Spring-Loaded Bed for K40 Laser Acts As an Auto-Focus

Laser engraving and cutting has something in common with focusing the sun’s rays with a magnifying glass: good focus is critical to results. If materials of varying thicknesses are used, focus needs to be re-set every time the material changes, and manual focusing quickly becomes a chore. [Scorch Works] has a clever solution to avoid constant re-focusing that doesn’t involve sensors or motors of any sort. The result is a self-adjusting bed that compensates for material height changes, ensuring that the top surface of the material is always a fixed distance from the laser’s head.

The way [Scorch Works] has done this is to make two spring-loaded clamps from angle aluminum and a few pieces of hardware. When a sheet of material is placed into the machine, the edges get tucked underneath the aluminum “lips” while being pushed upward from beneath. By fixing the height of the top layer of angle aluminum, any sheet stock always ends up the same distance from the laser head regardless of the material’s thickness.

[Scorch Works] shows the assembly in action in the video embedded below, along with a few different ways to accommodate different materials and special cases, so be sure to check it out.

Continue reading “Spring-Loaded Bed for K40 Laser Acts As an Auto-Focus”

Fail of the Week: Did My Laser Cutter Tube Really Burn Out?

All the cool kids are doing it these days, or more like for many years now: you can get a laser cutter for a song if you don’t mind doing your own repairs and upgrades — you know, being a hacker. The downside is that some failures can really ruin your day. This is what [Erich Styger] encountered with his cutter that is just a bit more than a year old. This Fail of the Week looks at the mysterious death of a CO2 laser tube.

This is the infamous K40 laser cutter. Our own [Adam Fabio] just took one on a couple of months back and [Erich] even references Hackaday coverage of the K40 Whisperer project as what pushed him over the edge to make the purchase. We’ve followed his blog as he acquired the cutter and made upgrades along the way, but after an estimated 500 hours of use, a horrible teeth-gnashing screech sprung forth from the machine. [Erich’s] reaction was to hit the e-stop; that’s certainly why it’s there.

Chasing down the problem is a story well-told, but as is often the case with these FotW articles, in the end what caused the failure is not entirely known. We’d love to hear what you think about it in the comments below.

The investigation began at the power supply for the laser, but that didn’t yield any answers. Next he moved to the tube itself, noticing that the wire connection to the tube’s anode wasn’t soldered. The anode is an unknown material he suspects to be graphite and he found a video showing the “soldering” process for connecting a wire. (We added quotes to that as the video he linked doesn’t actually solder anything but the wrapped wire strands themselves.) The solution he found is a great tip to take away from the story. It’s a socket by TE Connectivity to which he soldered the wire. Assuming it’s power rated for the task, and won’t fall off during normal operation, this is a great way to do it.

But we digress. Even with the connection made, the old tube had to be replaced with a new one. It’s also notable that the portion of that anode inside the bad tube is orange in color when a new tube would be black like the part on the outside. Does this hint at why that tube died, and could this have been avoided? If you have insight, help us learn from this failure by leaving a comment below.

Scratch-Building A Supersized Laser Cutter

Now that 3D printers have more or less hit the mass market, hackers need a new “elite” tool to spend their time designing and fiddling with. Judging by the last couple of years, it looks like laser cutters will be taking over as the hacker tool du jour; as we’re starting to see more and more custom builds and modifications of entry-level commercial models. Usually these are limited to relatively small and low powered diode lasers, but as the following project shows, that’s not always the case.

This large format laser cutter designed and built by [Rob Chesney] is meticulously detailed on his blog, as well as in the in the video after the break. It’s made up of aluminium profile and a splattering of ABS 3D printed parts, and lives in an acrylic enclosure that’s uniquely isolated from the laser’s internal gantry. All told it cost about $2,000 USD to build, but considering the volume and features of this cutter that’s still a very fair price.

[Rob] carefully planned every aspect of this build, modeling the entire machine in CAD before actually purchasing any hardware. Interestingly enough his primary design constraint was the door to his shed: he wanted to build the largest possible laser cutter that could still be carried through it. That led to the final machine’s long and relatively shallow final dimensions. The design was also guided by a desire to minimize material waste, so when possible parts were designed to maximize how many could be cut from a one meter length of aluminum extrusion.

