The production of plastic products generally includes t […]
The production of plastic products generally includes the formulation, molding, machining, joining, modification and assembly of plastics. The latter four processes are carried out after the plastic has been formed into a product or a semi-finished product, also known as plastic secondary processing.
The key link in the processing of molded plastics for the production of plastic products. Various forms of plastic (powder, pellets, solution or dispersion) are made into articles or blanks of the desired shape. There are more than thirty methods of forming. Its choice depends mainly on the type of plastic (thermoplastic or thermoset), the starting form, and the shape and size of the product. Commonly used methods for plastic processing thermoplastics include extrusion, injection molding, calendering, blow molding, and thermoforming. Plastic processing thermosetting plastics are generally molded, transfer molded, and injection molded. Lamination, molding, and thermoforming are the shaping of plastic on a flat surface. The above plastic processing methods can be used for rubber processing. In addition, there are castings using liquid monomers or polymers as raw materials. Among these methods, extrusion and injection molding are used most and are the most basic molding methods. Machining of plastic products production Plastic products such as metal and wood are used to produce plastic products of very precise or small quantities. They can also be used as auxiliary processes for forming, such as sawing of extruded profiles. Because the properties of plastic are different from those of metal and wood, the thermal conductivity of plastic is poor, the coefficient of thermal expansion and the modulus of elasticity are low. When the clamp or tool is too pressurized, it is easy to cause deformation, it is easily melted by heat during cutting, and it is easy to adhere to the tool. on. Therefore, when the plastic is machined, the tools used and the corresponding cutting speeds must be adapted to the plastic characteristics. Commonly used mechanical processing methods include sawing, shearing, punching, turning, planing, drilling, grinding, polishing, and threading. In addition, plastic can also be cut, punched and welded by laser.
Bonding plastics for the production of plastic products The methods of joining plastic parts are welding and bonding. The welding method is hot air welding using electrodes, hot melt welding using hot poles, and high frequency welding, friction welding, induction welding, ultrasonic welding, and the like. The bonding method can be divided into a flux, a resin solution and a hot melt adhesive according to the adhesive used.
The purpose of surface modification in the production of plastic products is to beautify the surface of plastic products, usually including: mechanical modification, that is, using enamel, grinding, polishing and other processes, removing burrs, burrs, and size corrections on the parts; finishing, including coating with paint The surface of the part is brightened with a solvent, and the surface of the product is coated with a patterned film; the color is applied, including painting, printing and hot stamping; metal plating, including vacuum coating, electroplating, and chemical silver plating. The plastic processing hot stamping transfers the colored aluminum foil layer (or other film layer) on the hot stamping film to the workpiece under heat and pressure. Many household appliances, building products, daily necessities, etc., use this method to obtain patterns such as metallic luster or wood grain.