I’ve been meaning to try the laser paint PCB thing.

?

I’ve done similar which is to etch the metal by burning the paint with high power, like these: , , .? Used a bit too much power on the dog tag (thin stainless steel).

?

You can actually buy lasers that will etch copper and make a PCB, they’re a bit pricey though.

?

I have seen people burn off the paint, etch the board, then put it back into the laser to burn the holes.? The holes were a bit ugly.? Go surface mount and that problem goes away.

?

The fumes aren’t really a problem, lasers tend to have exhaust systems.

?

Various people have done what you’re proposing.? You design the machine with a replaceable head so you can make it a 3D printer, laser, drill, router, paste dispense etc.? I don’t think any of them have been all that successful.

?

You’re limited to maybe a 5W laser diode which is fine for burning paint.? Those things I linked to were done on a 50W laser which uses mirrors to bounce the beam around, feasible with a replaceable head but you’d probably need to adjust the alignment every time (plus a housing would be a good idea.)

?

I’ve seen the needle idea proposed as well, coat the board with something like wax and scratch it off.

?

Tony

?

?

?

Let us know when you try it.? I’m very interested in the idea.? Can you measure the laser line width when you try it?

Jeff

?

It’s been on the to-do list for a while.

?

The ‘kerf’ of a CO2 laser is about 0.15mm, say 6 thou when cutting stuff, so I guess that’s a reasonable guess for paint on copper.? The actual spot size of the laser is about 0.1mm.

?

Found this: which has a couple of nice pictures, he was using a 2W IR laser diode for that.? Mentions the line is 0.15mm wide as well.? No mention of time though, not that it matters much.? A lot of people raster when lasering the paint off, not sure why when isolation works and is faster.

?

A suggestion I’ve heard is to put the board back in the laser and remove the paint off the pads so the remaining paint becomes your solder mask.? I guess that’d work.

?

Tony

?

?

Not sure if you’ve entirely missed the point.

?

You burn off the paint exposing the copper, then you drop it into the etchant.? The remaining paint (on the tracks) acts as your mask.

?

Yeah you’ll get reflections like you will off any other metals (aluminium scatters IR quite well I’ve found), but keep your face out of the way and it’ll be right.

?

When YAG lasers are hobbyist-affordable, I’ll buy one and ‘do it properly’.

?

Tony

?

?

This is the sort of thing he’s describing:

?

Sticking a laser diode onto a 3D printer works because they’re both lightweight machines that need to move relatively fast, while a router moves slower but needs a stronger frame.

?

So you end up somewhere between an under-built router and an over-built printer that’s really really expensive.

?

For the price of just that ZMorph laser head you can buy one of those 40W Chinese lasers off eBay.? A bit rubbish, but hey, laser!

?

3D printers are moving towards that changeable tool head model because that’s one way of being able to automatically change out colours or material types, and it’s not too hard to make one of the heads a laser or basic drill or whatever.? Then resin will become cheap and we’ll all switch to that.

?

People put 3D print heads onto milling machines, it works but mills are usually too slow.? Plus do you really want your milling machine running a 30 hour job?

?

Tony

?

?

Glass tube??

?

What resonator?

?

With flying mirrors?

?

Ain’t gunna happen.

?

We’re not cutting either, so the beam is going to get reflected back all the time.

?

Still ain’t gunna happen.

?

It’s more likely to happen with a laser diode.

?

Tony

?

?

We’re not dealing with thousands of watts like the ‘experts’ who always chime in think we are, you don’t need much power to burn off paint.? Like the earlier link said he only used 2 watts.

?

The beam will scatter somewhat (it’s painted copper after all), plus defocus going through the lens, and it’s a long back to the tube through the mirrors.? It’s not going to have much power left after that.

?

For the equipment we’re using it’s a non-issue.? I’m sure someone has a friend of friend who heard about it…

?

It obviously works, I really should try it.

?

Tony

?

?

?