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GENERAL PROCESS - REF. #GP011 | View PDF
THE CHALLENGE
High power CO2 laser gas feed applications require a precise mixture of CO2, N2, and He to operate. Low power lasers come with a permanent supply of gas. Larger lasers, such as the ones used for high speed welding in the automotive and aerospace industries, require a continuous feed.
High power CO2 lasers may incorporate on-site gas mixing for the CO2 gas mixture in the laser. Flow control of shielding gas in the laser welding process has a dramatic affect on the quality of the weld. Shielding gas can be nitrogen, CO2, argon, air or a mixture. Oxygen is sometimes used to enhance the welding process due to the light absorbing properties of the oxide film.
Often, inexpensive flow meters are installed on original equipment, resulting in inconsistent gas flow and weld quality, and in the case of a flow interruption, these meters do not typically provide alarms to alert the operator, which can result in very costly waste and/or rework. This is an application that can benefit significantly from a more precise and versatile flow control device.
 THE BROOKS SOLUTION
Brooks variable area (rotameter) flow meters are perfect for critical purge and cooling flows. They use a precision glass measurement tube, with superior tolerances and stability to the more common plastic models. A Brooks Model 1355 with 2-5% accuracy can be supplied with direct reading scales for any gas. Equipped with an integral Model 8800 flow controller, the Model 1355 is optimized to hold flow constant with changes in feed pressure. Brooks VA meters can also be equipped with alarms and transmitters to alert an operator of a loss of flow.
 Brooks thermal mass flow controllers (MFC) are also an excellent choice. This device consists of an electronic flow meter, control valve and control electronics in a compact, integrated package. It will maintain the flow at the desired setpoint to better than 1% accuracy and it will alert the operator when gas flow is not present. Brooks MFCs are available in a wide range of flow rates and price ranges, in analog or digital configurations. |
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