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A new method for 3D printed surface smoothing wastes less material while achieving better accuracy:
Waseda University researchers have developed a process to dramatically improve the quality of 3D printed resin products. The process combines greatly improved surface texture and higher structural rigidity with lower cost, less complexity, safer use of solvent chemicals and elimination of troublesome waste dust.
[...] The Waseda researchers developed and tested a method called 3D Chemical Melting Finishing (3D-CMF), which uses a tool like a felt-tip pen to selectively apply solvent to particular parts of the printed piece which require smoothing. The new 3D-CMF method has major advantages over previous methods: removing less material to create less waste and achieve more accurate shaping; and using less solvent for better safety and lower cost. In addition, pen tips can be changed to further increase surface shaping accuracy. These improvements promise to move 3D printing into a much more attractive commercial position, as a realistic possibility for in-home consumer use.
Development of the Improving Process for the 3D Printed Structure (open, DOI: 10.1038/srep39852) (DX)
(Score: 2) by Fnord666 on Wednesday March 15 2017, @03:29AM (5 children)
(Score: 0) by Anonymous Coward on Wednesday March 15 2017, @04:54AM
Filabot didn't even invent these.
Been around for a long time
http://artprimo.com/catalog/marker-category-empty-markers-c-258_76.html [artprimo.com]
Yo grammma's been using them before you were born
https://www.google.com/search?q=empty-bingo-dauber&tbm=isch [google.com]
(Score: 0) by Anonymous Coward on Wednesday March 15 2017, @05:04AM
My friend prints ducts for brake cooling (rally cars) and just dips them in acetone or some similar solvent for a short time. Smooths out some of the lines from the low cost printer and also makes the part stronger. The acetone is kept covered otherwise, not much loss.
(Score: 3, Insightful) by VLM on Wednesday March 15 2017, @12:23PM (2 children)
I actually read, well, deeply skimmed, the report and the scientists are not guilty but the journalists are extremely guilty.
The report itself glosses over the invention and focuses on the "D" part of R+D the development. They went to enormous effort with some interesting technology to simulate and then reproduce precise results, then did some modest engineering beam strength analysis to verify the results and they have some interesting surface profiler that I'd like to learn more about or build one myself as a project. Its an interesting read.
Imagine if in 1970 some metallurgist gets all hot and bothered about obscure temperature profiles for annealing hardened steel so he uses a 60s minicomputer to numerically simulate some obscure steel annealing temperature profile to get some interesting theoretical results, then gets some F-4 turbine blades (well, probably classified then, lets say F-104 turbine blades) and hardens them and then does his obscure annealing profile on them for real then goes all Mr Engineer on testing the hell out of the steel to see if it actually has the computer predicted characteristics, then repeats the cycle a couple times until he's invented the high tech F-16 engine turbine heat treatment process, and when it does he publishes (actually it probably gets classified and buried for 25 years but whatever). Then some idiot journalist comes along and reports "Local man invents steel". Well, not really. Not exactly. Not really the point. Just no. Just say no to fake news.
That is not the problem with the study. There actually are at least three REAL problems with the study.
The first is every hearsay I have indicates molten ABS Fing stinks like a garbage fire. I've never used it personally. PLA is virtually odorless or at worst it smells corn like or you're sniffing the pigments. Its not the stinkiest thing in the room generally. The article comically claims this tech is useful for home use but ABS stinks so unless you're a makerspace with an open garage door, its not happening on Martha Stewarts kitchen table. And AFAIK solvent foolishness doesn't work on PLA or the solvents that work on PLA give you cancer so I'd rather have ugly "overbuilt" prints where I'm blowing 7 cents of PLA instead of 5 because I'm not smoothing it. I suppose if you print a plastic that smells like a smoldering trash fire you won't mind snorting some cancer solvent to smooth it. But you gotta accept that normies are going to WTF you as they print with delicious harmless PLA.
