Laser Cutter Alignment Mod Skips Beam Combiner

A lot of the DIY laser engravers and cutters we cover here on Hackaday are made with laser diodes salvaged from Blu-ray drives and projectors, which are visible lasers in the 400 – 450nm range (appearing as violet or blue). Unfortunately there is an upper limit in terms of power on visible diode lasers, most builds max out at 5W or so. If you need more power than that, you’ll likely find yourself looking at gas laser cutters like the K40. While the K40 is a great starting point if you’re looking to get into “real” lasers, it’s a very different beast from the homebrew builds using visible lasers.

With a gas laser the beam itself is invisible, making it much more difficult to align or do test runs. One solution is to add a visible laser to the K40 which can be used to verify alignment, but making sure it’s traveling down the same path as the primary laser usually requires an expensive beam combiner. Looking to avoid this cost, [gafu] wanted to see if it was possible to simply move the visible laser into the path of the primary beam mechanically.

An adjustable microswitch detects when the lid has been opened.

In the setup that [gafu] has come up with, a cheap laser module (the type from a handheld laser pointer) is moved into the path of the primary laser on an arm that’s actuated by a simple hobby servo. To prevent the primary and visible lasers from firing at the same time, an Arduino is used to control the servo given the current state of the K40’s lid. If the lid of the K40 is open, the primary laser is shutoff and the visible laser is rotated into position so the operator can see where the primary laser’s beam would be hitting. Once the lid is closed, the visible laser rotates out of the way and the primary is powered back up.

Running the cutting or engraving job with the lid of the K40 machine open now let’s [gafu] watch a “dry run” of the entire operation with the visible laser before finally committing to blasting the target with the full power beam.

We’ve covered many hacks and modifications for everyone’s favorite entry-level CO2 laser cutter. From replacing the controller to making it bigger, K40 owners certainly seem like a creative bunch.

Hacking A K40 Laser Cutter

The distinctive blue-and-white enclosure of the Chinese-made K40 laser cutter has become a common sight in workshops and hackerspaces, as they represent the cheapest route to a working cutter that can be found. It’s fair to say though that they are not a particularly good or safe machine when shipped, and [Archie Roques] has put together a blog post detailing the modifications to make something better of a stock K40 performed at Norwich Hackspace.

After checking that their K40 worked, and hooking up suitable cooling and ventilation for it, the first task facing the Norwich crew was to install a set of interlocks. (A stock K40 doesn’t shut off the laser when you open the lid!) A switch under the lid saw to that, along with an Arduino Nano clone to aggregate this, a key switch, and an emergency stop button. A new front panel was created to hold this, complete a temperature display and retro ammeter to replace the modern original.

Norwich’s laser cutter has further to go. For example, while we secretly approve of their adjustable bed formed from a pile of beer mats, we concede that their plans to make something more practical have merit. The K40 may not be the best in the world, indeed it’s probable we should be calling it an engraver rather than a cutter, but if that means that a small hackerspace can have a cutter and then make it useful without breaking the bank, it’s good to see how it’s done.

This isn’t the first K40 enhancement we’ve featured. Norwich might like to look at this improved controller, or even extend their cutter’s bed. Meanwhile if [Archie]’s name rings a bell, it might be because of his Raspberry Pi laptop.

Laser Smoothies At Maker Faire

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.

Take Control Of Your Cheap Laser Cutter

The relatively inexpensive K40 laser cutter/engraver machines from China have brought laser cutting to the masses, but they are not without their faults. Sure, they’re only powerful enough for the lightest cutting tasks, but on top of that, their bundled software is inflexible and disappointing. If your workshop or hackspace has one of these machines languishing in the corner, then the release of a new piece of software, K40 Whisperer from [Scorch], is an interesting and welcome development.

He tells us that the reverse engineering process required to understand the K40’s protocol was non-trivial, given that it does not use handy decimal numbers to issue commands. A spreadsheet was used to collate data packets and spot repeating patterns to analyse the inner workings. Feature-wise, the software reads SVG and DXF files, and can split SVGs by colour. It has a halftone algorithm for rendering grey scales, and cuts from the inside of each shape first to avoid pieces of work dropping out of the piece of material. Currently it works with the stock M2 Nano controller board and is available as a Windows download, though it can also be compiled for Linux distributions, or MacOS, and he is asking owners to test it with as many machines as possible to ensure compatibility with other boards.

He has posted a video of K40 Whisperer in action, which you can see below the break.

Continue reading “Take Control Of Your Cheap Laser Cutter”

Drop-in Controller for eBay K40 Laser Engraver Gets Results

[Paul de Groot] wrote in to let us know about a drop-in controller replacement he designed for those economical K40 laser engravers that are everywhere on eBay. With the replacement controller, greatly improved engraving results are possible along with a simplified toolchain. Trade in the proprietary software and that clunky security dongle for Inkscape and a couple of plugins! [Paul] felt that the work he accomplished was too good to keep to himself, and is considering a small production run.

Laser engravers are in many ways not particularly complex devices; a motion controller moves the head in x and y, and the laser is turned on or off when needed. But of course, the devil is in the details and there can be a surprising amount of stuff between having a design on your screen and getting it cut or engraved in the machine. Designing in Inkscape, exporting to DXF, importing the DXF to proprietary software (which requires a USB security dongle to run), cleaning up any DXF import glitches, then finally cutting the job isn’t unusual. And engraving an image with varying shades and complex dithering? The hardware may be capable, but the stock software and controller? Not so much. It’s easy to see why projects to replace the proprietary controllers and software with open-source solutions have grown.

Cheap laser engravers may come with proprietary controllers and software, but they don’t need to stay that way. Other efforts we have seen in this area include LaserWeb, which provides a browser-based interface to a variety of open-source motion controllers like Grbl or Smoothieware. And if you’re considering a laser engraver, take a few minutes to learn from the mistakes of other people.

Laser Surgery: Expanding the Bed of a Cheap Chinese Laser Cutter

Don’t you just hate it when you spend less than $400 on a 40-watt laser cutter and it turns out to have a work area the size of a sheet of copy paper? [Kostas Filosofou] sure did, but rather than stick with that limited work envelope, he modified his cheap K40 laser cutter so it has almost five times the original space.

The K40 doesn’t make any pretenses — it’s a cheap laser cutter and engraver from China. But with new units going for $344 on eBay now, it’s almost a no-brainer. Even with its limitations, you’re still getting a 40-watt CO2 laser and decent motion control hardware to play with. [Kostas] began the embiggening by removing the high-voltage power supply from its original space-hogging home to the right of the work area. With that living in a new outboard enclosure, a new X-Y gantry of extruded aluminum rails and 3D-printed parts was built, and a better exhaust fan was installed. Custom mirror assemblies were turned, better fans were added to the radiator, and oh yeah — he added a Z-axis to the bed too.

We’re sure [Kostas] ran the tab up a little on this build, but when you’re spending so little to start with, it’s easy to get carried away. Speaking of which, if you feel the need for an even bigger cutter, an enormous 100-watt unit might be more your style.

Continue reading “Laser Surgery: Expanding the Bed of a Cheap Chinese Laser Cutter”