laser diode pcb maker, engrave metal

[sz3bbylA]

To be honest I don't have a clue about lasers, ... just what i read on internet some explanations ( escuse my bad english )
I found this site who sell laser diodes, kit, etc ...
https://sites.google.com/site/dtrlpf/contact-info
maybe are many sites but this was found for the moment

I need to buy a laser diode who can engrave metal, also I would like to burn solder-mask from PCB (is possible with diode laser ???)
I already got a 3d printer and I try to attache a laser diode
I don't know to chose the right components
All I understand is I need a laser around 15 W ... to engrave metal ?
On ebay are lasers for sell 15W but there not continuous , are pulsed which means they sell 5-6w laser with extrapowered in pulse ttl which cannot work continuous more than 20 minutes for 300 pound .... very bad deal
on the other hand i have an idea to cool the diode with water , i cannot explain because i don't figure out how bigger is that copper around diode and i rely don't know also if is possible until i don't have module in hands

another problem is which temperature can arrive a laser diode in continuous power ???
which lens is better for make a thin point (i think i need something like 0.05 mm to 0.1 max)
blue-ray light or blue-violet (I understand blue-violet are more efficient)

I accept any suggestions
thank you

 

[diachi]

You need a lot of power to direct etch metal with a laser diode. Probably outside of your budget.

The method I've looked into in the past is painting the blank PCB with black spray paint, then etching that off with the laser. From there you just do a regular chemical etch and clean off the paint.

I haven't tried it that way but it seems to be the way to go for budget setups.

 

[smallfreak]

To be honest I don't have a clue about lasers

I already got a 3d printer and I try to attache a laser diode

All I understand is I need a laser around 15 W ... to engrave metal ?

Ah, well. I see. No clue. Otherwise you certainly would ask different questions on this topic. There are several problems here.

Matal usually is quite reflective so 90+% of the light is simply reflected elsewhere. To engrave metal you will need a really strong Laser source and waste most of its energy.

If you really manage to mount a 15W Laser on your 3D printer you should make sure to house this entire assembly in a VERY tight case. With a 15W Laser even diffuse, reflected light can permanently blind you very quickly. So you should be quite certain that light stays within the box.

As far as I know there ist nothing like "a 15W contonuous diode". To achieve such powers, the diodes are bundled into bunches, surrounded with a big block of metal and cooling supply, like this one: https://www.ebay.at/itm/NICHIA-NUBM...048732?hash=item3d66e1561c:g:qQQAAOSwWxNYwmyB. That certainly imposes some extra work focusing this multiple beams into a single spot.

Engraving anything other than wood or plastic is done at least with such devices: https://www.ebay.com/itm/182747314213

No diodes, but CO2 Laser with an invisible IR beam which can supply the power in a single beam but are devilish dangerous, because you won't see any spilled light that may leak out and not even the beam or spot on the target. And yet it may blind you.

Getting that much power to a precisely moving "scanner" can only be done by fiber optics. Whatever Laser source you have, it will be to bulky to mount it on the moving head.

The above linked item is one of the "ultra cheap" engravers. This is the price range you will face if you reduce your wishes to a bare minimum, you buy a cheap Laser tube with bad beam quality and short life, simple optical system, slow stepper motors for jagged lines (instead of servo motors) and a bare minimum of safety - even if you decide to build that all on your own.

A "good one" is at least 10 times of that price - used.

If you want to get into the "building a Laser device" business, you definitely should start with something less powerful to get a feeling about this technology. If you want to get into Laser engraving business, you probably will be better off, if you buy a complete machine designed for the intended material and sell your work.

Please don't get me wrong. What you want to do is similar to cooking explosives at home. Just some milliliters of self brewn Nitroglycerine with kitchen stuff and a recipe. It CAN be done, but there is a good chance to make some bad mistakes if you have "no clue about chemistry" and even then.

Btw. If you want to get the most power onto your target, a pulsed Laser can provide that, as it flashes the entire energy of the beam into a fraction of a second onto the surface. You just have to repeat that several thousand times per second. But this gives you the chance you can get rid of the evaporated material between two shots that forms a puff, infering with the beam.

 

[paul1598419]

A CO2 laser would be a good choice for a CW laser to engrave metal. But, since the wavelength is in the far IR, 10.6 um, ZnSe and NaCl are transparent in this range and you eye's cornea and lens block all of the light, keeping it away from your retinas. I don't know of any fiber optics that will work at this wavelength, but you will get the biggest bang for your buck using a CO2 laser.

 

[sz3bbylA]

you guys have perfectly right.
thank you so much for information's.
And I appreciate your straight response

First one I don't want to spend extra money for my scope

Is normal for every one who don't have a clue about this staff to think like me.

