Giving 3D Printed Parts A Shiny Smooth Finish

No matter how good a 3D printer gets, you’re always going to have visible print layers. Even with very high-quality prints with sub-0.1mm layer height, getting a shiny and smooth finish of injection molded plastic is nearly impossible. That is, of course, until you do some post-print finishing. [Neil Underwood] and [Austin Wilson] figured out a really easy way to smooth out even the jankiest prints using parts you probably already have lying around.

The technique relies on the fact that ABS plastic and acetone don’t get along together very well. We’ve seen acetone used to smooth out 3D printed objects before – either by dunking the parts in an acetone bath or brushing the solvent on – but these processes had mixed results. [Neil] and [Austin] had the idea of using acetone vapor, created in a glass jar placed on top of a heated build plate,

The process is pretty simple. Get a large glass jar, put it on a heated build plate, add a tablespoon of acetone, and crank the heat up to 110C. Acetone vapor will form in the jar and react with any printed part smoothing out those layers. The pic above shows from right to left a 3D printed squirrel at 0.35 mm layer height, 0.1 mm layer height – the gold standard of high-end repraps – and another print with 0.35 layer height that was run through a vapor bath for a few minutes. Amazing quality there, and cheap and easy enough for any 3D printer setup.

You can check out the tutorial video after the break along with a video showing exactly how dangerous this is (it’s not, unless you do something very, very dumb).



142 thoughts on “Giving 3D Printed Parts A Shiny Smooth Finish

  1. Beware that smoothing 3D printed parts with a solvent is PATENTED, just like many other OBVIOUS little things you can do while making 3D printed parts also have been granted ridiculous patents. Some obvious examples are:
    1) Keeping your 3D printer at a warm temperature in a temperature-controlled box is patented. There is prior art for this for temperature controlled work spaces. Stupid patent!
    2) 3D printing a batch containing more than one part the same build platform is patented. There is prior art for building things in batches. Stupid patent!
    3) 3D printing parts on a conveyor belt is patented. There is prior art in Henry Ford’s assembly line. Stupid patent! Sadly, the “open source” MakerBot guys were granted this patent for 3D printing on an assembly line conveyor belt.

    The US patent system is horribly broken. And it was recently made worse, buy restricting prior art searches to cut costs. It is up to Makers like us to fight the patent trolls when they attack us with these stupid patents. And if you try to make enough money to get noticed by the patent trolls while using acetone to smooth your parts, can you afford to fight them. And what’s up with the MakerBot conveyor belt patent? MakerBot? Really? WTF?

    1. Smoothing method for layered deposition modeling
      Patent Application Number: 8,123,999
      Date Published: Feb. 28, 2012
      Assignee: Stratasys
      “Stratasys has patented a method to achieve this slick surface finish by submerging parts in a liquid bath that melts the plastic — basically, anti-wrinkle cream for 3-D printers.”

      1. Ha. Check out the patent.

        > “The method of claim 2, wherein the solvent is selected from the group consisting of methylene chloride, an n-Propyl bromide solution, perchloroethylene, trichloroethylene, and a hydrofluorocarbon fluid”

        Acetone isn’t covered in the claims. This method isn’t patented. And since it’s on the Internet now, it’s unpatentable.

        1. Doesn’t mean someone won’t try (and most likely succeed). Though from my non-legal understanding as long as we aren’t selling this the patent problem is moot. If you sell a jar with acetone and a heater for smoothing parts, you might run into problems, but given these are easily obtainable everywhere, hobbyists can easily do this at home.

          1. No, any use, whether commercial or not (i.e. whether you make money or not), is forbidden if it’s patented. Obama’s issuing an executive order to curtail this, but it falls short of stopping this ludicrous patent trolling. But it’s a step.

            Here’s an article

        2. It’s covered by the independent claim (1), which refers to *any* solvent that “transiently softens the modeling material”.

          Note, oddly-specific qualifier alert: All of the independent claims include:
          “observing condensation of the solvent vapors…”
          “discontinuing the exposure … after the condensation of the solvent vapors stops”

          They may be specifically to qualify around some existing prior art. Whether that is the case or not, to infringe the patent you(r device) must employ some means of actively observing the process. You don’t really have to worry about this smoothing your own parts in your basement, but when employing the step in a commercial printing service or in a printer that it sold. An “easy” way around this patent is to smooth parts without actively observing the process. For example, if an open-sourcerer were to come up with an algorithm that determined the optimal exposure time based on the step height to be smoothed, maximum part thickness and the estimated surface temperature of the part vs. the solvent vapor. (I.e. use thermo to model when the condensation will finish, if that’s important, without having to watch the process). I would suggest simply monitoring the weight of the part, but that may count as “observation” of the condensation process.

