geert_2

I have no experience with it, but PP is said to be difficult to print (warping + hard to stick to the bed). Have you considered PET? It is somewhat chemically resistant too, can handle higher temperatures (~80°C) and it still prints rather easily.

You can always make a model solid if you select 100% infill, or if you make the walls thicker than the model itself. Except that solid is not perfectly solid: there will always be tiny gaps inbetween the extruded saugages. Printing slow minimises them, but does not eliminate them. To make a wall print reliably, I always make all walls minimum 0.5mm wide in the CAD-design, for my 0.4mm fixed size nozzles (old UM2). When the file is exported to STL, smooth corners are cut into straight segments. So, in some spots a 0.40mm wall might become 0.41mm, and in others it might be 0.39mm, which in older slicer versions lead to that part not being printed because it was too thin (less than 0.4mm). So now I just stay on the safe side, and 0.5mm also works well on a design grid. (I don't know how newer slicer versions handle this, I haven't tried.) Yes, I did make a lamp shade, but printed it in PET for better temperature resistance, and for translucency. There is a LED lamp inside now. Do not use PLA, even not for LED-lamps, CFL- or TL-lamps: they still go higher than 50°C. And even with PET (or any other higher temp material), allow air flow and some distance. All lamps are designed with some free airflow around them in mind. And even then, some of my LED spots still get to ca. 100°C (so I wonder how long they will live, definitely not the advertised 25000...50000 hours). Never use 3D-printed parts for incandescent lamps: at best the plastic leaks away, at worst it could catch fire and burn down your whole house. These need heat resistant bakelite, porcelain, or similar.

I never got small threads to print reliably, without a lot of post processing. And also tapping threads in PLA didn't work: everything melted, even with good lubrication and very slow movements, and the threads were very weak anyway. It wasn't worth the effort for me. So, now I usually design a slot in which I can drop a nylon nut, and use a nylon screw. Sometimes I provide a sort of retention, so that the nut can not fall out if the screw is totally removed. Needs no post processing at all. See the pics (these are M4). Or if the thing needs to be locked only once, a snap fit also works. But it is likely to break if unlocked after some time, as the PLA gets harder and more brittle. This is probably not the answer you are looking for, but it might be an alternative in some cases...

What about the indicators that flip from blue to pink at a certain moisture level? These seem to be quite stable, until the stuff gets defect and becomes yellow-brown instead of blue/pink. But I have no idea at which level they flip over, nor what the hysteresis is, if any...

Ah okee, I see. Yes, then it rather looks like a problem in the motors, wires, or drivers indeed. But that is out of my experience...

Crazy or not, the light works really well for this nice model, I think.

Thanks for the clarification. I think the gyroids add an extra dimension to the typical fluidness (I don't know a better English word) of your designs. It fits well together. I wonder how long it will take before industrial designers are going to try gyroids in overmoulding, in their injection moulded tooth brushes, decorative vases and statues, and sex toys indeed? Sort of gyroids, because you can't injection mould cavities with deep undercuts of course. With misty, translucent materials the effect might work. I haven't seen anything like this yet, apart from marbles.

Do I understand it correctly that for the first model (the red dancer) you split the original model into multiple models? Thus into a sort of "shell model" and an "infill model" (or multiple infill models). And then adjust each one separately to your desires? And then have them printed all in one shot with different colors and settings? Does your method also work with fine layer heights (like 0.06mm...0.1mm), 0.4mm nozzle, and double wall shells? Or would that diffract and reflect the light flow too much? For example if you wanted to smooth the edges with acetone like cloakfiend's method?

There is a very good film of user gr5 on bonding and warping issues (both are related). Try searching this forum for it; it is posted in several topic (but I don't know them by head).

That toc-toc sound might also come from the nozzle being blocked, so the filament can not move, or not enough, and the stepper skips steps? Or it could be a build-in protection, to prevent the feeder from grinding the filament in case of a blocked nozzle. The old UM2 also has this feature, and when the nozzle is blocked, or you try to extrude too much material too fast, it also makes this sound while the feeder steps back. I am not saying that this is the case in your printer (I don't know that model), but it might be worth looking into, just as another option on the list?

Yes this is a good idea too. In addition to marking the pulleys with a marker as gr5 says, to check for looseness, also try moving the print head manually when the printer is switched off. It should move smoothly in all directions, without excessive friction. Too much friction will cause the stepper motor to skip steps, or will force the pulleys to slip, whatever comes first. Once they start to slip, next time they will slip easier. (At least, that is my experience with motors and gears in model trains, but the concept is the same. I haven't had problems with my UM2 yet, but I keep the rods well lubricated).

Steep overhangs need support: the material needs something to stick to. Otherwise the printer is extruding spaghetti in the air, which is what you see here. There are several solutions: - Use the standard support settings in the slicer (Cura or whatever slicer you use). - Design your own custom supports in CAD into the model. This is what I prefer due to my often complex models. - Or design the model in such a way that there are no steep overhangs at all, and thus supports are not needed. Here you see a few support methods I regularly use, and which are designed to make their removal easier:

Thanks for the feedback. It could be helpfull for other people who do hardware modifications too.

You say it only happens when using Cura, but not when using the SD-card? - Does this mean that the problem is only when printing via USB, from within Cura? - Or does it also occur when you save that gcode file from Cura to hard disk, and then copy it to SD-card? - Is there a difference between saving to hard disk first, and then copying to SD-card, or saving directly to SD-card? - Or do you use a totally different slicer (instead of Cura) when using the SD-card? Could be that printing via USB makes a difference, for whatever reason?

