geert_2

I like the "P" and "S" features, for easier alignment and assembly. I have to remember that concept. Are the two middle "vertical colums" separate parts? If so, I would print them in a separate batch. Then, if something would go wrong half way a print, you don't lose everything. And you can already start post-processing the first parts when the next are still printing.

Or you could design the supports yourself, in whatever material you wish. The disadvantage is that it may take more time to design the supports than to design the model. An example of a custom support: at the bottom a thin (0.5mm) flat plate in PLA with large area for good adhesion to the bed. Then a tree-like support structure, also in PLA. Then a roof, still in PLA, with interlocking features on top of it. Then a layer in water-soluble PVA which mechanically locks into these features, so the PVA has good mechanical grip to the rest of the support structure in PLA. And finally the real model. In this way you could absolutely minimise the use of support material, and still get good stiff supports with good adhesion. Also remember to design-in features to make support removal easier: holes where you can get in with pliers, cutters; or thin parts where you can easily break off the supports, etc... All this would be very hard to generate with automatic methods.

It is best to clean the nozzle's outside after every print, so that no black residu builds up. I usually do this immediately as soon as the print finishes: just wipe it with a paper cloth, when still hot. But you can do it later too, after warming up the nozzle a bit. Wiping the nozzle with silicon oil prior to starting a print also reduces build-up of residu for some materials (PLA), but less with others (PET), in my experience. Reducing temperature and making sure you have no overextrusion may also help.

I am a bit hesitant to click on non-descriptive short links like these. In this case they may be honest and harmless, but I can not differentiate such links from spam or viruses (like in malicious e-mail links). More and more spam is now custom-made and thus getting harder to recognise, both in mails and on forums. So I am not going to take the risk. I would suggest that you upload pictures to the forum, so that we can always see them immediately, without need to download anything; and that you use long and descriptive links to an HTML-webpage for any downloads, but not directly to the files, and no short links. This still doesn't guarantee safety, but the risk is lower.

I can't help with Blender, as I haven't used that yet. But if the design is an STL-file or STEP-file, you could open it in free editors like DesignSpark Mechanical (requires registration) or FreeCAD, and design the supports there. But expect a serious learning curve and study time. DesignSpark Mechanical can not edit STL-files, but you can edit supports (and other stuff) around it, and save that combination again as an STL. Brim will certainly help the legs to stick better, although I can't say if it is going to be enough, but will not improve the overhangs of course. If the first layer is set to 0.3mm in Cura, then I think a real height of about 0.2mm in the print would be best. But this is only an educated guess, not the holy thruth. :-) You will have to experiment, and if it fails, consider that part of the learning cost.

I haven't made ABS slurry yet, so I am guessing here. But similar amounts of salt and sugar also do not dissolve in water, unless you stir it very well all the time. Heating usually speeds up any reactions, but for acetone this could be extremely dangerous and cause explosions, so never heat it. I guess you will have to use a stirrer, or keep stirring manually very often. PS: doesn't the plastic lid on the left bottle dissolve?

Just to be clear: my salt method works very well for *PLA* only as far as I know. So for PLA it can replace all other bonding methods for me. But it does not work for ABS. For NGEN it works a little bit. I have no idea what it does for nylon or other materials (let us know if you would ever try it), but I guess you have better chances with dilluted wood glue, glue stick, hair spray, 3D LAC or so. As kmanstudios says, I have also noticed that cheap alcohols and other cleaning aids do leave traces of oils or soaps on the glass, sometimes making things worse. Isopropyl alcohol (as also used in desinfectants) seems to work better to dissolve oils.

Cleaning the glass plate with soap-water or some window cleaners might also destroy bonding. Soap does remove oils, but it itself is anti-stick: you can not glue anything to soap. Could this be a cause? So, after cleaning the glass plate with any method, I always clean it again two times with warm tap water only (pure, untreated, not softened, no additives). As kmanstudios says, the weather can have an influence too. Before discovering the "salt method" (=gently wipe the glass plate with a tissue moistened with salt water) to get my PLA to firmly stick to the build plate, on humid days it would often come loose. While on freezing cold and dry days it would stick well. This without any other differences in models and circumstances. I guess the steam caused by water evaporation in wet nylon might also reduce bonding? You can not glue to steam. So, drying the nylon prior to printing, and then keeping it in a box with disseccant while printing, might also help?

