How To Identify Plastics Before Laser Cutting Them

If you own a pickup truck, you’ll quickly find yourself making friends with people who just happen to need help moving next weekend. Trust me, it’s almost magical. And if you own a laser cutter (or work in a hacker/maker space that has one) you’ll get some odd requests to cut or engrave plastic items of unknown type. Before you do, you should read this (pdf) chemistry lab written by [David A. Katz] to learn how to identify what type of plastic it is.

There are several reasons why you don’t want to cut or engrave some types of materials. A few make a gooey mess that you’ll regret even trying. Others make a horrendous odor. Some hackerspaces will even charge you extra if you stink up the place (aka: malodorous material charge.) Some tend to catch on fire. Yikes.

But that’s not the worst of it. Some types of plastic release potentially deadly hydrogen chloride gas. It’s bad for the optics, it’s wreaks havoc on the electronics and mechanics of the machine, and could do a really good job of messing up your lungs forever. In the video after the break, you can see the flame test for such plastics in action at the NYC Resistor as they test several common items using nothing more than a blow torch and some copper wire. In short, if the flame test produces a green flame, do not put it in the laser.

If you want to see a good list of what is and what isn’t ok to cut, head on over to ATXHackerspace’s wiki. They will give you a nice run down with lots of notes and helpful hints as well.

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Laser Cut Settlers Of Catan Board = Best Christmas Gift Ever

[JoshBaker] wanted to make something special for his brother this past Christmas.  He decided on making a wooden game board version of the Settlers of Catan game. [Josh] used CorelDraw to construct the vector images needed for the board. Then, he set out cutting the base, engraving and cutting out the many wooden pieces with a laser cutter. All the pieces were stained and then sealed with polyurethane. He assembled the base so that the removable hex tiles, ports, and resource numbers sit nicely in the recessed parts and don’t shift during gameplay. He complemented the board with tokens and game pieces that he hand-painted. [Josh] also created a new set of cards to fit with the board’s aesthetic.

The board is done incredibly well, not to mention beautiful to look at. The hex tiles’ designs are very detailed. The stained and engraved wood really adds to the atmosphere of the game. We featured a coffee table that would be perfect to play it on. [Josh] has listed all of the vector files for the version he gave his brother, as well as additional ones for the Cities and Knights Expansion. We wish we could have seen the look on his brother’s face when he got such an awesome Christmas gift!

[via Instructables]

Fold A Hexapod From Pilfered Office Supplies

Hexapods are wonderful things. With their elegant gait and insect-like caricature, they’re an instant hit for coffee-table-conversation-starters. They’re also wonderfully expensive, with the redundancy of each leg chewing viciously into your pocket. This price point is a deal-breaker for many, but for others, it’s a challenge to let one’s design skills defy that barrier. [Mike Estee] is one such engineer who’s done his best to design away a stock structure with a cardboard variant that wont break the bank.

On the table, [Mike] assembles his hexapod frame from budget servos, corrugated cardboard, paper clips, and tape. The result is a hexapod frame that can be built for practically just the cost of the servos (about $80 in this case). In his posts, [Mike] details the design evolution of the frame focusing especially on the legs, which he intended to be folded from a single sheet. After a few revisions, [Mike] succeeded, and he’s graciously posted his latest revision on his blog [PDF].

While we’ve certainly seen impressive budget hexapods before, we really appreciate the elegance and simplicity of a design made entirely from a single sheet of cardboard. His progress is a step forward to reaching a ubiquitous low-cost, force-control based robot platform. While that’s a milestone many of us hope to see in the future, he’s done a fantastic job designing a proof-of-concept frame template that anyone can cut out and assemble with a couple of spare hours.

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PCB Manicure Wields Laser Cutter For Your Nails

Wearable electronics is a hot topic these days. Although these fancy talons are only for show, they could lead to more in the future.

