geert_2

It's an old post, but it may still be useful for some people. If you can get the image to show on a computer, the simples solution may be to make a screendump, save that as JPG-file, maybe clean it up in Photoshop or Gimp, and try to import that JPG-file in Cura. Another solution could be to make a photograph from the screen (e.g. at the doctor), or make a scan or a photo of a röntgen or of similar transparant slides. Then you don't need any conversion software.

Yep, but looking at the picture... is it removable (if i want to change the nozzle)? On a standard Ultimaker2, if you remove the aluminum plate with the fans, the silicone just slides off the nozzle. That is why you need to use non-stick silicone as used for mould making and casting. So it works just like removing a cast from a mould. Once the nozzle is out, you could force the rest out of the aluminum plate, if necessary. Or you could just break the silicone piece, or cut it off, and apply fresh silicone. This sort of silicone is not that strong and tears apart easily. Note that some molten filament may still creep under the silicone around the nozzle. That will depend on the hardness of the silicone, and on the liquid filament: whether it is repelled by the silicone or not. For example water is strongly repelled by silicone. So any silicone tubing is absolutely water-tight. However, most oils are not repelled, and they slowly seep through silicone. Molten parafine (candle lights) also slowly seeps through silicone. Also solvents and vapours may seep through. That is why it is a good idea to use plenty of silicone oil on a fresh silicone mould, prior to using it for casting: the silicone oil will saturate the silicone mould, so the vapours and liquids of the casting plastic will not get into it so easily. This will prolong mould life. So I could imagine that vapours or liquid plastic of filament might also to some degree seep into (or under) such a silicone cover. This will just be a question of trial and error. But for those cases where filament build-up around the nozzle is a real problem, it might be worth trying. Also check if your silicone is heat resistant enough: most go to about 250°C, some lower, some higher. Some people even use them for casting lead and tin figurines.

What may also help is to cut the tip of the filament off under an angle of 45° or 60°, then the wheels get a better grip. (Provided of course that they spin in the right direction...)

If you printed +400 hours on an UM2, even at only 210°C (PLA), then the teflon coupler will definitely be deformed and need replacement. Whatever else there may still be. So I would suggest: do yourself a favour and replace it.

It will depend on the materials you use, and if your printer has a heated bed or not. - For PLA you can just wipe the glass plate with salt water, and print on that, with the bed heated to 60°C. Thus absolutely requires a heated glass bed, it does not work on a cold bed. - For any other material, you could try gr5's method: wipe the glass plate with dilluted Elmer's wood glue (1 part glue in 10 parts water if I remember well), and let that dry in a thin layer. - I have also heard good comments on 3DLAC spray.

I just realised there may be an easier and faster way to create such covers. At least for some printer models. In short: - Find an undeep spoon, or something with a round hollow inside (e.g. cut off a part of a ping-pong ball). - Fill that cavity with non-stick silicone paste. - Heat up the nozzle a bit, e.g. to 100°C to speed up curing. - Push the spoon up against the nozzle. - Let the silicone cure. - Remove spoon, remove flashes. - And ready: you now have a silicone nozzle tip cover that is flush with the nozzle. Notes: - Only use non-stick, two-component mould making or artistic silicone, platinum cured (="additive"). Do not use tin cured silicones, as they are not form stable and not chemically stable, they may decompose. Do not use sticky sanitary or building silicone either, as they cure slowly (require moisture of the air), and you may have a hell of a time removing it afterwards. - Be sure that the nozzle tip is completely filled with filament, so the silicone can not enter into the nozzle. It will not stick, but may still be difficult to get out. - Use silicone paste, no liquid (it will leak away everywhere). Or if you only have liquid, after mixing let it cure until it is a paste, before applying. - The spoon must be slightly undeeper than the length of the nozzle that is sticking out below the aluminum fan mount (on an Ultimaker 2, I don't know how it looks on other printers). - Push the spoon firmly up against the nozzle, so the silicone will be flush with the nozzle tip. Also have a look at the picture. This is based on an Ultimaker2, but the basic concept should also work for other printer heads. The advantage is that you don't have to measure up your nozzle and you don't have to design any custom moulds anymore. I haven't tried it myself yet, but I have used enough silicones to believe that it should work. :-)

I am wondering why you would need that? To start a print, you have to go to the printer anyway, to clean the glass plate, to check and re-apply bonding aid, to check filament (and if necessary straighten it), to check if printing starts well (good flow), to check bed adhesion, etc. And then while printing, it is a good idea to regularly pass by, to see if everything is still all right. I don't see how you would do that from sitting behind a (remote) computer?

