Production process of plastic products
According to the inherent properties of plastic, it is a complex and heavy process to make it a plastic product with a certain shape and use value. In the industrial production of plastic products, the production system of plastic products is mainly composed of plastic molding, machining, decoration and Assembly consists of four sequential processes.
In these four processes, plastic molding is the key to plastic processing. There are as many as thirty kinds of molding methods, mainly to make various forms of plastics into products or blanks of desired shapes. The molding method mainly depends on the type of plastic, the initial shape and the shape and size of the product. The commonly used methods for plastic processing thermoplastics include extrusion, injection molding, calendering, blow molding and thermoforming. Transfer molding, also used in injection molding, lamination, molding, and thermoforming, is the shaping of plastics on a flat surface. The above-mentioned 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 more, and they are also relatively basic molding. method.
The mechanical processing of plastic product production is to borrow plastic processing methods such as metal and wood to manufacture plastic products with a small size or a small number. It can also be used as an auxiliary process for forming, such as sawing of extruded profiles. Different from wood, plastic has poor thermal conductivity, low thermal expansion coefficient and elastic modulus. When the fixture or tool is pressurized too much, it is easy to cause deformation, and it is easy to melt when heated, and it is easy to adhere to the tool. Therefore, when plastic is machined, the tools used and the corresponding cutting speed must be adapted to the characteristics of the plastic. Commonly used machining methods include sawing, shearing, punching, turning, planing, drilling, grinding, polishing, threading, etc. In addition, , Plastics can also be laser cut, punched and welded.
The methods of joining plastic parts in the production of plastic products include welding and bonding. The welding method is hot air welding using electrodes, hot melt welding using hot electrodes, as well as high frequency welding, friction welding, induction welding, ultrasonic welding. etc., the bonding method can be divided into flux, resin solution and hot melt adhesive bonding according to the adhesive used.
The purpose of surface modification of plastic products production is to beautify the surface of plastic products, which usually includes: mechanical modification, that is, using processes such as filing, grinding, polishing, etc., to remove burrs, burrs, and size corrections on parts. Finishing, including coating the surface of the product with paint, brightening the surface with a solvent, and coating the surface of the product with a patterned film. Color application, including painting, printing and hot stamping; metal plating, including vacuum coating, electroplating and chemical silver plating, etc. Plastic processing hot stamping is to transfer the colored aluminum foil layer on the hot stamping film to the workpiece under heating and pressure. Many household appliances, building products, daily necessities, etc., use this method to obtain patterns such as metallic luster or wood grain.
Assembly is the operation of assembling plastic parts into complete products by methods such as bonding, welding and mechanical connection, such as plastic profiles, which are assembled into plastic window frames and plastic doors after sawing, welding, drilling and other steps.