geert_2

Have you tried the "salt method"? See here for the manual (PDF-file): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Let us know if it works.

Oils do reduce bonding, and wax being oily by nature... Probably you need more mechanical grip? Maybe blue painter's tape might work? Or any other rough sheets? (Has anyone ever tried a sheet of sandpaper?) Or maybe you could melt a thin layer of wax or parafine/stearine all over the build plate, and let that cool? I have no idea if it would work, but the parafine/stearine from candles is sometimes very difficult to remove from glass. So it could work? Tea lights usually consist of parafine, very thin birthday candles consist of stearine, and normal candles are a parafine/stearine mix. Stearine has a higher melting point and is harder, as far as I remember.

You could compare it to material fatigue cracks in plastic parts: they too do usually occur in the same region: where the load stress is highest, or where there is a weak point in the model. So you would see fatigue cracks around screw threads, around inserts, at sharp corners, at attachment clips, around changes in part thickness, in thick solid blocks with uneven cooling and high shrinking, etc. I am not saying this is the case here, I don't know, but it seems one of the possibilities. So if there would be poor layer adhesion, due to whatever reason (too low temp, wrong cooling, underextrusion,...), it would seem logical that it shows up in those areas with the most stress. But that does not exclude other possible causes, of course. (Note: a quick googling for hips gave recommended temperatures of 230°C to 250°C, with extremes from 220°C to 270°C. Poor layer adhesion seems to be not uncommon. And hips seems to absorb moisture which influences print quality. So these things might be worth looking into further also.)

When looking at the photos, to me it seems that the models do only crack after the printing, or later on, but not immediately: some of the broken layers are partially stuck to the upper part, and partially to the lower part. And the cracks are in a similar region, but not at the same layers. So I would guess this is caused by poor layer adhesion and shrinking, rather than by Z-movement problems? Could it be underextrusion due to printing too cold? Or a worn out teflon coupler? Or partially blocked nozzle? Or filament problems (to thick, variations in diameter, near the end of the spool and wound up too strong,...)? I have never used hips, so I can't say anything about the required temperatures or environment.

The ratio does not really matter, and I have never exactly measured it. I just mix it so it is "quite salt", but not so much that the salt does not dissolve anymore. The water evaporates anyway when applying it to the glass. More important is that you gently wipe the moistened tissue over the glass plate, and very gently keep wiping while it is drying, so you get a very fine, thin, even mist of salt stuck to the plate. Almost invisible. This seems to work best. (There are a few photos in the manual that show it.) For me the biggest advantages of this method are: - excellent bonding when the build plate is hot (60°C), no bonding at all when cold, - no need to remove the glass plate from the printer, - easy, fast and cheap to apply, no mess, - gives peace of mind, no more worries about bonding, Geert

Hello, I can understand and read a bit of German (Deutsch), but can not write it. If you can read English, you can find the manual on the "Salt method" here: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Basically, it consists of gently wiping the glass plate with a tissue moistened with very salt water, prior to printing, and let that dry into an even, very thin mist of salt. Then print PLA with the glass plate at 60°C. This gives a very strong bonding while hot. At the end, when the glass cools down to 25°C, the models just pop off, there is no bonding at all. Since I use this, I have never had warping problems when printing Ultimaker PLA or colorFabb PLA/PHA (I have not tried other materials yet). I often have long, difficult models, 100% filled.

If it might be printed in a plate of let's say 1cm x 1cm, and used as a sticker on the skin (like morfine stickers), that would be easier. But you also need to keep in mind that the stuff needs to be heated to about 210°C (for PLA plastic, biodegradable and food safe, and sometimes also used in medical implants because of that). So the medication should not degrade at that temperature. However, personally, I wouldn't want to have any particles injected. Never. If they accidentally get into the blood stream, they will block the blood transport to the heart, brains, eyes, organs and whatever else. So, that would make people braindead, blind and cause heart failure. Similar to the side-effect that kids experience when powdering and injecting their Ritalin doses, to experience the cocain-rush (that's why Ritalin is called "kiddy coke"). Any injection system based on particles is inherently unsafe and will cause severe problems in a number of cases.

