Electronics > Manufacturing & Assembly

What's the fastest way to etch PCBs?

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I recently bought a 50watt JPT fiber laser. After learning all about it I finally came to the point that I was ready to laser engrave the mask for etching. I'm able to laser engrave both sides using alignment holes that I mill first. After the engraving I tried Ferric Chloride, but it takes way to damn long. I did sand the copper down before spray painting the clad. After 30 or so minutes a good amount of the copper was eaten away on one side but nothing on the other side. Some of the paint failed on the side with eaten away copper as well. What am I doing wrong here?

What temperature was the FCl?   Hotter is much faster.

Were you agitating the mix or leaving it sit?  For single sided boards you can get away with leaving it sit sometimes (but it doesn't always evenly etch).  For double-sided you definitely need to agitate.

It's been a while since I last etched a PCB, but I use hydrogen peroxide + an acid + salt instead of ferric chloride.

I was etching at room temperature. I would agitate every few minutes or so. Im doing double sided. Im about ready to ready again after burning through most of the copper. Curious to see whats left after the burn. im assuming some of the paint is missing.

Wow. OK. I heated up the ferric chloride and that worker much faster. I have to see what caused it to work much faster though. I chewed through a lot of copper with the laser.

Burning the copper with the laser likely leaves the surface oxidized/scorched and that will not etch well. Also, if the laser is actually melting the copper, then you are going to get metal deposits all over the place. Likely not what you want.

Seriously, if you want to make mask for PCBs, just laminate a sheet of dry resist on it and expose a transparency using a bank of UV leds (I have seen people try to use a low power laser for direct plotting on the resist but it is difficult to get right). Or do a toner transfer. Don't mess with a laser for this.

That 50W laser is much more useful for other things than this.

Finally, when etching boards yourself, make sure to not make the newbie mistake of not using copper pours - large areas of copper take ages to etch and use up a lot of your etching solution as well.


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