The Latest In 3D Printed Part Smoothing: Use A Brush

Part smoothing for 3D printed parts, especially parts printed in ABS, has been around for a while. The process of exposing an ABS part to acetone vapor turns even low-resolution prints into smooth, glossy 3D renderings that are stronger than ever. The latest improvement in part smoothing for 3D printed parts is now here: use a brush. Published in Nature‘s Scientific Reports, researchers at Waseda University have improved the ABS + acetone part smoothing process with a brush.

According to the authors of the paper, traditional filament-based printing with ABS has its drawbacks. The grooves formed by each layer forms a porous surface with a poor appearance and low rigidity. This can be fixed by exposing an ABS part to acetone vapor, a process we’ve seen about a million times before. The acetone vapor smoothing process is indiscriminate, though; it smooths and over-smooths everything, and the process involves possible explosions.

The researcher’s solution is a felt tip pen-like device that selectively applies acetone to a 3D printed part. Compared to the print over-smoothed in a vat of acetone vapor, more detail is retained. Also, there’s a ready market for felt tip pens and there isn’t one for crock pots able to contain explosive vapor. This is, therefore, research that can be easily commercialized.

Fun with Fire: Oxy-Acetylene Basics

If generations of Hollywood heist films have taught us anything, it’s that knocking off a bank vault is pretty easy. It usually starts with a guy and a stethoscope, but that never works, so the bad guys break out the cutting torch and burn their way in. But knowing how to harness that raw power means you’ve got to learn the basics of oxy-acetylene, and [This Old Tony]’s new video will get your life of crime off on the right foot.

In another well-produced video, [Tony] goes into quite a bit of detail on the mysteries of oxygen and acetylene and how to handle them without blowing yourself up. He starts with a tour of the equipment, including an interesting look at the internals of an acetylene tank — turns out the gas is stored dissolved in acetone in a porous matrix inside the tank. Working up the hoses, he covers the all-important flashback arrestors, the different styles of torches, and even the stoichiometry of hydrocarbon combustion and how adjusting the oxygen flow results in different flame types for different jobs. He shows how oxy-acetylene welding can be the poor man’s TIG, and finally satisfies that destructive urge by slicing through a piece of 3/8″ steel in under six seconds.

We’ve always wanted a decent oxy-acetylene rig, and [Tony] has convinced us that this is yet another must-have for the shop. There’s just so much you can do with them, not least of which is unsticking corroded fasteners. But if a blue wrench is out of your price range and you still want to stick metal together, you’ll want to learn how to braze aluminum with a propane torch.

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Fail Of The Week: How NOT To Smooth A 3D Print

Many of the Fail Of The Week stories we feature here are pretty minor in the grand scheme of things. At worse, gears are ground, bits are broken, or the Magic Blue Smoke is released. This attempt to smooth a 3D print released far more than a puff of blue smoke, and was nearly a disaster of insurance adjuster or medical examiner proportions.

Luckily, [Maxloader] and his wife escaped serious injury, and their house came out mostly unscathed. The misadventure started with a 3D printed Mario statue. [Maxloader] had read acetone vapor can smooth a 3D print, and that warming the acetone speeds the process. Fortunately, his wife saw the looming danger and wisely suggested keeping a fire blanket handy, because [Max] decided to speed the process even more by putting a lid on the pot. It’s not clear exactly what happened in the pot – did the trapped acetone vapors burp the lid off and find a path to the cooktop burner? Whatever it was, the results were pretty spectacular and were captured on a security camera. The action starts at 1:13 in the video below. The fire blanket came in handy, buying [Max] a few seconds to open the window and send the whole flaming mess outside. Crisis averted, except for nearly setting the yard on fire.

What are we to learn from [Maxloader]’s nearly epic fail? First, acetone and open flame do not mix. If you want to heat acetone, do it outside and use an electric heat source. Second, a fire extinguisher is standard household equipment. Every house needs at least one, and doubly so when there’s a 3D printer present. And third, it’s best to know your filaments – the dearly departed Mario print was in PLA, which is best smoothed with tetrahydrofuran, not acetone.

Anything else? Feel free to flame away in the comments.

