Compression molding is a composite processing method that uses high pressure to cause the molding material to flow, enabling the production of components with medium complexity and large surface areas. TAFNEX™ Design Sheets (or unconsolidated chips) function like glass mat reinforced thermoplastic (GMT) as a flat molding material and can form basic features like ribs, thanks to their limited fiber length.
Compared to Injection Molding, Compression Molding offers lower investment costs, notably in mold expenses. Thus, it is also appropriate for medium-sized production quantities of functional components.
Compression Molding allows for short cycle times, typically ranging in the order of a few minutes, depending on the application.
A full Compression Molding production line can be automated with robots and conveyor belts, managing operations from handling the sheet material to post-processing tasks.
Compression Molding enables the production of semi-complex, high-performance components with basic functional elements. This technology allows multiple individual parts to be consolidated into a single component, significantly reducing assembly efforts.
The process of Compression Molding closely resembles that of Thermoforming. It begins with heating the TAFNEX™ Design Sheet above its melting point, typically done outside the mold using one of three heating technologies (listed below). Nevertheless, certain companies offer in-mold induction heating technology, which facilitates the entire process to take place inside the mold.
1. Heating the sheet above its melting point
2. Positioning the sheet in the open mold
3. Closing the mold + forming
4. Consolidation / cooling
5. Opening the mold
6. Demolding
For heating the TAFNEX™ Design Sheet outside the mold one of these technologies is utilized. Usually, infrared (IR) heating is used due to its efficiency, especially for thinner components. For very thin sheets or blanks, one-sided IR heating can be employed to reduce investment and operating costs.
+ very short heating times
+ energy-efficient
- temperature gradient across sheet thickness
-> Used for all type of sheets
+ very homogeneous heating
- very slow heating times (however, short cycle times are achievable through a paternoster system)
-> Typically used for very thick sheets
+ short heating times
+ homogeneous heating
+ pre-consolidation through applied pressure
- low matrix concentrations on the surface & poor surface quality
-> Used when pre-consolidation is beneficial
Using Compression Molding, a TAFNEX™ Design Sheet with one-sided reinforcements is transformed into a lightweight, function-integrated drone arm.
Automotive underbody shields can be produced using Compression Molding, such as by combining TAFNEX™ Structural Sheets with a PP-GF LFT core.
Using Compression Molding, a TAFNEX™ Design Sheet is transformed into a lightweight bicycle crank lever.