Complete Collection of Plastic Processing Techniques:

1. Injection molding

The most widely used molding method for plastic products. Injection molding machine is the main molding equipment that uses plastic molds to make various shapes of plastic products from thermoplastic or thermosetting materials. Injection molding is achieved through injection molding machines and molds.

In fact, it is similar to the plasticine we used to make when we were young. We put a piece of plasticine (plastic melt) into a box (mold) with a certain shape, press it with our hands (mold clamping pressure), and then open the box cover (mold opening) to obtain the product we want.

2. Extrusion molding

A processing method in which materials are continuously processed into various cross-sectional products or semi-finished products through the action between the extruder barrel and the screw, while being thermally plasticized and pushed forward by the screw. Mainly used for the preparation of pipes and sheets.

In fact, just like we usually squeeze toothpaste, we forcefully squeeze (screw transport) the paste, and the toothpaste (polymer melt) will come out through a small mouth (mold), forming a cylindrical shape (if the mold shape changes, the corresponding shape will be obtained).

3. Blow molding

Also known as hollow blow molding, it is 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). After the mold is closed, compressed air is immediately introduced into the parison, causing the plastic parison to expand and tightly adhere to the inner wall of the mold. After cooling and demolding, various hollow products are obtained.

This process can be seen as the production process of square watermelons currently appearing in the market. Firstly, after the watermelon naturally becomes an oval shaped small melon body (tubular plastic mold), a square box (mold) is inserted into the oval shaped small melon body. After the watermelon further grows (blows), it is bound by the square box (mold compression) and ultimately becomes a square shaped watermelon (bottles of different shapes).

4. Blister molding

A plastic processing process that primarily involves heating flat plastic hard sheets to become soft, using vacuum adsorption on the surface of the mold, cooling them to form, and applying them to various industries.

The entire process can be seen as a process of making fried eggs. The egg liquid (softened plastic embryo) is placed in a certain shaped kitchen utensil (mold), heated (adsorbed onto the inner side of the mold through vacuum softened plastic embryo), and the final shape is obtained.

5. Molding

Also known as compression molding or compression molding, it is the process of first placing powdered, granular, or fibrous plastic into the mold cavity at the molding temperature, and then closing the mold to pressurize and solidify it. Molding can be used for both thermosetting plastics, thermoplastic plastics, and rubber materials.

The principles of compression molding and injection molding are similar, but they can be used for the molding of thermosetting resins. That is to directly place the raw materials in a mold with a well-designed shape and texture, then pressurize, heat, and retain for a period of time, and then cool to obtain the corresponding product.

6. Rolling forming

The melt plasticized thermoplastic is extruded, extended and stretched by more than two parallel and opposite rotating roller gaps to become a continuous sheet product with certain size and quality requirements, and finally formed by Free cooling. The rolling forming process is commonly used in the production of plastic films or sheets.

Compared to extrusion molding, it only utilizes the pressure and tension between two or more rollers after the product is extruded. Make the product thinner.

7. Foam forming

It is the process of adding appropriate foaming agents to foaming materials (PVC, PE, PS, etc.) to create a microporous structure in the plastic. Almost all thermosets and thermoplastics can be made into foam plastics, and foam molding has become an important field in plastic processing.

Foam forming is particularly easy to understand. It is similar to the process of making Mantou. In order to make the same dough into large and soft Mantou, we usually add baking soda. It is actually the process of chemical foaming. During the heating process of the dough, baking soda will decompose industrial CO2, which will create bubbles in the dough, causing it to expand and become larger. Of course, plastic foaming, in addition to chemical foaming, can also be achieved by directly injecting gas into the melt through equipment.

8. Winding forming

The process involves winding continuous fibers (or cloth tapes, pre impregnated yarns) soaked in resin glue onto the core mold according to a certain pattern, and then curing and demolding to obtain the product.

The main molding method for thermosetting resins is to brush paint onto the wall, and after drying and molding, if the entire piece is peeled off, the shape of the substrate will be determined.

