting in cast lead letters in very old books. This is the method I use most. Obviously this is not suitable for making 3D-printed newspapers, but for occasional text like a watermark or part number, it is good enough. Later Jason Chall has made a real font out of my DSM-font, so you can use that font for technique nr. 1 above. For the files, see here (and then scroll down quite a bit): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ However, maybe you do not need DesignSpark Mechanical, and you can use that technique in your existing CAD-software? Most that I have seen, have that capability to hide elements by unchecking them in the model-tree, or by right-clicking on them and choose "Hide" or so. Be sure to save your design and make backup copies, before experimenting. A few examples of text set this way (with my font file, method 3). All characters are 3.5mm caps height, and legs are 0.5mm wide. Some are watermarks (=hollows), some raised normal text.

In your CAD-software, can you hide parts of a complex model? For example in DesignSpark Mechanical (=free but requiring registration, and only suitable for geometric models, not for organic life-forms): as long as the parts are not merged, I can simply hide each by unchecking it. And then make it visible again. This allows exporting each part separately. Let's say you have a cookie-cutter mould, named: "cookie", and the kid's name written on it: "kidname". Then I could hide "cookie", and save "kidname" separately as a model, or export to STL. And then I would make "cookie" visible again, but now hide "kidname", and save that as second model or STL. This should achieve what you want, if I understood it correctly? But this obviously requires that the parts are not yet merged into one single object in CAD. It should all be separate parts. I use a somewhat similar method to add text to a model, in such a way that I can easily reposition or alter it later on. And I only do the merging (required for my single-nozzle printers) at the very last moment upon exporting to STL. See this pic. This was for designing internal watermark text, shining through semi-transparent materials, but the idea is the same. Don't merge, export each part separately.

What about modeling custom supports in CAD? In that way you can make a wide and stable support in the same material as your model. And only a thin dissolvable support-layer in-between the support and model. Not sure if this would work, I have never tried it yet, but it might be worth experimenting on a small test-object? To make the dissolvable support material stick better to the custom support structure, you could add sort of dovetail ribs on top of it, so both interlock. See this concept-pic:

Forgot to say in the above post: that method is only good if the load is directed inwards, obviously. I used it to clamp two mould-halves together. For a load in both directions, or outwards, I use side-openings for inserting the nut afterwards. Sort of slots where the nut slides-in. This too can be with or without retention ridges, to prevent the nut from falling-out if the screw is removed. It is not suitable for every model and every print-orientation, but if it is, it works very well. Here too, I can use cheap standard nuts. See these real models:

Indeed, PLA parts do deform quickly, even here in Europe in mild spring and autumn weather. Not only on top of the dashboard in direct sunlight, but even in the dark in the trunk, the coolest place. Now I make parts for my car in PET or in colorFabb NGEN (which I think is similar?), both of which are still easy to print. Since then I haven't had parts warping. But these materials are harder to glue. While cyanoacrylate works very well for PLA, bonding is only mediocre for PET and NGEN, and tends to break suddenly under load, or due to temperature related expansion/shrinking. So I am not sure if this is a good idea for planes... I don't need painting, but if you do, it might be difficult. Before buying PET filament, try glueing and painting a PET water or cola bottle. I have no experience with 3D-printing ABS or PS (=polystyrene, which is typically used in HO-model railroads, houses, and planes that you glue together). As a kid I never had any trains or planes in PS warp, and PS is easy to glue and paint. So maybe this is worth trying, if you can find it? ABS is also easy to glue and paint, but might be prone to warping while printing, and layer-delamination later on. But you can acetone-smooth it to remove layer lines.

Are you sure a single layer is enough for strength? I think that might fracture or split soon due to baked-in stresses from the printing, or later due to loads in flying. I had single layer rods split, even when under moderate load, especially if the load was for a longer time (days, weeks). Test strength on test pieces first, before taking the plane into the air.

Generally, my experience is: print slow, cool, and in thin layers, with a material that does not cause too much blobs and strings (but that still fullfills your other wishes concerning temperature resistance and strength of course).

I don't know for your printer. You have to search for that in its manual, or a forum for that specific printer. For my Ultimaker 2 printers, there are the X- and Y rods (=with the drive belts and sliders), and the rods where the head hangs on. These require thin oil. Plus the Z-axis worm, but this requires grease. All have to be cleaned first, and then lubricated. But for other brands and models it may be completely different. And some may have sort of internal movements, slots, or sliding mechanisms (I don't know the correct English terminology), where pieces of dirt can get stuck in, that have to be removed first. And some printers may have self-lubricating bearings where oil is forbidden. With power off, I think you should be able to move most axis pretty easily if they are connected to a stepper motor via gears or belts. But never force them if you don't know the exact mechanism, so you don't damage anything. Also here: check the manual for your specific model. Or search on the internet, or Youtube, or so, how to do maintenance: "how to lubricate [your printer]". You might have luck.

