User:NWeigel/sandbox

Bulk moulding compound
The article has information that is relevant to the topic. The entire article is underdeveloped. The third paragraph is very hard to understand due to grammatical errors.

The article is neutral except for the statement in the second paragraph saying the material has better strength properties than standard thermoplastic products.

The article has no citations at all.

The ways I could improve the article would be to verify the statements within the article and correct them if they are incorrect, add citations to the article, rewrite the third paragraph, and add any other information I find that is relevant to the article.

Bibliography:

Has information on how BMC is made.

Has information on concentrations of resin, styrene, filler, and reinforcement in BMC, the ways parts are manufactured using BMC, and the limitations of the parts made using BMC due to its properties.

Has information on the length of fibers used with BMC and where BMC is used.

Bulk moulding compound drafting
Bulk moulding compound (BMC), bulk moulding composite, or dough moulding compound (DMC), is a ready-to-mold, glass-fiber reinforced thermoset polymer material primarily used in compression moulding, but also used in injection moulding and transfer moulding. Typical applications include demanding electrical applications, corrosion resistant needs, appliance, automotive, and transit.

Manufacturing
BMC is manufactured by mixing strands (Greater than 1/8” and less than 2" ) of chopped glass fibers, styrene, an initiator, and filler in a mixer with an unsaturated thermoset resin (commonly polyester resin, vinyl ester resin or epoxy resin). The mixing is done at room temperature and stored at low temperatures to slow down curing prior to molding. The concentration of the mixture can vary depending on application, but is typically 30% glass fibers, 25% filler, and 45% resin, styrene, and initiator . The material is provided in bulk or in logs approximately 4" in diameter. The glass fibers in BMC result in better strength properties than standard thermoplastic products.

The viscosity of BMC dictates how effectively it can fill a mold. When at high viscosity, the the pressure applied to the BMC is not enough for it to flow, and when at low viscosity, the fibers will stay in one place while the rest of the material flows without them. This constrains the amount of each component that can be used when mixing BMC. Having a large amount of fibers or longer fibers improves mechanical properties but makes the BMC more viscous. Adding fillers can lower the cost of the BMC or improve a certain property, but causes the BMC to become more viscous. Adding more styrene lowers viscosity but causes the moulded BMC to become brittle. When at an optimal viscosity to allow flow, components made using BMC can be up to 16" in their longest dimension before the components of the mixture begin to separate.