9. Lamination molding

It refers to the forming and processing method of combining multiple layers of the same or different materials as a whole under heating and pressure. Commonly used in plastic processing and also in rubber processing.

It is similar to plastic molding, but can be used for multi-layer material molding. And molding is mostly a single material, single structure molding.

10. Coating Forming

It is a process of using plastic or organic sols to coat the surface of substrates such as cloth or paper, making imitation leather products, linoleum or plastic wallpapers, or coating powdered plastic on metal surfaces. Common plastic coated products include synthetic leather, linoleum, plastic wallpaper, and various metal coated products.

In fact, coating the melted resin on the surface of the substrate, and after cooling, the corresponding shape of the product can be obtained. Mostly used for making large and flat plastic products.

11. Pouring molding

It is a method of plastic processing. Early casting was the process of injecting liquid monomers or prepolymers into a mold under normal pressure, and then polymerizing and solidifying them to form products with the same shape as the mold cavity. In the 1960s, nylon monomer casting emerged. With the development of molding technology, the traditional casting concept of polyamide has changed. Polymer solutions, dispersions refer to polyvinyl chloride paste and melts, which can also be used for casting molding.

In the early days, it was actually a method used to shape thermosetting resins. Later, it was gradually used in thermoplastic resins. The process involves placing raw materials that have not yet solidified into a mold and reacting them with external additives or stimuli. Similar to the formation of square watermelons mentioned above.

12. Dropping molding

It utilizes the variable state properties of thermoplastic polymer materials, which have viscous flow properties under certain conditions and can restore solid state properties at room temperature. By using appropriate methods and specialized tools for inkjet, it is molded into the designed form according to requirements in its viscous flow state, and then solidified at room temperature.

The molding method used for thermoplastic resins is like lighting a candle, and the paraffin oil will fall down. If it drips onto a mold with a certain shape, it will appear in a certain shape after cooling.

13. Compression molding method

Mainly used for the production of thermosetting plastic products. The product is formed by heating it to melt, pressing it into a mold, and then heating it to cross-link and solidify it. After demolding, the product is obtained.

Mainly used for the molding of thermosetting resins.

14. Resin transfer molding

It is a process method of injecting resin into a closed mold to soak in reinforcing materials and solidify them. This technology does not require prepregs or hot pressing tanks, effectively reducing equipment costs and molding costs. This technology has developed rapidly in recent years and is widely used in fields such as aircraft industry, automotive industry, and shipbuilding industry. It has also developed various branches such as RFI, VARTM, SCRIMP, and SPRINT to meet the application needs of different fields.

15. Extrusion molding

It is a pressure processing method that uses a punch or punch to pressurize the blank placed in the concave mold, causing it to produce plastic flow, thereby obtaining a workpiece corresponding to the shape of the mold hole or concave convex mold. During extrusion, the billet generates three-dimensional compressive stress, and even the billet with lower plasticity can be extruded into shape.

Similar to blow molding, except that it utilizes the pressure of the mold for molding. It's not compressed air.

16. Hot forming

It is a special plastic processing method that processes thermoplastic sheets into various products. A special plastic processing method for processing thermoplastic sheets into various products. The sheet material is clamped on the frame and heated to a softened state. Under external force, it is tightly pressed against the mold surface to obtain a shape similar to the mold surface. After cooling and shaping, the product is finished after trimming.

Similar to blow molding, the resin is first made into flakes instead of tubes during the blow molding process. The subsequent process is similar to molding. Place the sheet-like intermediate into a mold of a certain shape for heating and forming.

17. Hand layup molding

Also known as manual lamination molding or contact molding, it refers to the process of manually laying reinforcing materials on a mold coated with a release agent, while brushing resin until the required thickness of the plastic product is reached, and then obtaining the plastic product through curing and demolding.

The molding method of thermosetting composite materials is similar to masonry in terms of overall height. First place a layer of resin underground, then place a layer of bricks on top of the resin, and then apply the resin to this layer of bricks, and so on. However, the hand layup of the resin is placed in the mold, which will ultimately only wait for the desired shape of the product.