          1. I can’t agree enough about the failures of the patent system. It is a thoroughly broken bureaucracy that is being abused by those corporations and individuals wealthy and greedy enough to play the system. The original purpose of the patent system was to put technology into the public domain, not to stifle competition and slow the progress of innovation.

            It’s up to the hacker community to come up with a good response to this problem, as ultimately garage makers and hacker spaces will come into conflict with companies using the patent system to defend the ownership of ideas that should be in the public domain.

            We are already seeing the start of this with Kickstarter and Formalbs being sued by 3D Systems – a company that won’t even tell its customers the cost by volume of its consumables, instead claiming that it is a trade secret.

            We are transitioning beyond being simple consumers of goods, and as this dawns on companies like 3D Systems the inevitable response from them will be to bully and sue for every square inch of their evaporating market.

        3. They got rid of the prior art in the US didn’t they? Now the patent goes to the first that patents it no matter who invented it.. yes it’s insane and unfair to the max.

    2. Fortunately patents do not apply at all in any way to DIY projects so you’re free to do and duplicate any patented process in your home without any fear of reprise.

      Also unlike your 3 examples the process of smoothing a print by means of a heated solvent bath is not at all obvious and is exactly the kind of thing that should be patentable. It’s a specific and non-obvious process solving a specific problem in a specific way. Quite different from the 3 examples.

      1. The only thing different about this patent and prior art used to smooth rough parts (such as sawed edges of acrylic sheets, and other tooled plastic surfaces) is the 3D printer. The temperature of the solvent is not important. There is also prior art for warming a solvent to increase its etching or smoothing speed.

        Throwing a 3D printer into the mix on all of these patents most certainly is obvious. These frivolous patents must stop! And the software patents are even scarier. ;-(

      2. @Garbz: Those “do not apply” and “no fear of reprise” claims only work if you do not get noticed by the patent trolls. If you publish your DIY project in a blog or forum, you can get shut down. Open source projects HAVE been shut down by patent trolls. Do you have any evidence to support your claims?

        And though smoothing plastic parts in a heated solvent may not be obvious to YOU, it actually is obvious to me. “Obvious” is a rather subjective term.

        1. Patent trolls are famous for trying to stretch there patents as far as they can, to extort money from anybody who uses the same ideas that they stoll from somebody else. Take for example Apple, who copied ideas from Xerox Star, and then sued others who copied those same ideas. And patenting rounded corners? WTF? And patenting narrow bezels? Again, WTF? Even their patented GUI method of bouncing the icons off screen edges has prior art WITH A TOUCHSCREEN even! The patent system is insane. And just because the educational system is dumbing down society does not redefine what is obvious. And prior art is no longer as important when filing a patent anyway. The only thing that matters is CAN YOU AFFORD TO FIGHT THE PATENT TROLLS? Even juries give ridicious settlement awards FOR OBVIOUS STUPID PATENTS when it comes to technology patents, depending on whose fanboys are in the jury. You may as well flip a coin to decide which side wins, regardless of prior art…

          1. Apple is not a patent troll. They may be aggressive with their patents, but they attack products, not seek money.

            The two hallmarks of patent trolls are that they don’t produce goods, instead using patents for capital, and they go after anyone and everyone that could possibly cough up money. Lodsys is a solid example of a patent troll. Other examples include Acacia Technologies, Interdigital, and Intellectual Ventures. *These* are the companies to yell about. Don’t let some meaningless legal chess game (one that has no impact on you whatsoever) between Apple and Samsung blind you to that.

            Furthermore, design patents are a whole different issue. Apple has a very specific look and feel about its products, and if you think that’s the only way to do it, that it’s an inevitable design, then you’ve bought into Apple’s marketing more than any fanboy ever has, and you’ve got literally zero sense of industrial design on top of that.

          2. Whoa there son! Apple bought those rights from Xerox. Let’s get the history correct.

            If you infringe on someone’s patent with a personal project, they can come after you for damages because you would have otherwise had to buy one of their products instead of you making one yourself. That’s why. And it’s a bunch of BS. There was a Supreme Court decision about this over some crops. I can’t recall the details anymore.

          3. Windows 1.0 had rounded corners on the dialog buttons. Windows 2.0 through 8 does not, even though any design patents on the early Macintosh GUI are long expired. I suspect the reason why the default dialog button (what gets activated by hitting Return) has never been movable on Macintosh is because Microsoft implemented that on Windows.

