[laser etching]
- [Alexander] In just 10 seconds,
diodes generate a laser beam passed through mirrors
moving as fast as 10,000 millimeters per second.
- [Narrator] This is called a fiber laser,
and it can carve super intricate designs
into any metal, in just seconds.
The laser is essentially getting so hot,
the metal is just vaporizing away,
like a hot knife through butter.
Despite the laser's ability to cut through titanium,
you'll be surprised to discover
waving your hand in front of the laser
does absolutely nothing.
Fiber lasers simply aren't the right wavelength
to interact with organic materials at these energy levels.
We filmed the laser of regular speed,
then in slow motion
to reveal what we can't see with the naked eye.
[upbeat music]
- You can look almost anywhere in our modern world
and find something that's been marked by fiber lasers.
From consumer electronics to medical devices,
makerspaces, garages, and even small YouTube studios.
[upbeat music]
Fiber lasers start with diodes
that turn electricity into light.
The light travels to the laser cavity,
a portion of the fiber optic cable
that's doped with rare earth elements
where broad spectrum light
is transformed into that of a single wavelength.
Eventually, the laser exits the emitter
and is passed on to the galvo head,
where it's reflected by two mirrors
moving as fast as 10,000 millimeters per second,
which guide the laser beam to its target.
The result, a 60 watt beam of focused light
that can cut through titanium and steel.
[lasers screeching]
This fiber laser is pulsing anywhere
from 20,000 to 400,000 times per second,
and those pulses are lasting as little
as a billionth of a second.
[lasers etching]
These illustrations are drawn so rapidly,
you can only see them sweeping across the surface
with slow motion,
and the pulses are so fast
that even the highest speed cameras
have trouble capturing them.
Depending on the material used,
the laser can react differently.
For example, color is only possible on steel,
whereas, this aluminum can only be marked white.
- [Narrator] In this clip, we're marking aluminum.
- This is what I would consider a standard marking.
The goal here is ablation, which is a fancy word
for removing material from the surface of something.
- [Narrator] Generally, aluminum only comes up as white,
and the reason for this is because it's a raw element.
There's no alloy or other metals mixed in,
which means that there's no room
for weird chemical reactions to occur.
- The galvo mirrors are moving relatively quickly,
but they may need to be slowed down a bit,
depending on the reflectivity of the material
in order to ablate it.
We're using about 48 watts here,
which is 80% of our available power,
and the lasers pulsing 25,000 times per second.
Because our repetition rate is low,
it gives the laser lots of time to charge up between pulses,
which means a high energy beam,
so that we can actually chew in and remove that material.
Here, we're doing what we actually call a cleaning pass,
so we've dropped the wattage way down
and the laser's pulsing 45,000 times per second.
Raising the number of pulses per second
actually lowers the amount of time the laser has
to charge up for each pulse,
which results in a weaker impact with the material.
That's ideal, because instead of creating more mess,
we're actually using the laser here
to clean up the marking area,
so that we get better efficiency on future passes.
The low rate of ablation also means that this is great
for pushing debris and dust out of the way,
almost like a broom.
- [Narrator] In this clip, we're marking stainless steel.
- This is where things start to get really interesting.
Anybody can take a chainsaw and carve up a forest,
but this is the scalpel at work here.
- [Narrator] When metal gets hot, it expands,
and during these types of marks,
we actually have to lock the metal in place,
because the laser is generating so much heat,
the material begins to warp.
- Dropping the pulse width
from 200 nanoseconds to 175 nanoseconds,
in conjunction with lower energy output,
just 15 watts here, helps to make sure
that we aren't ablating away the material.
Because we're using a low power,
we can actually just heat the surface of the steel
in order to obtain this black mark.
The extremely slow scanning speed
of just 50 millimeters per second is essential here as well.
It gives those low powered pulses enough time
to actually heat the surface of the steel
to the perfect temperature.
If we're off by just a few degrees,
we could end up with a red or a blue,
or we could carve into the surface of the steel,
which is definitely not what we want.
- [Narrator] The steel is one of the only materials
that we can mark with color,
and that's due to the fact that the steel is ferrous,
which means it contains iron.
[ambient music]
- Color marking is the culmination
of everything that we've talked about so far.
As precise as we've had to be for the black marking,
it's nothing compared to getting these colors.
First, I have to point out that we reduced our pulse width
down to six nanoseconds.
That's six billionths of a second, six billionths.
Each pulse contains extremely small amounts of energy,
but we're pulsing the laser 300,000 times per second now,
and that energy adds up.
This fragile balance will apply an absolutely precise amount
of energy to the surface of the metal,
resulting in this beautiful color.
[intense music] [lasers whirring]
These machines permeate all of our lives,
whether we notice or not.
They're both a practical necessity and a hypnotizing wonder.
But most of all,
they're a reminder that technology can feel like magic
when you're living in the future.
[intense music]