My idea was to make pcb's like "diachi", after to cover it with soldermask , and arriving at pads, where components are soldered, to be burned by laser
I understand now is a very bad ideea (can be named crazy or insane).
normal anybody want more than this every time (engraving metal)



Maybe somebody can guide me to chose a laser to burn paint on pcb's , please.
with other words:
I like tools who work continuously (my printer can work a week without stop)
From all i read on internet are 2 models 405 nm and 445nm who i think are good for me
405 nm are no more than 1 watt , the spot is thin and strong but not enough power (blue-violet)
455nm are between 1w and 6w(bue-ray or blue-violet) spot biger than 405, power enough
2.5watt maibe 3watt ???
also is important to have some power to burn with around 50 mm/s to 100 mm/s
and also is important if i can have a spot length no more than 0.1 mm, ideal 0.05 mm

for soldermask I just write now from my imagination

It is possible or somebody tried already to mount a ultraviolet laser on machine ???, ... the same focused on 0.05mm for example and used like a printer to dry only necesay area on pcb's avoid pads ? (process is slowly , i can image)
or is any laser can dry epoxy or soldermask fast enough ? (blue violet maibe ... ????)
my experience is "0" and i try disparate to pass over that metod with soldermask and covered with a transparent foil printed, also i don't have cnc machine to clean pads.

I appreciate any idea from your experience

ps: I understand also is a paint who can be applied on metal and after burned by laser is the same like engraved (but i'm not sure if can be applied on plastic for example)


thank you so much

 

[smallfreak]

I dont't think your wish can be granted.

A 3W blue laser diode ist quite powerful. However the beam is pretty divergent in one axis ( i.e. a line or bar instead of a dot) and will not give you a perfect focus like a "single mode" (TEM00 mode = circular with gaussian profile) Laser. Multi-mode gives you more "power", but less quality. You can get lasers with good beam quality, but the "diodes" will have limited power.

To get power AND quality, you have to use other technology, like a solid (ruby, YAG) or gas (CO2, Argon, ..) Laser with a longer cavity.

And although 3W are a lot of power, you probably do not shoot a single hole into a copper plated surface with it. The copper just swallows and dissipates the heat. Maybe if the layer is really thin and you keept a good focus steady on one spot. Never would you achieve anything like 10cm/s plowing through the copper with a 3W diode. You may burn ornaments into wood that gets darker the more you heat it which helps keeping the heat within the material.

A 3W diode burns matches and paper, pops balloons (at short distance), will enable you to start a camp fire, but it will not engrave your PCB. To ablate the copper you either have to apply much more continuous power, or pulse the power into ultra short pulses so the metal is unable to dissipate the energy in this short time. This way you can shoot the atoms off the surface before they even notice. Here we are in the SolidState (Nd-YAG or Er-YAG) domain again. Pulsed Lasers are in fact the better choice when you have to remove material, as the target will not heat up and the thermal energy is mostly used to shoot a crater into the surface.

Exposing UV sensible solder mask with a low power UV Laser might work and can give you a very fine and precise layout. But unless you are trying to build µm sized circuits, the precision of such a laser might not be needed. I estimate that printing the layout onto a suitable clear foil with a laser printer and make a contact expoure with it and an ordinary UV lamp would get you the same result, but much quicker and much cheaper.

If you still want to build a UV laser diode onto your printer, there IS one 375nm. One guy already made a prototype pointer of it. It's just outside the visible violet, but counts as UV, since it is lower than 400nm. These diodes are rare and they are expensive and they are not "powerful". Sufficient to expose UV sensitive coatings, when the wavelength is suitable. You should have some experience in handling static sensitive components that may get damaged by just holding them wrong before you try yourself on such an expensive diode.

UV LEDs are available in higher powers and shorter wavelengths at a bargain price. Bulding an exposure box for contact exposure lithography with them will not be that costly.

If you really HATE the old fashioned contact exposure lithography, you might take a look at this paper where the photo sensitive resin is "flashed" with a micro mirror system (DLP) and conventional UV light source (sorry, no Laser here) + some sophisticated optics.

No matter how you turn it: What you want is $$$. The thechnology to achieve your intended result is still "sophisticated high tech". If you meet your good fairy, you have three wishes for free. Until then you have to pay them.

Or you keep using proven and cheap methods, as the KISS principle suggests.

 

[WizardG]

If you really want to try a laser for making your PCBs then IMNSHO you ought to use UV sensitive resist on your board and 'write' your pattern with a 405nm diode laser. Then you can just develop the resist and etch the board conventionally.