            Mac, round corners and immovable default button selection. Windows, square corners (or very, very slightly rounded, just a couple of pixels off the corner) and default button selection movable with the Tab key. Why? Because of the settlement the companies signed nearly 30 years ago.

            Whether a corner on a GUI element or physical object is rounded, square, ogive, concave or any other sort of shape should not be patentable, copyrightable or trademarkable. Why? Because all those shapes have been used over and over in the past.

            When it came to Apple’s claim that Samsung copied the shape of the iPhone, Samsung’s lawyer should’ve slapped a Palm LifeDrive on the table and said. “Looks to me like you copied Palm Inc.!”

        2. @geekmaster yes I do and the premise is quite simple. Patent infringement can only be claimed if you … infringe on a patent. To infringe you need typically need to actually have a commercial product (yes open source can be seen as a commercial product).

          In countries where you commercial isn’t part of the law (like the USA) the damages claimed will be in the form of damage to the business. Yes someone can sue you for making something using a patented technique but they would get laughed out of court if you’re not doing it commercially or preventing their income.

          Also every case of open source projects getting shutdown I have seen have been due to copyright and trademark infringement. Do you have any examples where actual patents resulted in a hobby project getting taken offline? Again note hobby project. Open source can still be commercial.

          1. I know of one: JMRI, a free / open source model railroad control program. The project is now back online, but a motivated commercial troll subjected the creators to patent and other litigation that dragged on for years and cost the developers untold thousands of $ in legal defense. See and .

            I agree that it is *extremely uncommon* for a patent holder to go after a hobby project or an individual DIY’er who isn’t selling anything, but that’s more of a strategic move than anything (not worth the $; and sometimes a lark project will go commercial later and lead to bigger winnings) – there is no actual exemption for noncommercial infringement in the US (or other countries I am aware of)

      3. Unlike copyright, it is not true that patents don’t apply to DIY, personal, or home use. If you produce an object that infringes a patent you are guilty of patent infringement, period. The only reason that it “doesn’t apply” is that you’re unlikely to get caught and/or prosecuted for a personal project.

        1. What’s your basis for saying copyrights don’t apply to “DIY, personal, or home use”? If you make five CD copies of a Backstreet Boys disc so you can have one in each of your five CD players, that’s copyright infringement just like your patent infringement example. Of course in both cases, you’re not likely to get caught.

          Maybe you’re thinking of the fair use exemption for copyrights, but the way that’s written, and the way it’s been interpreted in court, don’t give a blanket exemption for the situations you mention:

          I also believe there’s some court precedent for the legality of making a single backup copy of media you’ve purchased, but not more than one.

          I’m not defending the current state of copyright, but everyone should know what it is.

          1. Not an expert ont he subject either, but I believe you are referencing the old “For archival purposes clause”, that seems to have disappeared with the DMCA, at one point you were legally entitled to make a copy (For archival purposes) of just about anything that you purchased, but with the invention of DRM, I believe it’s illegal to circumvent the copy protection methods used to prevent you from making those ‘archival’ copies…not that this stops most people, nor will it ever stop a crook.

          2. Just saw this post and felt like I should reply. As regards patents and DIY – 35 USC § 271(a) says, “Except as otherwise provided in this title, whoever without authority ***makes, uses***, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the patent therefor, infringes the patent.” (emphasis mine). It’s certainly not likely to get you into trouble, but simply making something covered under a patent or using a patented process for your own use is technically in violation of U.S. patent law. Selling patented products is a separate violation and can be charged as such, as is active inducement to violate a patent. Interpret that as you wish.

        2. Yes, it’s infringement. However, there’s no real legal remedy for home use/DIY projects. Even if caught, they can only sue for lost profits or a reasonable royalty. That won’t even pay the filing fee.

        3. I’m not a lawyer, but even if applying a method in a non-commercial use were considered infringing, I have to imagine anyone would have a hard time coming up with a claim of damages.

      4. If you knew anything about polymer chemistry you’d find it obvious (no offence meant).

        Solvent baths are not new, although they have a cooling coil to accurately define the solvent/air interface, and to allow high-melting point solvents. As far as I know they’ve been around for at least 50 years, and you’ll find one in most well equipped machine shops, although they’re often called “xylene baths”.

        The two commonest ways of smoothing plastic involve either heat or solvents, and both go back to the beginnings of plastics manufacture.

        Letting this patent through would be like making a new food product and patenting the use of cutlery to eat it with.

