Image Number 2 for United States Patent #6149856.
In making thermoset and photo-set polymer-matrix composite parts, curing is the key process step that transforms the molecular structure of the composite material, stabilizing it in the desired shape. This curing system applies carefully controlled ultraviolet (UV) radiation dosages, appropriately distributed over the entire surface of the composite part, thereby rapidly curing the material while enabling direct monitoring and control of the curing energy. Previous photo-curing methods have applied generalized radiation to a part with conventional UV lamps. We provide great benefits in cure depth, speed and process control by precisely controlling all parameters of UV dosage, by computed control, by markings on the part, or by dynamic feedback control from embedded sensors or non-contact sensors. This system can apply greater radiation dose to areas of increased quantities of resin, such as support ribs, and lesser radiation dose to areas of decreased quantities of resin. This method can be enhanced by using differing resins which respond to differing wavelengths, and also by controlled changes of radiation field size or duration. This curing system also enables temporary joining of parts by sufficient partial or controlled-area photo-setting, which may also be integrated with lay-up or winding operations. As a result, these partially cured parts can be handled safely through later stages of the manufacturing process, such as final photo-setting or baking operation in an oven or autoclave.