Laser diode burn/engrave! Help

Hi everybody!

This is my first post here.

For start I wanna to apologize for my english! I'm not a native, but I'll try to explain in minimum details what I want.

I even know for where I begin... :undecided:

Well, I've read a lot of stuff on internet and here on the forum...but it seems as more I read more I get confused.

So, I'll say what I need.

I'm looking for a laser diode that could burn/write/engrave a PCI surface! Just the surface, and isn't made of copper! It's like this on the picture:
PrintedCircuitBoardImagem


I guess the surface of this kind of board is made by varnish ink, so that laser have to be powerful enough to burn the "skin" the board.

My goal is not to draw a circuit on the board! Is just write words and numbers on it.

I hope you have understood!

I read around, that the low wavelength is better for making/burn in non black materials, then the wavelenght have to be lower for my purpose, right?

I would like that you guys could indicate the best diode laser, lens and drivers, In order to I possibly can do what I want

I'm sorry for ask all for you, but I'm a tired to looking for and don't find what I need even more because I'm in a hurry! :cryyy:

Thanks in advance for who help me!:thanks:

It's called solder mask. Any reason why a pen or marker won't work?

No, is a normal PCI, but I'll use the laser in my mini CNC to write/engrave bar code and serial numbers.

Will a balloon filled with propane and popped with a high power laser ignite the propane a make any significant noise or light show as the gas burns?

tysonlee said:

Will a balloon filled with propane and popped with a high power laser ignite the propane a make any significant noise or light show as the gas burns?

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I guess this has nothing to do to my topic, am I right?

Guys, I know what I asked is difficult to answer, but could someone help me? I'm still waiting a answer! Thanks

I'm still waiting for an answer, too. Any reason why a pen or marker won't work?

Cyparagon said:

I'm still waiting for an answer, too. Any reason why a pen or marker won't work?

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I'm sorry Cyparagon... I thought I answered this question here:

luuizc said:

No, is a normal PCI, but I'll use the laser in my mini CNC to write/engrave bar code and serial numbers.

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My goal for this project is use laser to write on the PCI, but didn't have any reason to a pen or marker doesn't work.

The laser will write serial numbers. Imagine if I use pen or a marker to do this, someone could use a specific liquid to erase the numbers!

Ran some tests for you, using three lasers:
-445nm, 1.1W: burns very quickly on both sides, board and components get very hot and also erodes the board material itself. Hard to draw anything with precision (but I'm not a machine).
-650nm, 200mW: doesn't burn the unvarnished front at all, burns the varnish away relatively quickly with minimum collateral damage.
-405nm, 200mW: burns both sides but takes a lot of time to burn the varnish.

Assuming you just want to burn away the varnish and that your varnish has the same absortion spectrum (which may or may not be true) I'd suggest you to use a 650nm 200mW laser. It's strong enough to leave marks and weak enough not to destroy the board. I used the DX "dilda" and it would be easy to install just the driver/module/lens assembly on the CNC head. Remember to keep the distance stable or you'll have to add some sort of focusing mechanism.

BTW it smells bad and the fumes are probably toxic. Doing it once in a while might be fine but for mass production you'll have to take care.

Atomicrox said:

Ran some tests for you, using three lasers:
-445nm, 1.1W: burns very quickly on both sides, board and components get very hot and also erodes the board material itself. Hard to draw anything with precision (but I'm not a machine).
-650nm, 200mW: doesn't burn the unvarnished front at all, burns the varnish away relatively quickly with minimum collateral damage.
-405nm, 200mW: burns both sides but takes a lot of time to burn the varnish.

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Hi Atomicrox!

That was exactaly what I needed!

I was thinking about to attach a optic fiber on the diode to increase the precision. What you think?

Can you sell me those laser? 650nm and 445nm? If yes, for how much?

You're welcome

I don't think using fiber is a good idea, the power loss will be too high and the 1.1W laser will most likely melt it. In any case you can get a pretty good precision (<1mm) with the 650nm laser as long as you keep the distance fixed, which shouldn't be too difficult with a machine.
What are you gonna use as CNC? Arduino + steppers or an off-the-shelf solution?

I'm not very keen on selling them but I'll send you a PM.

Yes, the laser will be fixed on the Z axis. Will be great if I get a <1 mm precision.

Which distance you think the laser has to keep from the board?

Actually I'm using a 18F4550 PIC to control the stepper motors! It's more difficult I know, but this is a project to my college and I'm studying this PIC.

I'm developing interface in C# that will send the signals through the usb to pic and this pic will command the drivers of the motors! Is basically this.

I'm waiting your contact.

About 5-10cm seems good to me but it's not very crucial as long as the Z distance is fixed. Don't focus too close because it will be easier to defocus.

Cool, good luck with your project! Some other members here have made their own CNCs, you might want to search for the posts and avoid some of the common mistakes

Where do you study?

I love to program in C# as well. Are you using a serial-to-usb converter?

Don't forget to post some videos of your progress here

Check your PM's.

I would say a high power 405 diode 500mW-700mW would give you the best results as it has the greatest power density. Check this out.:beer:
Laser 530: April 2011

Atomicrox said:

Where do you study?

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I study computer engineering at the university santa Cecilia at Santos-SP

Atomicrox said:

I love to program in C# as well. Are you using a serial-to-usb converter?

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No, the PIC184550 has a USB interface inside, then you can use the PIC to receive and send signals through the USB!

DTR said:

I would say a high power 405 diode 500mW-700mW would give you the best results as it has the greatest power density. Check this out.:beer:
Laser 530: April 2011

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Thanks! It's yours that blog? Very interesting !

So, I saw that you sells the 12X S06J and others itens! How much would cost to me a full laser assembled with the diode, lens, drivers and other? Send me a PM!

luuizc said:

Thanks! It's yours that blog? Very interesting !

So, I saw that you sells the 12X S06J and others items! How much would cost to me a full laser assembled with the diode, lens, drivers and other? Send me a PM!

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The blog was from a customer of mine. Anyway I have the full dropin diode/driver/lens/ combo modules. All you would need to do it put it in a 12mm drilled heastink which is pretty standard and apply 3-5V from a 1A+ capable power source. See the last two options on this page. That is complete as you can get them from me.:beer:
https://sites.google.com/site/dtrlpf/home/diodes/s06j-12x-405-diodes