Extrusion blow Molding is a method of manufacturing hollow thermoplastic parts.
Well-known blow moulding objects include containers of bottles, barrels, cans, boxes and all packaged food, beverages, cosmetics, pharmaceuticals and commodities. Large blow moulding containers are usually used in the packaging of chemical products, lubricants and bulk materials. Other blow moulding products include balls, bellows and toys. For the automotive industry, fuel tanks, car shock absorbers, seat backs, central brackets, and handrails and headrest covers are blown.
For mechanical and furniture manufacturing, blow molded parts have housings, door frames, racks, pottery cans or boxes to have an open face. The most common plastic blow-moulding materials are high-density polyethylene, which is made of most milk bottles. Other polyolefin are also often processed by blow moulding.
Styrene polymers, polyvinyl chloride, polyester, polyurethane, polycarbonate and other thermoplastics can also be used for blow moulding. Engineering Plastics have recently been widely accepted in the automotive industry. Material selection is based on mechanical strength, weathering resistance, electrical properties, optical properties and other properties. 3/4 of blow molding products are made by extrusion blow molding method.
Extrusion is the forcing of the material through a hole or mold to make the product.
The extrusion blow molding process consists of 5 steps:
1.Plastic type embryo (extruding of hollow plastic pipe);
2. The mould is closed on the embryo, clamping the mould and cutting off the embryo;
3. Blowing the cold wall to the mold cavity, adjusting the opening and maintaining a certain pressure during cooling;
4. Open the mold, remove the blown parts;
5. Finishing the flying edge to get the finished product. Polymer mixing is defined as a process by which a polymer or polymer system can be raised to a higher grade by a melt mixture. Mixing process from single additive to a variety of additive treatment, polymer alloy and reactive mixing, the scope of a wide range. It is estimated that one-third of the U.S. polymer production to be mixed. Mixed ingredients can be customized according to the performance requirements of the final application.
Mixed products have mixed properties, such as high gloss and excellent impact strength, or precision die-plasticity and good stiffness. Well-blended polymers are usually cut into grains for further processing.
Increasingly, however, the industry is interested in combining blending with the next process, such as profile extrusion, which avoids heating the polymer again. People use various types of melt mixing equipment, from roller mixer and batching mixer to single screw and twin-screw extruder. Continuous mixing (extrusion machine) is the most commonly used equipment, because he can provide consistent quality products, and can reduce operating costs. There are two kinds of mixing types: distributed mixtures can be distributed evenly without high shear stress in mixed ingredients.
This type of mixture is known as an extensibility mixing or laminar mixing. The dispersed mixture is also called a strong mixing, in which high shear stress is applied to break the cohesive solids.
For example, when the additive pellet is smashed, the actual particle size becomes smaller. Blending operations often require two types of blending in one process.
Related Industry Knowledge
- Injection system
- Clamping system
- Hydraulic system
- Electrical control
- Heating / cooling
- Lubrication system
- Safety monitoring
- Before operating the main points
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