The laser features a movable Z axis that’s similar in design to what you might see in a Prusa-style 3D printer, with each corner of the gantry getting an 8 mm lead screw and smooth rod which are used in conjunction to lift and guide. All of the lead screws are connected to each other via pulleys and standard GT2 belt, but as of this version, [Rob] notes the Z axis must be manually operated. In the future he’ll be able to add in a stepper motor and automate it easily, but it wasn’t critical to get the machine running.

He used 3D printed parts for objects which had a relatively complex geometry, such as the laser tube holders and Z axis components, but more simplistic brackets were made out of cut acrylic. In some components, [Rob] used welding cement to bond two pieces of acrylic and thereby double the thickness. Large acrylic panels were also used for the laser’s outer enclosure, which was intentionally designed as a separate entity from the laser itself. He reasoned that this would make assembly easier and faster, as the enclosure would not have to be held to the same dimensional tolerances as it would have been if it was integrated into the machine.

[Rob] gives plenty of detail about all the finer points of water cooling, laser control electronics, aligning the mirrors, and really anything else you could possibly want to know about building your own serious laser cutter. If you’ve been considering building your own laser and have anything you’re curious or unsure about, there’s a good chance he addresses it in this build.

Short of having the fantastically good luck to find a laser cutter in the trash that you can refurbish, building your own machine may still be the best upgrade path if you outgrow your eBay K40.

Continue reading “Scratch-Building A Supersized Laser Cutter”

Flagging Down Aliens with World’s Biggest Laser Pointer

As you’re no doubt aware, humans are a rather noisy species. Not just audibly, like in the case of somebody talking loudly when you’re in a movie theater, but also electromagnetically. All of our wireless transmissions since Marconi made his first spark gap broadcast in 1895 have radiated out into space, and anyone who’s got a sensitive enough ear pointed into our little corner of the Milky Way should have no trouble hearing us. Even if these extraterrestrial eavesdroppers wouldn’t be able to understand the content of our transmissions, the sheer volume of them would be enough to indicate that whatever is making all that noise on the third rock orbiting Sol can’t be a natural phenomena. In other words, one of the best ways to find intelligent life in the galaxy may just be to sit around and wait for them to hear us.

Of course, there’s some pesky physics involved that makes it a bit more complicated. Signals radiate from the Earth at the speed of light, which is like a brisk walk in interstellar terms. Depending on where these hypothetical listeners are located, the delay between when we broadcast something and when they receive it can be immense. For example, any intelligent beings that might be listening in on us from the closest known star, Proxima Centauri, are only just now being utterly disappointed by the finale for “How I Met Your Mother“. Comparatively, “Dallas” fans from Zeta Reticuli are still on the edge of their seats waiting to find out who shot J.R.

But rather than relying on our normal broadcasts to do the talking for us, a recent paper in The Astrophysical Journal makes the case that we should go one better. Written by James R. Clark and Kerri Cahoy,  “Optical Detection of Lasers with Near-term Technology at Interstellar Distances” makes the case that we could use current or near-term laser technology to broadcast a highly directional beacon to potentially life-harboring star systems. What’s more, it even theorizes it would be possible to establish direct communications with an alien intelligence simply by modulating the beam.

Continue reading “Flagging Down Aliens with World’s Biggest Laser Pointer”

The Electric Imp Sniffs out California Wildfires

The wildfires in California are now officially the largest the state has ever seen. Over 50,000 people have been displaced from their homes, hundreds are missing, and the cost in property damage will surely be measured in the billions of dollars when all is said and done. With a disaster of this scale just the immediate effects are difficult to conceptualize, to say nothing of the collateral damage.

While not suggesting their situation is comparable to those who’ve lost their homes or families, Electric Imp CEO [Hugo Fiennes] has recently made a post on their blog calling attention to the air quality issues they’re seeing at their offices in Los Altos. To quantify the problem so that employees with respiratory issues would know the conditions before they came into work, they quickly hacked together a method for displaying particulate counts in their Slack server.

The key to the system is one of the laser particle sensors that we’re starting to see more of thanks to a fairly recent price drop on the technology. A small fan pulls air to be tested into the device, where a very sensitive optical sensor detects the light reflected by particles as they pass through the laser beam. The device reports not only how many particles are passing through it, but how large they are. The version of the sensor [Hugo] links to in his blog post includes an adapter board to make it easier to connect to your favorite microcontroller, but we’ve previously seen DIY builds which accomplish the same goal.

