Plastic processing, also known as plastic molding, is the process of processing plastics or synthetic resins into plastic products. It can be said to be one of the largest production sectors in the plastics production industry. Plastic processing is developed because of the development of synthetic resins. With the continuous improvement of science and technology, plastics
The processing technology has also been greatly improved. At present, it is mainly composed of the steps of batching, molding, cnc plastic machining, joining, modification, and assembly. Let’s take a closer look at its technological process.
Plastic Processing Process
This is the first step in the plastic processing technology. In addition to the polymer, it requires the addition of some plastic additives such as stabilizers, plasticizers, colorants, etc., so that the performance of the processed plastic products will be greatly improved. improve, and also reduce production costs. The polymer and additives are mixed together and dispersed as a dry mix. It can also be processed into pellets.
This is the most critical step in the plastic processing process. We need to make various forms of plastic into the desired shape. There are many ways to form this, and the choice is mainly based on the type of plastic, the initial shape, and the size and shape of the product. If it is a thermoplastic, extrusion, injection molding, calendering, blow molding and thermoforming are generally used; if it is a thermosetting plastic, molding, transfer molding, or injection molding can be used. In addition, there are castings using liquid monomers or polymers as raw materials.
3.CNC Plastic Machining
This step can be seen as an auxiliary process of forming. It can borrow the cnc plastic machining methods of metal or wood to manufacture some plastic products with precise dimensions or small quantities. However, the performance of plastic is completely different from that of metal and wood. The tools and cutting speed used in machining must conform to the characteristics of plastic.
This step is to join the plastic parts together. There are two main methods: welding and bonding. The welding methods are mainly hot air welding, hot melt welding, high frequency welding, friction welding, ultrasonic welding, etc. The bonding method is done using adhesives such as flux, resin solution and hot melt adhesive bonding.
The purpose of this step is to beautify the surface of plastic products, generally through mechanical modification, that is, grinding, filing, polishing, etc.; and then finishing, such as coating the surface of the product with paint, covering the surface of the product with a patterned film, etc. ; There are also coloring, such as painting, printing, etc.; there are also metal plating, including vacuum coating, electroplating, and chemical silver plating.
This is the last step in plastic processing, which is to combine the individual plastic parts processed into a complete plastic product.
Several of the most common plastic processing processes
- Extrusion: Extrusion is also called extrusion in plastic machining and extrusion（Different from aluminum extrusion） in rubber processing. It refers to a processing method in which the material passes through the action between the extruder barrel and the screw, is heated and plasticized, and is pushed forward by the screw, and continuously passes through the head to make various cross-sectional products or semi-products. Extruded products are continuous profiles, such as tubes, rods, wires, plates, films, wire and cable coatings, etc. The extruded products produced by Baoyi use a variety of unused raw materials, among which the most commonly used are cnc machining peek,PC, ABS, PVC, PS, PE, PP, TPE, TPE, TPU, etc. After the processing is completed, there are many plastic products such as LED lampshades, drain pipes, supermarket price tags, etc. that appear in our lives. The processing technology is extrusion.
- Injection Molding: Thermoplastic injection molding, a method in which the plastic material is melted and then injected into the film cavity. Once the molten plastic enters the mold, it is cooled and shaped into a cavity-like shape. Injection-molded products are also very common in our lives. Our most common products are: computer case shells, connectors, mobile phone shells, keyboards, mice, stereos, etc.
- Blow molding: also known as hollow blow molding, a rapidly developing plastic processing method. The tubular plastic parison obtained by extrusion or injection molding of thermoplastic resin is placed in a split mold while it is hot (or heated to a softened state), and compressed air is introduced into the parison immediately after closing the mold to blow the plastic parison. It expands and sticks closely to the inner wall of the mold, and after cooling and demoulding, various hollow products are obtained. The plastic processing technology for bottles, barrels, cans, boxes and all containers for packaging food, beverages, cosmetics, medicines and daily necessities that are common in our lives is blow molding.
The above is the technological process of plastic processing. The most important ones are the first two steps. The latter four processes are carried out after the plastic has been formed into a finished product or semi-finished product, which is regarded as the secondary processing of plastic. In the process of plastic processing, it is inevitable to encounter various problems, among which the plastic processing shrinkage problem is the most common and the most difficult one. Only by minimizing this problem can a higher quality of the product be guaranteed. However, with the continuous improvement of plastic processing technology, it is believed that this problem will be solved in the future.