Rotary Vane Vacuum Pump for Vacuum Forming
Vacuum forming is also a commonly used thermoforming method for the production of plastic packaging containers, which is widely used in the processing and packaging material industry. Vacuum forming is generally used to manufacture open shell products from thermoplastic sheets.
The principle is simple, that is, after heating the plastic sheet to a certain temperature, it softens to a viscoelastic state, and then the rotary vane vacuum pump is used to pump the inside of the mold. The pressure difference forms vacuum suction, so that the sheet is deformed and attached to the contour surface of the mold, and finally it is cooled, shaped and trimmed.
Vacuum Forming System
The whole set of vacuum blister unit is generally composed of upper and lower heaters, temperature controllers, bearing plates, pressing frames, rotary vane vacuum pumps, vacuum chambers, mold temperature control machines, cooling devices, etc. The parameters are stored and controlled by the computer, and the control is simple. When producing a certain type of product, user only need to call out the corresponding parameters.
Vacuum forming relies on vacuum pressure difference to stretch and deform the sheet. At present, the vacuum is easy to realize, master and control, so that the vacuum forming products have the advantages of low price and high production efficiency, and have been widely used. Its form can be divided into three types: moldless molding, punch (male) molding and concave (female) molding.
Vacuum moldless molding, that is, after heating the sheet to the required temperature, place it on the clamping ring and press it tightly, and then use a vacuum pump to evacuate, and control the degree of vacuum to make the sheet reach the required forming depth. In this method, the part does not touch any mold surface, and the surface of the part has high gloss and no defects. However, during the molding process, it can only change the stretching degree and outline shape of the part, and cannot form a complex shape.
The difference between punch (male) molding and concave (female) molding is the difference between the contact surface of the molding material and the molding die. The products formed by them are of high quality on the side that adheres to the cavity wall, and the structure is also more distinct and meticulous, but the punch forming is more favorable for the manufacture of products with larger wall thickness and depth, while the concave die is not suitable for the production of very deep depths product.
At the same time, it has its own characteristics in internal and external dimensional accuracy and product thickness. Punch forming, the inner dimensions of the product are accurate, the largest part of the wall thickness is at the top of the punch, and the thinnest part is at the junction between the side and the bottom of the punch. For concave moulding, the outer dimensions of the product are accurate, and the largest part of the wall thickness is in the top of the mold. The thinnest part is at the junction of the side and bottom of the cavity, and as the depth of the cavity increases, the wall at the corner of the bottom of the product becomes thinner.
Rotary Vane Vacuum Pump Features
The overall design of the rotary vane vacuum pump
The rotary vane pump motor and the pump adopt an integrated design, which makes the whole pump more compact and lightweight.
Appearance design of rotary vane vacuum pump
The motor casing of the vacuum pump is made of aluminum alloy material, which has high heat dissipation efficiency, ensures long-term continuous normal operation, and has a good appearance.
Internal design of rotary vane vacuum pump
The oil tank of the rotary vane vacuum pump is treated with a partition, and an oil and gas separation device is installed in the exhaust gas, so there is no oil injection and oil mist pollution is reduced.
Oil return design of rotary vane vacuum pump
In order to avoid the oil return to the vacuum pump, the rotary vane pump is specially designed in the air inlet, which can prevent the pump oil from flowing back and polluting the evacuated device and the pipeline after the pump is stopped.
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