Micro-Nano Laser Machining
Typical examples of Micro Hole Drilling in Ceramics, Plastic and Metals.

Photo below illustrates the significance of pulse parameters – Picosecond vs Nanosecond

CO2 lasers (Carbon Dioxide)

CO2 lasers are gas powered lasers with a sealed laser tube (no gas filling required) that have been the mainstay of laser machining for decades. These lasers operate in the infrared spectrum (10.6 microns) with average powers in the kilowatts with high repetition rates. In the field of laser micromachining, the applications are limited because the smallest achievable spot size is 50-75 microns diameter. Still, the laser is applicable for certain "through hole" applications where high throughput and low operating costs are required.

Short pulsed CO2 lasers operating at 10.6 micron wavelength. The CO2 (Carbon Dioxide) lasers operate at average power of 150W with repetition rates of 10khz. The CO2 laser has the highest processing speed, two orders of magnitude faster than excimer lasers and one order of magnitude faster than DPSS lasers.

Of course, there are consequences to this processing speed. They include thermal effects such as potential melting or cracking, limited machining dimensions (0.003") and tolerances (0.0015") and not suitable for blind hole drilling or precise selective material removal.

CO2 lasers are the industrial workhorse of laser machining utilizing a spot size of .003" or .004'. Machining tolerances approach one-half the laser spot size. CO2 laser machining is a thermal process, liquefying the material to allow coaxial gas to push the machined material out the back side. Unlike a UV laser (DPSS or Excimer at 355nm or 266nm), the CO2 laser vibrates the molecular bonds of the material, generating heat that is used to liquefy the material. Similar to DPSS lasers, CO2 lasers deploy a direct write approach where the focused beam traces the pattern to be machined.

 

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