[Rhys Goodwin] has been working on a system to print resist onto copper clad using an inkjet printer. This is a toner transfer alternative as it still uses toner, just not quite as you’d expect. The first step is to modify an inkjet printer, separating the carriage from the feed rollers in order to increase the clearance for the substrate. Instead of printing with etch resistant ink, as we’ve seen before, [Rhys] prints with black ink and then covers the board (ink still wet) in laser toner. Once there’s good adhesion he blows off the excess and bakes the board in a sandwich press, with spacers to keep the iron from touching the surface of the copper clad. This cooks the resist into a hard plastic layer and the board is ready for the acid. Watch him walk you through the process after the break.
[Rhys] uses the same method for silk screen, printing in red and baking the ink onto the substrate without added toner. This produces a nice looking board but it’s still quite a bit of work. It certainly sheds more light on the process than that laser-printer method from back in May. We hope you’ve been inspired by this and come up with the next innovation that makes this process easier.
Continue reading “Direct to PCB inkjet printing”
[James] has been refining a method of negatively etching metal with a laser. He had been using a product called Thermark which is designed for this process, but it’s quite expensive. He found that paint designed for wood stoves works just as well. To prepare the surface he bead blasted it and then cleaned of the residue and finger prints off with acetone. The board was preheated in an oven before covering it with the spray paint. He ran the laser at 98/100 power and 90/400 speed at a step size of 0.1mm to achieve the results above. This should immediately make you think about making circuit boards. We’d love to ditch the toner transfer and we’re always looking for one more reason to get a laser cutter.
Who would have thought that some corn starch could be made into toner transfer paper? We’re not sure of the advantages (perhaps its cheaper?), but if you have a lot of time or just love to get sticky [Matthew Sager] shows the proper method for making the paper, printing, and then etching a PCB.
If you’re just getting started making PCBs, we recommend you check out these DIY circuit etching videos to get a better grasp on the printing and etching steps.
[Tanjent] send us a link to his tutorial on the toner transfer process for fabricating circuit boards. We’ve seen a lot of these in the past, but we liked how his is straight to the point while also sharing several tips and options along the way. Notably, he ”tints” the copper clad before trying to adhere the toner to it by swabbing on a bit of etchant. His reasoning for this is that the toner has more trouble sticking to the shiny copper. Just a bit of etchant will pit the surface and let the toner stick better.
He’s still using paper as a medium and not printing toner powder directly to the copper clad. His paper of choice is HP Brochure Paper while we use glossy pages from the union newspaper. But like us, he does use copper chloride as an etchant, which you can learn to make yourself. We’re still looking for a definitive solution for disposing of this chemical. We’ve been using the same batch for years and recently it’s turned cloudy with impurities. If you’ve got disposal tips let’s hear them in the comments section.
Tired of every printed circuit board you etch coming out brown? Take a page out of [Dane’s] book and dye your PCB to just about any color you want. One hour submerged in a 200 degree bath of Rit dye turned his brown FR4 substrate to the desired dark green. We give him points for being dangerous enough to use a broken bottle as a vessel, yet wearing eye protection at the same time.
We never really thought of doing this, but it’s pretty interesting that it works. We’ve stained the substrate when removing etch resist so this should have been obvious, but wasn’t.
[Bart] built a giant laser etcher from scratch. One of his first test engravings included the Hackaday skull-and-wrenches on a polished granite floor tile (we love it when people do that). He used an XMOS controller and Mach3 CNC software to handle the device. With just two axes to worry about this seem like an easy project. The difficult bit is controlling, cooling, and focusing the laser. Oh, and if you screw up, you could be blinded, burned or horribly maimed. But if you start from the beginning you’ll see that [Bart] knows what he’s doing.
[Jonathan Ward’s] pcb mill is as impressive as it is inexpensive. Twenty-six plywood parts, labeled A-Z, are used to assemble the machine along with the customary precision rods, stepper motors, and router assembly. His bill of materials prices the unit at $458.18, a small price to pay in order to forgo a multi-step etching process.
His test board shows some fairly fine pitch that could turn out most home-project circuit boards. We’ve contacted [Jonathan] regarding the specifics of milling the plywood parts out of a 2 foot by 4 foot sheet of plywood. Watch for an update with any information he’s willing to share. We hope he’ll make the milling files for the plywood parts available so that you can build a copy of the device for your own use.