Sheet molding compounds manufacture

A.2.4 Discontinuous-Fiber-Reinforced Polymer-Matrix Composites Sheet Molding Compound. Of the parameters influencing the mechanical properties in short-fiber-reinforced polymer-matrix composites, fiber composition, matrix composition, fiber geometry, and manufacturing method will be elaborated upon here. 

The matrix can be either a thermoset or thermoplastic. The oldest and still widest used material for compression molded products is phenolic. The thermoset materials used to manufacture fiber reinforced compression molded articles is unsaturated polyester sheet or bulk, reinforced with glass fibers, known as sheet molding compound (SMC) or bulk molding compound (BMC). In SMC, the 25 mm long reinforcing fibers are randomly oriented in the plane of the sheet and make up for 20-30% of the molding compound s volume fraction. 

In Europe, car manufacturers first used a half product, a sheet molding compound (SMC) made of sheets of fibers pre-impreg-nated with resin. In the USA they used a different process named RIM (Reaction Injection Molding) which allowed the bumper to be painted the same color as the rest of the structure. 

Sheet-Molding Compound) or SRIM (Structural Reaction Injection Molding) manufacturer, the surface quality or roughness is influenced by the type of reinforcement used (fibers, mats, roving), the particle size of the filler and the surface quality of the mold. 

Products such as sheet molding compounds (SMCs) and BMCs are usually manufactured by a two-stage process, in which resin, fillers and other additives are first mixed to a paste and then combined with fiber reinforcement, according to the required form of compound. For continuous production of SMC, the paste is thickened and metered by... 

Sheet processes are used to manufacture sheet molding compound (SMC), bulk molding compound (BMC) or thick molding compound (TMC). These materials are generally produced in sheet form for compression molding with matched metal hardened steel molds. 

SMA styrene maleic anhydride SMC sheet molding compound SMCAA Sheet Molding Compound Automotive Alliance SME Society of Manufacturing Engineers... 

The manufacture of cellulose acetate involves the acetylation of cellulose from cotton linters or wood pulp by acetic anhydride and acetic acid. Production started about 30 years ago, and early products that were developed include safety photographic films, airplane dopes, and acetate fabrics. It is now also produced in the form of sheeting, rods, and tubes and is widely used as a molding compound. 

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