Sheet Molding Compound (SMC)

Sheet molding compound (SMC) is a combination of uncured thermoset resins, fillers, additives and long glass fibers, in sheet form, that is used to make glass reinforced plastic (GRP) products. It is formed into products by compression molding. Compression molding involves placing a sheet of SMC onto a heated mold, then forcing it into the mold cavities using a heated plug. Heat from the plug and mold softens the SMC and allows it to flow into the mold cavities. After a few seconds, the heat begins to cure the SMC, which solidifies and hardens.
These materials are usually formulated to meet performance requirements of the part to be molded. SMC is ideal for large structural components due to its high strength-to-weight ratio, thermal resistance, good mechanical and electrical properties, decreased shrinkage, sink marks and warpage. SMC offers additional benefits in part design allowing localized rib reinforcement and bosses for fastening attachments and sub-assemblies. Significant tooling investment and overall component cost savings result from part consolidation. With the same coefficient of thermal expansion as Steel and excellent corrosion resistance, SMC is an ideal alternative to Steel and can be used in the same fluctuating temperature environments. The main benefit however is a typical 25% weight reduction achieved at similar strength to Steel.
Various types of SMC sheets and parts with different applications such as automotive, flame retardants, food grades and etc., are being designed and manufactured by the companies in this industrial group.

Advantages

– Increased strength-to-weight ratio compared to similar steel products
– High rate of production
– Ease of assembly results in cost reduction
– Complicated parts design and manufacturing possibility
– Appropriate electrical resistance (Electrical insulation)
– Reduced shrinkage
– Reduced warpage & sink marks
– Applicable in a wide range of temperatures
– Appropriate chemical resistance
– A suitable alternative for steel due to the same thermal expansion coefficient as well as excellent corrosion resistance
– The ability of producing A-class parts

Applications

– Automotive industries: (painted body panels, lightweight structural panels such as bumpers, valve covers, and engine shields, cooling pack, Tractor body parts …)
– Electrical industries: (electrical enclosures, lighting, solar …)
– Construction industries: (GRP sectional water storage tanks, manhole covers, shower bases, wall coverings and dropped ceiling, sinks…)
– Transportation industries: (subway train chair …)