Laser etching PCB, directly removing copper and drilling

[1089]

Hi,

I know etching Pcbs with lasers have been discussed before, but I have some questions that were not answered.

Can you etch off the copper from a PCB with a laser?
I have read that cutting/engraving/etching copper requires more power; how much more?

Is fibreglass safe to use in a laser cutter?
Could you easily 'drill' through the fibreglass? Vias/holes etc.?
Would it mess with the filter?

I know the previous topic on pcb etching discussed using spraypaint as a substitute for a layer that resists the copper etchant, but it still requires chemicals for the final product.
I would prefer a method that does away with chemicals and does not cost a fortune like commercial pcb manufacturing does.
Milling is always an option, but finding a machine with easy access remains a challenge.

My girlfriend's dad has a company making the Chocolate Graphics chocolates and they use a laser to engrave the perspex panels used to make the chocolates.
He said we could test if it works on a pcb, butI thought I'd ask for info here first.

So, what are your thoughts?

[mikeselectricstuff]

You need a different kind of laser to etch copper - I think they use a q-switched YAG in products like this. Seriously expensive - well into 5 figures

[250 Coupe]

As Mike says, a CO2 laser won't touch metal until you are into ridiculous power levels. At 70 watts, I can't even leave a mark unless there is some kind of coating that will react to the laser. When we tried to make some boards, we gave up with the laser and used the toner transfer method, it took 2 or 3 tries to dial it in but after that it worked great every time.

I don't think my laser will cut the FRP either, it will probably just make nasty smoke and an ugly line.

Your question reminded me of laserbits.com's new(?) product called LiquaMASK. It wouldn't take much power at all to cut it and it might be resistant to the chemicals used to etch. Of course, you do still need etchant which I do know you are trying to avoid.

It's ugly as sin but you can outline the traces with a very small ball in a Dremel and the heat the traces you want removed. If you get the copper hot enough, it will peel right off.

Michael

[1089]

Thanks for the reply guys.

It seems the only option I have is chemicals...
I'd love to do the Dremel idea, and I might, if I'm in a real hurry, but I'm too much of a neatness freak to use it all the time.

The other reason I'm looking for an alternative is that transfer paper is virtually impossible to find in the Western Cape (Province in South Africa) no electronics shop stocks it!
I would prefer that over laser printer since I have a high DPI inkjet.

The easiest solution seems to be the spraypaint, will try it when I get home.
Ordering PCBs are not an option on my budget since the average price is R450 ($70) each!

It sucks that pcbs are so expensive in an era with so many people tinkering around and making things. The internet gives anyone the information, you do not have to be an engineer anymore to know how to build an awesome circuit.

So, compromise...

my two cents...

[westfw]

transfer paper is virtually impossible to find in the Western Cape

There are a lot of alternatives to "transfer paper." Glossy photo paper, clay-coated magazine paper, label backing paper, transparency film...

Ordering PCBs are not an option on my budget since the average price is R450 ($70) each!

Can you not smuggleXXX/ import from china (Seeedstudio, itead, etc) like everyone else?

[1089]

Double post... Sorry

[1089]

Tripple post... Internet lagged... Sorry again.

[1089]

Honestly, I did not know there were so many methods, and since I tried to find a way without chemicals - I live in an apartment and the governing body prohibits chemicals in the drains - I might have skipped a few.

Can you not smuggleXXX/ import from china (Seeedstudio, itead, etc) like everyone else?

I'd love to, but our postal service is of such a nature that you literally wait six weeks for your order. By the time I get it, I have almost forgotten that I placed the order.
I have done it a couple of times, from various countries, mailing options and companies, six weeks minimum.
After the six weeks I get this tiny scrap of paper in my mailbox claiming I have to go to the post office and pay taxes, even though the delivery I paid for included a courier to my house.
I then have to go stand in a loooong queue at the PO, pay 14%/20% taxes and then I get my long awaited order...
All in all it sucks. I know for a fact that it is our post office that is the bottleneck, since I recenlty ordered a DSO Quad from Seeedstudio via DHL and recieved it in a mere 5 days, it cost me $65 for shipping, but it was worth not waiting so long.

So to the manual method! Will have to go do it at my parents'...

[250 Coupe]

There are many ways to create a resist mask.

I've used a Sharpie pen, and a kit from CG that had a few rubber stamps and an ink pad. There were the dry transfer rub-on traces and components from Radio Shack. I've also used the silk screen process, hand cutting the mask on a pre-treated screen. Then there was the pre-treated photo resist PCB stock. Just print onto a overhead projector film and leave it in the sun for a few hours. The roll of photo resist meant to be applied by the end user didn't work that well for me.

You could use the laser to cut a mask from thin Mylar or something not containing vinyl, tape it to the PCB and hand paint the traces with fingernail polish. You'd have to leave some bits uncut on the mask so it will stay together so there will be a few areas to do by hand but it will give you a good looking board.

You can cover the entire board with a polyester tape, trace your layout onto it and cut it with a #16 X-acto blade.

The toner transfer method doesn't require special paper, the advert inserts in your newspaper or pages from certain magazines work very well.

Google variations on "PCB etchant" to see if there are less dangerous alternatives to the usual chemicals. Some will require constant agitation, others may need to be heated. You may be able to treat some in house to render them safe. Around here there is a hazardous waste drop off program that will take used etchant along with many other nasty chemicals.

Hoping my rambling helps,
Michael

[250 Coupe]

Another thought has occurred to me...

I have a New banned pantograph rotary engraver, the old school kind that uses brass letter templates to engrave award plaques. It would be really easy to print out a PCB pattern and follow it with the stylus while using a cutter set to a few thousandths to cut through the copper.

Michael

[westfw]

It would be really easy to print out a PCB pattern and follow it with the stylus while using a cutter set to a few thousandths to cut through the copper.

no it wouldn't...

[Alphatronique]

HI

what about use laser for remove floor wax or paint coated PCB
then use etch for dissolve exposed copper ?

i alway wanted to try it on sensibbilised pcb whit my uv laser fitted on my lpkf machine
but never got time to try it and uv was really nasty on my vision
and that was not faster that use lpkf alone ;-(

Best regard

[lee321987]

If you want to avoid pouring chemicals down the drain, here is a link to a process that almost never requires chemical disposal:
http://www.instructables.com/id/Stop-us ... etter-etc/

The chemicals involved are hydrochloric acid (muriatic acid), and hydrogen peroxide, which I got from the hardware store, and drug store.

Guess I should post this quote from that Instructables' comments:

0xCyrusx0 says:
I'm surprised nobody has mentioned this, considering the intro picture contains hydrogen peroxide, acetone and hydrochloric acid.

Careful not to mix all 3, unless you're attempting to make unstable high explosives (Acetone peroxide http://en.wikipedia.org/wiki/Acetone_peroxide).

It's dangerous enough when you're attempting to make it, I wouldn't want anyone to accidentally make some and dry out the crystals, or store it in a container with a screw on top (The crystals will sublime, and recrystalize in the threads on the container. Unscrewing it will break the crystals and detonate. One person on internet forums has died this way).

Besides that, I'll be using this method from now on. I already have the peroxide and acid and acetone from...other projects *Wink*

[Casper Geng]

But can you tell me the details of you laser cutting amchine?