Kerfmeter Measures Laser Cutter Kerf Allowances On The Fly

May 3, 2023 by Dan Maloney 21 Comments

Nothing beats a laser cutter and a sheet of Baltic birch plywood or MDF when it comes to making quick, attractive enclosures. Burning out all the pieces and fitting them together with finger joints is super satisfying — right up until you realize that you didn’t quite get the kerf allowance right, and your pieces don’t fit together very nicely. If only there was a way to automate kerf measurement.

There is, in the form of Kerfmeter. It comes to us by way of the lab of [Patrick Baudisch] at the University of Potsdam, where they’ve come up with a clever way to measure the kerf of a laser cutter right during the cutting session. With the Kerfmeter mounted directly to the laser cutter head, a small test artifact based on an Archimedean spiral is cut into a corner of the workpiece. Pins on a small motor engage with the object and turn it until it jams in its hole; the wider the kerf, the greater the angle. Once the kerf is calculated, the rest of the design can be dilated by the proper amount to achieve a perfect fit. The video below shows it better than words can explain it.

What we like about this is its simplicity — all it involves is a motor and a microcontroller, plus a little software. It seems much faster than using a traditional kerf gauge, not to mention more precise. And while it does use up a little bit of material, the test pattern is really pretty small, all things considered. Seems like a reasonable trade-off to us. Still, if you want to figure out your kerfs the old-fashioned way, we’ve got you covered.

Continue reading “Kerfmeter Measures Laser Cutter Kerf Allowances On The Fly” →

Smoke Some Weeds: Lasers Could Make Herbicide Obsolete

April 26, 2023 by Lewin Day 53 Comments

We’ve all tangled with unwelcome plant life at one point or another. Whether crabgrass infested your lawn, or you were put on weeding duty in your grandfather’s rose patch, you’ll know they’re a pain to remove, and a pain to prevent. For farmers, just imagine the same problem, but scaled up to cover thousands of acres.

Dealing with weeds typically involves harsh chemicals or excessive manual labor. Lasers could prove to be a new tool in the fight against this scourge, however, as covered by the BBC.

Continue reading “Smoke Some Weeds: Lasers Could Make Herbicide Obsolete” →

New Tool Helps Create Laser-Cut Doom Maps

April 19, 2023 by Lewin Day 7 Comments

Doom has a larger cultural footprint than the vast majority of video games ever made. That inspired [Theor] to see if it was possible to laser-cut some of the game’s maps to create a real-world model of those famous original levels.

Level data was extracted from the game’s original WAD data files using code written in Rust. Maps are described by multiple “lumps” within the WAD file format, each containing information on vertexes, walls, and floors. This data was scraped and converted into SVG files suitable for laser cutting. [Theor] then built a visualizer that could display what a stacked-up laser cut map would look like in 3D, to verify everything worked correctly. With that done, the map could be laser cut without worries that it would come out a jumbled, janky mess.

[Theor] kept the finished product simple, creating the map as a stack of blue acrylic pieces. We can imagine this tool being perfect for creating a high-quality diorama though, with some work done to paint the map to match what the player sees in game. If you happen to take that approach, don’t hesitate to notify the tipsline!

Better Laser Cuts: Know Your Kerf

April 15, 2023 by Al Williams 19 Comments

The recent crop of laser cutters are nothing short of miraculous. For a few hundred dollars you can get a machine that can easily engrave and — subject to materials — cut well, too. [Nate] has been taking advantage of a laser to make boxes that join together using finger joinery. The problem is, the pieces have to fit exactly to get a good box. While setting dimensions in software is fine, you need to account for how much material the laser removes — something traditional woodworkers and machinists know as kerf.

You can, of course, employ trial and error to get good results. But that’s wasteful and potentially time-consuming. [Nate] built a “tolerance fence” that is quick to cut out and allows accurate measurement of kerf. You can quickly use the tolerance fence to make measurements and increase your chances of nailing your boxes on the first cut.

You have to customize the fence based on the thickness of your material. [Nate] uses Lightburn, which probably has a kerf offset already set by default in your layers. If not, you’ll need to turn it on and set an estimate of your kerf size. Then you are ready to cut the fence pieces and see how they fit together.

If the fit is too loose, you want to raise the kerf setting and try again. If it is too tight, you lower the kerf setting. As [Nate] says, “Lower equals looser.”

The results speak for themselves, as you can see in the treasure chest image [Nate] provided. Well worth the effort to get this parameter right. We do enjoy laser cutting and engraving things. If you are cutting and don’t have air assist, you really need to hack up something.