If I had to print this for myself, and it was my own design so I could edit the design files, then I would create custom supports as in this quick and dirty Photoshop image: Pink = thin solid layers of 0.5mm height. Blue = support columns. The 0.5mm solid bottom layer (covering the shown area or maybe even the whole area that is now dark grey) is to get a good grip on the glass plate for this high model. When printing overhangs, the molten edges of the print sometimes curl up, causing the print head to hit them hard on the next pass. So you need a very good bonding to the glass to withstand these impacts, and to distribute the force over a large area. Otherwise the thin legs might be knocked over. The 0.5mm pink top layer support would sit a little bit below the actual surface it supports, with a gap of 0.3 to 0.5mm (test what works best for this size). Sometimes I use a flat top surface on such supports, but usually I design small ribs into it of 0.5mm wide. Like an anti-slip floor mat. This makes the support easier to remove, and it gives a better bottom surface on the model. See this test model: And the tree-style supports would be strong enough, easy to remove, and not consume too much material and time.

A similar problem also occurs on an UM2: the priming being pulled onto the printbed, which would sometimes cause problems. Originally I also used tweezers (pincette), to prevent this from happening. Until I found this "filcatch" thing in a post from another user (I don't remember his name). He 3D-printed it, but I made it from inox spring steel, so it lasts forever. This prevents the primed stuff from being dragged around. I don't know if this method for the UM2 could be adapted to work on an UM3 too?

If the print was easy to remove, and the glass at room temp, then I guess it broke already while cooling down. I also had this once, but with PET. The model was difficult to remove, but not exceptionally hard. While cooling, I had already heard some weird cracking sounds, louder than the normal sounds of the print coming loose. So I guess if it cracks, it is while cooling, due to the differences in thermal expansion. Maybe some sort of fatigue in the glass, or just a weak point due to a scratch or so?

All plastics do absorb moisture (water) and oils to some degree. But you can not control that as far as I am aware. Except very crudely by drying a plastic in an oven to remove most moisture. I think you would be better off printing a sort of sponge to mechanically retain the liquid. But that may be hard to model. Or even better: print a shell or container, and fill that with a suitable product, such as a sponge, salts, or the polymers used in sanitary pads. The latter are also used for plants, to regulate water absorption: when giving the plant water, these polymers do absorb all excess at once, and then slowly release it during the next days or weeks.

Dat probleem had ik in het begin ook. Mogelijke oorzaken: te grote afstand tussen glasplaat en nozzle, of slechte hechting aan het bed. Oplossing in het eerste geval voor UM2 (voor UM3 weet ik niet): tijdens het printen van het skirt manueel de hoogte een beetje bijregelen door aan de drie schroefjes te draaien. De eerste laag moet goed aangedrukt zijn, maar ook weer niet extreem. Oplossing in het tweede geval: eerst bed grondig reinigen met isopropyl alcohol of zoiets, dan opnieuw reinigen met alleen water. En dan één van de vele bonding methods toepassen. Voor PLA gebruik ik mijn "salt method": de glasplaat afvegen met een papieren doekje, bevochtigd met zout water. Zachtjes blijven vegen terwijl het opdroogt, zodat een bijna onzichtbaar laagje zout achterblijft, als een fijne mist (dat ziet er een beetje uit zoals de aanslag op een wijnglas dat te lang in de kast gestaan heeft). Voor de volledige omschrijving, zie de PDF-manual op: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Andere mensen gebruiken verdunde witte houtlijm (vb. ca. 1 deel lijm op 10 delen water), of haarlak (op doekje spuiten, dan daarmee glasplaat afvegen), of 3D LAC spuitbus, enz...

In my experience, when printing only in PLA, then atomic pulls do work reasonably well if done regularly, every week or so. Then, inside the nozzle, it burns into a dull brittle layer, but does not really build-up. But PET seems to build-up more, especially in the corners of the nozzle, and is more difficult to remove. It becomes a sort of hard coating. And it takes a lot more atomic pulls to get that cleaned out. Would be nice if we could just heat up the nozzle with its own heater to burn out the residu. Remove filament and bowden tube, heat-up nozzle, burn residu away, brush ashes off, blow dust off, and ready to go. A bit similar to how exhaust filters in a diesel car engine are cleaned, just by increasing temp (in this case by injecting diesel fuel into the exaust, so it burns in the filter).

