Today's KNOWLEDGE Share:AUTOCLAVE CURING PROCESS:

 Today's KNOWLEDGE Share:

AUTOCLAVE CURING PROCESS:

Autoclave curing is a convective heat transfer process used for the curing of FRPs. In autoclave a closed vessel is maintained at a certain temperature and pressure for a definite time depending upon the type of resin under curing. The composite cured by autoclave technique can be prepared by the hand lay-up process or vacuum bagging process using prepregs. After preparation of the laminate stack, the component is placed in the autoclave chamber at a particular temperature and pressure for a particular time. Using certain optimized parameters, the components get cured/solidified. Mostly all types of composite laminates can be cured using cylindrical autoclaves. Large volumetric components of aircraft and wind energy generation wings can be easily cured using autoclave chambers. 

The autoclave curing chamber contains a pressure chamber in which components get cured under the required pressure and heat. The cylindrical shape of the vessel provides for both a flat and a cylindrical body for curing. For proper curing of components, the pressure should be maintained at a sustainable limit. The pressure vessel is made leakproof and the door is properly sealed after closing. The required pressure in the chamber is achieved using an air compressor mounted on the outer body of the chamber. For vacuum bagging, vacuum is maintained by two hose pipes connected to a vacuum compressor. Temperature sensors and thermocouples are placed inside the chamber for detecting temperature. Vessel pressure can be maintained by a safety valve that is mounted on the chamber to release excess pressure above the required level. For heating up the chamber, gas firing and electric heaters are used to complete polymerization/curing of polymer composites. Direct gas firing is mostly preferred for large volumetric components (aircraft and wind turbine blade), although direct heating systems are preferred for small components (automotive components). Large components require high thermal energy to spread over the surface of the components that can be only achieved by the gas firing method, whereas for small components the polymerization of components can be easily achieved by direct heating. The design of the gas firing tube should be done according to prescribed measurements to avoid leakage during operating hours. 

Bibliographical Reference:

Reinforced Polymer Composites: Processing, Characterization and Post Life Cycle Assessment - Page 82

Source:#managingcomposites/#thenativelab