Even at only 100mW or so your write speeds can probably exceed 100mm/sec. And the single mode 405nm diodes can easily be focused to a spot size of 100um with simple optics

 

[hakzaw1]

'I don't think your wish can be granted. '
cmon!!
he went to a larger font AND added some BOLD.
of all the ways to etch metal-- lasers are at the bottom of the list.(if there at all)

 

[sz3bbylA]

thank you again for this gold information's
I swear from hart to have some patience to read all I will write, please, for a good understanding

All I know is I what make pcb's (my own for my small projects home and to produce some prototypes)
possibilities are :

1. 405 nm to burn tinny layer of paint over pcb's
problems are:
I don't know wich power to chose because I saw between 300 mw to 1600 mw (ebay )
I don't know if light spot can be adjusted visible over pcb
I don't know if color is important

2. 455nm burning also paint over pcb's ... from my searching no more than 2w, 2.5 w, and spot can be adjusted visible ... ?!?!
googling on internet I saw people explain with this kind of laser can approach to a spot length 0.03 but I don't think so.
0.05 to 0.1 i think is enough

why all this prblems?
I want to make pcb's with smd components with double foil copper
I would like to engrave the product at the end because i'm not so happy printing letters over part on my 3d printer

so , I see in your posts many kind of lasers
from there I unserstand only spot lenght and watt, and color (for example blue-violet there most powerful, and please don't laugh )
because I never used this kind of staff I cannot figure out exactly how deep it can burn and which material are suitable

about soldermask I never used but i want to begin using.
I wasn't sure if a transparent foil printed with pads over soldermask can stop drying on processing under uv lamp
idea was to obtain also some more quality using a spot uv drying soldermask like printing on a usual printer


I appreciate some suggestions (power, color laser ) also link's from where to buy

for me is very easy to buy from ebay but I think there websites where are lasers with more quality and less prices, also full kit included with ttl

thank you one more time for all suggestions

 

[diachi]

What does "adjust visible" mean?

 

[smallfreak]

I'm still not really sure if I understand WHAT you want to do.

Cutting out the circuit paths by vaporizing the copper on a dual sided conventional PCB blank? --> No. Not with any of that.

"painting" the circuit onto the UV sensitive lacquer with an UV laser so you later can etch the copper chemically where the lacquer was exposed (or not exposed, depending on the type of lacquer)? --> Yes, may be possible, if you have a wavelength the lacquer is sensitive to (see the data sheet of the lacquer). It probably will take longer than the conventional "print on foil" approach.

Writing (engraving) something into the protective lacquer that is usually applied over the copper? --> That may be done. Take a dark lacquer and a strong blue laser. That might produce enough heat to damage the coating in a controlled manner.

The spot can be adjusted visibly. Certainly you have to wear proper safety goggles. Always. You would choose some that block enough light that you can watch the focus. Usually you would not focus at full power, but at much lower power. You have to control output power anyway to use the laser as an optical ink. If you use invisible IR or UV light, focusing is more complicated. You have to focus onto a target that makes the spot visible, like an IR detection card.

Btw. the "blue-violet" ones are not inherently "the most powerful". What you need is Watt/mm². And you will need a color that is absorbed by the material, otherwise the energy does simply not affect the material. It is correct, that a single photon of violet or UV light has more energy than a red or IR one. But frequency is only one part of the game.

If you remember Albert Einstein, you know he got his Nobel price not for his great Theory of Relativity, but for his works on quantum mechanics, namely the laws behind the photo electric effect. What did he observe that led to such a revolutionary discovery?

He new that light might induce electric energy in certain materials. When shining light on Selenium, the material produces an electrical current with a certain voltage. Putting more light on it will certainly raise the voltage, right? Wrong. Stronger light produces stronger current, but it will not raise the voltage. But "bluer" light will do. The shorter the wavelength, the higher the voltage - which in turn does not increase the current, just the voltage. All that leads to the discovery of the quantum nature of light.

Taking a violet light instead of a blue one will kick the electrons heavier and they "shoot around faster", but you will not kick MORE of them. Your application however is to induce thermal energy into the material until it "degrades". So you need total power, not power per photon.

Regarding to the depth: You can only expect some result right on the focus point. The light ray is focused as a cone, starting thick, reaches a tiny focus and diverges again behind it. It now depends how "deep" the usable focus area is. A very short focus results in a steep conus. A long focus stays tight longer, potentially penetrating deeper.

I would not expect a usable depth much more than the focus diameter itself. Tiny. And you will make sure the focus stays right in the ideal distance, so eventually you will need an automatic feedback and focus device. A looong focus might ease that requirement.

 

[hakzaw1]

I hope the effort taken to reply is appreciated.. good job SF.. ^^^
& I also hope he has a local friend to help translate ...
to the OP: of everything we give you here Please remember to
always protect your eyes --start with lowest possible power,
until you have everything correct. best wishes hak

 

[sz3bbylA]

Ok. Thank you.
Verry Good information.

1. I want to paint a PCB with ordinary thin layer spray black and to remove it with laser
2. After to remove cooper with normal solutions used to have circuit board (conventional methods)
3. Must use solder mask to cover it. And here I quit thinking to do it with laser so normal methods used by all people and UV lamp
4. Using paint sprayer and after again laser to mark circuit board like taking off negative of text
5. Engrave on solder mask wich don't know if is really possible ...