[Hugo] then goes on to provide firmware for the Electric Imp board that reads the current particulate counts from the sensor and creates a simple web page that can be viewed from anywhere in the world to see real-time conditions at the office. From there, this data can be plugged into a Slack webhook which will provide an instantaneous air quality reading anytime a user types “air” into the channel.

We’ve covered a number of air quality sensors over the years, and it doesn’t look like they’re going to become any less prevalent as time goes on. If anything, we’re seeing a trend towards networks of distributed pollution sensors so that citizens can collect their own data on their air they’re breathing.

[Thanks to DillonMCU for the tip.]

Fail of the Week: Laser-based Persistence of Vision Gadget

[XTronical]’s idea for a laser-based persistence of vision gadget failed, but the basic idea seemed sound. A row of inexpensive red lasers shine into a spinning mirror and are reflected onto a distant surface, making 8 scan lines. A reflective object sensor detects mirror position, and by rapidly turning individual lasers on and off, a pattern can be drawn out.

That was the idea, anyway. A quick prototype consisting of some small and economical red laser diodes and a double-sided mirror hot glued to the shaft of a small DC motor formed the guts of the unit. [XTronical] worried that the spinning mirror might be unstable or unreliable, but that part performed just fine. The problems, he found, were mainly with the lasers.

[XTronical] had hoped to turn the lasers on and off directly via the digital I/O pins of an Arduino, but here’s where a lot of little issues sank the project. First of all, hot glue was handy for mounting but the lasers were cumbersome to align by hand, and the hot glue made it troublesome to effect repairs when units failed. In addition, the beams had inconsistent brightness and spot sizes, which made for poor visuals. [XTronical]’s approach of controlling the lasers by applying and cutting power may also have been a source of trouble. It’s possible that these lasers cannot turn on and off fast enough, but it’s hard to say without measuring.

Sensible ideas can be rendered unworkable by an accumulation of small problems, and that seems to have been the case here. A video overview is embedded below; is this approach doomed, or can it be made workable?

Continue reading “Fail of the Week: Laser-based Persistence of Vision Gadget”

The How and Why of Laser Cutter Aiming

Laser aficionado [Martin Raynsford] has built up experience with various laser cutters over the years and felt he should write up a blog post detailing his first-hand findings with an often overlooked aspect of the machines: aiming them. Cheap diode laser cutters and engravers operate in the visible part of the spectrum, but when you get into more powerful carbon dioxide lasers such as the one used in the popular K40 machines, the infrared beam is invisible to the naked eye. A secondary low-power laser helps to visualize the main laser’s alignment without actually cutting the target. There are a couple of ways to install an aiming system like this, but which way works better?

[Martin] explains that there are basically two schools of thought: a head-mounted laser, or a beam combiner. In both cases, a small red diode laser (the kind used in laser pointers) is used to indicate where the primary laser will hit. This allows the user to see exactly what the laser cutter will do when activated, critically important if you’re doing something like engraving a device and only have one chance to get it right. Running a “simulation” with the red laser removes any doubt before firing up the primary laser.

That’s the idea, anyway. In his experience, both methods have their issues. Head-mounted lasers are easier to install and maintain, but their accuracy changes with movement of the machine’s Z-axis: as the head goes up and down, the red laser dot moves horizontally and quickly comes out of alignment. Using the beam combiner method should, in theory, be more accurate, but [Martin] notes he’s had quite a bit of trouble getting both the red and IR lasers to follow the same course through the machine’s mirrors. Not only is it tricky to adjust, but it’s also much more complex to implement and may even rob the laser of power due to the additional optics involved.

In the end, [Martin] doesn’t think there is really a clear winner. Neither method gives 100% accurate results, and both are finicky, though in different scenarios. He suggests you just use whatever method your laser cutter comes with from the factory, as trying to change it probably isn’t worth the effort. But if your machine doesn’t have anything currently, the head-mounted laser is certainly the easier one to retrofit.

In the past, we’ve covered a third and slightly unconventional way of aiming the K40, as well as a general primer for anyone looking to pick up eBay’s favorite laser cutter.