Heißpresseverfahren

Heißpresseverfahren, or hot pressing, is a forming and densification method in which heat and mechanical pressure are applied simultaneously to a material located in a mold. In a typical setup, a die or platen is heated while a hydraulic or servo-driven press applies uniaxial pressure, followed by a dwell period at elevated temperature and a controlled cooling under pressure. This combination promotes particle rearrangement, sintering or resin curing, and results in a dense solid component.

The process is used with a wide range of materials, including metal and ceramic powders, polymer-based composites, carbon-fibre-reinforced materials, and wood-based panels such as fiberboard and particleboard. It is valued for producing parts with high density and a refined microstructure, often yielding improved mechanical properties and dimensional stability compared with pressureless molding or conventional sintering. Temperature and pressure settings are chosen according to the material system: metals and ceramics typically require high temperatures near or above their sintering points, while polymers are pressed near or above their glass transition or melting temperatures.

Key parameters include temperature, pressure, dwell time, heating and cooling rates, and the atmosphere inside the tooling (vacuum or inert gas to prevent oxidation or degradation). Advantages of the method include reduced porosity, strong bonding between constituents, and the ability to form complex shapes in relatively few steps. Drawbacks include high capital costs for equipment, potential anisotropy due to uniaxial pressure, and size limitations. In industry, Heißpresseverfahren is commonly used for dense ceramics and metal components, polymer composites, and wood-based panel production, among other applications.