Polytetrafluoroethylene (PTFE)

PTFE, commonly known as the "King of Plastics," is a high-performance engineering plastic widely used in various industrial fields due to its unique chemical stability, high-temperature resistance, corrosion resistance, and extremely low coefficient of friction. PTFE can be molded using various methods, each with its specific applications and advantages. These methods mainly include compression molding, extrusion molding, injection molding, isobaric molding (hydraulic molding), spray molding, and special molding technologies.

1. Compression Molding: This is one of the most commonly used molding methods for PTFE. It involves placing pre-formed PTFE powder into a mold and then pressing it under high temperature and pressure. This method is suitable for manufacturing relatively simple shapes and large sizes, such as sheets, rods, and tubes. The advantages of compression molding are high product density and good mechanical properties, but the mold cost is high, and the production cycle is relatively long.

2. Extrusion Molding: Extrusion molding is suitable for manufacturing continuous lengths of tubes, rods, and films. This method involves extruding a PTFE paste or pre-compressed rod through a die of a specific shape while applying pressure to shape it. Extrusion molding can produce products of unlimited length and with smooth surfaces, but the cross-sectional shape of the products is relatively simple.

3. Injection Molding: Although PTFE has extremely high melt viscosity, making direct injection molding difficult, it can be partially melted and then injection molded through special modification treatments or the addition of additives. This method is suitable for manufacturing products with complex shapes and high precision requirements, such as gears and bearings. The advantages of injection molding are high production efficiency and high product precision, but the equipment cost and technical requirements are also relatively high.

4. Isopressing (Hydraulic Molding): Isopressing uses a liquid to transmit pressure, causing PTFE powder to be uniformly compressed and shaped within a mold. This method is suitable for manufacturing large, complex-shaped products and can ensure the uniformity of density and performance of the products. The advantages of isopressing are high product quality and strong adaptability, but the equipment is complex and the operation is more difficult.

5. Spray Coating: Spray coating involves applying a PTFE dispersion or suspension to the substrate surface using a spray gun, followed by drying and sintering to form a coating. This method is suitable for manufacturing surface coatings with anti-corrosion, wear-resistant, and friction-reducing functions, and is widely used in chemical, machinery, and electronics industries.

6. Special Molding Technologies: In addition to the conventional molding methods mentioned above, there are some special molding technologies, such as stretch molding and blow molding. These methods are selected and applied based on specific needs and product characteristics.

When selecting a molding method, factors such as the product's shape, size, performance requirements, and production costs must be comprehensively considered. Furthermore, the PTFE molding process requires careful control of parameters such as temperature, pressure, and molding time to ensure the quality and performance of the product.