PTFE (Polytetrafluoroethylene) is a high-performance plastic known for its excellent chemical resistance, low friction, and non-stick properties. Molded PTFE is used in various industries, including chemical processing, electronics, and medical devices, due to these remarkable characteristics. The molding process for PTFE is unique compared to other plastics due to its high melting point and non-flowing nature. Below is an overview of how PTFE is molded.

1. Types of PTFE Molding Processes

There are primarily two methods used to mold PTFE: compression molding and ram extrusion. Both techniques involve different steps, but they share the goal of creating solid PTFE parts that maintain the material’s inherent properties.

  • Compression Molding: In this method, PTFE powder is placed into a mold cavity, which is then heated under pressure. The heat causes the PTFE powder to expand and bond into a solid form. Once the part has cooled, it is removed from the mold and finished to the desired specifications. This process is typically used for producing parts like seals, gaskets, and bushings.
  • Ram Extrusion: This method is used to create continuous shapes like rods, tubes, or sheets. PTFE powder is loaded into a barrel, where it is compressed and heated by a ram to form a dense, uniform shape. This method is ideal for producing larger quantities of PTFE parts with consistent dimensions.

2. Sintering Process

After the initial molding, PTFE must undergo a process called sintering. During sintering, the molded PTFE part is heated to a temperature high enough to allow the particles to fuse together without fully melting the material. This process ensures the part achieves the required strength, density, and durability.

3. Post-Molding Operations

Once molded and sintered, PTFE parts may require additional finishing steps, such as machining or trimming, to achieve precise dimensions and smooth surfaces. Since PTFE is difficult to machine due to its hardness, specialized tools and equipment are often needed.