Liquid composite molding comprises all the composite manufacturing methods, where the liquid state matrix material (e.g. epoxy resin) is forced into the dry preformed reinforcing material (e.g. carbon fiber fabric). The main objective is to reach a full impregnation as the resin propagates between the fiber bundles and fibers. The impregnation driving force is usually resulting from pressure difference. Resin transfer molding (RTM) utilizes positive operating pressures, while in vacuum infusion the pressure is lower than the atmospheric pressure level. Vacuum assisted resin transfer molding (VARTM) operates with positive injection pressures, while the mold cavity is kept under vacuum. Positive operating pressure techniques require matched molding (two or more part molds), while vacuum infusion is usually done using a flexible membrane (e.g. polymer foil) on the mold.
Our company is covering the whole processing range of liquid composite molding techniques. We are offering solutions from raw material characterization, through process modeling to component manufacturing.
Raw material characterization
Both resin and reinforcement materials should be characterized to understand their influence on the impregnation process. Resin properties like viscosity build-up or degree of conversion in time at different temperatures can be measured. Reinforcement materials are characterized by their permeability at different fiber content ratio, geometrical distortion degree and/or stacking sequence (e.g. with flow enhancing layers).
We are able to model and optimize the whole liquid moulding process with the help of the PAM-RTM software, in which the whole liquid molding processing chain is included. Reinforcement preforming, mold filling and curing can be simulated in 3D simulation environment. The measured resin and reinforcement properties can be directly implemented and process optimization can be done in a virtual environment.
AAC is able to manufacture samples/components by resin transfer molding (RTM), vacuum assisted RTM and vacuum infusion. Our mobile injection machine (injection system from Tartler GmbH) can process a wide range of thermoset resins. Resin injections with constant flow rates (0-0.5 l/min) or constant pressures (up to 90 bar) at elevated temperatures (up to 130°C) can be realized. Flow rate, temperatures and pressures can be recorded in time, giving an opportunity to verify the results of the process modeling.
Mould and Injection characteristics:
- Size: 40 cm x 40 cm
- Maximal curing temperature: 180 °C
- Injection for 1K system: up to 0.5 l/min
- Maximal pressure: up to 90 bars
- Volume: 5 Liters pre-mixed resin-hardener