The Advantage of Laser Welding in Sealing Sensor
The application of laser welding in processing sensor
Sensor is a kind of high precision testing instrument, which has strict requirements in military, aviation, aerospace industry. Before applying sensors have to be tested strictly. Whether a sensor is hi-tech value-added depends on high technology and technical processing.
Due to the environmental conditions, sensors that need metal encapsulation generally adopt sealing welding, such as pressure sensors, hall sensors, photoelectric sensors, temperature sensors, etc. This kind of sensor contains sensitive components and integrated circuits, filling inert gas or vacuum to cut off the outside, with requirements of pressure, air tightness, weld strength and leak rate. In the process, the requirement of welding quality is high, deformation must be little and cannot damage the internal components and circuit.
Now, the main manners of sealing sensor welding are resistance welding, tungsten argon arc welding, plasma arc welding, electron beam welding, ultrasonic welding, vibration welding, hot plate welding and laser welding, etc. Compared with other welding manners, laser welding has the following advantages:
• High depth-to-width ratio. The welding line is deep and narrow.
• Minimum heat input. Due to high power density and fast melting process, thermal deformation and heat-affected zone is small.
• High density. High cooling rate after welding is easy to make the welding line micronization to improve strength of welding line and toughness.
• Solid welding line. High temperature heat source reduces the impurity content to make the weld strength and toughness even higher, compare to that of parent metal.
• Precise control. Due to the small focus spot, weld can be precise positioning to improve production efficiency.
• Non-contact welding. Magnetic and air have no negative effect on the laser.
• Due to low average heat input and high accuracy, laser welding can reduce processing costs. At the same time, the cost of laser welding is low, which can reduce the cost of artifacts.
The prospect of laser welding application
Laser welding is a kind of new and high technology, due to its unique characteristics, especially suitable for sensor seal welding. Many foreign sensor manufacturers apply laser welding in sensor processing, but in domestic, laser welding only applies in military sensor products and parts of scientific research.
Compared to foreign products, China’s laser welding device completely can be competent for domestic product sensor processing, and the price is only 1/3-1/5 of the similar foreign products. In order to improve the level of domestic sensors as well as the development of national laser industry, China’s laser sensor manufacturers should adopt domestic laser welding machine to produce and process sensors.