Vacuum pump is used in vacuum suction moulding. It is also a commonly used thermoforming method in the production of plastic packaging containers. It is widely used in the processing of packaging materials industry. Vacuum suction moulding is generally used to make open shell products of thermoplastic sheets. The principle is simply to heat the plastic sheets to a certain temperature, soften them to viscoelastic state, and then vacuum the mold through vacuum pump suction. The pressure difference forms vacuum suction, so that the sheets are covered on the contour surface of the mold after deformation. After cooling and shaping.
What is the composition of the vacuum suction unit?
The whole vacuum suction unit is generally composed of upper and lower heaters, temperature controllers, bearing plates, pressing frames, rotary vane vacuum pumps, vacuum chambers, mould temperature controllers, cooling devices, etc. The parameters are controlled by computer storage, and the control is simple. When a certain type of product is produced, only the corresponding parameters can be adjusted.
Vacuum suction molding relies on vacuum pressure difference to make sheet tensile deformation. At present, the vacuum is easy to realize, master and control, which makes the vacuum suction molding products have the advantages of low price and high production efficiency, and has been widely used. It can be divided into three forms: die-less forming, punch (positive) forming and concave (negative) forming.
Vacuum mouldless forming is that the sheet is heated to the required temperature, pressed on the clamping ring, and then vacuum pumped. By controlling the vacuum degree, the sheet reaches the required forming depth. In this method, the parts do not touch any die surface, the surface gloss of the parts is high, and there are no defects. However, during the forming process, the drawing degree and the outline shape of the parts can only be changed, and the parts with complex shape can not be formed.
The difference between punch (positive) forming and concave (negative) forming is that the contact surface between the forming material and the forming die is different. The products formed by them are of high quality on one side of the cavity wall, and the structure is more distinct and meticulous. However, the punch forming is more advantageous for the manufacture of products with larger wall thickness and depth, while the die is not suitable for the production of products with large depth. At the same time, they have their own characteristics in dimension accuracy and product thickness. The inner dimension of the product is accurate, the largest part of the wall thickness is at the top of the punch, the thinnest part is at the junction between the side and the bottom of the punch, the outer dimension of the product is accurate, the largest part of the wall thickness is at the bottom of the cavity, the thinnest part is at the junction between the side and the bottom of the cavity, and with the increase of the depth of the cavity, The wall at the bottom corner of the product becomes thinner.
Vacuum suction moulding pump design features:
1. Vacuum suction moulding pump overall design
The motor and pump of vacuum suction moulding pump adopt integrated design, which makes the whole pump more compact and lightweight.
2. Vacuum suction moulding pump Appearance design
The motor shell of vacuum pump is made of aluminium alloy. The aluminium alloy has high heat dissipation efficiency, guarantees long continuous normal operation, and has a good appearance.
3. Vacuum suction moulding pump Internal design
The oil tank of the vacuum pump is treated as a separator and an oil-gas separation device is installed in the exhaust, so there is no fuel injection and oil mist pollution is reduced.
4. Oil Return Design of Vacuum Pump
In order to avoid the return oil of vacuum pump, the vacuum pump is specially designed for intake, which can prevent the back flow of pump oil after shutdown from polluting the pumps and pipelines.
With the continuous expansion of vacuum technology in various application fields, the demand for vacuum pumps is increasing, and the further the vacuum pumps are in the vacuum suction molding industry, the more extensive they are.