Hello, First: check if your print bed is very close to the print head, when printing the first layer, so that the first layer is squeezed well into the bed. Otherwise, no bonding method will work. Then I recommend that you start printing with the default values for PLA: 210°C nozzle temp, 50mm/s, 60°C bed temp. These are a good all-round average. And fine-tune later on. For good bonding, I always wipe the glass plate with very salt water prior to printing: - First clean it with pure tap water only (no soap, because that reduces bonding). - Then moisten a tissue with very salt water, and wipe the glass plate. - Gently keep wiping while the water evaporates, leaving a very thin, even mist of salt stuck to the plate, almost invisible. This always works very well for me, since more than a year and 1000+ objects: I have no corners lifting, even not for very difficult objects (long, 100% filled, big chamfers). See the full manual with tips at: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ The advantage of the "salt method" is that salt water is very easy to apply, is cheap, and there is more than enough available in the world... Others have good success with applying wood glue dilluted with water (10% glue), and wiping that on the glass plate with a brush, and let it dry into a very thin almost invisible layer. And others prefer a spray can such as 3DLAC. But I have never used that. Geert

Ha, okay. That makes things a bit easier. When I hear the word "laser", I still think of those big, old devices we had in school, emitting light that runs for 100km in a knife-sharp beam. Sort of scrap military or scientific stuff. But that said, I still would wear very dark laser-safe glasses, as long as spare eyes are not available on the market...

Hello Cloakfiend, Out of curiosity: have you ever tried filling your artwork with glued sand or little stones? (The sort of very small stones that they also use in modern composite floors, I don't know the correct English name.) This will add weight and improve mechanical stability. And a heavy piece of art feels more valuable than a lightweight one. A dry mix of composite glue and rough sand or small stones would be best, I think, just like they do on floors. This stays in place easily, and does not heat up when curing. (Don't use pure liquid composite glue alone, this gets extremely hot: I have had plastic cups melting, and on large pieces it may even burst in flames or explode due to huge internal stresses...) Of course, you would need to do the aceton-smoothing first, before filling, otherwise aceton may get trapped inside and cause all sorts of damage. And then co the painting after the filling.

I am not sure if it is a good idea to add laser cutting/engraving stuff to a machine that is not designed for it. You would first need to completely cover the machine with a laser-safe enclosure, or else it may be cutting/engraving your skin and eyes too. A laser that can cut through metal, surely can cut through skin, light sensitive eye-cells and even skulls. And then the rays bouncing around still may be cutting/engraving the inside of the machine: the print head, rods, belts, glass plate, aluminum heated bed, side panels,...

I don't know the official specs, but the cards in my two UM2's are both SanDisk 4GB SDHC cards, Class 4, and both were delivered with the printer from Ultimaker. They are from begin 2015. The "class" is about the maximum data transfer speed that the card can read or write, which is important for HD-video (usually requires Class 10). But I think for 3D-printing anything will do, since everything else in the system will be slower anyway...

Thanks. I saved this as PDF for the future (=easier to find back than searching through hundreds of posts). We can never know too much usefull methods.

For PLA a difference of 10°C in bed temp can make a huge difference in bonding: 60°C is optimal and very strong. At 70°C the model becomes too flexible, so corners can be peeled off the build plate due to warping forces in case of difficult models. At 50°C bonding is clearly less strong, and a few corners may start to lift. At 40°C models may suddenly pop off halfway the print. At 20°C there is no bonding at all. At least, this is my experience, but your's may vary if your circumstances do vary. For other materials, temperatures will be much different, but I think the same effects will play. You need to find the balance where the bottom layer of the material gets a little bit soft, but not too much, a bit above its glass transition temperature. I would suggest testing this on a small test design, so you don't waste too much time and filament. If you created the design, or if you can edit it, you might also try to create the supports manually, or at least their bottom layer. If the bottom layer of the supports would be a solid layer of let's say 0.2mm thick, it should stick much better than individual lines.

I don't need it for PLA, but I am going to keep this method in mind for when I would print other materials (I doubt if my salt method would work then), it seems interesting. I haven't seen Elmer's wood glue here in Europe though (but I haven't searched either, so just from memory). Is it that kind of general liquid white honey-like glue that is also sold as general kid-safe wood/paper/cardboard glue, and is water-soluble? Do you remove the glass plate to apply it, or just apply it while in the printer? And how well do parts come off after cooling down, do they pop-off from themselves, or do you need to pry them off?

I usually heat it up to about 200°C and then wipe it with a thick (!!!) paper tissue. If I am around when the printer finishes printing, I immediately wipe the outside before it is cooled down. Heating the nozzle up to about 120°C (depending on the material) and then wiping it with a piece of scrap filament also works.

Also, try printing such fine details cool and slow. I recommend making a small test piece with similar text, and then printing that at various speeds and temperatures, to get a feeling of what to expect. For example, in my experience fine text (character Caps-height of 5mm, line-width 0.5mm, and 0.2mm raised, layer height 0.1mm) prints much more beautiful at 190°C and 20mm/s than the default 210°C and 50mm/s, when printing in colorFabb PLA/PHA. For other materials the best settings will be different, but the general rule should apply too, I think. But it will not be perfect, so you may need to cut off any defects with a knife or fine scalpel, and to very gently sand it. (A scalpel is a small, very sharp surgical knife, and blades come in various sizes and models.)

