Armed with an overseas CNC machine retrofitted with custom electronics, [Eric] has taken to wowing us with his suite of home-fabricated slingshots. In a more recent stint, he’s just polished off his Enzo Carbon Fiber Hydra Slingshot, complete with a build log that’s loaded with step-by-step insights.
[Eric’s] build started with a few carbon panels laying dormant in his shop for half a year. After epoxying two of these boards together for added thickness, he machines them down with his retrofitted Sable-2015 “Lunchbox CNC.” His final product accepts a few press-fit inserts, a few more machined ABS edge pieces for aesthetics, and behold: a professional slingshot that’s about as beautiful as it is dangerous.
Although the Sable-2015 CNC machine (made in Taiwan) isn’t a frequent flyer here on Hackaday, it had dozens of proud owners on a few hobby machinist forums that will rave about its wares. We’re proud to see a small-but-sturdy machine that we could carry one-handed be put to such delicate work.
[Eric] could’ve had us with his Lunchbox CNC Instructable, but he’s taken his craftsmanship to the next level by leveraging his homebrew tools and living the bootstrapped-machine-shop narrative. Slingshots don’t land here too often on these pages, but if you’re hungry for another machine monster, have a look at [Dennis the Menace’s] Triple Threat.
Now that anyone can go online and get a fairly decent 3D printer for around $200, they’ve officially fallen out of the “Elite Hacker” arsenal and are now normal, if perhaps highly specialized, tools. That’s great for the 3D printing community as a whole, but what about those who want to be on the fringe of technology? Telling people you have a 3D printer at home doesn’t get that wide-eyed response like it used to. What’s a “l33t” hacker to do?
Enter the laser engraver/cutter: it’s like a 3D printer, but easier to build and has a higher capacity for bodily harm! While there are a couple good options for kits and turn-key setups out there, just like the early days of 3D printers, some of the best machines are still home built. In his latest video, YouTuber [MakerMan] takes us through his build which features an impressively low part count.
To start his build, [MakerMan] strips down four printers and salvages seven high quality 8 mm linear rods; a huge cost saving tip in itself. We’ll certainly be picking up any printers we see in the trash for the next couple months hoping to score some rods. With the addition of some cheap LM8UU bearings and 3D printed holders for them, [MakerMan] has a smooth 2D motion platform for just a couple bucks. The frame of the machine is built out of type of aluminum square tubing you can find at the hardware store, no expensive extrusion here.
For the laser itself, [MakerMan] is using a six watt PLH3D-6W-XF from Opt Lasers. This module features integrated driver and cooling, so all you need to do is provide it power and a stable means of moving it over the work piece. They even offer a magnetic “dock” which allows you to remove the laser from the mount without any tools for servicing or tool changes. [MakerMan] reports he’s been able to engrave stainless steel with this laser module, and cut thin wood.
Most CNC robots people see involve belts and rails, gantries, lead screws, linear bearings, and so forth. Those components need a rigid chassis to support them and to keep them from wobbling during fabrication and adding imperfections to the design. As a result, the scale is necessarily small — hobbyist bots max out at cabinet-sized, for the most part. Their rigid axes are often laid out at Cartesian right angles.
One of the exceptions to this common configuration is the delta robot. Deltas might be the flashiest of CNC robots, moving the end effector on three arms that move to position it anywhere in the build envelope. A lot of these robots are super fast and precise when charged with carrying a light load, and they get put to work as pick-and-place machines and that sort of thing. It doesn’t hurt that delta bots are also parallel manipulators, which means that the motors work together to move the end effector, with one motor pulling while the matching motor pulls.
But while Cartesian CNC bots are sturdy workhorses, and deltas are fly-weight racehorces, neither can really cut it when you want to go gigantic. In terms of simplicity and scale, nothing beats cable bots.
Cable Bots
Cable bots use wires or strings pulled by reel-mounted motors, with dimensions limited only by the room to mount the motors and the tensile strength of the cables used. When the strings are tensioned you can get a surprising degree of accuracy. Why not? Are they not computer-controlled motors? As long as your kinematic chain accounts for the end effector’s movement in one direction by unwinding another cable (for instance) you can very accurately control the end effector over a very wide scale.
The following are some fun cable bots that have caught my eye.
The wristwatch was once an absolute necessity, as much fashion statement as it was a practical piece of equipment. Phones in our pockets (and more often than not, in our faces) replaced the necessity of the wristwatch for the majority of people, and the fashion half of the equation really only interests a relatively small subset of the population. The end result is that, aside from the recent emergence of smartwatches and fitness trackers, walking down the street it’s fairly unlikely you’ll see many people wearing a traditional watch.