I also couldn't do an atomic method with ABS+ (=improved ABS with less warping): it always broke off, just like yours. So I had to flush the remaining ABS with PLA first, and then do the atomic method with PLA. I don't know if this was a problem of that specific ABS+ (which seems to be more flexible than regular ABS), or if it was caused by using lots of PLA first, which might have conditioned the nozzle inside, so that the ABS+ sticks too hard. If you want to try a much more gentle but equally effective atomic method, have a look at my manual here (second entry): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ I let the filament cool much longer, and then reheat it, so its inside is more solid. And I replaced the hard pulling by gentle wiggling and rotating. Also, after flushing a bit of filament, I do a "manual retraction" to avoid big blobs of filament getting stuck in the coupler. This gives far less risk of doing damage to the printer or dislocating the teflon coupler than with the normal atomic method. See details and photos in the PDF-manual.

I like this idea. It is remarkably simple (from a slicer point of view: redo the top layer with different settings and direction), but it is remarkably effective. Definitely worth developing further.

In my couplers usually the bottom inside 2mm are burned, and the next 3 to 4mm have severe dents. So cutting all this off is not really an option anymore for me, unfortunately. Then I don't have anything left... :-) However, what does help a little bit for me is taking a long brass M3 screw or M3 thread, rounding off one end (so it has no sharp edges), and use that as a file to gently (!) scrape the inner walls of the coupler. This will scrape off burnt residu that might block the path. I do this while doing an atomic pull. No need to remove the coupler from the machine. Just poke through the coupler from above with the M3-thread, but always very gently and lightly. Don't slam it into the nozzle. It has to be a brass screw: nylon is too soft, and steel or inox is too hard: that might damage the nozzle-inside and eat too much material away from the coupler. After that, I do another atomic pull to remove the grinding dust and debris, so it will not block the nozzle or make the next print dirty. This does not do any miracles, but you may be able to use the coupler a few more weeks, for example when you ran out of spares.

The strings might be caused by retraction being switched off, so that the nozzle leaks while traveling. Have you checked that? The thick line at the height of the top of the big part, might be caused by the sudden change in area of the part. This suddenly gives a different cooling time of the next layer (actually less time to cool), which often shows up in my prints too. Try printing cooler or print two or three parts at the same time, and see if that helps. The thinner part halfway seems like: or underextrusion, or there is something wrong with the Z-movement (which you already addressed). Does this occur only when the printer has been off for some time? Or always? And always at the same *height* (for objects of different size too), or always at the same *time* after starting? If it would always occur at the same height, also for different objects, I would think of something wrong in the Z-axis. If that underextrusion would only occur after the printer has been off for hours, and always around the same *time* after the start (when printing at the same speed), could it be that a part of the filament has been flattened in the feeder, due to being too long under pressure? And that that flattened piece is now too wide and has difficulty getting through the print head, coupler and nozzle? You could write a black mark on the filament with an alcohol marker, just before it is entering the feeder, and see if that mark just moves up to the feeder when the problem occurs? I am just thinking aloud...

