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Rapid prototye - Commonly used plastic materials and processing methods

Oct 15,20

Definition and classification of plastics
Plastic is plastic, is a polymer organic material as the main component of the material, it is finished in the processing of solid shape, in the manufacturing and processing process, can borrow the flow of plastic to shape.Plastic for the synthesis of polymer compounds, the main component is synthetic resin, resin accounted for about 40% of the total weight of plastic ~100%.The basic properties of plastics depend largely on the nature of resins, but additives also play an important role.Some plastics are basically made of synthetic resins with little or no additives.
1.Characteristics of plastics
1)It's a high molecular organic compound.
2)It can exist in many forms, such as liquid, solid, colloid, solution, etc.
3)It can be molded.
4)There are a wide variety of different monomer compositions that can result in different plastics.
5)A wide range of applications, diversified products.
6)It has different properties.
7)The processing methods can be diversified.
2.The Advantages of plastic
1)Most plastics have strong corrosion resistance and do not react with acids or bases.
2)Plastic is cheap to make.
3)Durable, waterproof, light weight.
4)It can be easily machined into different shapes.
5)It's a good insulator.
6)Some of the plastic can be used to make fuel oil and fuel gas, which reduces crude oil consumption.
3.Disadvantages of plastics
(1)When it comes to recycling waste plastics, sorting is difficult and not economically viable.
(2)Plastics burn easily, and some of them produce poisonous gases when burned.For example, when polystyrene burns, it produces toluene, a small amount of which can cause blindness and symptoms such as vomiting when inhaled, and the burning of PVC also produces hydrogen chloride, a toxic gas.In addition to burning, high temperatures can also cause plastics to break down toxic components, such as benzene rings.
(3)Plastics are made from products refined from petroleum, which has limited resources.
(4)Plastics cannot be broken down naturally.
4.Classification of plastics
(1)According to the performance of plastics after they are heated, they are divided into the following categories.
Thermoplastic.Thermoplastic is a plastic that melts when heated, flows to a mold, cools and forms, and melts again when heated.It can be heated and cooled to produce reversible changes (liquid ←→ solid), that is, physical changes.General purpose thermoplastics whose continuous use temperature is below 100, polyethylene (PE/HDPE), polyvinyl chloride, PVC, polypropylene PP.
Thermosetting plastics.Thermosetting plastics refer to the plastics which are insoluble in any solvent after curing under heat or other conditions and cannot be softened again by means of heating.Thermosetting plastics decompose when heated to too high a temperature.Such as phenolic plastics (commonly known as bakelite) epoxy plastics, etc.
(2) According to the different use characteristics of plastic, plastic is usually divided into the following several items.
Universal plastics.General plastic generally refers to the production of large, wide use, good molding, cheap plastic.General purpose plastics usually have polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and so on.
Engineering plastics.Engineering plastics generally refer to the plastics that can bear certain external forces, have good mechanical properties, high and low temperature resistance, good dimensional stability, and can be used for engineering structures, such as ABS, polyamide PA, polysulfone, etc.
Special plastics.Special plastics generally refer to plastics with special functions, which can be used in aviation, aerospace and other special applications.Such as fluorine plastic and organic silicon, with outstanding high temperature resistance, self-lubrication and other special functions.Reinforced plastics and foam plastics have high strength, high cushioning and other special properties, these plastics belong to special plastics.

5.Method of plastic forming
Plastic molding is the process of making the final plastic product from a polymer made from a synthetic resin.The processing methods of handboard model (usually called the primary processing of plastics) include CNC machining, 3D printing, duplicate molding, lathe processing, plastic blow-up and so on.