In the heat insulation process of solid rocket motors, due to the chaotic heat insulation structure of some engines, molding techniques are adopted. For the parts with chaotic structures, in order to obtain a fine and non-porous preform, how should we obtain a qualified heat insulation molded part and solve this problem?
EVP vacuum pump technicians combined with their many years of experience in the vacuum pump industry, customized countless vacuum solutions, analyzed and researched the molding of molded parts, explored a new process method. that is, the application of roots vacuum pumps in the molding of molded parts , There are many types of vacuum pumps, why choose Roots vacuum pumps?
The thermosetting plastic transfer molding process is to close the mold before feeding, and the plastic raw materials are heated in a separate feeding cavity to be in a molten state, and then pressed into the cavity at high speed through the mold’s gating system under pressure, and continue to be heated and compressed in the mold And curing molding. Like compression molding, it has a feeding chamber and a chamber, which are all pressed on a hydraulic press. Their main differences are as below :
(1) Thermosetting plastic transfer molding is first clamping the mold and then pouring molding, while compression molding is the first charging and then closing the mold, heating and pressing in the chamber.
(2) The transfer mold has a pouring system, while the compression mold has no pouring system.
(3) The gas during the molding process of the transfer mold is not easy to be removed from the chamber, so it is generally necessary to open an exhaust groove; there is an exhaust action during compression molding, and the gas generated during molding can be exhausted through the exhaust action, generally not required Another exhaust slot is provided.
Roots vacuum pump is a mature technology for vacuum acquisition equipment. After combining with backing vacuum pumps (common rotary vane vacuum pumps, water ring vacuum pumps, piston vacuum pumps, screw vacuum pumps, etc.) to make a pump unit, the backing vacuum pumps are expanded The working range under low inlet pressure can be widely used in industrial applications.
According to general experience, after the Roots vacuum pump is configured, the system vacuum can be increased by an order of magnitude. If equipped with a two-stage Roots pump, the system vacuum can be further increased.
2.Increase the pumping capacity
The pair of rotors of the Roots vacuum pump do not touch each other and can run at high speed, so Roots pumps with smaller geometric dimensions can also achieve higher pumping speeds. After selecting a suitable backing pump combination, a small pumping speed backing pump can pump a large amount of gas. Compared with a single backing pump with the same pumping speed, it can significantly reduce energy consumption.
Roots vacuum pump structure:
Roots pump structure: In the pump chamber, two “8” shaped rotors are installed perpendicular to each other on a pair of parallel shafts, and a pair of gear belts with a transmission ratio of 1 rotate in opposite directions. There is a certain gap between the rotor, the rotor and the inner wall of the pump casing to achieve high-speed operation. Since Roots vacuum pumps are vacuum pumps without internal compression, the compression rate is usually very low, so high vacuum pumps and medium vacuum pumps require backing pumps. The ultimate vacuum of a roots vacuum pump depends on the structure and manufacturing accuracy of the pump itself and the ultimate vacuum of the backing pump. In order to improve the ultimate vacuum of the vacuum pump, Roots pumps can be used in series.
The compression molding process is the oldest and infinitely dynamic molding method in the production of composite materials. It is a method in which a certain amount of premix or prepreg is added to a metal pair mold and then heated and pressurized to solidify and form. The application of Roots vacuum pump in the molding of molded parts can obtain qualified insulation molded parts under certain vacuum pressure.