Giving 3D printed parts a shiny smooth finish

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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).

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MakiBox turns plastic pellets into 3D objects

The holy grail of desktop 3D printers – aside from manufacturing full color objects in any shape imaginable – is turning tiny plastic pellets into a plastic filament. Many projects have attempted this with moderate levels of success but turning pellets into filament still an open problem. MakiBot hopes to solve this problem by manufacturing plastic filament just in time to be squirted out a nozzle onto the print bed.

MakiBox is seeing a lot of potential with their pellet drive. Instead of sending huge amounts of pellets into an auger extruder, the team realized the best option would be to send pellets into the hot end one at a time. This makes for better thermal characteristics and produces a very consistent filament.

Turning plastic pellets into 3D objects is an enticing idea but producing a filament on the fly is an interesting concept. While the MakiBox team is making custom color filament right now, in the future it might be possible to mix colors for full-color prints.

Videos demonstrating the extruder after the break.

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Making plastic filament at home

There’s one problem with the popularity of plastic-extruding 3D printers such as the RepRap and Makerbot; since they’ve become so popular, the price of plastic filament has skyrocketed over the past few years. Without a way to produce filament at a hackerspace or home lab, the price of 3D printed objects will remain fairly high. Project Spaghetti hopes to rectify that by building a machine to make plastic filament for 3D printers.

The folks behind Project Spaghetti – a loose amalgamation of makers going under the title of Open Source Printing, LLC – have successfully built a machine that is able to produce short lengths of plastic filament.

Early machines used a plunger to press small pellets of ABS plastic through a heated steel pipe to produce filament. There are a few problems with this approach, especially when the temperature is set to 480F, but the team was able to make a bit of filament with this design.

Although the team is using a piston to force melted plastic out of a nozzle, they do have a screw-drive ‘plan B’ in the works. This design should allow for continuous extrusion for theoretically endless reels of plastic filament, every RepRappers dream and a neat way to win 40 grand. [Read more...]

Arduino tells you how rough your last mountain bike ride was

If you want to see what kind of abuse you’re causing your body when out on those single-track rides this system is just the thing. It’s an Arduino data logger that [Wdm006] takes along on the rides with him. When he gets back home, a Python scripts captures the data dump and graphs it. It may sound like a neat trick, but he’s got something planned for that information.

The enclosure mounts to the stem of his bike. It houses an Arduino board with a data logging shield of his own design. That shield holds an SD card for storage, and breaks the other pins out as screw terminals. Right now there’s an accelerometer on the front fork, and some method of recording wheel speed. This is the research phase of an anti-lock brake system (ABS) he plans to build for mountain biking. No word on what hardware he’ll use for that, but we can’t wait to see how it comes out.

Welding and casting ABS

Anybody who has a 3D printer always has a ton of useless plastic lying around. Some of that plastic may be from useless baubles, but most of it is in bad prints, short bits of filament, and general scraps. [Luke] found an interesting way to put those ABS scraps to use, and ended up turning trash into valuable plastic parts.

Commonly sold as nail polish remover, acetone will turn anything made out of ABS into a puddle of plastic. [Luke] makes glue using the same process – he fills a small container half full of acetone and half with small bits of ABS. After a day or so, he has a nice thin glue that dries into solid ABS. [Luke] used this to create a 400mm long piece of extruded t-slot. We don’t know if it would be suitable to build a child RepRap from, but it would sure be an interesting experiment.

[Luke] also did a little bit of casting with his ABS glue. With a thicker solution of ABS and Acetone, he managed to make this ‘thing’. The entire process is explained over at Thingiverse, We can’t wait to see what can be done with this stuff.

Multiple material 3D printing

It’s no surprise that we’re wild about 3D printing, especially [Devlin]. Now we’re absolutely out of our minds for this multi-material polyjet machine that is featured in the video above. Before we go any further it’s worth mentioning that this post is not advertising, we just think this machine is unbelievable.

It is capable of printing 600 dpi in 3D using multiple materials at the same. Two types of rigid material, one like ABS and the other like polypropylene, as well as seven levels of a soft material all exist on the same print head. They can be deposited along with a support material at the same time. In the video you can see enclosures that come out of the printer with rubber-like padding already mounted in the hard plastic shell. They even show a bicycle chain that is fully assembled after printing. Cost for these machines? We don’t want to know, it’s just fun to dream about having unrestricted access to one.

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Veteran robot features eight legs and BeagleBoard

This spider-bot was built by [Zhanx] during his deployment in Iraq. He didn’t have prior hardware building experience and started out on this project when he received an Arduino to play with in September. Must be a fast learner! The parts are laser-cut from ABS plastic and connected to 24 servos. He sourced an SSC-32 serial servo control board to take care of the motor connections.

[Zhanx] has since migrated from the Arduino to a BeagleBoard which you can see perched atop the body in the video after the break. This should give him plenty of speed and power to improve the movement routines. There’s some nice work here but adding rubber feet, like on yesterday’s hexapod, wouldn’t hurt.

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