[Rich Olson] wrote in to share his technique for making dual-sided printed circuit boards using a laser cutter. Unfortunately this still depends on etching copper clad boards with chemicals. But his process makes it really easy to produce well-defined and precisely aligned etch resist on both sides of the board all at once.
This can be really tough to do with the toner transfer method. The most common way would be to use a light box to align the two printouts of resist, taping them together before putting the copper clad in between and sending the whole thing though a laminator. [Rich] uses a scrap of acrylic to ensure alignment. He tapes it to the bed of his Epilog laser cutter and cuts the board outline out (that’s the void you see in the image). He removes the scrap and uses it as a stencil for cutting out the copper clad. After prepping the board he coats both sides and sends it through the laser cutter to burn away the paint where he wants to remove copper. Don’t miss his video embedded after the break.
The acrylic outline trick is similar to the laser cutter fence we heard about several weeks back.