The Classification And Composition of Vacuum Hot Pressing Sintering Furnace Are Introduced

Vacuum hot pressing sintering furnaces can be divided into the following categories according to the different temperatures used. Due to the difference in the use of temperature, the heating and insulation methods used in the heating chamber are very different. The temperature of the furnace below 800℃, the heater often uses iron chromium aluminum, nickel chromium wire as the heating element, and the insulation material is often used high temperature aluminum silicate insulation felt. Temperature at 1000℃- 1600℃ often used metal molybdenum, silicon molybdenum rod, silicon carbon rod as heating elements, insulation materials commonly used composite carbon felt, mullite felt and so on. At 1600℃--2400℃, graphite tubes are commonly used as heating elements, or induction heating is used, and graphite felt is commonly used as insulation materials.

Composition of vacuum hot pressing sintering furnace (resistance heating)

1. Furnace shell: The furnace shell is composed of the furnace body and the furnace door, which is a double-layer cooling water jacket structure. ① The furnace shell of the equipment is designed according to the maximum pressure range. ② The shell is horizontal, side opening translation door, the shell has a vacuum system interface, temperature measuring interface, water-cooled electrode interface, charging and discharging interface and sight hole interface, etc., all designed according to the high vacuum static seal standard; The upper and lower pressure head device on the furnace body (one set of each), the thermocouple device and the baffle mechanism are all high-vacuum dynamic sealing structures, and the furnace door and shell are welded structures. (3) For the small size of the hot press furnace, the door and the furnace body are connected by hinges. Because the graphite indenter, charge and graphite furnace are relatively light, the side-open furnace door is often combined with the thermal insulation side door in the heating room, which is convenient for the installation of heating elements, indenters, molds, etc., and the inlet and outlet of materials. (4) For large hot press furnaces, due to the graphite indenter, material and graphite mold is heavier, it is designed to be a mobile water-cooled cable, the furnace door and the heating chamber are integrated, through the internal and external ingeniously designed track, the heating chamber can be moved to a specific position outside the oven, to achieve the external material and the external mold and facilitate the maintenance of the heating chamber (such as replacing the heater, etc.).

2, heating chamber: composed of stainless steel shell and insulation materials and heating body, heating room side door and the furnace door is connected as one, the heater is connected with the external power supply through the water-cooled electrode. The heating elements in the heating chamber are uniformly arranged along the circumference to ensure the temperature equalization of the temperature equalization zone. The connection mode of heating element, the support mode and the insulation mode of heating chamber are specially designed according to the different temperature and atmosphere. The heating chamber of a large hot press furnace can be designed to be moved outside the oven, so the heating chamber is mostly designed as an integral structure.

3, temperature measurement system: heating chamber working area in the upper middle and lower three temperature measurement points, medium temperature furnace adopts high temperature oxidation resistance, high mechanical strength, good chemical stability, the use of thermocouple temperature measurement, temperature indication by the electronic control cabinet digital display table to display and control. The high temperature furnace adopts the combination of far infrared thermometer and thermocouple.

4, inflation system: the system is supplied by the air source (gas cylinder), through the drying cylinder for water removal, the drying cylinder filled with a large number of silica gel desiccant, in the mirror can be observed in the color change of silica gel, to determine whether the silica gel dehydrated activation. Finally, the gas is imported into the vacuum chamber through the valve, and the pressure shall not exceed.

5, vacuum system: the system is usually composed of diffusion pump and mechanical pump high vacuum diffusion pump unit. The valve is a special vacuum baffle valve, and the diffusion pump is provided with a cold trap to prevent the oil return of the diffusion pump. The system with Roots vacuum pump has a coarse pumping bypass line to increase the pumping rate, and the vacuum degree is measured by a combined digital vacuum gauge. The mechanical pump of the front stage has the function of automatically releasing gas work when the pump stops.

6. Press system: composed of press and hydraulic station. Small press generally adopts two beams and two columns; The larger press adopts two beams and four columns. The oil cylinder, water-cooled press shaft, cement asbestos plate, graphite press shaft and high-strength graphite mold together form the pressure ring system, the hydraulic station of the large press adopts double pump configuration, the oil pressure control adopts closed-loop control, and the advancing speed of the main cylinder is uniform and adjustable. In addition, the hydraulic system can be connected to the small manual oil pump, when the sudden power failure, can be timely to the large oil cylinder pressure, so as to prevent waste. A grating ruler is arranged on the press oil cylinder to calculate and control the relative density of the product by accurately measuring the displacement of the large oil cylinder. For small press, a pressure sensor can be connected between the upper oil cylinder and the water-cooled press shaft, which can accurately control the pressure and achieve the relative density of the material and the pressure correspondence.

7, electronic control system ① with programmable controller PLC, according to the process requirements for automatic control of equipment; (2) The digital display temperature control meter of Japan Conductive Company is used for intelligent control and display of the heating process, so that the heating process is carried out step by step according to the process requirements. This table is the main control temperature meter; ③ For large hot press furnaces, three single-phase thyristor SCR power supplies are used to achieve three-zone temperature control. (4) Composite digital display vacuum gauge, thermocouple meter under low vacuum, ionization meter under high vacuum; ⑤ The temperature is measured in two ways, the middle and low temperature stage is a thermocouple, and the high temperature stage is a two-color infrared optical thermometer; ⑥ grating meter and secondary instrument used to display indenter displacement, accuracy; ⑦ Load sensors and secondary instruments are used to display press pressure; ⑧ Can be configured with color paperless recorder, gas pressure, temperature, displacement, press pressure for memory traceable record; ⑨ All instruments and control components are centralized in a central electric control cabinet; ⑩ Set the necessary alarm and protection, such as overtemperature, low water pressure, low air pressure;

8. Air control system: composed of small air compressor, pneumatic triplets, electromagnetic directional valve, pipeline, etc. Pneumatic valves used to drive vacuum systems and charging systems.

9, water cooling system: according to the requirements of each part of the vacuum furnace for cooling water, make water drainage, valves, pipelines; Forced cooling of furnace body, furnace door, water-cooled pressure shaft, water-cooled cable and water-cooled electrode; The main water inlet pipe distribution water pressure detection switch; It is required to use the manufacturer's own water tank or the main inlet and outlet water pipe.