Solder To Aluminum

June 11, 2020 by Al Williams 95 Comments

If you’ve ever tried to solder to aluminum, you know it isn’t easy without some kind of special technique. [SimpleTronic] recently showed a method that chemically plates copper onto aluminum and allows you to solder easily. We aren’t chemists, so we aren’t sure if this is the best way or not, but the chemicals include salt, copper sulfate (found in pool stores), ferric chloride as you’d use for etching PCBs, and water.

Once you have bare aluminum, you prepare a solution from the copper sulfate and just a little bit of ferric chloride. Using salt with that solution apparently removes oxidation from the aluminum. Then using the same solution without the salt puts a copper coating on the metal that you can use for soldering. You can see a video of the process below.

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Soon… Inkjet Your Circuit Boards

June 10, 2020 by Al Williams 35 Comments

Printed circuit board fabrication — especially in basements and garages — have been transformed by the computer revolution. Before that, people would use a permanent marker or little decals to layout circuit boards prior to etching. Sometimes, they’d do it on film and use a photo process, but they did make decals that you applied directly to the board to resist the etch. Now a team from Georgia Tech, University of Tokyo, Carnegie Mellon, and the University of Nebraska has brought things full circle. Their process inkjet prints silver traces on a substrate that they can then transfer to a circuit board — no etching required.

They start with a standard Epson inkjet with cartridges that have silver-bearing ink. The patterns print on a transfer paper that ensures the particles fuse so there’s no sintering step required to make sure the traces are all conductive. A sticky backing is applied and peels the pattern off the transfer paper. You can see more in the video below.

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Dremel Workstation’s New Job: Applying Threaded Inserts With Cheap Soldering Iron

June 10, 2020 by Donald Papp 11 Comments

Dremel has been helping people fit square pegs into round holes for years, and [concretedog] saw that the Dremel 220 Workstation — a piece of hardware similar to a drill press — could be convinced to hold a cheap soldering iron just as easily as it holds a rotary tool. A soldering iron makes an effective thermal insert tool, and the job of heating and pressing the threaded metal rings into plastic is made much easier when it can be done similar to operating a drill press. With a few modifications and a 3D-printed adapter, the thermal insert rig was born.

Whenever one is working around a design that already exists, it pays to be flexible and adjust to the unexpected. The Dremel 220 has a holder intended to clamp a rotary tool, and the original plan was to simply design and print an adapter so a soldering iron could sit in place of the rotary tool. That plan changed upon realizing that the entire rotary tool holder disconnected from the tool’s frame with a single bolt. It made much more sense to make the soldering iron replace the rotary tool holder, instead.

The resulting modified soldering iron is mounted via standoffs to a 3D-printed adapter with a copper foil heat shield. [concretedog] admits it’s not ideal from a heat management perspective, but it makes a fine prototype that seems to work well for light duty. The next step would be a metal version.

If you’re intrigued by threaded heat-set inserts, you can learn all about how to use them from Joshua Vasquez’s guide to the handy things. And should you prefer to make your own DIY press from 3D printed parts and off-the-shelf hardware, we have that covered as well.

Vernier Calipers And Micrometer Screw Gauges, Measuring Without Compromise

June 8, 2020 by Jenny List 62 Comments

I needed a temperature controller module recently, so off I went to Banggood to order one. As one does I found myself browsing, one thing led to another, and I bought a micrometer screw gauge. While micrometers are pretty expensive devices, reflecting their high precision engineering and construction, this micrometer cost me only about £8, or just under $10, definitely in the spirit of our long-running series of reviewing very cheap tools in search of a diamond in the rough. But perhaps more importantly, this is also the cue for an examination of high precision dimensional measurement. So I’ve assembled a collection of micrometers and vernier calipers of varying quality, and it’s time to dive in and measure some very small things.

Some of you will be metrology enthusiasts with an array of the finest devices available, but I am guessing that many of you will not. The ubiquitous precision measurement device in our community appears to be the digital caliper, a sliding clamp with an LCD display, an instrument that can be had in its most basic form for a very small outlay indeed. For the purposes of this piece though we’re not looking at digital devices but their analogue precursors. If you want a feel for metrology and you’d like some of those heritage tools that parents pass onto their kids then it’s time to learn something about the vernier caliper and the micrometer. Continue reading “Vernier Calipers And Micrometer Screw Gauges, Measuring Without Compromise” →

Adjustable Jig Eases PCB Stencil Alignment Process

June 7, 2020 by Dan Maloney 8 Comments

PCB stencils make application of solder paste a snap, but there’s a long, fussy way to go before the paste goes on. You’ve got to come up with some way to accurately align the stencil over the board, which more often than not involves a jury-rigged setup using tape and old PCBs, along with a fair amount of finesse and a dollop of luck.

Luckily, [Valera Perinski] has come up with a better way to deal with stencils. The Stencil Printer is a flexible, adjustable alignment jig that reduces the amount of tedious adjustment needed to get things just so. The jig is built mostly from aluminum extrusions and 3D-printed parts, along with a bunch of off-the-shelf hardware. The mechanism has a hinged frame that holds the stencil in a fixed position above a platen, upon which rests the target PCB. The board is held in place by clamps that ride on threaded rods; with the stencil flipped down over the board, the user can finely adjust the relative positions of the board and the stencil, resulting in perfect alignment. The video below is mainly a construction montage, but if you skip to about the 29:00 mark, you’ll see the jig put through its paces.

Granted, such a tool is a lot more work than tape and spare PCBs, but if you do a lot of SMD work, it may be worth the effort. It’s certainly less effort than a solder-paste dispensing robot.

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Testing Hardware With ASCII Waveforms

June 6, 2020 by Al Williams 14 Comments

Testing software is — sometimes — easier than testing hardware. After all, you can always create test files and even fake user input before monitoring outputs using common tools. Hardware though, is a bit different. Sometimes it is hard to visualize exactly what’s happening. [Andrew Ray’s] answer? Produce simulated waveforms using ASCII text.

The process uses some custom tools written in OCaml, but the code is available for you on GitHub. The tool, called Hardcaml, allows you to write test benches for hardware — not a new idea for FPGA developers. The output, however, is an ASCII text waveform and common software development tools can check that waveform against the expected output.

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A DIY Electronic Load With A Twist

June 6, 2020 by Tom Nardi 13 Comments

If you’re testing a power supply or battery pack, an electronic load is a nice tool to have. By watching the voltage as you crank up the resistance, you can verify the unit’s real-world capabilities quickly and easily. But [Xavier Bourlot] wanted a bit more information than is generally afforded by these devices, so he came up with his own scratch built load that can measure the voltage at multiple points in the circuit.

Now at first glance, it might not be obvious why you’d want such a capability. But [Xavier] is looking to do something very specific with this device: analyze the efficiency of DC-DC converters. The idea is that if the electronic load can measure the voltage on both sides of the converter, it can calculate what kind of losses are being incurred.

Could you do this with a multimeter and a traditional electronic load? Sure. But if it’s the kind of thing you’ll be doing a lot of, it’s not hard to see why this method would be preferable.

But even if you ignore the converter analysis capabilities, this looks to be a very useful device to have around the lab. [Xavier] says it can sink more than 5 amps, and handle an input voltage as high as 100 volts. Powered by an ATmega328P, the load is also fully programmable and even features an I2C expansion port that you can use to hang additional hardware or sensors on. The stock firmware is already quite capable, and the list of future enhancements has some very interesting entries such as the ability to log data over serial or to a SD card.

We’ve seen a number of programmable electronic load projects over the years, ranging from Arduino shields to VFD equipped units that would be the pride of any hacker’s bench.