Faux Silkscreen On A PCB Made With A Laser Cutter

If you’re getting PCBs professionally made, silkscreen usually comes free as part of the package. However, if you’re making your own, the job is on you. [Tony Goacher] makes his own PCBs on a CNC router, so he’s not getting any silkscreening as part of that bargain. But he wondered—could he do something analogous with a laser cutter?

The answer is yes. The silkscreen layer was first exported from DesignSpark, with the file then sent to LightBurn to prep it for laser cutting. The board outline layer was first engraved on to a piece of scrap as an alignment aid. Then, the board was placed in the laser cutter, with the silkscreen scorched directly on to the fiberglass.

The results are encouraging, if imperfect. [Tony] says he ran at “quite fast speed at quite high power.” The markings are all there, but they’re a little melty and difficult to read. He noted at lower speeds and lower power, the results were a bit more readable.

PCBs aren’t really an ideal engraving or laser marking material, but this technique could be servicable for some basic markings on DIY PCBs. We look forward to seeing how [Tony] improves the process in future. Video after the break.
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All I Want For Mr. Christmas Is Some New Music

It’s true — you really can find anything (except maybe LEGO) in thrift stores. When [thecowgoesmoo] picked up a Mr. Christmas Symphonium music box one day, they knew they wanted to make it play more than just the standard Christmas and classical fare that ships with the thing.

So they did what any self-respecting hacker would do, and they wrote a MATLAB script that generates new disk silhouette images that they then cut from cardboard with a laser cutter. They also used various other materials like a disposable cutting mat. Really, whatever is lying around that’s stiff enough and able to be cut should work. You know you want to hear Van Halen’s “Jump” coming from a tinkling music box, don’t you? Be sure to check out the video demonstration after the break.

If you don’t want to wait around until a Mr. Christmas lands in your lap, why not make your own hand-cranked music box and accompanying scores?

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Man playing custom zither made with a laser cutter.

Laser Cut Zither Instrument Kicks It Old World Style

Learning to play an instrument takes a certain level of dedication — and you can add another layer of dedication on top of that when it’s an instrument not found at your local Guitar Center. But it’s an entirely new level of dedication when someone crafts the instrument from scratch. If you’re looking for an example, check out this custom wooden zither [Nicolas Bras] built from laser cut parts.

The basic design of the instrument utilizes the sloted interlocking edges that are then glued together in lieu of traditional fasteners. Standard sized guitar tuning pegs and the accompanying steel guitar strings were then strung across two laser-cut bridges held in place by the string tension alone. The project began as way for [Nicolas] to learn the capabilities of his newly acquired laser cutter, but he himself is no amateur when it comes to constructing one-of-a-kind musical instruments. Just last year, he created a zither with bungee cords from the hardware store.

Zithers are German in origin, though some of the earliest zither-like instruments date back to 400 BCE China. The laser cut version [Nicolas] created had five strings to hammer on, though the type used in classical music arrangements typically contain upwards of thirty strings. The zither family of instruments may have given way to the electric guitars of today — it’s always neat to see new tech leveraged to embrace some old world charm.

For more on the art of DIY music production, check out this post on myriad of DIY musical instrument builds all played in concert.

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This Laser-Cut One-Piece Wedge Tenon Locks Wood Joints Tight

Woodworkers have always been very clever about making strong and attractive joints — think of the strength of a mortise and tenon, or the artistry of a well-made dovetail. These joints have been around for ages and can be executed with nothing more than chisels and a hand saw, plus a lot of practice, of course. But new tools bring new challenges and new opportunities in joinery, like this interesting “hammer joint” that can be made with a laser cutter.

This interesting joint comes to us from [Jiskar Schmitz], who designed it for quick, solid, joints without the need for glue or fasteners. It’s a variation on a wedged mortise and tenon joint, which strengthens the standard version of the joint by using a wedge to expand the tenon outward to make firm contact with the walls of the tenon.

The hammer joint takes advantage of the thin kerf of a laser cutter and its ability to make blind cuts to produce a tenon with a built-in wedge. The wedge is attached to a slot in the tenon by a couple of thin connectors and stands proud of the top of the tenon. The tenon is inserted into a through-hole mortise, and a firm hammer blow on the wedge breaks it free and drives it into the slot. This expands the tenon and locks it tightly into the mortise, creating a fairly bulletproof joint. The video below tells the tale.

While the hammer joint seems mainly aimed at birch plywood, [Jiskar] mentions testing it in other materials, such as bamboo, MDF, and even acrylic, although wood seems to be the best application. [Jiskar] also mentions a potential improvement: the addition of a ratchet and pawl shape between the wedge and the slot in the tenon, which might serve to lock the wedge down and prevent it from backing out.

