The industrial laser system performance is affected by the increased temperatures generated from the laser operation. As the operating temperatures increase, the laser wavelength also increases, reducing overall optical conversion efficiency. It is critical for the wavelength of light energy from each emitter to be within a very narrow band. Proper cooling helps maintain the beam alignment in front of the emitter.
The high powered lasers used in laser cutting, printing, welding, marking, and drilling, require a strong beam focus. Unfortunately these applications often see wide fluctuations in heat load due to constantly changing beam power levels and the beam being turned on and off. The temperature fluctuations associated with these heat load changes can cause overheating of key laser components, such as the laser heads. Cooling at a consistent, precise temperature will improve the beam quality as well as protect the laser system investment with the reduction of thermal stress. Reducing the thermal stress that causes component failures will improve the mean time between failure (MTBF) and ensure optimal laser performance.
The type of cooling required is determined by several factors, including; laser wattage, resonator efficiency, resonator and optics temperature requirements, and ambient temperature conditions.
For laser systems in which the resonator and optics operating temperature requirements are at or below ambient, vapor compression (VC) designed water chillers are typically used for cooling. VC water chillers embody a refrigeration system composed of a compressor, condenser, expansion valve, and evaporator, that transfers heat from the process cooling water directly to the air via an air cooled condenser or to a facility chilled water system through a water cooled condenser. VC water chillers are able to handle very high heat loads and when equipped with the proper control systems are able to hold the process cooling water within very precise temperature tolerances <±0.5°F.
The GDTS laser cooling solution
The Intelligent Laser Cooling System (iLCS) is an OEM-specific VC chiller that incorporates technology to integrate better with customer’s equipment, and takes less time to install, setup, and operate. Using machine-to-machine communication linked to customer’s building management systems, built-in electronic sensors monitor the tank levels, de-ionized water quality, fluid pressure and flow, and automatically adjusts the motorized hot gas bypass to modulate the refrigeration circuit, enabling precise temperature control. The iLCS incorporates one refrigeration circuit that can provide cooling to multiple fluid circuits, eliminating the need for multiple chillers. Another unique feature is the use of dual compressors to better match the variable heat loads, improve efficiency, and reduce component failure. The intelligent controller alerts customers of the chiller health and predictive measures to prevent downtime. When the chiller needs maintenance, the interior design coupled with the use of wire harnesses aids the technician to quickly service the unit, limiting downtime.