In addition to checking the filament diameter and adjusting the settings accordingly in Cura as Sander said, I would suggest you begin with 100% flow rate, 0.1mm layer height, 50mm/s, 210°C nozzle temp, and 60°C bed temp for printing PLA, thus about the default values, and see if that works well. Then you can try to manually lower temp to see how that affects the print. If you print slower, you can print cooler too (e.g. 20mm/s at 195°C), since the filament then has more time to heat up in the nozzle. And vice-versa. But I almost never had to change flow rate. Expect a learning curve in finding the best balance between speed and temp for your models and circumstances; it may take some trial and error.

Has this been printed with support, or without? I guess it is PLA? I think you could still reduce stringing further by reducing temp and speed.

It is very long ago since I used electronics calculations, but I guess capacitors and inductors are not going to work. They will be way too resistive, and the spacing of conductive layers or lines will be too far apart to get any usable effect. I also think strings and blobs in the prints might cause short circuits. But - if you find a suitable filament - it may work for touch sensors, or for crude resistors to power a small LED lamp, for anti-static arm bands, or similar stuff. So, I guess in an HO-scale model train and scenery you might be able to use it to power the LED lamps?

Could a factor be that the layers don't have enough time to cool down? Or that the nozzle is too hot, and then melts the previously printed tiny columns? If I had to do that on an UM2 (I don't have an UM3), I would try to print it as cool as possible, and very slow. Maybe 180 to 190°C at 20mm/s? And I would probably print a dummy tower next to it for extra cooling time. Maybe you could try various settings on a small section of this model?

Do you mean that you edited the nozzle temp, bed temp and fan settings on the UM2 itself, and saved it there? This indeed does save new settings in a name like "custom+number". In that case, on the printer, you can go to: materials > settings > save to SD card (or something similar, I don't know the exact wording by head). This saves a file "material.txt" to your SD-card, which you can edit in Notepad. When editing this file in Notepad, I would suggest you change the material's name "custom4" into something more meaningfull. I use names like "PLA200" for pla printed at 200°C (PLA is always printed with 100% fan). And "NGN225F" for NGEN, printed at 225°C with fan. Or "NGN225NF" for no fan. And so on. In this way I can use only one gcode file with various materials and fan settings, by simply changing the material. There appears to be a maximum length for the material name (8 characters?), and it seems that it does not allow spaces and underscores. So I use capitals and numbers only. This is just from experience, I don't know the official specs. Maybe one of the developers can point towards that info?

On one of our UM2 I also had this a few times, but it was always in dry winter weather, when I touched the printer frame and got an electrostatic discharge with spark. It was on those cold dry days when I would get a shock and spark when touching almost everything. Sometimes the sparks were up to 10mm long, so that must be several 1000 volts. This discharges seems to interrupt something in the printer; it could be a shielding or grounding problem. After a power off and on, everything was fine again. Your problem could be totally unrelated of course. Does it stop when you are not around at all (then probably unrelated), or when or shortly after you touched it (then maybe related)? And in what weather or environmental conditions?

Normally you should not need rafts to print. I even never use brims or "mickey mouse ears". If required for overhangs, I design my own custom supports into the model. So I would suggest you just try leaving out the raft. I don't know the gcode commands, but would it be possible to manually add a "pause" command in the gcode, at the correct spot in the model? Then it would always be at the right height, regardless of any raft or other support stuff used. Maybe one of the UM-software specialists could help you out here?

I don't know the MP Mini either, so this is a *very wild guess*. But to me this looks a bit like you are using a 1.75mm filament in a 2.85mm printer? However, if you would be using the correct filament, I would indeed look for a temperature/cooling problem somewhere in the system, like Nicolinux suggested? Or some piece of tubing or coupler that is missing or mounted incorrectly (similar to the white teflon coupler in Ultimaker printers), which is supposed to contain the molten filament?

I try to simulate that in the design by adding a small rounding. This works somewhat, but is not optimal. The problem is that this approach is not compatible with desired roundings at the bottom. And it gives a bit of deformation of the first two or three layers. So indeed a solution in the slicer to reduce only the outer edge (but not the infill, so we still get good bonding) of the first layer with a user-selectable distance would be very nice. Good idea.

If it is in the gcode, I guess you should be able to see it in Cura when - in layer view - zooming in quite a lot. The "jumps" should be visible. Concerning the "salt method" for bonding, see the full manual (PDF-file) with pics at:https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

Instead of using water to glue them, what about a thin layer of wood glue, or PVA-slurry? First try manually with a few centimeters if that works. Also, you could design your own tool to align and glue these filament ends, print that, and clamp it in a vise or so. Just two simple plates with some 2.9mm diameter indentations, and some alignment features, will do. It would be an interesting experiment.