Laser And Webcam Team Up For Micron-Resolution Flatness Measurements

March 16, 2023 by Dan Maloney 36 Comments

When you want to measure the length, breadth, or depth of an object, there are plenty of instruments for the job. You can start with a tape measure, move up to calipers if you need more precision, or maybe even a micrometer if it’s a really critical dimension. But what if you want to know how flat something is? Is there something other than a straightedge and an eyeball for assessing the flatness of a surface?

As it turns out, there is: a $15 webcam and a cheap laser level will do the job, along with some homebrew software and a little bit of patience. At least that’s what [Bryan Howard] came up with to help him assess the flatness of the gantry he fabricated for a large CNC machine he’s working on.

The gantry arm is built from steel tubing, a commodity product with plenty of dimensional variability. To measure the microscopic hills and valleys over the length of the beam, [Bryan] mounted a lens-less webcam to a block of metal. A cheap laser level is set up to skim over the top of the beam and shine across the camera’s image sensor.

On a laptop, images of the beam are converted into an intensity profile whose peak is located by a Gaussian curve fit. The location of the peak on the sensor is recorded at various points along the surface, leading to a map of the microscopic hills and valleys along the beam.

As seen in the video after the break, [Bryan]’s results from such a quick-and-dirty setup are impressive. Despite some wobblies in the laser beam thanks to its auto-leveling mechanism, he was able to scan the entire length of the beam, which looks like it’s more than a meter long, and measure the flatness with a resolution of a couple of microns. Spoiler alert: the beam needs some work. But now [Bryan] knows just where to scrape and shim the surface and by how much, which is a whole lot better than guessing. Continue reading “Laser And Webcam Team Up For Micron-Resolution Flatness Measurements” →

Laser Scanner Upgraded To Use PCB Motor

February 22, 2023 by Chris Lott 10 Comments

[Rik]’s Hexastorm laser scanner project originally used a discrete polygon mirror controller+motor module from Sharp to spin a prism. But the scanner head was a bit difficult to assemble and had a lot of messy wires. This has all been replaced by a single board featuring a PCB-printed motor, based on the work of [Carl Bugeja]. The results are promising so far — see video below the break.

Since the prism is not attached to anything, currently it will fall off if mounted in the intended vertical orientation. One of [Rik]’s next steps is to improve the mount’s design to constrain the spinning prism. The previous Sharp motor was specified to 21000 RPM, but was only driven to 2400 RPM in [Rik]’s first version. This new PCB motor spins at 2000 RPM in these tests, comparable to his previous experiments ( we’re not sure about the maximum RPM ).

See our original writeup from 2019 to review the goals of this project, and be sure to checkout details and documentation on the Hexastorm project page. To learn more about PCB motors, read our article about [Carl]’s first design and visit his Hackaday.io page. Thanks to [Jonathan Beri] for the tip.

Continue reading “Laser Scanner Upgraded To Use PCB Motor” →

Picking A Laser Hack Chat

February 20, 2023 by Dan Maloney 25 Comments

Join us on Wednesday, February 22 at noon Pacific for the Picking a Laser Hack Chat with Jonathan Schwartz!

You’ve got to admit that it’s a pretty cool world to live in that presents a problem like, “Which laser cutter should I buy?” It wasn’t all that long ago that decisions on laser purchases were strictly in the realm of Big Science, and the decision was driven as much by spending grant money as by the specifics of the application. If you were in need of a laser back then, chances are good you had some deep pockets, or at least access to someone else’s pockets.

Fast forward a couple of decades or so and buying a laser is an entirely different exercise. Lasers have become a commodity, and finding the right one depends entirely on your use cases. Lasers are no longer jealously guarded laboratory instruments, but workhorses on the vanguard of the desktop manufacturing revolution. They engrave, they cut, they melt — in short, they do a LOT of work. And it’s up to you to choose the right laser for the job.

To help us sort all this out and come up with a plan for figuring out the best laser for any use case, we’ve invited Jonathan Schwartz back on the Hack Chat. Jon dropped by back in March of 2021 to share his wealth of laser experience thanks to his laser-cutting business. This time around we’re going to focus — err, concentrate — oops, drill down — oh, whatever! — on the more practical aspects of buying a laser. We’ll talk about laser types, fiber lasers, applications vs. laser specs — anything you can think of. If you have questions about buying a laser, we’ll have answers!

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 22 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.