Printing Wax onto PCB – Simple, Quick DIY PCB’s

I stumbled across this YouTube video at dorkbotpdx.org.

The video is presented by Jeffrey Gough of  Warranty Void If Removed. He is working to make DIY Printed Circuit Boards (PCB’s) much quicker and easier. He is aiming to reduce the PCB manufacturing process to two steps: print, etch. His ink-jet-based printing mechanism will directly print wax onto the PCB material to resist chemical etching.

The video talks about many different methods of making DIY PCB’s (maybe the first 30 minutes). Most ‘normal’ methods use printed circuit board material which is fibreglass boards covered in copper. A circuit is formed by removing the unwanted copper using a chemical etching process. The mass-production methods use photographic technology to apply an image differentiating the circuit and unwanted copper  using a technology which protects the required copper from the etching chemicals (it is actually many steps, as the industrial process is more complex than the one used by DIY PCB techniques). DIY PCB makers often use a photographic process which leaves a protective chemical ‘film’ over the required copper. This requires several steps before getting to a stage where the copper clad fibreglass can be etched into a PCB.

The approach proposed on the video is very different. Jeffrey Gough prints wax straight onto the board, and the wax resists the etching process. So there is no need to make intermediate ‘tools’ to create the photographic image, and no need for intermediate ‘manufacturing’ processes.

His approach is to modifying a low-cost (€40) Epson ink jet printer so that it can print wax straight onto blank PCB material. He did a lot of reverse engineering to build a piece of electronics which could take over driving Epson’s print head. It appears to be able to print tracks as fine as 0.1mm, which is better than most commercial PCB manufacturing process (that I can afford :-)

The print head is heavily modified to keep the wax liquid while being printed. When liquid wax is ‘fired’ from the print head nozzle, in the same way as ink is ejected, it solidifies (freezes) on contact with the PCB copper, forming a wax covering which protects the copper from the etching chemicals.

The development is far from complete, but it shows real promise. It might revolutionise PCB production for professional design engineers, and not just DIY makers. If it were robust enough, every school and colleague that does any electronics would use it. For me, making one-off, prototype PCB’s is the slowest, and often most costly part of exploring an idea. This would remove that obstacle. By using Surface Mount Technology and Devices (SMT/SMD), I could make a PCB in well under an hour using this process. I’d use surface mount technology to minimise the drudgery of drilling hoes in the PCB. I’d solder the whole board in my trusty mini-oven using solder paste.

One slightly frustrating part is Epson could probably bring this to a production prototype stage in a few months with a few people.  If anyone at Epson is reading this, there may be a real market for such a printer, and Epson are one of the few printer manufacturers who use piezoelectric print heads, so the market may have very little competition while the products are developed, sold and improved.

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