Laser Cutting Wooden Pogo Pin Test Jigs

Now as far as problems go, selling so many products on Tindie that you need to come up with a faster way to test them is a pretty good one to have. But it’s still a problem that needs solving. For [Eric Gunnerson] the solution involved finding a quick and easy way to produce wooden pogo test jigs on his laser cutter, and we have a feeling he’s not the only one who’ll benefit from it.

The first step was exporting the PCB design from KiCad into an SVG, which [Eric] then brought into Inkscape for editing. He deleted all of the traces that he wasn’t interested in, leaving behind just the ones he wanted to ultimately tap into with the pogo pins. He then used the Circle tool to put a 0.85 mm red dot in the center of each pad.

You’re probably wondering where those specific parameters came from. The color is easy enough to explain: his GlowForge laser cutter allows him to select by color, so [Eric] can easily tell the machine to cut out anything that’s red. As for the size, he did a test run on a scrap of wood and found that 0.85 mm was the perfect dimensions to hold onto a pogo pin with friction.

[Eric] ran off three identical pieces of birch plywood, plus one spacer. The pogo pins are inserted into the first piece, the wires get soldered around the back, and finally secured with the spacer. The whole thing is then capped off with the two remaining pieces, and wrapped up in tape to keep it together.

Whether you 3D print one of your own design or even modify a popular development board to do your bidding, the test jig is invaluable when you make the leap to small scale production.

The Practical Approach To Keeping Your Laser In Focus

You could be forgiven for thinking that laser cutters and engravers are purely two dimensional affairs. After all, when compared to something like your average desktop 3D printer, most don’t have much in the way of a Z axis: the head moves around at a fixed height over the workpiece. It’s not as if they need a leadscrew to push the photons down to the surface.

But it’s actually a bit more complicated than that. As [Martin Raynsford] explains in a recent post on his blog, getting peak performance out of your laser cutter requires the same sort of careful adjustment of the Z axis that you’d expect with a 3D printer. Unfortunately, the development of automated methods for adjusting this critical variable on lasers hasn’t benefited from the same kind of attention that’s been given to the problem on their three dimensional counterparts.

Ultimately, it’s a matter of focus. The laser is at its most powerful when its energy is concentrated into the smallest dot possible. That means there’s a “sweet spot” in front of the lens where cutting and engraving will be the most efficient; anything closer or farther away than that won’t be as effective. As an example, [Martin] says that distance is exactly 50.3 mm on his machine.

The problem comes when you start cutting materials of different thicknesses. Just a few extra millimeters between the laser and your target material can have a big difference on how well it cuts or engraves. So the trick is maintaining that perfect distance every time you fire up the laser. But how?

One way to automate this process is a touch probe, which works much the same as it does on a 3D printer. The probe is used to find where the top of the material is, and the ideal distance can be calculated from that point. But in his experience, [Martin] has found these systems leave something to be desired. Not only do they add unnecessary weight to the head of the laser, but the smoke residue that collects on the touch probe seems to invariably mar whatever surface you’re working on with its greasy taps.

In his experience, [Martin] says the best solution is actually the simplest. Just cut yourself a little height tool that’s precisely as long as your laser’s focal length. Before each job, stick the tool in between the laser head and the target to make sure you’re at the optimal height.

On entry level lasers, adjusting the Z height is likely to involve turning some screws by hand. But you can always add a motorized Z table to speed things up a bit. Of course, you’ll still need to make sure your X and Y alignment is correct. Luckily, [Martin] has some tips for that as well.

Creating A Laser Cutter From A 3D Printer

The average FDM 3D printer is not so different from your garden variety laser cutter. They’re often both Cartesian-coordinate based machines, but with different numbers of axes and mounting different tools. As [Gosse Adema] shows, turning a 3D printer into a laser cutter can actually be a remarkably easy job.

The build starts with an Anet A8 3D printer. It’s an affordable model at the lower end of the FDM printer market, making it accessible to a broad range of makers. With the help of some 3D printed brackets, it’s possible to replace the extruder assembly with a laser instead, allowing the device to cut and engrave various materials.

[Gosse] went with a 5500 mW diode laser, which allows for the cutting and engraving of wood, some plastics and even fabrics. Unlike a dedicated laser cutter there are no safety interlocks and no enclosure, so it’s important to wear goggles when the device is operating. Some tinkering with G-Code is required to get things up and running, but it’s a small price to pay to get a laser cutter on your workbench.

We’ve seen [Gosse]’s 3D printer experiments before, with the Anet A8 serving well as a PCB milling machine.