For online-manuals (when there is no PDF available), a good solution might be to provide an additional CSS-sheet for printing to your website, so that pages are nicely filled, with correct margins, and navigation bars are removed when printed (useless on paper). I often "print" manuals and webpages to PDF, so I can store them locally in an easy to find directory, and I can read them offline. This is more convenient than finding things back online in the ever changing web. In this way you at Ultimaker only have to update the website, and we can always easily "print" it to PDF. Maybe you could consider this?

Try to print with the nozzle temperature as cool as possible. And try putting a fan in front of the printer, to remove the heat as soon as possible. On very small items, I sometimes gently blow compressed air onto the print to cool it down faster. (Warning: only use compressed air from a compressor, never from a spray can: they may contain highly explosive gasses instead of air, and you don't want that on hot nozzles...). More cooling will not eliminate the effect, but it will reduce it.

To test if it is the little fan: when the noise starts, just put your finger on the fan and stop it. It doesn't have enough power to cut off your finger. If it is the fan indeed, that noise indicates its bearing is getting worn out or running dry. This is a typical problem of cheap bearings, also in computer fans, model railroad trains, and model cars. Don't leave it screaming, because that further wears out the bearing, and it slows down the fan and reduces cooling. In the beginning, after warming up, the noise may go away, but that does not solve the problem, and it will gradually get worse. If it is the fan, of course. You could temporarily repair it by removing the fan, removing the sticker at the center of the blades so that the bearing becomes visible, and then oil that bearing. A drip of oil (of a sort that does not dry out easily) should do for several months. Then repeat when the noise restarts. Don't use too much oil, or it goes flying everywhere, and you don't want that on your glass bed. If your printer is still in warranty, of course it would be better to request a replacement fan.

In the beginning it really was a problem for me indeed: I often have difficult prints: long, 100% filled, with chamfers or roundings at the bottom, 5 to 15mm high. These excert a lot of warping force, even when using PLA. Printing on bare glass sometimes worked in cold dry weather, when it was freezing outside. But it never worked in rainy weather: then the filament would curl up immediately. I disliked the glue-stick methode: too messy, and bonding was still poor. And I could not use blue tape, since the underside of my models had to be totally flat. So I had to find something else... It took me some time and some testing to discover the "salt method": now I just wipe the glass plate with very salt water before a print. When dry, this leaves a very thin, even mist of salt stuck to the plate. Since then I have no more problems: models stick very well when the glass is hot (60°C), and they pop off by themself when at room temp (25°C). I only print with PLA, so I don't know for other materials. Also, I don't know why it works, but it does. Could it be surface tension? Soap decreases surface tension and decreases bonding. So I thought salt might help since it works in the opposite way of soap: it increases surface tension. Other things that might play a role could be surface roughness, or electrostatical charge?

For a better adhesion to the glass plate, when printing with PLA, you might try my "salt method": - Clean the glass plate with handwarm pure tap water only, no soap. - Wipe the glass with a tissue moistened with very salt water, and gently keep wiping until it dries and leaves a thin, even mist of salt stuck to the glass. - Then print your model with the glass heated to 60°C. This gives a very good bonding when hot. For me this works much better than using the glue stick, or than printing on bare glass. I never use brims or rafts, even not for difficult models (except for inverted pyramids, thus top-down). I have only used it with PLA. - After completion, let the glass plate cool down to room temp (25°C), and then the models will pop-off by themself. No force required. See the full manual and tips and photos at: https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ Let us know how well it works for you. Geert

I have my printers installed in a laboratory fume extraction cabinet (which I had anyway), so no need for this. But this thing looks a bit overkill to me, and it makes it a lot more difficult to reach the printer and to tune it while printing. If you only want to extract fumes, without enclosure, you might also consider trying solder fume extraction equipment. RS-components and Farnell should have them. Or maybe a simple kitchen fume extraction would also work? At least if you put another filter in it (maybe active carbon could work?).

Maybe you can get it done with newer versions of Cura, but for older versions (I use 14.09), the following might be a work-around: if you designed these parts or you can open them in a 3D-editor, you could arrange them in the editor, and save that composition as a new design. Then Cura will consider this as one single model and print it. I am not sure why Cura draws the grey unusable area around models, also in all-at-once mode, but I guess it is to avoid the nozzle bumping into other model parts when moving from one part another, when combing is off.

The biggest advantages of the "salt method" are: - It is a very comfortable, clean and fast method. - Since using this, I never had to take the build plate out of the printer. - And it sticks very well for PLA when hot (better than glue or bare glass). But it has no bonding at all when cold (less than bare glass). So I have no more worries about warping, and I never needed brims, rafts or whatever since using the salt method. I haven't tried any other filament than PLA, so if you try, please let us know. I am very interested in the results, negative or positive.