Holls with a drill machine I already got

So, ... for all of this I trying to find a laser not so expensive and with enough power to do all this stuff

I'm ok to understand a laser is not a lamp who can be turned on off and is necessary some protection and some testings on the beginning

I don't know which laser to choose like power , color length of wave light

Thank you

 

[smallfreak]

OK, I did some research (that you could have done too).

The best option seems to mount some "laser head" onto your "printer" that is capable to produce a couple of watts and that is itended for such application, like this one or this one. But other than the advertizing states, the feedbacks do suggest, that it ist "NOT able to engrave aluminium" and that the focus might be "less than 1mm". As told before, that is a problem of ALL multi-mode (=powerful) diode lasers. You can probably safely ignore the paragraph about increasing the efficiency by pulsing the diode Laser. Pulsing might help, if the device is able to produce the full power in a smaller pulse, It does not help, if you just switch it off more quickly. This only reduces the totally applied power.

Certainly I do not take responsibility on whether such Laser can be successfully do what you want it to do. You will at least have to check with the supplier whether it meets your specifications on spot size. And you will have to try for yourself which includes the possibility that in the end it might not work out at all and you have to try to limit your expenses, selling this stuff again.

You can expect an expense at least in the $250 - $400 range plus customs and VAT, no matter what Laser you might buy in the end.

Is this color suitable to expose UV sensitive solder masks? Maybe, maybe not. Check with your vendor for the lacquer.

You should do some reality check before investing in a Laser that might not work, even if it could (please note the pretty massive frame construction in the second example).

Mount a felt pen with a tiny tip into your printer. Mount a weight of at least 1/2 kg to it to simulate "the Laser and optics". Take a piece of crinkled cardboard to simulate the PCB and then try to write something on it with your device.

The tip should never scratch or penetrate the surface and the tip should never lose contact where there should be a line. Try to write something tiny to see whether your printer is capable of moving at the desired precision with such a heavy load on top. Try to move across the surface and reposition to the same spot from different directions to see, whether you can reliably repeat it in the intended precision. This test can be done with a needle instead of a pen. Move somewhere, poke a small hole into the cardboard and then move away and back again. Will you be able reliably sink the needle into the same hole? You can try the writing test with the needle too. Try to write something by carefully scratching the cardboard without penetrating the paper.

If you can do this with the needle (and weight), you later can do the same with a laser head mounted instead.

Ah, yesss - the pen or needle has to be fixed rigidly onto the moving printing head without any flexibility in any direction. Some decades ago the same technique was used for 2D plotting lines on paper with a pen. These pens have been mounted flexible with pressure applied by a spring to ensure good contact to the surface when writing. This works well with a physical pen but not with a light beam. To simulate the light beam, the tip must not be mounted flexible.

I'm ok to understand a laser is not a lamp who can be turned on off and is necessary some protection and some testings on the beginning

A Laser IS some kind of lamp and you can turn it on and off as you like. A thousand times per second if you like. You can vary the applied power by changing the on/off ratio per cycle or you can drive the current with an analog signal to change the laser brightness. It all depends on the electronics that drives the diode. Every diode has a minimum current that you must apply before it starts to lase and it has a maximum current that you must not exceed or the diode will die. The range in between allows for wide variation in brightness and power.

Certainly you will not get this with a usual "Laser Pointer", that is the main topic in this forum. These are mainly beautifully crafted hand held devices with an on/off button. Some of the more expensive one have several modes like "low power, half power, full power" that can be cycled by doing several "coded" pushes of the button. But these gorgeous looking Laser-Sabers are not meant to be mounted on a cutting device or being controlled by an external computer.

So even getting a high power Laser diode (with suitable driver electronics), a proper heat sink and a power supply is not sufficient. Your software HAS to control the power output during the entire process. Unless your "Printer" has an additional 4th dimension you can control by your software (like temperature control for various printing materials) that you might be able to rework as "power control", you will need an additional interface.

A possible workaround would be: Use a short focus lens and lift the leaser quickly to defocus the beam, when you want to stop "engraving" and refocus again quickly when engraving should continue. This might be not so easy as it sounds as you have to work agains the weight of the construction.

 

[Encap]

Have a look at the low cost high quality engraving heads that Polish company OPT lasers makes - see: https://optlasers.com/cnc-3d-lasers/

 

[CurtisOliver]

1064nm is typically used for marking metals rather than 10600nm. But I have sucessfully marked steel (brushed,anodised etc) And lightly marked aluminium using a 80W CO2. As for visible diodes, it isn't likely as the most powerful diodes we have are multimode and wouldn't achieve the necessary power density to effectively mark with any clarity.