A Laser Cutting 101

If you’ve worked with a laser cutter before, you might not find much new in [Maker Design Lab’s] recent post about getting started. But if you haven’t, you’ll find a lot of practical advice and clean clear figures. The write up focuses on a tube-style laser cutter that uses a gas-filled tube and mirrors. Some cheap cutters use a diode, and many of the same tips will apply to those cutters.

You can probably guess that a laser cutter can cut like a CNC and also engrave where the cut doesn’t go all the way through. But it can also mark metals and other surfaces by using a marking solution. If you’ve done CNC or 3D printing, the process is similar, but there are a few unique things to know, like the use of the marking solution.

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Make Your Own MIDI Controller With An Arduino

Engineers create something out of nothing, and no where is this more apparent than in the creation of customized computer hardware. To make a simple MIDI controller, you need knowledge of firmware design and computer architecture, you need knowledge of mechanical design, and you need to know electronic design. And then you need the actual working knowledge and experience to wield a tool, be it a hammer, laser cutter, or an IDE. [Mega Das] brought together all of these skill to build a MIDI controller. Sure, it’s for bleeps and bloops coming out of a speaker, but take a step back and realize just how awesome it is that any one person could imagine, then implement such a device.

The electronics for this build include a printed circuit board that serves to break out the connections on an Arduino nano to a dozen arcade push buttons, four slide pots, two rotary pots, and a handful of screw terminals to connect everything together. Mechanically, this is a laser-cut box engraved with some fancy graphics and sized perfectly to put everything inside.

Yes, we’ve seen a lot of MIDI controllers built around the Arduino over the years, but this one is in a class by itself. This is taking off-the-shelf parts and customizing them to exactly what you want, and a prodigious example of what is possible with DIY hardware creation. You can check out the build video below.

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Custom Inflatables Are Only A Laser Beam Away

Carl Sagan one said “If you wish to make an apple pie from scratch, you must first invent the universe.” It might not be a very accurate description of the relative difficulty level of baking, but the logic is sound enough: there’s often a lot of ground work that needs to be to covered before you hit your ultimate goal. A perfect example of this principle is the inflatable raft that [ralph124c] hopes to eventually create; before he can set sail he has to perfect making balloon animals with his laser cutter.

In the long run, the raft will be constructed from sheets of TPU coated fabric that are fused together with a hot iron. But before he spends the time and money on building the real thing, he wants to do some scaled down tests to make sure his design works as expected. He makes a cryptic remark about learning the hard way that inflatables are prone to bouts of strange behavior, and out of an overabundance of caution we’ll just take his word for it.

He hoped to test his designs with the much cheaper LDPE film, but he found that the hot iron didn’t fuse it together in the way he was hoping. His mind turned to his 60 watt laser cutter, and wondered if the desired effect could be achieved by turning the power down as low as possible and quickly moving across the material.

His first attempts either blew right through the film or did absolutely nothing, but eventually he had the bright idea to move the laser farther from the LDPE. This put the beam out of focus, which not only expanded the area it would cover, but reduced the energy being delivered to the surface. With a bit more experimentation, he found he was able to neatly weld the pieces of material together. He even found that he could increase the power slightly to cut through the film without having to adjust the laser focus. With the ability to create complex inflatable shapes, perhaps [ralph124c] will create balloon version of Carl Sagan or an apple pie to celebrate.

Of course, this technology isn’t limited to birthday balloons and model rafts. The ability to quickly and easily produce custom inflatable shapes could be a huge boon to anyone working in soft robotics, and we’ve even seen similar concepts applied to haptic feedback systems.

[Thanks to Arthur for the tip.]

Eight Years Of Partmaking: A Love Story For Parts

Over my many years of many side-projects, getting mechanical parts has always been a creative misadventure. Sure, I’d shop for them. But I’d also turn them up from dumpsters, turn them down from aluminum, cut them with lasers, or ooze them out of plastic. My adventures making parts first took root when I jumped into college. Back-in-the-day, I wanted to learn how to build robots. I quickly learned that “robot building” meant learning how to make their constituent parts.

Today I want to take you on a personal journey in my own mechanical “partmaking.” It’s a story told in schools, machine shops, and garages of a young adulthood spent making parts. It’s a story of learning how to run by crawling through e-waste dumps. Throughout my journey, my venues would change, and so would the tools at-hand. But that hunger to make projects and, by extension, parts, was always there.

Dear partmakers, this is my love letter to you.

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