As a way to reduce the overall vehicle weight, Mazda has developed a plastic molding technology that dramatically lowers the mass of plastic automobile parts. This new molding technology involves mixing supercritical fluid*1, made from an inert gas such as nitrogen or carbon dioxide, into the plastic as a foaming agent. This is combined with a technique called core-back plastic molding*2, which enables the thickness of the molded part to be increased while using less plastic. This unique technology has enabled us to reduce the amount of plastic used in parts by about 20% to 30% while achieving strength and rigidity equal or superior to that of conventionally produced parts.
This molding technology can be extended to almost every plastic part used in an automobile, providing the potential for a substantial reduction in materials and overall weight. It also has less environmental impact than conventional chemical foaming and helps make recycling easier.
- *1Supercritical fluid: Any substance at a temperature and pressure above its thermodynamic critical point. Nitrogen or carbon dioxide in the supercritical fluid state can dissolve plastic more readily than when in the gaseous state, allowing the formation of foam with a uniform micro-cell structure.
- *2Core-back plastic molding: A molding method in which foamed plastic is injected into a mold, after which the mold's volume is increased, causing the plastic foam to expand.
