We’re kind of surprised we haven’t covered this concept before since it only uses techniques that are commonly avaialable for home PCB fabrication. [Ray] made this solder paste stencil out of a sheet of copper using the same etching techniques you would for a circuit board. He designed and printed a resist pattern, with toner everywhere except the places where there should be holes in the stencil. He transferred the toner to the copper using an iron.
The difference here should be obvious; this a thin copper sheet with no substrate. Because of that, you must protect the copper surface before etching. he covered the entire thing, both sides, in packing tape. After that it’s into the Cupric Chloride bath to dissolve the exposed parts. Once the tape and toner has been removed you can scree a precise amount of solder paste onto your boards.
This isn’t for everyone, but if you’re assembling many boards it’s not a bad approach. If the stencil is no longer used it can be recycled, but we do wonder how corrosion on the copper will affect the stencil’s performance.
The idea for this technique came to [Ray] from a guide that’s been around for years.
When [Adr1an] wrote in to share a link to his PCB etching tutorial he mentioned that he knew we had already covered a ton of these guides. He’s absolutely right, not only have we featured a great number of them, but we also wrote our own quite a while ago. But that doesn’t mean we ignore them when they come in on the tips line. In fact, we read all of them that have something to offer and are pleased to feature the ones that are well presented… like this one!
[Adr1an] went all out with his writeup. He not only covers all of the elements that go into this, but discusses where to purchase them and his thoughts on how he arrived at the choice. He’s using the toner transfer method and prefers Brother branded toner for its coverage and resistance to over-etching. He prints on HP Everday Photopaper, then uses a laminator to transfer to the copper clad board. For this guide he used 2oz copper but prefers 1oz copper as it etches faster. His etchant of choice is Ferric Chloride, which can be ordered as a dry powder. He uses the direct etch method of loading etchant into a sponge an applying that to the board.
The board he makes in the guide looks great, and it only took him 28 minutes!
Although not a hack in itself, many of you may be interested in seeing how a printed circuit board is made in the manufacturing world. This tour of Advanced Circuits does a good job of explaining the process. The article explains how a PCB will go through a CAD/CAM review, drilling, deburring, and the various chemical etch, plating, and curing processes.
Although many hackers make their own PCBs, having it professionally done can be a good option depending on how many copies are needed. One benefit of this is that PCBs can be checked by an optical inspection process, or even by a “flying lead” machine which works by contacting leads automatically in a computer controlled setup.
A video of this incredible machine is included after the break. Around 0:26 is when it really starts to get going. Continue reading “Tour of Advanced Circuits – A PCB Manufacturer”
Printing PCBs using the toner transfer method works pretty well, but there are some downsides, such as incomplete trace transfers and the like. HackHut user [rucalgary] decided to go the inkjet route instead, and picked up an Epson printer on clearance at his local electronics shop. This method is not new by any means, but his printer conversion is one of the simplest we’ve seen as it does not rely on any additional sensors to function.
Once he got home, he tore the printer down immediately, removing the paper input and output trays as well as the scanner bed. After all of the extraneous parts were removed, he got to work raising up the printer head, as well as the printer head rest mechanism. He mentions that the latter component is absolutely crucial to proper functionality down the line. Once the print head and its associated components were relocated, he added a pair of aluminum rails for feeding his print tray into the machine.
With everything complete, he filled up a spare cartridge with ink (he says that MISPRO yellow works best) and ran some test boards through. He is quite pleased with how things turned out, and is more than happy to give you a quick tour of his completed printer via the video below.
Continue reading “Direct to PCB resist printing requires minimal additional components”
[James] came up with a way to make small numbers of high-contrast instrument panels cheaply, and without too much labor. We’ll make with the bad news right away; you’re going to need a laser cutter to use this method. Traditionally, panels that look like the one above are etched onto special composite that has one color at the surface and a contrasting color beneath. [James] started with plain old acrylic, etched his labels, then filled the voids with black wax crayon. Just scribble all over the etched face to rub wax into the grooves, go through a couple of cleaning steps using white spirit, then bake the panel to even out and harden the wax layer. He’s got several examples of his work, including medallions that are used to label LED indicators.
What if there were only two steps for making your own printed circuit board; print, etch? That’s what [Jeff Gough] has been working on and he presented the process in his talk at 27C3. In the first portion of the video after the break [Jeff] talks about various industrial PCB manufacturing processes in a depth you may not have heard before. We found it to be interesting but at about thirty minutes into the clip he begins the presentation of his modified printer. It’s an inkjet that can print wax onto copper clad board. The wax acts as a resist for chemical etchants, and provides very high resolution. He’s using a heavily modified print head, which brings to mind that diy piezo inkjet head which also has wax printing in its future plans. This certainly seems promising and if the process can be simplified it might do away with the toner transfer method.
Continue reading “Printable wax as PCB etch resist”
What do you get when you mix a simple X/Y plotter, a Flyback transformer, and an unhealthy disregard for safety? Possibly the worlds most dangerous jumbo Etch a Sketch! [Kalboon] started off by making an imprecise X/Y movement device, similar to a CNC machine setup, but with less emphasis on precision. This rig is powered by some commonly salvagable materials, including an old scanner, a remote control car, and some hobby servos. We like this approach because most of these materials could be scrounged from a parts bin, surplus sale, or craigslist for little to no actual cost. The flyback transformer comes from an old TV or monitor, though if you have
common sense safety concerns, we would recommend just mounting a dry erase marker and a dry erase board to substitute out the high voltage bits. For people wanting a low cost introduction project to making a CNC or Makerbot style build, this isn’t a bad place to start.