Hackaday Prize Entry: PCBs On Demand with Etchr

The ambitious etchr – the PCB Printer is just a concept at the moment, but it’s not often we see someone trying to tackle desktop PCB production in a new way. Creator [Jonathan Beri] is keenly aware that when it comes to creating electronics, the bottleneck for most workflows is the PCB itself. Services like OSH Park make professionally fabricated PCBs accessible at a low cost, but part of the bargain is that turnaround times are often measured in weeks.

[Jonathan]’s concept for etchr is a small system that automates not only etching a copper-clad board with all the attendant flooding and draining of chemicals, but applying a solder mask and silkscreen layer labeling as well. The only thing left to do would be to drill any required holes.

The idea behind etchr is to first take a copper-clad board with photoresistive film or spray applied to it, and fix it into a frame. A UV projector takes care of putting the traces pattern onto the board (and also handles a UV-curable solder mask in a later step) and the deep frame doubles as a receptacle for any chemical treatments such as the etching and cleaning. It’s an ambitious project, but the processes behind each step are well-understood and bringing them all together in a single machine is an intriguing approach.

Desktop production of PCBs can be done in a few ways, including etching via the toner transfer method (whose results our own Elliot Williams clearly explained how to take from good to great). An alternative is to mill the PCBs out directly, a job a tool like the Othermill is designed specifically to do. It’s interesting to see an approach that includes applying a solder mask.

Circuit Love With Multicolor Solder Masks

The cheapest PCBs – and therefore most common – are green solder mask with white silkscreen. It works, but it’s also incredibly boring. This is the way things were done up until a few years ago with the explosion of board houses trying to compete for your Yuan, and now getting a red, yellow, black, blue, green, and even OSH purple is possible. This doesn’t mean multiple solder masks aren’t possible, as [Saar] demonstrates with his demonstration of multicolor solder masks and circuit love.

We’ve seen a lot of [Saar]’s designs, including a mixing desk, a cordwood puzzle, and an engineer’s emergency business card, but so far his artistic pieces have been decidedly monochromatic. For this build, [Saar] teamed up with Eurocircuits to create a board that exploits their capabilities.

Althought Eurocircuits has PCB PIXture, a tool for putting graphics on PCBs, [Saar] made this with his own tool, PCBmodE.  The design of both the red and yellow variants are abstract, and only meant to be a demonstration of what can be done with multicolor solder mask. It looks great with five backlit LEDs, and with an acrylic top and bottom, makes a great coaster or art piece.

We like [Saar’s] work so much that we put his Cordwood puzzle in the Hackaday Store.

One-Off Kapton Solder Masks

soldermask

With the proliferation of desktop routers, and a number of easy methods to create PCBs at home, there’s no reason anyone should ever have to buy a pre-made breakout board ever again. The traditional techniques only give you a copper layer, however, and if you want a somewhat more durable PCB, you’ll have figure out some way to create a solder mask on your homebrew PCBs. [Chris] figured Kapton tape would make a reasonable soldermask, and documented the process of creating one with a laser cutter over on the Projects site.

The solder mask itself is cut from a piece of Kapton tape, something that should be found in any reasonably well-stocked tinkerer’s toolbox. The software for [Chris]’ laser cutter, a Universal Laser Systems model, already has a setting for mylar film that came in handy for the Kapton tape,

Of course, getting the correct shapes and dimensions for the laser to cut required a bit of fooling around in Eagle and Corel Draw. The area the laser should cut was taken from the tCream and tStop layers in Eagle with a 1 mil pullback from the edges of the pads. This was exported to an .EPS file, opened in Corel Draw, and turned into a line art drawing for the laser cutter.

The result is a fast and easy solder mask that should be very durable. While it’s probably not as durable as the UV curing paints used in real PCBs, Kapton will be more than sufficient for a few prototypes before spinning a real board.