Spray molding

Spray molding is the modification of the hand-lay process where the resin and glass fiber are deposited simultaneously on the molding tool. The fibers are mixed with the resin at the spray head before being deposited on the mold surface. Subsequent consolidation of the laminate is achieved by rolling in a similar manner to the hand-lay process. This method is suitable for large components. Here the capital cost is higher and the process is very operator sensitive. 

PHAs can be manufactured to many different materials and shapes, by processing on conventional equipment for polyolefins or other plastics, e. g. injection molding, extrusion, film blowing and fiber-spray molding [141]. Furthermore, they can be processed in latex (granules in water), or in solution... 

Appropriate amounts of x y resin and liquified amine were mixed together and evacuated at 60 c in a vacuum oven for t i minutes to remove air bubbles. The reaction mixture was poured into a hot (85°C) aluminum mold vhich was prepared in advance by lic tly spraying mold release agent (ISi 515, Green Chem. Products Inc.) to the inner surfaces of the mold. Samples were cured two hours at 85 C followed by two hours at 150 c (standsuxl cure). In some cases samples were subjected to eui alternate, high temperature cure of two hours at 85 C and two hours at 175 C (HT cure). After curing, samples were stored in a desiccator until use. 

RHR rate of heat release RSM reaction spray molding... 

Spray molded article. [Data from Xresino, J, Cassala, B, Horton, S D, European Patent EF2646498, Oct. 9,2013, PofyOne Corporation.]... 

Mold is opened and the part ejected Number of layers, consisting of a mixture of reinforcement (usually glass cloth) and resin (thermosetting), are placed in mold and contoured by roller to mold s shape. Assembly is allowed to cure (usually in an oven) without application of pressure. In modification of process, called spray molding, resin systems and chopped fibers are sprayed simultaneously from spray gun against mold surface roller assist also is used. Wet lay-up parts sometimes are cured under pressure, using vacuum bag, pressure bag, or auto-clave... 

FIGURE 4.56 Complete spray mold for the manufacture of instrument panels... 

After completing a production run the mold surfaces should be washed scrupulously with a mild alkaline solution such as sodium nitrate. After drying, the mold surfaces should be sprayed with an oil or silicone base spray. Mold surface temperatures and size of ejectors have a considerable influence on the cycle time with respect to deep draw components, such as computer housings etc.. 

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