I sort my designs first by directory, with an appropriate directoryname for each project. Then within each directory I usually use a syntax similar to this: "modelname_yyyymmdd.extension" to differentiate between versions. For example, a cable clamp in the shape of a snake (a "snakeclamp"), would sit in the directory "clamps", and its name could be: "snake_v20160912.rsdoc". In which "rsdoc" is the native file format extension of my DesignSpark Mechanical 3D-editor (on Windows). Often I have more than one version a day, so I add "a", "b", "c", etc... to the version. Then I always save a JPG-file of the design too, with the same name. And the STL-file and G-code file. The JPG-files make it very easy to browse through the directory with an image viewer (I use IrfanView), and to recognise each design immediately. In summargy, for this "snakeclamp" that would give these four files: snake_v20160912a.rsdoc snake_v20160912a.jpg snake_v20160912a.stl snake_v20160912a.gcode If an update is required to the model on the same day, the files would be: snake_v20160912b.rsdoc snake_v20160912b.jpg snake_v20160912b.stl snake_v20160912b.gcode If in the gcode a model is duplicated, so I get multiple printed at once, I usually add that amount to the filename too, with syntax: "..._x2.gcode". Thus this clamp will be printed twice: snake_v20160912c_x2.gcode Of these files, I only copy the gcode-file to the SD-card for the printer. Maximum size of the filename to be displayed on the printer is 20 characters, so I try to limit my filenames to that. If the name has to be too long to differentiate between models, then I leave out a few characters of the filename on the SD-card only. E.g.: a too long name like "snakeclamp_bighead_v20160912a_x2.gcode" could be truncated to "snk_bg_20160912a_x2.gcode" on the SD-card. This is still recognisable, and I can still see the version and the amount of copies. But on the computer, I always keep the full filenames. Usually I do not include much other parameters into the filename, since I print most of my prototypes with the same settings anyway, optimised for a good balance between quality and speed, and they are close to the defaults. This syntax, in combination with the JPG-images, makes it very easy to quickly find back all my designs. Edit: for a picture of the snake clamps for the Ultimaker bowden tube, see at the bottom of this page: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

When I want models to sit closer together than Cura allows me to do, I multiply them in my 3D-editor (DesignSpark Mechanical) in the desired amount and positions. And then I export that combination as STL. Now Cura recognises this as only one object. In this way you can put things as close together as you want. But then they will always be printed all together of course, and not one by one, since Cura thinks it is only one object. Have you tried this approach?

It appears that your mould has vertical side walls? To make removal of the casts easier, I would recommend that you use slanted walls where possible, if the model and its function allow it. For injection moulding a few degrees would do, but for 3d-printing (with rougher side walls) I would recommend more, maybe 10° or so. Also, it may be a good idea to design a few holes or extensions in the outsides of your mould, or to make screw threads on places that will not be filled with the casting material, so that you can get a good grip with pliers, hooks, screws, or whatever tools, to get both mould parts apart after casting. If your silicone auto-cures in a few weeks after opening, it probably is industrial or sanitary one-component silicone? This cures due to the moisture in the air. If you want longer shelf-life, try using real two-component mould-making silicone. There are a lot of good instruction videos on Youtube. Search for: "silicone mould making and casting". Anyway, I really like this idea of silicone covers: it may not only keep the nozzle clean(er), but also prevent silicone from getting in-between the cooling plates in case of failed prints.

If you want to make it easier to prove that a design is yours, then I would suggest you print (thus model) your name and logo into several parts of the design. Then at least, if anyone makes a verbatim copy or abuses your original files, it is obvious. Remodeling is still possible, but takes more effort. And since "copiers" are known for not wanting to put too much effort into their work (otherwise they wouldn't be copying in the first place, and they would create original designs), this may discourage them just enough not to do it. Another approach is: just don't care. Make sure that you create good stuff. And if people copy it, then at least you know that you created lots of good stuff all around the world. Let them have it. Edit: the above is just a *general* remark. Concerning this specific concept: this idea is not totally new: even my grandparents already used this method in gardening. But then with standard plastic PVC drain pipes and 90° elbows, glued together. It has been around for ages, probably since the time of Newton. So I don't think you can talk about copyright infringement anyway here, since both models are clearly different.

In films they use very fragile "glass" which scatter without causing wounds. You can hit someone on the head with a bottle of this "glass", shattering it to pieces, without killing him (as we have seen often enough in films). I don't know for sure how this is made, but if I remember well, I once read it is moulded from some sugar-like stuff? So, maybe you could use that, Make a mould, maybe with 3D-printing, and then cast such materials in it?

For PLA and PLA/PHA-blends, do *not* cover the front opening. These need lots of cooling air, so the heat can escape, otherwise the model is likely to warp. Also make sure the fans are on, except for the first layers. Could that be the problem?

