Demand and development of ultra-high vacuum furnaces

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High Demand for Vacuum Furnaces

As the core components of communication equipment, vacuum electronic devices play a vital role in cutting-edge technology and space communications. In recent years, the rapid development of new technologies such as terahertz has put forward higher requirements on the performance of vacuum electronic devices, which urgently need to be replaced, which has led to the growing demand for high-performance, high-reliability and long-life process equipment. As one of the key equipment in such processes, ultra-high vacuum furnaces can perform heat treatment and welding operations in a clean high vacuum environment to achieve material degassing, purification and permanent connection. Its core performance is mainly reflected in the acquisition of high-limit vacuum, uniform distribution of furnace temperature and reliability under high temperature conditions.

Terahertz technology has great application prospects in ultra-high resolution radar, electronic countermeasures and multi-dimensional imaging. In recent years, the rapid development of cutting-edge science and technology industries such as space technology, vacuum electronic technology and semiconductors, especially the surge in demand for high-power terahertz wireless communication devices, has put forward higher requirements for process equipment of microwave tube devices.

Among them, the demand for high-performance large and medium-sized vacuum furnaces has increased significantly, requiring the use of pure oil-free vacuum systems to quickly obtain higher working vacuum and pursue excellent temperature uniformity. The core performance indicators of a vacuum furnace are mainly reflected in aspects such as working vacuum degree, furnace temperature control accuracy and temperature uniformity technology, which are directly related to the heat treatment of the device, welding quality and the effect of material degassing and purification.

Characteristics of vacuum brazing

Under vacuum conditions, the brazing material is melted by heating, and the vacuum brazing process is realized by its wetting and diffusion. The main characteristics of vacuum brazing are as follows: ① There will be no problems such as pores, slag inclusions and oxidation pollution; ② The brazing material has good fluidity and is easy to weld complex structure workpieces; ③ It is suitable for brazing of stainless steel, refractory metals and dissimilar metals; ④ It can effectively remove volatile impurities and gases to improve welding quality; ⑤ The surface of the workpiece is clean and bright after brazing.

Design and development of ultra-high vacuum furnace

Equipment indicators involve the acquisition of ultra-high vacuum, ideal surface degassing rate and vacuum furnace structure design. Combined with the optimization needs of traditional equipment, the following design principles are proposed: ① High configuration and high cleanliness: Use a fully oil-free multi-stage vacuum system, strictly follow the cleaning process, and control the pollution source. ② High reliability and long life: Focus on optimizing the furnace body sealing structure to adapt to long-term high-temperature processes. When wearing parts such as sealing rings can be replaced, the life of the whole machine is more than 10 years. ③ Safety: The lifting system is stable and self-locking; the equipment and control cabinet are properly grounded; multiple related protections such as furnace temperature and cooling water. ④ Easy to maintain: modular design such as heaters and insulating pads.

The furnace needs to provide an ultimate vacuum of 2×10-7 Pa, the maximum heating temperature is not less than 1300 ℃, and the furnace body is a vertical bell-shaped structure. The pressure rise rate is required to be kept static for 24 hours, and the vacuum degree in the furnace is not less than 8×10-2 Pa. The vacuum degree in the furnace must be strictly controlled during the heating process to ensure that the vacuum degree throughout the process is better than 2×10-4 Pa, and the temperature can be quickly raised from room temperature to 1200 ℃ within 70 minutes. The equipment is suitable for vacuum brazing and heat treatment of various metals such as stainless steel and Kovar alloy. It is mainly composed of components such as vacuum furnace body, vacuum system, heating system, lifting system and control system.

Vacuum furnace