Plastic mold common sense - injection molding

Plastic mold common sense - injection molding

Extrusion blow molding is a method of making hollow thermoplastic parts. Well-known blow moulding objects are bottles, barrels, cans, boxes, and all containers for food, beverages, cosmetics, medicines, and daily necessities. Large blow - moulded containers are commonly used for packaging of chemicals, lubricants and bulk materials. Other blow moulds are balls, bellows, and toys. For the automotive industry, fuel tanks, car shock absorbers, seat backs, center brackets, and armrests and headrest claddings are blow moulded. For machinery and furniture manufacturing, blow moulded parts may be casings, door frames, frames, pottery POTS, or boxes with an open side.

Shanghai Injection Molds

polymer

The most common blow molding material is high-density polyethylene, the polymer that is used to make most milk bottles. Other polyolefins are also often processed by blow molding. Styrene polymers, polyvinyl chloride, polyesters, polyurethane, polycarbonate and other thermoplastics can also be used for blow molding, depending on their use. Engineered plastics have recently gained widespread acceptance in the automotive industry. Material selection is based on mechanical strength, weather resistance, electrical, optical and other properties.

process

Three-fourths of blow molding products are made by the extrusion blow molding method. The extrusion process is to force the material through a hole or die to make a product. Extrusion and blow molding process consists of five steps: 1. Plastic embryo (hollow plastic tube extrusion); 2. 2. Close the flap closing mold on the mold, clamp the mold and cut off the mold; 3. Blow and expand the mold to the cold wall of the mold cavity, adjust the opening and maintain a certain pressure during cooling, open the mold and unload the blown parts; 5. Trim the flaps to get the finished product.

extruded

Polymer blending is defined as the process of improving the grade of a polymer or polymer system by melt mixing. Mixing processes range from the addition of a single additive to the treatment of multiple additives, polymer alloys and reactive mixtures. It is estimated that one-third of all polymer production in the United States goes through blending. Blends can be customized according to the performance requirements of the final application. Blend products have hybrid properties, such as high gloss and excellent impact strength, or precision molding and good stiffness. The blended polymer is usually granulated for further processing. However, there is growing interest in the industry in combining blending with further processes, such as extrusion of profiles, to avoid reheating the polymer.

hybrid

Various types of melt mixing equipment are used, from roll mills and batch mixers to single - and twin-screw extruders. Continuous mixing (extruder) is the most commonly used device because it provides consistent quality and reduces operating costs. There are two types of mixing: distributed mixtures that can be uniformly distributed without the use of high shear stresses in remixing ingredients. Such mixtures are referred to as extensional or laminar mixtures. Dispersed mixing is also called strong mixing in which high shear stresses are applied to break up cohesive solids. For example, when additive pellets are broken, the actual particle size decreases. Mixing operations often require two types of mixing in the same process