Drill a hole with a laser

[The Purple Death]

I'd look at an old ruby laser. Even a small one will poke such a hole into a razor blade. I made the video below over ten years ago.

Maybe I missed it, but how powerful is that ruby laser? I mean, I have no idea how to tell what would work from what would not in the way of ruby lasers unless I have more info.

 

[farbe2]

The laser that we have selected, BDR209, is designed to be pulsed and at 2x the normal optical output power. I was assuming that we all knew that, but I guess not.

That's not really what he is talking about.
More like q-switched or mode locked. Lasers like that can produce puls trains that consist of very short pulses. For solid state lasers, this almost always means: lower CW output power but much higher instantaneous power. Like a 1W CW laser producing very short rapid 10kW pulses. This diode will not be able to reach these power levels. You can increase the optical power to maybe 2x over CW but thats it.

The ruby laser capable of punching holes trough razor blades might actually have LESS CW power than the 1W 405nm diode.
Its high peak power just vaporizes the material before it even gets a chance to heat up.

However its beam quality isn't very good considering the high mode count of the (often used) plan parallel cavity.
Low repetition rates do the rest = very slow speeds for cutting and engraving.

Any constrains regarding beam size at the laser module?
I would suggest trying a 405nm diode to burn / cut your desired material. If that works good, we can certainly work out a beam forming setup to get the beam to the right shape.

 

[The Purple Death]

Any constrains regarding beam size at the laser module?

Not really.

I would suggest trying a 405nm diode to burn / cut your desired material. If that works good, we can certainly work out a beam forming setup to get the beam to the right shape.

Currently, the diodes I have are based around trying to get experience with lasers. They're not really practical for anything other than laser pointers. Which is fine, but not for what I'm trying to do.
Shipping will take a bit, but I can get the BRD209 or another laser in the near-visible/visible light spectrum.

Barring that there's something else we need to discuss, I'll not reply again until I obtain a laser to do the work.

PS: About what sort of cost do you expect for a beam forming setup? $100? $1000?

 

[The Purple Death]

Wait a second! Wouldn't it be possible to use a MM laser with a prism* to split the light and then we could isolate the frequency we want/is the strongest, and direct that at our target?

* I think that there are mirrors and/or other optical devices that can do this as well, I just don't recall what they are referred to as.

EDIT: I recall some such thing being used for argon lasers.

 

[farbe2]

Wait a second! Wouldn't it be possible to use a MM laser with a prism* to split the light and then we could isolate the frequency we want/is the strongest, and direct that at our target?

* I think that there are mirrors and/or other optical devices that can do this as well, I just don't recall what they are referred to as.

EDIT: I recall some such thing being used for argon lasers.

Just forget that idea. The modes of MM diodes are way too close to split them with reasonable efficiency. And you will end up loosing so much power that a SM diode makes way more sense.

It really depends, a MM diode can certainly work depending on your requirements of hole size to depth and acceptable taper.
But your 12um target is very small and will very much limit the depth possible by MM diodes. (thats 0,012mm, are you aware?)

A "lens system" would run you roughly 50-500$ or so, depending on the lenses you end up needing. E.g. if they are available from Chinese bulk suppliers or only from Thorlabs/Edmund.
Prisms can be even less than that, but introduce (substantial) losses and dont correct astigmatism.

 

[kecked]

I bought a pulsed 1064nm from I think laser tree? On eBay for 400.00. Does like 10kw peak. Never tried making holes but it can certainly do so. No idea the beam size but it seems sub mm

 

[The Purple Death]

I was also thinking about 1064nm ND:YAG lasers. If we want to have a Q-switched laser, as mentioned above by farbe2 , wouldn't that work? Or we could even frequency double it to 532nm if needed.

 

[farbe2]

Shorter wavelengths are much better for small holes with high aspect ratios.

At 1064nm you are looking at roughly 100um depth (0,1mm) for a 12u hole (0,012mm).
That’s for the best possible laser. Not sure what the beam parameters of the cheap Lasertree units is.
Even an M² of 2 will reduce that to 0,05mm drill depth.

532nm will double all that. So 0,2mm depth for a perfect laser and so on.

You need all the help you can get (lower wavelength) to get small deep holes.

 

[Amak87]

Hello,

TLDR: See bottom.
I've written this in long form for completeness. I'm sure I'd get a lot of questions otherwise.

So for some time I've had the option of getting a laser attachment for my 3D printer, but I never opted for that, because all I'd do with it is some engraving which wasn't as important as some of my other projects.
Well, recently I found myself needing to drill a lot of very very tiny holes in either very thin wood or very thin plastic (I'll have to try a few things to discover which is more optimal/workable). Holes that are 0.010mm-0.012mm in diameter. Now drill bits for such holes start in the hundreds of dollars (USD) for just one drill bit. As you might imagine, even if I used my 3D printer to hold the drill and do the drilling, I'd still probably break a few and so I'd end up spending thousands for these holes.

Then it occurred to me, I could use a laser to accomplish this! The problem is that most powerful blue lasers that I see people reviewing, visually appear to focus down to a few mm in size. That is to say, I'm orders of a magnitude off from the level of accuracy I require. Now I'll grant you, this could very well be a trick of the light. But still, I have no idea how to determine what the focus point size is for my laser at a given distance.

How do I get a blue laser to focus down to the size of 0.01mm-0.12mm?

Thanks!

You won’t be able to accomplish this in plastic, the heat will cause the plastic to melt and give you undesired results. Atleast not for less than the drill bits themselves lol

 

[kecked]

I have a 50kw peak 355nm laser that runs at 1 kHz 380ps pulse microchip unit. They are not hard to find. Bet that could drill very nicely. Average power is only like 20mw.

 

[CurtisOliver]

Wavelength, pulse width and frequency is important for working with some plastics. The lasers I have most experience with for material processing are CO2's. However the same effect can apply from shorter wavelength visible CW's. Plastics like ABS, HIPS, PET, PVC don't react well to high power CW. You get a visible heat radius, and a heat depression where the hole should be and the rest fuses itself back together. CO2's are not true pulsed lasers but modulated, so you do have some control on some machine models to adjust DPI which acts like pulse repetition control only with a fixed pulse width/duration. Diode based cutting heads also act in the same way with PWM control. By lessening the power and adjusting the pulse repetition (DPI) and increasing the passes you can machine these plastics more gently achieving a cleaner cut. This is where true pulsed lasers come into there own. The ability to control the pulse repetition/frequency and the pulse width allows you to deliver a set amount of power in an allocated timescale and gives the material the ability to cool between pulses. A high amount of peak power in a small amount of time has the effect of ablating or vaporising the material on contact rather than gradually heating it up to melting point and burning through. This is why MOPA fiber lasers are better for plastic engraving over ordinary fiber sources, because they have greater control over their frequency and pulse duration. If you are after cutting loads of tiny holes with accuracy. You need a laser source that is pulsed and low wavelength. A pulsed UV source is ideal, but can be very expensive unless you get lucky like kecked.

 

[Ricker]

Can you have someone make you a template with the correct size and positioning with metal, then beam size would be less of an issue, saving you a lot of money? Just having to clean any residue that may collect in the holes.