Everyone knows that globes are cool — what else would you use as the centerpiece of your library/study? But, sadly, making your own isn’t a simple process. Even if you had a large (preferably hollow) sphere to work with, you’d still have to devise a clever way of printing the map in sections that can be glued to the curved surface. Wouldn’t it be easier if you could just laser cut flat sections, and assemble them to form a faceted “globe?”
Well, it is, and you can! Because, [Gavin] over at tinkerings.org (a Hackaday favorite) has created the files to do just that! This map projection, originally designed by the very interesting Buckminster Fuller, is designed to be either laid flat or three-dimensionally on an icosahedron (a 20-sided polyhedron). That makes it perfect for laser cutting, as each of the 20 faces can be cut from flat stock.
We are all used to Fused Deposition Modeling, or FDM, 3D printers. A nozzle squirts molten material under the control of a computer to make 3D objects. And even if they’re usually rather expensive we’re used to seeing printers that use Stereolithography (SLA), in which a light-catalysed liquid monomer is exposed layer-by layer to allow a 3D object to be drawn out. The real objects of desire though are unlikely to grace the average hackspace. Selective Laser Sintering 3D printers use a laser on a bed of powder to solidify a 3D object layer by layer.
While an SLS printer may be a little beyond most budgets, it turns out that it’s not impossible to experiment with the technology. [William Osman] has an 80 W laser cutter, and he’s been experimenting with it sintering beach sand to create 2D objects. His write-up gives a basic introduction to glassmaking and shows the difference between using sand alone, and using sodium carbonate to reduce the melting point. He produces a few brittle barely sintered tests without it, then an array of shapes including a Flying Spaghetti Monster with it.
The results are more decorative than useful at the moment, however it is entirely possible that the technique could be refined. After all, this is beach sand rather than a carefully selected material, and it is quite possible that a finer and more uniform sand could give better results. He says that he’ll be investigating its use for 3D work in the future.
We’ve put his video of the whole process below the break, complete with worrying faults in home-made laser wiring. It’s worth a watch.
A laser cutter is a great tool to have in the shop, but like other CNC machines it can make a lousy neighbor. Vaporizing your stock means you end up breathing stuff you might rather not. If you’re going to be around these fumes all day, you’ll want good fume extraction, and you might just consider a DIY fume and particulate filter to polish the exhausted air.
While there’s no build log per se, [ZbLab]’s Facebook page has a gallery of photos that show the design and build in enough detail to get the gist. The main element of the filter is 25 kg of activated charcoal to trap the volatile organic compounds in the laser exhaust. The charcoal is packed into an IKEA garbage can around a prefilter made from a canister-style automotive air cleaner – [ZbLab] uses a Filtron filter that crosses to the more commonly available Fram CA3281. Another air cleaner element (Fram CA3333) makes sure no loose charcoal dust is expelled from the filter. The frame is built of birch ply and the plumbing is simple PVC. With a 125mm inlet it looks like this filter can really breathe, and it would easily scale up or down in size according to your needs.
Every laser cutter enthusiast eventually pops the question: how on earth do I align an invisible beam that’s more-than-happy to zap my eyeballs, not to mention torch everything else in its path? We hate to admit it, but laser cutter beam alignment is no easy task. To greatly assist in this endeavor, though, some folks tend to mix a red diode laser into the path of the beam. Others temporarily fixture that diode laser directly in the beam path and then remove it once aligned.
Few of us document the progression of our side projects. For those who do, those docs have the chance at becoming a tome of insight, a spaceman’s “mission log” found on a faraway planet that can tell us how to tame an otherwise cruel and hostile world. With the arrival of the RDWorks Learning Lab Series, Chinese laser cutters have finally received the treatment of a thorough in-depth guide to bringing them into professional working order.
In two series, totalling just over 90 videos (and counting!) retired sheet-metal machinist [Russ] takes us on a grand tour of retrofitting, characterizing, and getting the most out of your recent Chinese laser cutter purchase.
Curious about laser physics? Look no further than part 2. Wonder how lens size affects power output? Have a go at part 39. Need a supplemental video for beam alignment? Check out part 31. For every undocumented quirk about these machines, [Russ] approaches each problem with the analytic discipline of a data-driven scientist, measuring and characterizing each quirk with his suite of tools and then engineering a solution to that quirk. In some cases, these are just minor screw adjustments. In other cases, [Russ] shows us his mechanical wizardry with a custom hardware solution (also usually laser cut). [Russ] also brings us the technical insight of a seasoned machinist, implementing classic machinist solutions like a pin table to produce parts that have a clean edge that doesn’t suffer from scatter laser marks from cutting parts on a conventional honeycomb bed.
At its heart is an Arduino Uno and an Adafruit Motor Shield v2. The green laser is turned on and off by the Arduino through a transistor. But the part that makes this really a fun machine to watch at work are the two stepper motors and two mirrors that reflect the laser in the X and Y directions. The mirrors are rectangles cut from a hard disk platter, which if you’ve ever seen one, is very reflective. The servos tilt the mirrors at high speed, fast enough to make the resulting projection on the wall appear almost a solid shape, depending on the image.
He’s even written a Windows application (in C#) for remotely controlling the projector through bluetooth. From its interface you can select from around sixteen predefined shapes, including a what looks like a cat head, a heart, a person and various geometric objects and line configurations.
There is a sort of curving of the lines wherever the image consists of two lines forming an angle, as if the steppers are having trouble with momentum, but that’s probably to be expected given that they’re steppers controlling relatively large mirrors. Or maybe it’s due to twist in the connection between motor shaft and mirror? Check out the video after the break and let us know what you think.
There’s just something about wielding a laser pointer on a dark, foggy night. Watching the beam cut through the mist is fun – makes you feel a little Jedi-esque. If you can’t get enough of lasers and mist, you might want to check out this DIY “laser sky” effect projector.
The laser sky effect will probably remind you of other sci-fi movies – think of the “egg scene” from Alien. The effect is achieved by sweeping a laser beam in a plane through swirling smoke or mist. The laser highlights a cross section of the otherwise hidden air currents and makes for some trippy displays. The working principle of [Chris Guichet]’s projector is simplicity itself – an octagonal mirror spun by an old brushless fan motor and a laser pointer. But after a quick proof of concept build, he added the extras that took this from prototype to product. The little laser pointer was replaced with a 200mW laser module, the hexagonal mirror mount and case were 3D printed, and the mirrors were painstakingly aligned so the laser sweeps out a plane. An Arduino was added to control the motor and provide safety interlocks to make sure the laser fires only when the mirror is up to speed. The effect of the deep ruby red laser cutting through smoke is mesmerizing.