    3. I love the part, where they first explain how polishing plastic parts with solvents/solvent vapors is common practice in the industry, and then go on to explain: “Despite the need in rapid prototyping for an expedient and inexpensive surface finishing technique Applicant is unaware of any teaching or suggestion in the prior art to use a vapor polishing technique for the smoothing of objects formed by layered manufacturing rapid prototyping techniques.”
      I think my definition for “prior art” would be very different from that of the patent owner.

        1. It’s like Feynman’s nuclear airplane patent.

          “Feynman, think up a few things that we can patent with this new nuclear power.”
          “Boats, cars and planes.”
          “Boats and cars are already taken, you get airplanes.”

      1. US Patent law makes even this dangerous as hell. Experimental use doesn’t seem to apply anymore. I can’t cite the case, but several years ago I remember a university laboratory getting sued by a company for developing a cancer treatment using one of their patented microscopes. The problem was, the university couldn’t afford the tool, so as a means to an end, they custom fabricated an analog of the patented tool. The court ruled the university infringed, even though they used it for research, and not directly for profit.

        Our US patent law is a nearly hopeless mess, which stifles invention more than it protects it.

    4. I couldn’t agree more about the patent system being broken. In this instance, there might be simple way to work around the problem, however. It would be nice to have a simple method based on liquid immersion, but that avoids the use of pure acetone, which is too aggressive. Immersion is not only convenient, it also avoids the problem of non-uniform vapor exposure, and eliminates the need to work with heated acetone.

      Acetone is highly soluble in water, so perhaps immersion in a dilute acetone solution (say, 5%?) followed by air drying would provide good results. It might take some experimentation with acetone concentration, but such an approach might work quite well. Alternatively, you could immerse the part in the dilute acetone for a period of time proportional to the amount of smoothing desired, remove the part, dunk the part in a water bath to remove residual droplets of acetone on the surface (which could result in a mottled surface), and then let the part air dry. The duration of the dilute acetone dip (and the concentration of the acetone solution) would control the depth of penetration of the “smoothing agent”, as a patent attorney might say. If I had some ABS parts on hand I’d try it. All I have is PLA.

      Please keep in mind that one quick and dirty experiment that fails to provide the desired results is not necessarily an indication that the proposed technique will not work. Most likely some degree of careful experimentation will be required.

      1. Too much coffee! Can’t “calm down”. Actually, I am concerned about frivolous patents infringing many of my DIY interests, not just 3D printing. It makes one a bit afraid to publish in some cases, just BECAUSE of various open source projects that have disappeared after receiving takedown notices from patent trolls.

    1. I think this is one of those “patent pending” and never actually approved. Because there is noting patentable in using acetone as dissolvent. If that is patentable it should be already in production price. Otherwise one can patent water vapor use and send checks to all the sauna owners. :)

    1. I think it is an exaggeration to say it loses all detail, but there it probably a relationship between the ideal smoothing time with the size of both the ridges and the smallest preservable detail.

    2. What “detail”? The model used in the post doesn’t have much fine detail in the first place, and what it does have is preserved. The shiny surface just makes it harder to see the surface contours in the photographs compared to the matte surface.

    1. Nope, acetone doesn’t melt PLA, though it makes it brittle. The solvents that can be used for PLA are very nasty, far worse than the offgassing from printing ABS that drives people to use PLA.

  2. BTW, the “worst case” scenario for the acetone catching on fire is really uncalled for. The autoignition temperature is 465C. The instructions here indicate a set temp between 90-110C.

    The biggest warning I would have given is “WEAR GOGGLES”. My mom was using pure acetone in paint stripping of some antique furniture. She was wearing gloves, but not goggles. She had a dot of acetone land in her eye. We had to emergency flush out her eye and then go to the ER. NOT FUN ONE BIT.

    1. It should also be said acetone should be used in a well ventilated area, the fumes are toxic. Basically, read the warnings on the label and determine how far you need to go to assure your own safety.

    2. The problem of having a glass jar full of hot vaporized acetone is not its autoignition point, but the fact that you can ignite it with static electricity or other ignition source and then your glass jar will say “boom”.

      BTW. an option to heating the jar would be closing the lid and drawing a partial vacuum to force the acetone to evaporate. A bicycle pump should be completely sufficient. The resulting gas would have little enough air that it couldn’t ignite, and the plastic parts won’t be subject to heat so thin and delicate parts won’t sag.

    3. I think the warning is appropriate and yes acetone vapor can be dangerous, both from ignition or inhalation. On the other hand the hacker/maker crowd, myself included, are pretty good at ignoring people who tell us not to do something. It actually inspires me to break the rules some times.

