It mainly includes a concave die with a variable cavity composed of a concave die combination base plate, a concave die assembly and a concave die combination clamping plate, and a convex die with a variable core composed of a convex die combination base plate, a convex die assembly, a convex die combination clamping plate, a cavity cutting assembly and a side cutting combination plate. The coordinated changes of the punch and die of the mold and the auxiliary forming system. It can process a series of plastic parts of different shapes and sizes.

To improve the performance of plastics, various auxiliary materials such as fillers, plasticizers, lubricants, stabilizers and colorants need to be added to the polymers to become plastics with good performance.

Synthetic resin is the main component of plastics, and its content in plastics is generally between 40% and 100%. Because of its large content and the fact that the properties of resin often determine those of plastic, people often regard resin as a synonym for plastic. For instance, confusing polyvinyl chloride resin with polyvinyl chloride plastic or phenolic resin with phenolic plastic. In fact, resin and plastic are two different concepts. Resin is an unprocessed raw polymer. It is not only used to make plastics, but also serves as a raw material for coatings, adhesives and synthetic fibers. While a very small portion of plastics contain 100% resin, the vast majority of plastics, in addition to the main component resin, also require the addition of other substances.

2. Fillers, also known as fillers, can enhance the strength and heat resistance of plastics and reduce costs. For instance, adding wood powder to phenolic resin can significantly reduce costs, making phenolic plastic one of the cheapest plastics, while also greatly enhancing mechanical strength. Fillers can be classified into two categories: organic fillers and inorganic fillers. The former includes wood powder, rags, paper and various fabric fibers, etc., while the latter includes glass fibers, diatomite, asbestos, carbon black, etc.

3. Plasticizers Plasticizers can enhance the plasticity and flexibility of plastics, reduce brittleness, and make plastics easier to process and shape. Plasticizers are generally high-boiling-point organic compounds that are miscible with resins, non-toxic, odorless, and stable to light and heat. The most commonly used ones are phthalates. For instance, when producing polyvinyl chloride (PVC) plastic, if a large amount of plasticizer is added, soft PVC plastic can be obtained. If no plasticizer is added or only a small amount is added (less than 10%), hard PVC plastic will be produced.

4. Stabilizers: To prevent synthetic resins from decomposing and being damaged by light and heat during processing and use, and to extend their service life, stabilizers should be added to plastics. Commonly used ones include stearates, epoxy resins, etc.

5. Colorants Colorants can give plastics various bright and beautiful colors. Organic dyes and inorganic pigments are commonly used as colorants.

6. Lubricants: The function of lubricants is to prevent plastics from adhering to metal molds during molding and to make the surface of plastics smooth and aesthetically pleasing. Commonly used lubricants include stearic acid and its calcium and magnesium salts, etc. In addition to the above-mentioned additives, flame retardants, foaming agents, antistatic agents, etc. can also be added to plastics.