[Shelby] and [Colleen AF] showed people how to include a laser cutter in your nail care at a recent event at NYC Resistor. The technique used here starts off with a base coat of the background color before heading to the laser cutter. Now don’t worry, you don’t need to risk any of your digits. A type of reverse silk screen is made with the laser by deeply etching the artwork into a piece of flat acrylic sheet. Those voids are then filled with the secondary color for the circuit traces and the excess is removed with a squeegee. A sponge is then used to transfer the paint from the recesses in the acrylic to the nails.

Granted, PCB finger nails might not be your cup of tea, but it does make us wonder: What if conductive ink was used? Would it be possible to build a circuit on your own fingernail? Obviously you would want to use a sticky, conductive glue rather than solder. (Please don’t try to reflow solder your fingers at home.) What kind of power supply would fit? What could you build? We also see other possible applications of the process like labeling non-flat surfaces. Let us know what you think in the comments below.

UPDATE: [David Flint] points out in the comments that this is a type of offset gravure printing.

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Hackaday Links: December 14, 2014

 

The Progressive Snapshot is a small device that plugs into the ODB-II port on your car, figures out how terrible of a driver you are, and sends that data to Progressive servers so a discount (or increase) can be applied to your car insurance policy. [Jared] wondered what was inside this little device, so he did a teardown. There’s an Atmel ARM in there along with a SIM card. Anyone else want to have a go at reverse engineering this thing from a few pictures?

[Alex]’s dad received a special gift for his company’s 50th anniversary – a Zippo Ziplight. Basically, its a flashlight stuffed into the metal Zippo lighter we all know and love. The problem is, it’s battery-powered, and Zippo doesn’t make them any more. It also uses AAAA batteries. Yes, four As. No problem, because you can take apart a 9V and get six of them.

‘Tis the season to decorate things, I guess, and here’s a Hackaday snowflake. That’s from [Benjamin Gray], someone who really knows his way around a laser cutter.

HHaviing trouble wiith a debounce ciircut? HHer’s a calculator for just thhat problem. Put iin the logiic hhiigh voltage level, the bounce tiime, and the fiinal voltage, and you get the capaciitor value and resiistor value.

A harmonograph is a device that puts a pen on a pendulum, drawing out complex curves that even a spirograph would find impressive. [Matt] wanted to make some harmonographs, but a CNC and a printing press got in the way. He’s actually making some interesting prints that would be difficult if not impossible to make with a traditional harmonograph – [Matt] can control the depth and width of the cut, making for some interesting patterns.

The Mooltipass, the Developed On Hackaday offline password keeper, has had an interesting crowdfunding campaign and now it’s completely funded. The person who tipped it over was [Shad Van Den Hul]. Go him. There’s still two days left in the campaign, so now’s the time if you want one.

Generating Laser Cut Boxes In C

[Mike] is a laser cutting newbie and has never had the opportunity to create a file and send it off to a laser for cutting. He knew he didn’t want to squint at a CAD package, nudging lines by tenths of a millimeter, only to screw something up and have to do it all over again. His solution, like so many other automation tasks, was to create a program that would generate a box of any size in .SVG format.

[Mike]’s program runs in C, and only requires a few variables set in the program to create a box of any size. There’s no argc or argv for the program – the one thing that would turn this into a command line utility that simply creates SVG boxes. Perhaps another time.

The rest of [Mike]’s hackerspace, Fab Lab xChc, was impressed the program worked the first time. With this small bit of C code, [Mike] has an easy, simple tool to generate laser cut boxes. The only remotely complicated bit of C this program uses is printf(), so even an Arduino can spit out the SVG for a laser cut box.

Laser-cut Album Released

In some alternate universe, where laser cutters and phonographs are more common than MP3 players, it makes a ton of sense to release laser-cutter files for your band’s new album (Translated). In this universe, it’s wacky and awesome.

The new EP from ASIC, alias [Patric] from Fablab Zürich, is out as PDF before it’s out in other forms of digital download, and the trailer video (embedded below the break) looks fantastic.

The release draws on this Instructable by Amanda Ghassaei to turn the music into PDFs suitable for feeding into a laser cutter, and we think it’s classy that she gets a shout-out on the label’s release page.  Everything else about the album will be released under a Creative Commons license to boot.

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