In composite technology, autoclaves are pressure vessels used to process parts and materials which require exposure to elevated pressure and temperature for the curing. The pressure is necessary to reach a sufficient level of fiber content and to reduce the residual porosity in the composites. Parts processed in an autoclave are often vacuum bagged to enable the pressure to operate isostatically on the workpieces. In simplest form, the workload is fully contained inside a loosely-fitting bag made of resilient plastic. When vacuum is drawn, the bag is compressed by atmospheric pressure and compacts the components inside. Between the parts and the bag, an absorbent material (bleeder) provides a channel for the evacuation of the air and wicks up the excess resin squeezed out during curing.
The composite department of AAC operates an autoclave from the company “Scholz GmbH” to manufacture molded composite structures. Rated at 10 bar and 300°C, the autoclave allows us to process high temperature epoxy, prepregs and thermoplastic materials.
An autoclave process sequence is performed as follow:
- Prepare plies
- Stack plies in tool
- Add dry material to absorb excess resin and remove volatiles
- Apply vacuum bag & cure in autoclave
- Oven post-cure for environmental durability
- Length: 1 m
- Diameter: 50 cm
- Maximal temperature: 300°C
- Maximal pressure: 10 bar
- Vacuum connections for bagging
- Cooling system for temperature control