SMC (sheet molding compound) is a mixture of resin, low-profile additives, filler, and fiberglass. It is a plate with a removable film on the top and bottom.
The SMC manufacturing process consists of direct compression with hydraulic presses in a steel-heated matrix. Hardening takes from 2-5 minutes depending on the thickness and shape of the product. Once hardened, the product is taken out of the mould and mechanically processed.
ВМС (bulk molding compound) is a mixture of the same components as SMC. The main difference is that the fibre is shorter (3 to 12-15 mm) and the filling degree is higher.
Using various types of resins and other basic components (mineral fillers, shrinkage compensators, reinforcement fibres, pigments, etc.) makes BMC one of the most versatile and flexible technical construction materials, enabling the creation of products with miscellaneous properties and qualities.
Examples of application:
1. electrical distribution boxes 2. bodies of light reflectors 3. electrotechnical parts 4. flashlight and headlight bodies
Pure maleic unsaturated polyester resin in styrene. Suitable for SMC and BMC compounds with good physical and mechanical properties.
Orthophthalic unfilled resin for SMC/BMC hot pressing.
Unsaturated polyester resin in styrene, orthophthalic neopentyl glycol.
Magnesium oxide used as a thickener for SMC and BMC compounds.
Advantages of the technique:
1. high productivity, high quality of the final product 2. environmentally friendly, little waste 3. reproducible and low labour cost
Disadvantages of the technique:
1. very expensive equipment and tooling that pay back only in the case of large-scale production 2. limited range of the physical and mechanical properties of the products because the fibre direction is not adjustable