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Beyond WD-40: Lubes for the Home Shop

If your shop is anything like mine, you’ve got a large selection of colorful cans claiming to contain the best and absolutely only lubricant you’ll ever need. I’ve been sucked in by the marketing more times than I care to admit, hoping that the next product will really set itself apart from the others and magically unstick all the stuck stuff in my mechanical life. It never happens, though, and in the end I generally find myself reaching for the familiar blue and yellow can of WD-40 for just about every job.

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Tie-Fighter Quadcopters Anyone Can Build

These are things of beauty, and when in flight, the Tie Fighter Quadcopters look even better because the spinning blades become nearly transparent. Most of the Star Wars-themed quadcopter hacks we’ve seen are complicated builds that we know you’re not even going to try. But [Cuddle Burrito’s] creations are for every hacker in so many different ways.

tie-fighter-drone-partsFirst off, he’s starting with very small commodity quadcopters that are cheap (and legal) for anyone to own and fly. Both are variations of the Hubsan X4; the H107C and the H107L. The stock arms of these quadcopters extend from the center of the chassis, but that needs to change for TFFF (Tie Fighter Form Factor). The solution is of course 3D Printing. The designs have been published for both models and should be rather simple to print.

ABS is used as the print medium, which makes assembly easy using a slurry of acetone and ABS to weld the seams together. Motor wires need to be extended and routed through the printed arms, but otherwise you don’t need anything else. Even the original screws are reused in this design. Check out test flights in the video after the break As for the more custom builds we mentioned, there’s the Drone-enium Falcon.

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Even Easier Toner Transfer PCBs

One of the most popular methods of homebrew PCB fabrication is the toner transfer process. Compared to UV-sensitive films and CNC mills, the toner transfer process is fantastically simple and only requires a laser printer. Being simple doesn’t mean it’s easy, though, and successful toner transfer depends on melting the toner to transfer it from a piece of paper to a copper clad board.

This is heatless toner transfer for PCB fabrication. Instead of using a clothes iron or laminator to transfer toner from a paper to board, [simpletronic] is doing it chemically using acetone and alcohol.

Acetone usually dissolves laser printer toner, and while this is useful for transferring a PCB from paper to board, it alone is insufficient. By using a mixture of eight parts alcohol to three parts acetone, [simpletronic] can make the toner on a piece of paper stick, but not enough to dissolve the toner or make it blur.

From there, it’s a simple matter of putting a piece of paper down on copper clad board. After waiting a few minutes, the paper peels off revealing perfectly transferred board art. All the usual etching techniques can be used to remove copper and fabricate a PCB.

This is an entirely novel method of PCB fabrication, but it’s not exactly original. A few days ago, we saw a very similar method of transferring laser printed graphics to cloth, wood, and metal. While these are probably independent discoveries, it is great evidence there are still new techniques and new ways of doing things left to be discovered.

Thanks [fridgefire] for the tip.

Ultrasonic Misting Vapor Polisher for 3D Printed Parts

If you’ve ever seen 3D printed parts form an extrusion type printer, one of the first things you’ll notice is the texture. It’s caused by the printer laying down its plastic layer after layer. This surface texture isn’t always desirable, so people have found a few ways to smooth the 3D printed part out. For example if you are using ABS, you can rinse or “paint” the part with acetone. Another method of smoothing is heat up some acetone in a container, and let the acetone vapors do work to smooth the finished part.

[Mike] from engineerdog.com thinks he may have found a more elegant solution using an inexpensive ultrasonic humidifier you can buy online for about $40 USD. This room humidifier uses a piezoelectric transducer that can vibrate liquids at a high frequency to produce a mist. [Mike] removed the transducer and electronics from the humidifier and mounted it into a paint can.  This is where the acetone is stored, and turned into a vapor by the transducer. An aquarium pump is used to transfer the highly concentrated vapors into the polishing chamber (an extra large pickle jar.) He added a spring loaded, electrical timer (the kind you might find in the bathroom at an office building) to make his vapor polisher as easy to use as a microwave oven.

[Mike] concludes his post with some strength testing of parts before and after acetone treatment, and was surprised to find that the parts were weaker after the treatment.  You can read more about that on his blog and see a video of the vapor polisher after the break.

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