Yes, indeed. I also tried lots of different custom support designs for smoothest bottoms. What works best for me is: - A thin but solid bottom layer (e.g. 0.4mm). - Then a sort of tree-like scaffold, which leaves me lots of room to use pliers or hooks later on to pull the support out. - Then I split the tree in thinner branches. - Next again a thin solid layer, just below the bottom of the real model. - And finally small ridges of 0.5mm wide, separated 1mm. - And a gap of 0.2mm (minimum, for very fine models) to 0.5mm (for bigger models) between these ridges and the real model. Then the bottom of the model is still not smooth, but at least way smoother than with standard supports (of Cura 14.09, haven't tried later versions yet). Smaller gaps between the ridges and model give smoother bottom, but make the support more difficult to remove. Also for supports in-between model parts, I use a similar approach, as shown on this test piece, where I tried out various gap sizes.

I use Cura 14.09 on two computers (haven't found time to try later versions...), and on both retractions were enabled by default. I heard and saw our printers doing retractions even before I knew what retractions were, when I began 3D-printing.

If you want "non-stick" silicone, make sure to use mould-making silicone, but *not* sanitary silicone (which may be very sticky). Silicone for mould making and casting is available from dental laboratory suppliers (dental labs use it to make casts of teeth models), or from special-effects suppliers for the film and theatre industry for their masks and props. There do exist liquid versions, where you have to mix liquid A and B in correct ratios, and versions that you can paste-on, but liquids are better as they give much more detail. But these silicones are not strong: they tear easily. They do exist in very soft (skin-like) and harder versions. Just make sure that you have a mechanical way to fix the model after casting (screwing, clamping,...), since it will not stick... :-) Edit: spraying a bit of silicone mould release spray on the silicone moulds, makes them even less sticky, and it increases their life. Silicone is heat resistant to about 250°C. As a quick fix to existing items, you could also consider spraying them with silicone mould release spray to prevent anything from sticking to it. Just do *not* spray on the glass print bed...

For me standard Loctite Cyanoacrylate glue "Super Glue-3" works well. They also sell a special version of this glue with an activator for plastics: wipe over the plastic with the activator (=a sort of felt pen like a fluo-marker, but colorless), let that dry for one minute, then glue as usual and let it cure. But be fast to bring parts together, because the activator also speeds up the curing. I found this in the Delhaize supermarket, among the paper, pens, and other school stuff: "Loctite, super glue-3, All plastics". Of course, grinding may also help, due to the increased contact surface. But do not grind too rough: cyanoacrylate bonds are strongest when the glue layer is as thin as possible (ideally only a few molecules).

Similar visible deformation could also occur when the layer surface to print brutally changes from very big to small. Thus when the part suddenly gets a lot smaller (with a step, not gradually). This gives very different layer cooling times for the big surface and then the small surface. The small surface may not have enough time to cool, and thus deform. This often gives similar lines too in my prints at such changes in print layer area.

Have you tried printing the parts directly on the glass plate, without raft or supports? That should give nice flat bottom layers. If you print on a raft or on supports, the first layer of the model will always look ugly: there has to be a gap between supports or raft, and print, otherwise you can not remove the support from the model. But that makes the first real model layer sag and distort, thus ugly and with holes in it. If you don't mind assembling, try modeling the parts in such a way that every part has one big flat plane on which to print it. Else, it is best to design your own supports, or play with the support parameters (closer together, smaller gaps), for finer results.

I hope you didn't leave a 2 meter sized print in your hot car? No, it was an experimental dental appliance, a sort of spoon or fork on which you can put silicone paste and then make an impression of the teeth. About 12cm long, 5 cm wide, and 3 to 6mm thick. But even that warped badly on a mild spring day, not even summer. And then it was in a silver (light reflecting) car, not even a black one... Also a few clamps warped badly. Heat treating these parts in an oven helps a bit, but not enough. So I would be *very* careful when transporting anything bigger, that took weeks or months to make.

If you leave a part printed in PLA in a hot car in the sun, it *will* warp, although some brands warp more than others. Thus PLA is unsuitable for anything that gets hotter than ca. 50°C. If it needs to get *really hot*, as in projectors, you might consider casting: make the mould in PLA, or make the original model in PLA and then cast a silicone mould from it, and then cast the final item in a heat resistant material (clay, gipsum, whatever) in that mould. Plastic in combination with projector lamps that go up to several hundred degrees celcius, doesn't sound like a safe idea to me.