Vacuum pump for Compression Molding

The most difficult problem in cold processing of aluminium alloy sheet is the deformation of workpiece. Our technicians have customized numerous vacuum solutions based on years of personal experience in vacuum pump industry. The processing technology of aluminium alloy sheet is analyzed and studied. Aiming at the problems of difficult clamping and large deformation in the process of processing, a new process method is explored. There are many kinds of vacuum pumps in the application of vacuum moulding of sheet metal. Why choose Roots vacuum pump?

Roots vacuum pump is a well-developed vacuum acquisition equipment. It cooperates with the front vacuum pump (common rotary vane vacuum pump, liquid ring vacuum pump, slide valve vacuum pump, screw vacuum pump, etc.) to form a pump group, which expands the working range of the front vacuum pump under low inlet pressure and can be widely used in industry.

1. Improving Vacuum

According to general experience, after equipping Roots vacuum pump, the vacuum degree of the system can be increased by one order of magnitude. If equipped with two-stage Roots pump, the vacuum degree of the system can be further improved.

2. Increase pumping speed

A pair of rotors of Roots Vacuum Pump do not contact each other and can run at high speed. Therefore, Roots Vacuum Pump with smaller geometry size can also achieve higher pumping speed. After choosing a suitable combination of front-stage pumps, a large amount of gas can be pumped out by the front-stage pump with small pumping speed. Compared with the single front-stage pump with the same pumping speed, the energy consumption can be significantly reduced.

Vacuum moulding is a process that uses vacuum pressure to suck thermosetting resin into the pre-vacuum mould, and to make resin permeate and flow in the fiber reinforced body, and finally solidify it into composite material. This process has broad application value in aviation industry, automobile manufacturing, ship manufacturing and so on. Flax fibers are abundant in China. Flax fibers can be used as reinforcing materials in vacuum moulding process to promote the utilization of renewable resources and reduce product costs. In the process of vacuum moulding, permeability is an important parameter for computer simulation of vacuum moulding process. The permeability value was measured by test method, and then the filling process of resin was simulated by PAM-RTM, a simulation software of liquid moulding. The influence of vacuum pressure and temperature on filling time was explored, and a lot of process tests were avoided. It is of great significance for saving raw material cost, shortening test period and die design.

Roots vacuum pump structure:

Roots vacuum pump structure: In the pump chamber, there are two “8” shaped rotors installed vertically on a pair of parallel axles, driven by a pair of gears with transmission ratio of 1, which rotate synchronously with each other in reverse. There is a certain gap between the rotor and the inner wall of the pump housing, which can realize high speed operation. As Roots vacuum pump is a kind of vacuum pump without internal compression, the compression ratio is usually very low, so high and medium vacuum pumps need front-stage pumps. The limit vacuum of Roots vacuum pump depends not only on the structure and manufacturing accuracy of the pump itself, but also on the limit vacuum of the front pump. In order to improve the vacuum limit of the pump, Roots pump can be used in series.

The application of Roots vacuum pump for Compression Molding of sheet metal parts, compared with the existing non-vacuum aided moulds, simplifies the process, reduces the possible deformation in the actual sheet metal cutting process as much as possible, and better controls the deformation of parts, improves the surface defects of existing products, and reduces the defect rate of products from 40% to 10%. Thus, the parallelism of the whole part and the surface accuracy of the moulded product are guaranteed.