      On that note!!! :-)

      Acetone vapor can be some pretty cool stuff if you very carefully do some dangerous things with it. The vapor is heavier than air and tends to pool in low spots. If there is no ventilation this can be a real problem. It can also be used to make a seriously cool river of fire effect down a sloped channel such as a piece of metal roof gutter. By soaking a small rag with acetone and placing it at the high end of the gutter held at a slope the gas will flow down the channel. Turn out the lights and strike a match and the effect is pretty cool.

      As a disclaimer this is obviously a very stupid and dangerous thing to do that I would NEVER recommend anyone tries because you are likely to lose an eye or something!!! It can also be an effective display of the safety risks of acetone. You choose.

  3. Awesome technique! I think the key now will be integrating changes to the initial 3D model designs to account for a standard vapor bath, similar to how they change the masks on semiconductors to take advantage of interference effects. Sounds like a good math & chemical engineering type of problem for some programmer to solve!

    1. I’m in a drafting and Design school at the local college. We’re doing specifically this kind of drafting right now, with casting compensation and other modifications for machined parts after the original process.

      My first question would be “Given a vapor filled chamber of 100% acetone, and a calibration cube, how long does it take to reduce by 1mm per face?”

      Unfortunately, my printer is 98% done. I’m only waiting on the last few parts to finish and start printing for the Midwest Reprap Festival. But I plan on contributing this data once I get it up and running.

      1. In my experience, acetone adds volume, and then reduces back to size when it goes away. It causes the part to swell temporarily, and whatever apparent volume you lose is because it flows into the existing crevices that are left on the surface.

        So the change in dimensions depends on the surface roughness.

  4. I like what Dax said about drawing a vacuum. I would add that perhaps overly-sharp edges could be added to a model to compensate for the smoothing? Seems like a script could even be written to perform this mathematically.

    Also, it would seem that the addition (safely of course) of a small brushless fan would cause more vapor to soak into the outer skin at a faster rate, before it had a chance to saturate farther into the piece and cause sagging. Maybe I am not being reasonable here.

  5. You know what’s worse than the patent system, stupid people trying to interpret it.

    You are now complaining about what Stratasys has been doing for decades and spent capital to innovate. The reason that these hobby devices came about is because Stratasys and similar companies had to publish the details of these invention to receive the patent. Your so called innovators used these published documents to come up with their low cost alternatives.

    If you cover a copyrighted song and try to sell it for profit, you have to pay royalties. These designed lower cost versions of the same invention and are now trying to profit from them.

    Only reason these hobbyist made these projects open source is because they knew they could not receive a patent for it. They love the technology and they shared their experience with it and these companies had left them alone pretty much until now because they are realizing that it impact their company’s well being. And rightfully so. Unless you can prove that someone else came up with these ideas first, then file a motion for reexamination with the USPTO and submit your prior art.

    Otherwise, negotiate and pay royalties, or solve the problem with a different solution. You make the solution open source by putting it in the public domain or file for your own patent. And remember, Stratasys started with a glue gun in 80’s.

    Is there room for improvement in the patent system, absolutely yes. I firmly believe that patent terms are too long in this day and age of rapid innovation.

    1. “And remember, Stratasys started with a glue gun in 80′s. ”

      And people have been making objects by building them layer by layer out of coiled clay since 25,000 BC. Your point?

      The idea of additive manufacturing in plastic wasn’t novel even in the 80’s. Obvious and trivial ideas should not be patentable.

      1. Really did they use a heated applicator tip to extrude clay? Hell nature’s been doing it for eons. Yeah in the 80’s Stratasys did come up with a novel way to do the same thing. That is what the patent system is based on. If they didn’t, the system is designed to autocorrect errors. If someone believes they unjustly received a patent they can file a suit. The patent system is a democracy, the government dolls out patents based on what information they can find and what the applicant provides to them. If they cannot find prior art and the applicant has a persuasive argument, they get their patent. Then it becomes the peoples responsibility to uphold the patent or strike it down during its term.

        The biggest problem is when patent litigation goes to trial and you have lay people that don’t know anything about the invention or patent law are asked to lay down judgement. The patent system will only improve when more citizens make the effort to understand it instead of bitch about it.

        1. It’s that “if” the USPTO cannot find prior art which is the sticking point. The office has become quite lax in its search of its own patent records to look for prior art.

          The problem is getting a patent invalidated that should never have been granted when it’s insufficiently “novel” and different from one or more prior patents.

          This problem with the USPTO goes back a very long way. Look up the Selden patent on the automobile. Selden was granted a utility patent on using any sort of motor or engine, (electric, steam, internal combustion etc.) to power a wheeled vehicle. He managed to extract royalty payments from everyone making automobiles, except for Henry Ford. Ford fought back, won the case and the Selden patent was invalidated.

