The toner transfer process of producing PCBs has evolved tremendously over the last few years. It started out by printing PCB layouts onto magazines with a laser printer, then some clever people figured out that glossy inkjet photo paper would work just as well. Now there’s a new substrate for you – packing tape – and it seems to work pretty well.
[David] was designing a cheap board for a robot kit for a workshop and needed 100 tiny PCBs. They were simple boards, and perfectly suited for home PCB manufacturing. He started off by printing directly onto glossy magazine paper, but this wasn’t an ideal solution. During one run, some of the toner landed on the packaging tape he was using to secure the boards. A bit of serendipity came into play and [David] discovered packaging tape is usable in the toner transfer process.
The technique is simple enough: put some packaging tape on a piece of paper, print a board layout (reversed!) on a laser printer, and go through the usual clothes iron/laminator/etching process. [David] is actually using a hair straightener for transferring the toner over to the copper clad board – interesting, and in a pinch you can use the same tool for reflowing SMD components.
[Dan Comeau] is a modern-day Renaissance DIY Jedi — or so he says… He loves re-purposing things and hacking in general. But one of his favorite pastimes is producing custom hand-made knives. He etches his logo on each, using a professional etching machine, but when a fan asked how to do it themselves, he came up with this simple and easy way to etch metal at home with a few things you probably already have!
It’s actually incredibly simple. Just by cracking open a DC power supply (a wall wart will do just fine), you can easily make your own etching/marking device with a few modifications. Ideally you want something in the range of 5-12VDC at 1A or more. Continue reading “Etching Steel With a DC Wall Wart”
Many hobbyists and hackerspaces have the $500 Chinese 40W lasercutters which most of us know are about as successful at etching metals as a featherduster is at drilling. [Frankie] and [Bryan] have figured out a way to use the laser to chemically activate an etching process. See experiment part 2 as well.
First, to be clear, they are using a quality 40W Epilog Zing, not the cheap one, but40W is40W. They mixed the plaster (calcium sulfate) with Isopropyl until it resembled white ketchup. After either thinly painting or airbrushing the material onto the stainless surface (both worked), the mixture is dried with a heatgun then put into the laser. 100% power and 5% speed was what worked for them.
The result was an engrave with a noticeable bite. Something they claim had no effect at all without the mixture.
Stainless steel is an alloy of iron and some chromium – not the same as chrome-plated steel. [Frankie]’s explanation of the chemistry is that the surface layer of the stainless is a transparent chromium oxide. With the heat of the laser, the calcium and chromium swap dance partners. Calcium takes the oxygen and chromium takes the sulfate. The calcium oxide washes off but the chromium sulfate causes the etch.
Next time you’re at your local space, give this a try.
The last few years have seen great strides in budget printed circuit board manufacturing. These days you can have boards made in a week for only a few dollars a square inch. Flexible PCBs still tend to be rather expensive though. [Mikey77] is changing that by making flex circuits at home with his 3D printer. [Mikey77] utilized one of the properties of Ninjaflex Thermoplastic Elastomer (TPE) filament – it sticks to bare copper!
The TPE filament acts as an etch resist, similar to methods using laser printer toner. For a substrate, [Mikey77] lists 3 options:
.004″ thick “Scissor cut” copper clad board from Electronics Goldmine
.002″ thick pure copper polyester taffeta fabric from lessEMF.com
<.001″ Pyralux material from Adafruit, which is one of the materials used to make professional flex PCBs.
A bit of spray adhesive will hold the Flex PCB down on the printer’s bed. The only issue is convincing the printer to print a few thousandths of an inch higher than the actual bed level. Rather than change the home position on his Z axis, [Mikey77] used AutoDesk 123D to create 3D PCB designs. Each of his .stl files has a “spacer bar”, which sits at the bed level. The actual tracks to be printed are in the air a few thousandths of an inch above the bed – exactly the thickness of the substrate material. The printer prints the spacer bar on the bed, then raises its Z height and prints on the flexible PCB material. We’re sure that forcing the printer to print in mid-air like this would cause some printer software to throw errors, but the system worked for [Mikey77] and his Makerbot.
Once the designs have been printed, the boards are etched with standard etching solutions such as ferric chloride. Be careful though – these thin substrates can etch much faster than regular PCB.
[Frank Zhao] wanted to try his hand at making a transparent circuit board. His plan was to etch the paths with a laser cutter and fill in the troughs with conductive ink. The grooves are ~0.1mm deep x ~0.8mm wide.
He used nickel ink, which is slightly cheaper than silver ink. The ink was among the least of his problems, though. At a measured resistance of several hundred ohms per inch, it was already a deal breaker since his circuit can’t function with a voltage drop above 0.3V. To make matters worse, the valleys are rough due to the motion of the laser cutter and don’t play well with the push-to-dispense nature of the pen’s tip. This caused some overflow that he couldn’t deal with elegantly since the ink also happens to melt acrylic.
[Frank] is going to have another go at it with copper foil and wider tracks. Do you think he would have fared better with silver ink and a different delivery method, like a transfer pipette? How about deeper grooves?
Fail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.
Making a few PCBs with the toner transfer method is a well-known technique in the hacker and maker circles. Double-sided PCBs are a little rarer, but still use the same process as their single-sided cousins. [Necromancer] is taking things up a notch and doing something we’ve never seen before – double-sided PCBs made at home, with color silkscreens, all make with a laser printer.
For laying down an etch mask, [Necro] is using a Samsung ML-2167 laser printer and the usual toner transfer process; print out the board art and laminate it to some copper board.
The soldermasks use a similar process that’s head-slappingly similar and produces great results: once the board is etched, he prints out the solder mask layer of his board, laminates it, and peels off the paper. It’s so simple the only thing we’re left wondering is why no one thought of it before.
Apart from the potential alignment issues for multiple layers, the only thing missing from this fabrication technique is the ability to do plated through holes. Still, with a laser printer, a laminator, and a little bit of ferric or copper chloride you too can make some very nice boards at home.
[Morag Hickman] is an artist who makes use of ferric chloride for something other than etching a PCB. She uses the process to etch beautiful designs into her jewelry.
[Tortoise Butler] is a small film crew that created this three and a half minute film on the art of etching copper, and it is an absolute pleasure to watch. There are no computers, no toner transfers, and she doesn’t even etch on a flat surface. It’s an excellent example of doing something different — why not add etching to finish off a project? If you’ve already done PCBs, it can’t be that hard to do a logo instead!
Anyway, it’s been a while since we’ve shared a handmade hack, and we think this is a great example that deserves the spotlight. Don’t forget to send in your own handmade projects to the tips line!
Stick around after the break to enjoy the film — we recommend watching it full screen and in HD.
Continue reading “Copper Etching: Not just for PCBs”