What you could also do, is make a hex cage with a protruding ridge at the bottom, for retention. And then using brute force, push the nut through the opening past the ridge. Then it can't fall out. It will take a bit of trial and error to get your tolerances right, but then it should work fine. If you use a conic top surface of the cage, you need no supports. Also use a conic chamfer at the bottom, to make sliding the nut in easier, and to remove elephant feet due to printing. I find it easiest to design the nut separately, then move a copy into the model and subtract it. This is way easier than designing the cage directly in the model, and easier to make multiple holes: you only need to make one nut, and then you can copy and subtract it as many times as required. Obviously, do this on small test pieces first, using the same printing parameters (speed, temp, flow, layer-height,...) as you would in the real print, until you get your dimensions and tolerances right. See the designs below. Left is the base model with a hole where an M4 screw has to go through. Center is the nut with all features described. And right is the nut subtracted from the base-model, leaving the cage. Using a metrinch-style nut makes printing easier: it gives less problems with rounded corners due to the print-head slowing down and lines getting thicker, and due to the filament being pulled inwards. So it allows for tighter tolerances, and less risk of the nut rotating in the cage. I designed the metrinch-aspect just visually: I started with an hex-shape for an M4, and then added both rounds on the flats and corners by guestimating. But it works. If you keep this special nut as a separate file, you can re-use it later in other desings. Edit: for clarity: in this way you can use cheap standard metal or nylon nuts, no special inserts or other things required. To make inserting the nut easier, you can temporarily mount it on a screw: that gives a better grip.

I don't know your printer, so I have to do a bit of general guessing. I think it could be the printer missing steps, but it could also be the object becoming a bit loose and wiggling? Or a defect in the model or slicer-bug? First, in Cura (or other slicer) always check the model in Layer-View, to see if this defect is there or not. Check if the printer head moves smooth in X- and Y-direction. Movement could be blocked by debris, or lack of lubrication. Then, while printing, keep watching closely what happens. You should be able to see the difference between wiggling and skipping. While printing, you could also push the head, to see how hard it is to get it to miss steps. If it is very hard to do, this is unlikely to be the problem. If it misses steps at the first touch of your finger, it could very well be the problem. Although I don't know your filament, for such small objects, 210°C looks a bit hot for PLA-materials. I would normally do 195...200°C for such models, which should give less stringing. But that could depend on printer and material. Try on the fly to change temp in steps of 5°C, and see what happens.

For strength, I think PLA would do if it is for just touching or picking up things, but maybe not for carrying a full body weight. But PLA is not temperature-resistant, so you can not leave it in the car in a sunny environment. Even not in moderate European springs and autumns. Don't ask how I know. :-) In that case maybe PET could be a good choice, but print this with cooling fans off or very low for good layer bonding. ABS might not give enough layer bonding? For comfortable attachment to the body, you could provide enough room around the connecting area, and then fill this with soft silicone paste. The same silicones that are used to make "wounds" and face masks in films: these are very soft and skin-safe. That would also absorb some shocks. If the material has to be softer and more shock-absorbing, maybe nylon would be better? Or make moulds by 3D-printing them, and then cast the body-part in softer materials? Or cast in a mix of soft and hard, like a nylon core, surrounded by soft silicone or soft polyurethane? Thus simulating bone and flesh? Use plenty of release spray for casting urethanes, because they glue like mad. Be sure to carefully sand the mould, so it is smooth. Otherwise the layer lines will make removal very difficult, and they will accumulate dirt and bacteria. If it was for myself, I think I might prefer the moulding and casting method. Also, silicones can be autoclaved and desinfected: they are quite temperature resistant and chemically inert.

Yes, but: the filament should be equally strong, durable, easy to print, non-warping, and have the same layer bonding as standard PLA, I think. And it should not damage brass and steel nozzles, e.g. not be so acid that they dissolve, and not leave burned residu stuck to the nozzle. And at a comparable price as PLA now. Also, production should not use more energy than it does now. And it also should not be so self-decomposing that prints fall apart, like we had with some other bio-stuff: in our city we once had waste bags (NL: vuilniszakken) that were so bio that they decomposed in two days, but the truck came only once a week... The traditional "bio" way of doing things, twice as expensive for half the quality, is not going to work here, I am afraid. The amount of waste coming from 3D-printing is already very minimal compared to the amount of waste coming from most household- or industrial processes. There is not that much to gain for average users. I think you have to calculate all these things in from the beginning. That said, do not stop researching, even not if you do not have success immediately. All good things we have now, came from continued research and development. A lot of new inventions were inferior to existing things in their first iterations, but became better later on.

Great idea. This might become a trendsetter if more people see it. Then we might see vampire masks dripping of blood, terminators, the guy with metal teeth from James Bond films (don't remember his name), and so on. Could get really interesting. :-)

I prefer to print a dummy "cooling-model" next to the real model. The dummy can be empty, except for the top which should have a less or more complementary print-area as your problem-area, so the total print time per layer stays almost equal. So the nozzle is moved away from the real model while printing the dummy, and the model has time to cool down. The advantage of the dummy is that the print speed and material flow stay constant, and thus the temperature and viscosity of the molten plastic. Disadvantage is that is wastes some filament. See the pics below. The first pic shows the problem: the hot nozzle staying on top of the cones, and preventing cooling and solidifying. The second pic shows a hollow dummy (except its top), used in a real design.