The second is this looks incredibly hand operated and a PITA and everyone I know of who solvents ABS despite the stink and cancer, dips or sprays or vapor polishes. Using a brush results in a filthy mess and a drippy finish and of course a dirty brush to deal with. If you want it strong, print it bigger. If you want a nice finish, the world of plastic model paint will give a better result than Fing around with any solvent. If you must use a solvent, almost any method of using a solvent works better than using a brush. Finally if you insist on shooting yourself in the foot, this linked article does a lot of engineering development on possible low volume mass production of brush solvent finishing, but its still a dumb idea maybe 99% of the time. Yet its not that awful. Sure I'm never going to woodwork up one of those plywood "very fat woman bent over in the garden" um decorations or stylish person repellents or WTF they are, but a magazine article about it might be tangentially interesting from a how to jig saw something the size of a person standpoint. Apologies to any SN readers who have something like that in their garden or (gasp) front lawn, but thats just how I feel aesthetically.
The third problem is the article subscribes to the pi (LOL pi day) in the sky that a 3d printer will be a normal home appliance, so surely his finishing technology will be of great residential use. Having a printer for a couple years its exactly like a soldering iron or table saw in that if you're a skilled artificer your hands are kinda tied without it, for for my grandma its just an expensive paperweight. Actually its very much like owning a residential computer or laser printer.
(Score: 2) by opinionated_science on Wednesday March 15 2017, @02:14PM (1 child)
in a research project I did last year for the local uni, I compared some 3D prints of different sorts for a functional shape I designed.
One of the attractive (and reasons for expense) of Shapeways, is that they make a nice finish.
Even their default "scrubbed" one was quite effective.
I'm curious as to whether hot-air could be used to smooth the lines?
(Score: 5, Informative) by VLM on Wednesday March 15 2017, @02:43PM
I'm curious as to whether hot-air could be used to smooth the lines?
There's three ways to work it theoretically. Experimentally my half way attempt results were not promising.
From a theoretical standpoint organic chemicals mostly are pretty sharp melting points. The purer something is the sharper the melting point. So in the old days in ochem lab we used these 1950s melting point apparatus which were top lit microscopes with heated stages and mercury thermometers and at 113.9C crystals of vitamin C on a microscope slide look identical to room temp and at 114C you got a little transparent puddle of liq ascorbic acid instead of the crystals. Pretty sudden stuff. The less pure something is the smoother the melting point for ochems. Of course there's glass which isn't a plastic organic chemical. And there are alloys with sharp melting points like 63/37 old fashioned lead solder, which also isn't an organic chem plastic. Of course 3-d printed stuff usually has ground up pigment in the filament which makes it randomly mushy depending how much pigment and which pigment color. So every mfgr and every color will have a slightly different mushiness. In the old days before FT-IR spectrograms and NMR machines and xray diffraction, melting point was all they had, like a century ago they had books of ochem melting points to help identify an ochem. From memory its weird that all fun small to mid size organic chemicals melt somewhere from like 50C to 300C. A melting point apparatus for inorganic metallurgy would be pretty hard core compared to ochem melting point apparatus, thousands of degrees and all that.
Another theoretical problem is you can flame polish glass quite easily because glass doesn't burn very well but trying to flame polish PLA or ABS would result in a fire. You'd have to stay cooler than ignition temp, preferably way below. That might not work well enough. Maybe pre-heat to just under melting then a quick hot bath just above.
Thin sections are cheap and to save money and print time people tend to print thin sections and use slicer generated structure in the middle and the melting isn't going to be very even on thin walls, so in theory if it worked people would have to change their typical slicer settings to squirt out thicker walls, which will make slower more expensive prints which will make people with model paints or engineering prints where they don't care about the surface, annoyed.
In practice hot PLA is mushy over a range but I haven't had much luck smoothing it. I've made little standoff mounts for circuit boards and stuff and later soldered on the board and that hasn't melted the PLA but boys will be boys so I played with the soldering iron and the PLA much as with a very smooth touch and steady caffeine free fingers I can shrink heat shrink tubing with my soldering iron, but I can't smooth PLA with my iron. Not to say that failure proves its always impossible especially maybe with some preheat... I have never tried the SMD rework blower on PLA, now I feel motivated to give it a shot. I'll probably result in a melted mess and/or a fire so I'm not really in that much of a hurry. My lab area is mostly fireproof for vacuum tube reasons which is a whole nother topic, so aside from the fumes a little fire would be safe (I'll try a widget the side of a match not the size of a shipping crate so even worst case is only about as toxic dangerous as striking a match)