Different types of CO2 laser

Co2 laser tube

The physical design of a CO2 laser consists of a gas filled tube sand wedged between a pair of mirrors, this tube is excited by a RF or DC electrical discharge. Contrary to popular belief CO2 is not the only gas apparent inside these tubes. The gas composition of a typical CO2 tube is a mixture of:
77% He (Helium) 13.5% N2 (Nitrogen) 9.5% CO2 (Carbon Dioxide).

Why is my tube branded as CO2 and not a Helium tube?..
Well, the sealed CO2 Tube requires the gas to flow or a pumping mechanism, this is achieved by exciting the nitrogen molecules through electrical discharge. This causes the N2 to collide with the CO2 molecules.

Types of CO2 Lasers

  • Axial gas flow:  Gas is physically pumped in one end and out the other of the tube, this fresh gas replaces the depleted CO2. He & N2 are commonly added to increase efficiency. Typical power outputs of 40-80w per meter for this tube.
  • Transverse gas flow:  Gas flows across the tube as apposed to down the length of the tube, this ensure a fresh mixture along the entire length of the tube. Typical power outputs of 10kW per meter can be achieved with this type of arrangement.
  • Sealed tube:  Similar to sealed HeNe lasers but with dimensions tuned to CO2 excitation wavelength. Typical power outputs of 1-160W are typical of the type of tube.

DC & RF Excitation

Most if not all China import lasers feature a sealed tube design and are DC excited, power control is achieved with pulse width modulation and not current control on this type of laser. Power to the tube is pulsed (pwm) the duty cycle of this pulse (time on vs off) dictate the RMS power (root mean square). Due to the nature of a pwm digital signal only an analog current meter can be used to read this signal.



11 thoughts on “Different types of CO2 laser

  1. Pejman H says:

    I have one 150 w Chinese laser cutting machine,

    i was wondering if there is any way that to convert sealed laser tube with gas fed laser tube, i was going to get three gasses and using precision regulates to feed the gasses daily or weekly, is that possible, or do you guys have any product to make that possible,

    • admin says:

      Hello, Yes its possible to convert to a pass thru gas tube.
      But it wont be financial viable. I know the 150w tubes are expensive to replace but in order to feed the gas mix to the tubes without regulators more expensive than the price of a replacement tube you would have to get your desired gas premixed.

      We are hoping to soon offer gas replacement services, where we can service and regas china tubes.

      Thank you for your comment, i hope my reply helps you some how.


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