How does a laser work?
More importantly – how is a laser beam generated and what should you do to maximise the life of your laser tube?
In a glass tube CO2 laser’s the most expensive consumable item is the laser tube, these typically range from around £220.00 for a reputable 60W tube all the way up to £1,500.00 for a 150W tube from Reci or EFR.
Laser tubes manufactured by reputable suppliers, such as the EFR or RECI tubes used on the Lightblade, typically have a minimum life of 18 months.
Across our customer base we normally see 18-36 months of tube life (by tube life, we mean with minimal loss in performance) before the power starts to degrade and a new tube is required. However, we have seen tubes fail much, much, faster in certain applications.
The laser tube is essentially a carefully balanced molecular chain reaction. Unwittingly abuse your tube in the search for more power, higher cut speeds or thicker materials and you will significantly reduce the lifetime of the tube and set yourself up for a big bill.
So, what’s the best way to maximise tube life and keep costs down?
Well, first its worth understanding how a laser tube works.
The clue is in the name: LASER or Light Amplified by Stimulated Emission of Radiation. At a high level, as you put a charge across the gas mix in a CO2 laser, you excite the gas mix. That in turn releases photons (light) that are collimated (bounced back and forward to align the beam) and then targeted through a partially reflective mirror at the end of the tube.
Our tame super user goes into much more detail in the attached video, but as a brief description of the fundamentals – that’s about as complex as it gets.
Where things start to go wrong, is where users try to “overdrive” the tube in search of more power. As a side note – all Lightblade’s have a software safety stop, matched to each tube and machine during PDI at Thinklaser, to prevent this from happening.
What does over driving mean?
Essentially it is when you apply too much charge to the tube, creating a breakdown in the gas mix. Under normal conditions – the gas mix remains the same (10% Helium, 10% CO2 and 80% Nitrogen). But when over driving, the excited Nitrogen molecules cause the CO2 to breakdown to CO (Carbon Monoxide) and O2 (Oxygen). These gases are no good in the production of photons and so cannot be used to generate a beam.
The more of the CO2 stock you degrade = the less molecules able to generate photons = less laser beam generated.
If you stick within the tube’s recommended operation window, this shouldn’t be an issue. As mentioned, all Lightblades come pre-setup to prevent over driving, but its useful to understand the risk and potential detriment to tube life that working the tube above its limits continuously has.
And with that, we turn to our tame superuser for a more detailed run through on the science behind a laser tube and how best to prevent overdriving.
As always – a big thanks to Russ for all the hard work that goes into the production of these tutorials.
If you are unsure about your laser tube life or need any advice on how to check you tube running current – please feel free to get in touch, alternatively check out our FAQ section on the website where we will be releasing a series of technical FAQ’s to get you up and running even faster.