Molding of plastic bottle

Molding of plastic bottles refers to the process of making final plastic products from polymers manufactured by synthetic resin manufacturers. Processing methods (usually called one-time processing of plastics) include pressing (moulding), extrusion (extrusion), injection (injection), blow molding (hollow forming), calendering, etc. A total of six processes are required: compression extrusion injection blow molding calendering foaming.

1. Compression molding

Pressing is also called moulding or pressing. Pressing is mainly used in the moulding of phenolic resin, urea-formaldehyde resin, unsaturated polyester resin and other thermosetting plastics.

2. Extrusion

Extrusion, also known as extrusion molding, is the use of extruders (extruders) to heat the resin through the mold continuously, extrusion of products of the desired shape. Extrusion is sometimes used in thermosetting plastics and in foam forming. The advantage of extrusion is that products of various shapes can be extruded with high production efficiency, automation and continuous production. The disadvantage is that thermosetting plastics can not be widely processed by this method, and the size of products is prone to deviation.

3. Injection molding

Injection moulding is also called injection moulding. Injection moulding is a method of using injection moulding machine (or injection moulding machine) to inject thermoplastic melt into the mould under high pressure and obtain products by cooling and curing. Injection moulding can also be used for thermosetting and foam moulding. The advantages of injection moulding are high production speed, high efficiency, automatic operation, and the ability to shape complex parts, especially suitable for mass production. The disadvantage is that the cost of equipment and mould is high, and the cleaning of injection moulding machine is difficult.

4. Blow molding

Blow moulding is also called hollow blow moulding or hollow moulding. Blowing moulding is a method of blowing hot resin blanks closed in the mould into hollow products by means of the pressure of compressed air. Blowing moulding includes two methods: blown film and blown hollow products. Film products, bottles, barrels, pot containers and children's toys can be produced by blow moulding.

5. Calendaring

Calendering is a method of forming film or sheet material, which is made of resin and various additives after anticipated treatment (kneading, filtering, etc.) through the clearance between two or more rollers of calender turning to opposite direction, and then stripped off from the roller of calender, and then cooled and finalized. Calendering is mainly used in the forming process of PVC resin. It can produce films, sheets, sheets, artificial leather, floor tiles and other products.

6. Foaming

The process of forming microporous structure of plastics by adding appropriate foaming agents into foaming materials (PVC, PE, PS, etc.). Almost all thermosets and thermoplastics can be made into foam bottles. According to the cell structure, it can be divided into open-cell foam plastics (most of the pores are connected with each other) and closed-cell foam plastics (most of the pores are separated from each other). This is mainly determined by the manufacturing methods (chemical foaming, physical foaming and mechanical foaming).