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Take The Tedium Out Of Fabric Cutting, Make The Laser Do It

Fabric must be cut before it can be turned into something else, and [fiercekittenz] shows how a laser cutter can hit all the right bases to save a lot of time on the process. She demonstrates processing three layers of fabric at once on a CO2 laser cutter, cutting three bags’ worth of material in a scant 1 minute and 29 seconds.

The three layers are a PU (polyurethane) waterproof canvas, a woven liner, and a patterned cotton canvas. The laser does a fantastic job of slicing out perfectly formed pieces in no time, and its precision means minimal waste. The only gotcha is to ensure materials are safe to laser cut. For example, PU-based canvas is acceptable, but PVC-based materials are not. If you want to skip the materials discussion and watch the job, laying the fabric in the machine starts around [3:16] in the video.

[fiercekittenz] acknowledges that her large 100-watt CO2 laser cutter is great but points out that smaller or diode-based laser machines can perfectly cut fabric under the right circumstances. One may have to work in smaller batches, but it doesn’t take 100 watts to do the job. Her large machine, for example, is running at only a fraction of its full power to cut the three layers at once.

One interesting thing is that the heat of the laser somewhat seals the cut edge of the PU waterproof canvas. In the past, we’ve seen defocused lasers used to weld and seal non-woven plastics like those in face masks, a task usually performed by ultrasonic welding. The ability for a laser beam to act as both “scissors” and “glue” in these cases is pretty interesting. You can learn all about using a laser cutter instead of fabric scissors in the video embedded below.

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An Open-Source Antikythera Mechanism

When the Antikythera Mechanism was first discovered, it wasn’t viewed as the wonder that we know it today. Originally the divers who found the device and the first scientists to look at it wrote it off as an astrolabe or other some other common type of clock. It wasn’t until decades later when another set of scientists x-rayed the device and surveyed more of the shipwreck where it was found that it began to become one of the more important archaeological discoveries in history. There have been plenty of attempts to recreate this device, and this replica recreates the mechanisms of the original but is altered so it can be built in a modern workshop.

The build, which took the creators several years of research and development to complete, started off with the known gear schemes found on the original device. However, the group wanted to make it with modern technology including 3D printers and laser cutters, so although they worked from an understanding of the original 2000-year-old device there are some upgrades and changes to accommodate those who want to build this in a modern workshop. Gears made from plastic instead of brass have more friction, which needed to be reduced by building custom bearings machined out of brass. And to complete the machine a number of enclosures of various styles are available to use as well.

Additionally, all of the designs and schematics for this build are open source for anyone to build or modify as they would like, although the group putting this together does plan to sell various parts for this as well. There will be some issues with use, as they point out, since the ancient Greeks didn’t have a full enough understanding of cosmology to get a machine like this to stay accurate for two thousand years, but it’s a fascinating build nonetheless. Reasearchers are still discovering new things about this device too, including the recent find of an earliest possible start date for the machine.

Getting A Rise With Laser Cutting

Your first 3D print probably seemed pretty amazing. But if you revisit it after a few years, you’ll likely notice it wasn’t nearly as good as you thought. We improve our printers and our processes and the new better results become normal. If you have a laser cutter, you may go through the same iteration. At first, you are happy just to get scorch marks on the workpiece. But when you move to cutting, you want cleaner cuts. You put tape over the work, add air assist, and invest in a honeycomb bed. Each step gets you better results, but you can always improve.

[The Louisiana Hobby Guy] (also known as [Rich]) knows a lot about the practical side of lasers. He suggests using standoff pins to not just secure the part to the honeycomb bed but lift it up a little, allowing air to flow under the part and lets the laser easily cut all the way through. You can see them in action in the video below.

This is a cheap upgrade to prevent flashback when cutting. [Rich] explains how to size them properly and even how to make your own if you don’t want to buy them off the shelf. You can laser cut hold-down pins from plans [Rich] provides, although he prefers to 3D print them, and you can do that, too. Most beds look similar, but if yours is an oddball, you might have to modify them slightly. He has regular dog clamps and the antiflashback standoffs, so you can make some of each. You can also buy them online. Most do not have the antiflashback feature, but at least one vendor that [Rich] points out does have them

If you don’t like the ones [Rich] shows, you can find 3D models for similar pins in the usual places. You can also design them yourself if you want them exactly how you want.

A good thing to add to your laser cutting workflow. [Rich’s] channel is full of great stuff. If you want to know more about air assist, we’ve added it to our cutters. If you are serious about precision cuts, know your kerf, too.

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