When it comes to CNC machines, your SureFine has screws on its axes, and the Bodgeport does too. A shopbot has an amazing rack gear system, but when you start to dig into the small CNC routers available for under $2,000, you’ll only find belts moving a router back and forth. This isn’t to say belts won’t work — you can create a fine CNC machine with bits of rubber. However, belts stretch, they wear out, and if you want more precision screws and racks are the way to go.
The WorkBee CNC machine is the first desktop CNC router we’ve seen that uses screws instead of belts. It’s a project on OpenBuilds, and a reasonably well-configured machine is now available from ooznest for about £1,700 ($2,200 USD), or just a bit more than other CNC routers that consist of a Dewalt router and some aluminum extrusion.
The WorkBee CNC is based on the OX CNC machine, another cartesian router machine built around the OpenBuilds aluminum extrusion. The OX, while a fine machine for DIY tinkerers, uses belts. The WorkBee trades them out for screws, and should gain better accuracy, much lower maintenance, and deeper cuts. Screws are slower, yes, but do you really need that much acceleration when routing a thick piece of wood?
Need to make something quick and dirty out of wooden beams, and want to use elements you know will work together? BeamCNC is a mobile assembly of stepper-controlled rollers and a router that sucks a 2×2 through it and drills the holes in pre-programmed intervals. Currently being developed as part of an Indiegogo campaign currently in preview, its creator [Vladislav Lunachev] has declared it open source hardware. It’s essentially a CNC mill that makes Grid Beam, a classic DIY building set that resembles Meccano, Erector, and other classic sets, only made full-scale for larger projects. While BeamCNC is not affiliated with Grid Beam, it takes the same general idea and automates it.
This year at Maker Faire, laser cutters were all the rage. Dremel announced a 40W laser cutter, but it won’t be available for purchase until this time next year, there is no price yet, and therefore doesn’t deserve further mention. Glowforge was out in full force, but the most interesting aspect of the Glowforge — a compact filter system that sits right underneath the laser — was not to be found. It looks like lasers are the next 3D printer.
Of course, those in the know have already been using laser cutters for years, and there are options for desktop CO2 laser cutters that cost less than a kilobuck. I speak, of course, of the ubiquitous K40 laser, a machine you can get off of eBay or AliExpress for the price of a generic, off-brand 3D printer. There is a downside to the K40, though: the control electronics and software are notoriously terrible. Fix that, though, and you have something really spectacular.
The Cohesion3D Mini
This year at Maker Faire, [Ray Kholodovsky] of Cohesion3D brought out his Smoothie-derived control boards for CNC machines and laser cutters. Of note is his K40 upgrade that turns the eBay special laser cutter into a 32-bit professional machine. This is the cheapest way to start lasing in your workshop.
We saw [Ray] at the Faire last year when he was demoing his Smoothie-derived boards for 3D printers and CNC machines. These are tiny, relatively low-cost boards that use Smoothieware, an Open Source, 32-bit CNC control system that is extremely extensible and very powerful. Basically, if you’re building a normal, ordinary DIY 3D printer, a RAMPS or RAMBO will do. If you’re doing something weird, like a 3D printer with strange kinematics, a 5-axis milling machine, or you’d like awesome engraving on a laser cutter, Smoothie is the way to go.
The stock board found in a K40 (left) and the Cohesion3D Mini (right). The Cohesion3D Mini is a drop-in replacement for the stock K40 board.
The Cohesion3D board is a direct, drop-in replacement for the control board found in the K40 laser. Since all of the K40 laser cutters are the same, and they’re really only a power supply and a CNC gantry, this is the one-stop-shop of K40 upgrades. The terrible electronics are gone, you don’t have to use Corel, and for a hundred bucks, you have something resembling a professional laser cutter.
The K40 laser has been around for several years now, but only recently have a few very interesting hacks and mods come out that push this blue light special laser cutter into semi-professional territory for people willing to get their hands dirty. A few months ago [Scorch] published K40 Whisperer, a piece of software that makes the stock electronics tolerable and able to accept normal SVGs and DXFs. The K40 has also been modified for a larger bed, and LaserWeb has been handling the software side of things for about two years now. Things are looking great for the K40 hacking scene, and Hackaday already has a, ‘I just bought a K40, now what?’ series in the works. Things are looking up for cheap laser cutters, and a Smoothie upgrade is just the cherry on top.