          Selden’s patent should not have been granted. It was as vague as many of these latter-day patents whose main intent is to stifle competition and/or to serve as a legal club to extort money from competitors.

          What’s the difference between a utility patent and a design patent? A utility patent covers a specific process or device, no matter the cosmetic details. For example, if GE had a utility patent on the refrigerator, no other company could make refrigerators without licensing the patent from GE – even if in every tiny detail and material their refrigerator was different from GE’s. But since the patents on most refrigeration technologies are very long expired, nobody has or can get a utility patent on the refrigerator, or the automobile, or the wheelbarrow…

          What they can get are design patents on specific *shapes* of all the components that are assembled into their refrigerators. That doesn’t stop another company from making refrigerator parts that do exactly the same things, as long as the *shape* is sufficiently different. It’s even possible to make parts that fit in place of the originals, as long as the *shape* of areas of the part that aren’t critical to the fit are different. Just claim the shape and location of the threaded connections as “prior art” and all the rest of the shape (which usually isn’t critical at all) as an “improvement” and the owner of the design patent on the original part can’t do a damn thing except for advising their customers to only use genuine original parts.

          As for the wheelbarrow, the USPTO screwed up in the and granted a utility patent on it to a guy who applied for a design patent on pivoting handles to mount onto the ends of the typical straight handles. Being an honest fellow, he informed the office of their error and IIRC got his design patent. i suspect he didn’t make a penny off his design. It’s been 15 or more years since I read about that but only recently have I seen wheelbarrows with pivoting handgrips. All the wheelbarrow manufacturers had to do was wait for the design patent to expire then start barrows with the grips – of course design patenting their specific shapes and citing the original design patent as prior art. Gotta keep anyone from making an *exact copy* while laughing about how the guy who first patented the idea got nothing.

        2. @Hashish, try thinking about the problem and perhaps you will slowly come around to understanding it. Sure, we need to support innovators, but at this point the patent system is completely unbalanced and is actually slowing the pace of innovation.

          Patent trolls are indefensible. It isn’t their right to make money by legally exploiting a antiquated and incapable patent office. This slows down the pace of innovation for the entire species, and the rest of us should take issue.

          The purpose of the patent system is not to maintain the ~$600 hourly rate that most patent lawyers charge, or to keep ownership of intellectual property in the hands of the wealthiest among us.

          Unfortunately the interests that lobby (and by lobby I mean *legally* bribe politicians and officials) for changes to the patent system are the same interests that make money by exploiting it. The best hope for a big paycheck that anyone working for the USPTO has is to leave and become a consultant in industry, helping those who can afford to cheat the system. This is the same problem with the IRS, but the difference is that instead of just stealing money those who exploit the patent office are stealing innovation – they are stealing the ability of the rest of us to enjoy the fruits of technological advance.

      1. They won’t remain perfectly unmixed, since cooler air will drop into the jar as the fumes bubble out like from a lava lamp. Keeping the top open just allows the air around to diffuse with the acetone and makes a nice pop and a crackle when you strike a match at it.

      1. Same here, but I’m in school for drafting and design tech. We have to learn both units and both standards of drafting. Yes, metric and imperial drafting styles and number layouts are different.

        And there is also an interesting article about NOT using an imperial threadrod for Z axis. Evidently, the imperial to metric conversion from thread to thread is some infinite repeating number, so you end up with Z drift errors.

  6. So, has anyone patented a way to check on the progress of the surface melt in a 3-D printer? For instance, by bouncing a laser beam or point-source light off of the object and measuring the specularity of reflection? If not, maybe now they won’t be able to because the art is being considered here on HAD :)

    And, to make the idea even more broad (like they do in patents), add a proof-surface to the object just for doing this measurement. Sort of like doing ellipsometry in wafer fab. We could also include a proof surface ruled in a sequence of varying groove depths to gauge the melt/time ratio.

    1. No, these were all done with an 0.5 nozzle. The three squirrels in the photo are 0.35mm layer height (with bath exposure), 0.1mm layer height untreated, and 0.35 mm layer height untreated from left to right.

      All the squirrels in the video were printed from the same machine (the yellow and black mendlemax in the background of the first video) with the the exception of the 0.1mm guy. That was printed on the red and black one about six months ago when I was calibrating and testing the extremes of my print limits. We keep it around the hackerspace as an example of “high quality” prints, though that definition may be changing quickly thanks to this.