If it is a standard UM2 (=non-plus), most likely you have one of the following: - deformed white teflon coupler after a couple of 100 hours of use (-->disassemble, check, and replace if necessary), - partially clogged nozzle (-->do atomic pulls, maybe carefully poke hole with soft needle without sharp edges (!!!) from below), - feeder wheel covered in filament dust (-->verify and blow clean), - filament is near the end of the spool, wound too tightly, causing huge unwinding-resistance, plus huge friction in bowden tube and nozzle (-->manually unwind a few meters, and manually straighten them). Or a combination of these, typically worn out teflon coupler, plus filament near the end of the spool. So, verify and where necessary handle these things, and then set the default temperatures and speed again (50mm/s, 210°C nozzle, 60°C bed) and try again. For doing gentle atomic pulls, you could have a look at my old manual here (and scroll down a bit): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ It also contains a few other tips.

Wow! As soon as enough people discover these pics, this technique is definitely going to become a hype, I believe. Especially since it doesn't require complex equipment or problematic chemicals, or so. Just a dual-nozzle printer, and talent of course. I think you should find a nice and easy to remember name for this method. :-)

Slimy liquids do not really "connect" to anything. You should try this at home with liquid honey, yoghurt, or even mayonaise. Try to pull them into circles on top of each other, while pouring them. It takes some time before the extruded sausage cools down and solidifies. In small holes, the nozzle is always too close to the rest, and keeps radiating 200°C, so that area does not really cool down at all. The same happens with printing small cones, like this test. As soon as the diameter gets too small, the top surface can not be cooled anymore, stays liquid, and deforms. Printing a dummy block next to it helps, as does printing as cool as possible, but it does not eliminate the effect. :

Probably this is not due to overextrusion, but due to the fact that when making a tight corner, the molten material is *pulled inwards* while still liquid. It's like trying to pull a rubber band around a hole: you pull it in the hole, not around. What I do is or calculate that effect into the design, thus design the holes a bit bigger based on experience and trial and error. Or else go through it with a drill afterwards. Use only a manual drill for PLA, since electric drilling melts the PLA.

When printing on glass, the bottom should look less or more like this (see photos below), thus quite flat and glossy, with the layer lines squeezed together. When on blue tape, it will of course be rougher, but the layer lines should still be very flattened. So, as the others said above, your bed is way too far off.

(I can read a bit of German, but can not write it well enough. Hope you understand a bit of English.) This is huge underextrusion, probably a flow-rate of only 30% to 40%, instead of 100%. See my flow-rate tests for comparison: https://community.ultimaker.com/topic/25522-photos-of-underextrusion-and-overextrusion-plus-flow-rate/ Could be a wrong setting (e.g. 1.75mm filament instead of 2.85mm), wrong printer definition or bug in printer definition, partially clogged nozzle, too high speed, too low temp, too much friction in the feeding traject,...

I do not have a dual nozzle printer, so no direct experience. But I did a lot of custom support modelling in CAD for printing in PLA. For complex parts such as hollow or difficult to access areas, I switch off automatic support, and design my own. Maybe the same ideas can be used for breakaway too? I would first make the basic support structure in PLA, with special features to make removal easier later on, and to provide good bonding to the glass. For example: tree-shaped structures, separate parts that can easily be wiggled loose (not one big chunk that you can not get out), holes to insert pliers and hooks, areas where you can get a knife in, big flat bottom plates on the glass for good bonding, etc... And then add the interface in breakaway between PLA supports and model. Here a few examples of support material I used for PLA only, single nozzle system. The ribs here are 0.5mm wide, with 1mm gaps. Goal of the ribs is to improve the underside of the model, and to reduce sticking of the support to the model. The extended supports (=wider than the model) facilitate removal, and improve the underside of the model too, because the first strands of filament of the underside can not fall off sideways. Thin layers of 0.5mm thick, separated by gaps of 0.5mm, also facilitate removal in hollow areas. And the holes in the supports are designed to fit my tools, pliers and hooks. The bridge at the bottom can save a lot of PLA and breakaway, and as added benefit, the supports do not destroy the text below.

Normally people use water and some sort of soap (?) for tumbling real metal parts. Is that recommended for 3D-printed metal-filled PLA too, or not?

Maybe it could also be the infill that is shining through? If you have a thin outer shell, and temperature of the bed, or of printing, is rather hot, it might slightly deform and let the infill shine through? Similar to in big ships, you see the internal reinforcements shine through the hull. Just guessing though...

Platinum-cured silicone should be food-safe. In the shops, there are a lot of silicone cup-cake moulds, and other silicone accessories for cooking. Also, platinum-cured silicone is used in dentistry for making impressions of teeth. As far as I understood, it is chemically almost inert; not much can destroy it. However, tin-cured silicone is not inert (and not stable either): it can easily decompose, so I wouldn't use that for food. It is good for single use industrial moulds. Only use platinum-cured silicone for foods. Be aware that silicone is not oil-tight: oils, solvents (thinner, ether, acetone, liquid PMMA,...), and liquid parafines leak through it. Don't ask how I discovered this, after I had melted parafine in the lab oven... :-) Silicone is watertight because it repels water.

Indeed, I forgot that... Would there be a possibility to connect upper structures to lower structures via a thin single wall, which you can easily cut away later? Similar to this concept of a spring? Here the blue is the desired spring, and the pink supports would be cut away after printing. In this way the overhangs are less steep. If you would print this with a thick shell it might work? (This is a picture I made some time ago for someone else who wanted to print a spring.)