Thermoplastic basic shapes molding
Molding is a common process to produce semi-finish parts, or basic shapes. This process is adapted to all materials, including high performance plastics. Even PTFE is easily molded, even if this particular fluoropolymer requires its own equipments.
Molded parts with specific tools for quality and performance
Molding of high performance plastic is an essential step to produce basic shapes, semi-finished or finished parts (after machining for example). Plastic or compound is compressed and heated in mold of desired shapes. PTFE molding process is slightly different, as the part is heated after compression (see below).
For high performance polymers, with high melting temperature, dedicated tools are needed, and strong know-how in cooling behavior and cristallinity is required to design the materials for its use. Indeed, in the same polymer family, different grades will show drastically modified properties, hence use cases.
Cost constraints of high performance polymers are also at stake in the molding process. The right mold design and molding process parameters allow limited or even no scrap to reach tolerances on final parts. This is highly critical as high performance polymers are quite expensive compared to engineering plastics.
PTFE molded parts require an impacting extra step
PTFE is a really specific thermoplastics, as it shows ultra high viscosity above melting point. Thus PTFE can’t be directly melted.
For enhanced performance, different molding technologies are available. The most common molding process of PTFE is based on axial molding, where molding pressure is applied on ends of the mould. For more complex parts and better properties, one solution is isostatic molding, where the mold is fitted in a chamber fitted with fluid. When pressure is applied to the chamber, it is equally applied on all the surface of the mold, thus allowing uniform properties.
Such know-how in the particular transformation steps, developed at 3P for more than 50 years of PTFE transformation, is also a strong asset in molding solutions for the other high performance plastics, including the 3P’s Xytrex® range.