  7. I cannot believe my eye’s reading these comments about these patents.I think a campaign is in order to boycott these company’s.I didn’t know any of this even though i am reading up most days to build my own.They took a open source dream and have smashed it into a million pieces.

  8. I wonder what DCM (Dichloromethane/Methylene Chloride) would do. warm it up in a sealed glass container and allow it to cool back down to re-condense. Do this outside of course. It has the advantage of being not-so-flammable (sort of).

  9. Now I want to see a software add-on that takes the original model and slightly exaggerates its features such that the post-acetone vapor result exactly matches the original model. Hell, given that, it wouldn’t be unreasonable to build a 3D printer with this as an automatic final step in printing. The software could analyze the model and come up with a combination of feature exaggeration, acetone vapor concentration, temperature, and vapor exposure time to get really damned close to perfection.

  10. I could see a nice add on vapor injection tip being designed based on this.

    It could have a small acetone vapor flow being directly aimed at the part right after the layer is put down. I would assume that the effect would happen faster on hot material so it would require less time. With a little digital trickery (algos) you could even limit the smoothing effect to specific places on the model.

    No doubt this would take a lot of experimentation to get right. Hopefully some genius with a little more free time and a bigger brain than I have comes up with a way to integrate this directly into the printing process.

    Great idea by the way.

  11. Could using vapor to smooth details be used in lens making?

    I’d like to 3d print some small lenses about 5mm in arrays then make a silicone mold, and cast an epoxy print of the mold for some custom led stuff.

    So what sort of vapor would smooth epoxy, particularly to easy to use 50/50 stuff used on timber finishing?

    I’ve made casts of bigger glass lenses and with a bit of care to avoid bubbles when stirring they turn out great, I’d like to go from computer model to part though.

    1. I would guess it really depends on what you are using the lens for. A lens for a camera would require very high precision and I doubt you would get that level of consistency with this aproach. On the other hand if you are just using the lens as a collector for a semi direction light intensity measurement this could be a great way of doing it.

      Good luck and if it works post a walkthrough of what you are doing on a blog. Maybe HAD will pick it up and crash your server. :-)

  12. @rgbphil.
    Just print the lenses=> smooth them => then make the silicone mold ;).
    This is great and I want to try this tonight! Problem is what do you do with the jar once the part is finished? Do you just close it to reuse later? Will the fumes build up or do I best place it outside after the process… Furthermore how toxic are the fumes really?

    1. as someone who practically washed in acetone while a chemist, it is not immediately toxic. However, it can lead to lung and other mucus membrane problems (rhinitis etc). But if you are sensible, it is pretty safe. As to storage, same as with any volatile liquid: seal it too tight and you might get a bang on a hot day.

      1. Thanks. Yes I found the msds report and indeed inspite some people stating it’s really dangerous and can cause cancer on some forums: the msds report says: CARCINOGENIC EFFECTS: A4 (Not classifiable for human or animal.) And light exposure just get’s processed by the liver (so as long as your not an alcaholic this is also not that bad ;) ). Anyway yeah was hoping for this and indeed best not seal that glass jar too tight. Thanks for the tips!

        Also I use acetone to clean my heatbed sometimes anyway (it makes parts stick better) which is probably about the same as doing the above smoothing process in terms of health hazard (meaning it’s harmless if you don’t be an idiot and start sniffing above the jar or do other stupid stuff like splashing it in your eyes etc.).

        Anyway this seems like indeed a leap forward. As regarding the aussies that did it first -> well but they did not come up with using the already heating print bed to do it. This guy definitely gets props for the easiest and cheapest solution to clean up your printed parts!

    2. From the material safety data sheet:

      Acute Potential Health Effects:

      Skin: May cause skin irritation. May be harmful if absorbed through the skin.

      Eyes: Causes eye irritation, characterized by a burning sensation, redness, tearing, inflammation, and possible corneal injury.

      Inhalation: Inhalation at high concentrations affects the sense organs, brain and causes respiratory tract irritation. It also may affect the Central Nervous System (behavior) characterized by dizzness, drowsiness, confusion, headache, muscle weakeness, and
      possibly motor incoordination, speech abnormalities, narcotic effects and coma. Inhalation may also affect the gastrointestinal tract (nausea, vomiting). Ingestion: May cause irritation of the digestive (gastrointestinal) tract (nausea, vomiting). It may also affect the Central Nevous System (behavior), characterized by depression, fatigue, excitement, stupor, coma, headache, altered sleep time, ataxia, tremors as well at the blood, liver, and urinary system (kidney, bladder, ureter) and endocrine system. May also have musculoskeletal effects. Chronic Potential Health Effects: Skin: May cause dermatitis.