Another reasonably easy method: design a nut, add a cone-shape on top, and a rounding at the bottom for easier inserting of the nut. And then subtract that coned nut from your design. Due to the cone on top of the nut, it prints well without causing overhang-problems. See the pics below. This is a metrinch-style design, which gives a tighter fit. This is an M4-nut, and the distance between the "flats" is the standard 7mm. Nylon M4-nuts can be pushed in with a little bit of force, and don't fall out. Although they can be pulled out by inserting a screw and then pulling. I tried printing this with 0.12mm and 0.3mm layers, 50mm/s, and both worked well. Try this on a small test piece first until you get the dimensions and tolerances optimal (might depend on material, layer thickness, temperature and speed). My procedure was: design the nut (red) outside of the model (cyan). Make as much copies as required if there are multiple holes. Move the nut into the model, and align its axis with the hole, and its bottom with the model-bottom. Then subtract the nut from the model.

The best practice is always to be very gentle with nozzles. No brute force, to avoid damaging brass nozzles, print head, and rods. Even if a rod is bent only 0.05mm, that is a complete layer-height of 0.1mm upon one rotation. I do very gentle cold pulls ("atomic pulls") very week, or every time I change filament color or type, or as necessity requires when there is accumulation of dirt in the nozzle. After each print, I immediately wipe the nozzle's outside, before it cools down. See my old (non-official) manual here: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

I never tried burning out a nozzle with a flame. But I did try to burn separate pieces of filament in a metal spoon, in the flame of a bunsen-burner. I let it slowly heat up, and finally catch fire and totally burn up. The results were: - Both plastics melted into a bubbling pool of hot liquid. The PLA being more liquid than the PET, which stayed more honey-like. - Ultimaker PLA and colorFabb PLA/PHA filament burned-out into a thin layer of black dust, a bit like coal powder, easy to remove by rubbing. - PET burned-out into a thick layer of hard, black, glossy varnish. This varnish got glued stuck to the spoon, and was very difficult to remove. So, whether burning residu out works on a nozzle, may depend on which materials were printed. Try this spoon-method first with the same materials, before doing it on a nozzle. Be very sure to stay well below the melting temp of brass, which can be reached easily with a bunsen-burner or similar. Don't go further than the metal glowing dark red. Once into orange and yellow, it starts deforming easily. The use of copper paste seems like a good idea: although the grease will burn-out, the copper particles provide good thermal contact, fill the gaps, reduce leakage, and prevent locking-up. After seeing the last photos, I also think a geometry mismatch between components (due to non-original and non-fitting components, or dirt-accumulation) at least worsens the problem, without ruling-out fan issues.

If you are just beginning, I would say: start with small test pieces that complete quickly. Stay with the printer while they print, and carefully watch what happens. This is important to lear fast, and to react fast if things wouldn't go as expected. Try different overhangs, wall thicknesses, infil percentages, bonding methods (stay with the printer!!!), speeds, layer thicknesses,... Begin with simple models with a couple of holes, curves, extrusions, slight overhangs, and see how they come out. Start from standard profiles, until you get bonding and general things good and routine. The standards are quite good. By beginning with dedicated small test models, and trying various things, you will learn the fastest. Later on, you could try printing slower, cooler and in thinner layers for more accuracy if that would be what you desire. Introducing 3D-printing in our lab in 2014, was one of the best decisions we made. I am still glad we did. It opened huge possibilities for prototyping and making small custom tools, and even clinical tools for use in the hospital. But 3D-editing and 3D-printing is a huge learning curve, just expect that it takes some time and effort.

Another option that might work, is printing parts separately, and glueing? You are going to see the split lines anyway when you abort and restart a print. So glueing might do as well? For alignment you could make an extrusion on one part and a mating indentation on the other part.

If the cookies or dough are soft enough, and if the cutter is open at the back so you can push them out, maybe you can get away with straight sidewalls, untapered? The constant width makes it easier to find optimal print settings. And then as desired go for single walled or double walled sides? A single wall has the advantage of easier cleaning, and no internal openings in which bacteria might grow. But it's weaker obviously. Also print rather slow and in thin layers, for smooth and strong walls.

A kitchen sieve sounds like a good idea: if you take a bigger one, and 3D-print a custom clamp for it, the sieving-area is wide enough so that small particles getting stuck to the sieve won't totally block it. Mosquito-gauze (not sure of the name in English) for the windows might also work well. Easily available in brico-shops, and cheap; usually made of nylon here.

I have heard about this method before, but never really seen it. If you have success, could you share a few photos of before and after, or treated/untreated next to each other? Is the effect more like acetoning ABS (high-gloss, very strong smoothing effect) or like acetoning PLA as cloakfiend does (satin, very mild effect)?