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.

A closeup picture showing the jagged edge of the cut

Debugging Laser Cut Wobble, The Scientific Way

December 29, 2022 by Arya Voronova 23 Comments

[PWalsh] was using his lasercutter to cut acrylic, expecting the cuts to have a pleasantly smooth edge. Alas, the edges turned out to be wobbly and sandpaper-like, not smooth in the slightnest. Bummer! Internet suggested a stepper motor swap, but not much in the way of insights – and that would’ve been a royal pain for sure. How would you approach debugging such a problem? Well, [PWalsh] didn’t want to swap crucial components willy-nilly, going the scientific way instead, and breaks it down for us.

Having compiled an extensive list of possible places to look for a fault in, he started going through fundamental assumptions. Do other lasercutters experience this issue? No, even the cheap ones can cut things properly. Is it water level causing intermittent cooling? Nope, not that. Is it the stepping settings? Tweaked, not that. Laser pulsing frequency? No dice. Continue reading “Debugging Laser Cut Wobble, The Scientific Way” →

Testing A Laser Cut Wrench VS A Forged Wrench

August 13, 2022 by Al Williams 30 Comments

It is easy to not think much about common tools like screwdrivers and wrenches. But not for [Torque Test Channel]. The channel does a lot of testing of tools and in the video, below, they test a new wrench that is, oddly enough, laser cut instead of forged like the usual wrench.

You would expect a machined wrench to be weaker than a forged wrench. We were impressed, though, that there is so much difference between wrenches when you start making measurements.

Speaking of measurements, we would like to see more details of the test setups shown both in the video and in some of the video clips included. We did enjoy seeing the examination of the internal grain structure of both wrenches.

Be forewarned. Watching this video is likely going to send you to the computer to buy some new wrenches, especially if you don’t have 30/60 head wrenches.

The real question is why laser cut a wrench? It doesn’t seem like it is actually better than the forged variant. It is more expensive, but the setup costs for forging are higher. Particularly for a tool made in the United States, forging is both expensive and it is difficult to find time on the limited number of large-scale forges left in the country.

Continue reading “Testing A Laser Cut Wrench VS A Forged Wrench” →

Custom Raspberry Pi Case Shows The Whole Workflow

July 25, 2022 by Donald Papp 29 Comments

If you are a process junkie and love seeing the end-to-end of how a thing is made and with what tools, then watch [Michael Klements] show off his Raspberry Pi case design. His case has quite a few cool-looking elements to it, and incorporates 3D printing as well as laser-cut and clear bent acrylic for a gorgeous three-quarter view.

[Michael]’s write-up (and accompanying video, embedded below) are partly a review of his Creality 3D printer, and partly a showcase of his Raspberry Pi case design (for which he sells the design files for a small fee on his Etsy store.) But the great part is seeing the creation of every piece that goes into the end product. Not everyone is familiar with the way these tools work, or what they can create, so it’s nice to see attention paid to that side of things.

Both the blog post and the video nicely show off what goes into every part. The video opens with unpacking and setting up the 3D printer (skip ahead to 4:58 if you aren’t interested), followed by printing the parts, laser-cutting the acrylic on a K40 laser cutter, bending the acrylic using a small hand tool, and finally, assembling everything. For the curious, there are also links to the exact parts and equipment he uses.

Like we said, it’s part 3D printer review and part showcase of a design he sells, but it’s great to see each of the parts get created, watch the tools get used, and see the results come together in the final product. And should you wish to go in the opposite direction? A one-piece minimalist case for your Raspberry Pi is only a 3D printer away.

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This Spherical Lamp’s Pieces Ship Flat, Thanks To Math

May 7, 2022 by Donald Papp 3 Comments

[Nervous System] sells a variety of unique products, and we really appreciate the effort they put into sharing elements of their design and manufacturing processes. This time, it’s details of the work that went into designing a luxury lamp shade that caught our eye.

Top: Finished lamp. Bottom: Partially-assembled.

The finished lamp shade is spherical, but is made entirely from flat-packed pieces of laser-cut wood that have been specifically designed to minimize distortion when assembled into a curved shape. The pieces themselves are reminiscent of puzzle cells; complex, interlocking cellular shapes found in many plants.

As usual, [Nervous System] applied a hefty dose of math and computational design to arrive at a solution. Each unique panel of the lamp is the result of a process that in part implements a technique called variation surface cutting for the shape of the pieces. They also provide a couple of nifty animations that illustrate generating both the piece boundaries as well as the hole patterns in each of the 18 unique pieces that make up each lamp.

As for making the pieces themselves, they are laser-cut from wood veneer, and assembly by the end user takes an hour or two. Watch a video overview, embedded just below under the page break.

We’re glad [Nervous System] takes the time to share details like this, just like the time they figured out the very best type of wood for laser-cutting their unique puzzles and didn’t keep it to themselves.

Continue reading “This Spherical Lamp’s Pieces Ship Flat, Thanks To Math” →

An OpenSCAD Library For All Your CNC Cutting Needs

January 2, 2022 by Tom Nardi 15 Comments

While there’s always the edge case, there’s a strong likelihood that if you’re using OpenSCAD, you’re probably working on a CAD model that you intend to 3D print at some point. Of course that’s not to say this is all you can do in OpenSCAD, but it’s arguably what it does best. If you wanted to make artistic models, or maybe render what your new kitchen will look like, there are other tools better suited to such tasks.

But thanks to lasercut.scad, a library that [Brendan Sleight] has been working on for the last several years, we might have to reconsider our preconceived dimensional notions. Instead of designing parts for 3D printing, his library is all about creating parts intended for subtractive manufacturing. Originally (as the name implies) it was geared towards laser cutting, but the project has since evolved to support CNC routers, vinyl cutters, and pretty much anything else that can follow a DXF file.

The library has functions for creating the standard tricks used to build things from laser-cut pieces, like finger joints, captive nuts, and assembly tabs. If it was something you once saw holding together an old wooden 3D printer kit back in the day, you can probably recreate it with lasercut.scad. It even supports a pretty wild piece of rotational joinery, courtesy of [Martin Raynsford].

Don’t have a way of concentrating a sufficient number of angry photons at your workpiece? No worries. The library has since been adapted to take into account a parametric kerf width, which lets you dial in how much of a bite your particular tool will take from the material when it does the business. There are even special functions for dealing with very thin cuts, which [Brendan] demonstrates by assembling a box from sheet vinyl.

Of course, those who’ve used OpenSCAD will know there’s not an “Export for CNC” button anywhere in the stock interface. So to actually take your design and produce a file your cutter can understand, [Brendan] has included a Bash script that will run the necessary OpenSCAD incantations to produce a 2D DXF file.

[Brendan] decided to send this one in after he saw the aluminum enclosure OpenSCAD library we covered recently. If you’ve got your own pet project that bends some piece of hardware or software to your will, don’t be shy to let us know.

The Many Ways To Solve Your Enclosure Problems

September 15, 2021 by Bob Baddeley 63 Comments

Most projects around here involve some sort of electronics, and some sort of box to put them in. The same is true of pretty much all commercially available electronic products as well.

Despite that, selecting an enclosure is far from a solved problem. For simple electronics it’s entirely possible to spend more time getting the case just right than working on the circuit itself. But most of the time we need to avoid getting bogged down in what exactly will house our hardware.

The array of options available for your housing is vast, and while many people default to a 3D printer, there are frequently better choices. I’ve been around the block on this issue countless times and wanted to share the options as I see them, and help you decide which is right for you. Let’s talk about enclosures!

Continue reading “The Many Ways To Solve Your Enclosure Problems” →