      Looks like an irritant in low concentrations, all the bad stuff happens at high concentration levels.

      1. Don’t you just love msds (which amusingly my spell check wanted to change to meds).
        After 8 years of flagrant abuse, I got allergic rhinitis. And the quantities of this and much more hazardous chemicals was at a far higher amount than a hacker would use. Be safe: if you can smell it, start thinking about a fan or an open window. Most likely SWMBO will let you know!

      1. You are people after my own heart. That pic is great!!!!

        If you ever find yourself on the treasure coast of florida send me a message. Beers on me.

        BTW, the funniest thing is that the advertisement that popped up next to the picture of the flaming jar was for Home Fire and Flood insurance. :-)

  13. i am getting tired of the makerbot-induced .1 mm layer height frenzy. I have always been able to print at .1 ever since my Cupcake. Don’t believe the makerbot marketing machine. If you are seeing irregularities in your print…you are doing something wrong, have bad filament, or mechanical issues. I now print PLA on an Ultimaker and my prints start at .1 and go below that easily. Try Cura. This field has grown immensely since my 2009 Cupcake, which still prints. That rant aside, I think this technique has promise for certain applications and effects. It looks like a ceramic squirrel! I guess there is no chance of combustion since you use a hotplate? i didn’t watch the video. I’ve read of folks using another chemical for PLA use but personally I don’t see a use aside from artistic purposes. Now that i say that, coverings on a robot would look sweet using this method! If you hear about a shed in KS blowing up then that would be me! :P

  14. I have a question. If you do this, will it become water-proof? I have tried before and failed to print something that is water-proof, probably because i am using a cheapo printer. but if there were a couple of small holes, would this seal them up or make them worse. Either way I’m still totally doing this for my other projects, i just wouldn’t want to waste the plastic, acetone, and electricity if someone already knows.

  15. Wow, patent this ….. Yeah ok, look I can see a patent being submitted for commercial purposes, but not this. So patent protection will not fly here. It’s like wanting to build your own car, you certainly can, but turning into a profitable business is where the patent protection comes into play, so this whole patent thing on this is moot, enjoy what info this post has to offer and smooth away your parts everyone !!!!

    Awesome post ….

  16. What is all that Patent BS? Even is something is patented you can make one for yourself! Anyone who knows about patent, should know this…

    I am so sick of those people… Go educate yourself about patents !

    Patent were initially invented to disclose invention in order for other to improve it.
    Today people only use it to keep other from doing just what patent were created for in the first place.

  17. I think that as long there isn’t a commercial intent it shouldn’t matter if a method is patented or not. You should be able to reproduce it for personal use without infringing any patent

  18. Eli Whitney was famous for his patented cotton gin but it made him almost no money because farmers just used his design and built their own. My point is It was illegal but patent protection is only as good as the money behind it and if the violators of your patent are not making direct money off it then there is no economic incentive to pursue it. Cost to return

  19. Laser cutting was shown to work with PLA in 2012 (; it would be theoretically possible to use a relatively low power laser to melt only tiny spots on a model’s surface and calibrate it to achieve different depths. Then, if such a laser would be mounted on a 3d printer it would e possible to print and refine with the same machine. With a clever-ish design and a camera one could get printing, scanning and refining in a single machine (and even an automated feedback control of the laser fininishing-engraving, since the scanner setup could also provide the depth of the point being treated).

    So long for the patent of such device, though :)
    Anyone thinks something like this might work?

  20. Old, so old. Acetone is used for ages to smooth machining marks of plastic parts, probably since when chemistry is invented. You can dip whole object to acetone and let it dry. Same result without “blowing up my eye brows” danger…

  21. If you have a Rep-Rap machine, be careful to keep the acetone away from any ABS components in your printer. You may want to use a lid with a ventilation tube to relieve the pressure and keep the gases away from your printer.

  22. You should really try Mipox TuneD3. They make sandpaper for printerd objects. They have different levels of quality depending on the sensitivity and makeup of the object. The latest is a combination of liquid abrasive and a polishing sheet. Modeled after Chemical Mechanical Polishing used for high planarity semiconductor manufacturing. It’s only like $5 for the high end stuff. you should check it out. Non toxic and much easier with higher quality finish because the abrasive is engineered specifically for the acrylic.

  23. I was about to try this. I’m especially curious what it will do with translucent parts. Then I got to wondering if the vapors might eventually damage the printer. I couldn’t find any info about that but found out acetone boils at 56C. So I’m going to try doing a vapor bath outside using a pot of boiled water as the heat source.

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