MDF (Medium-Density Fiberboard) is an engineered wood product made by breaking down hardwood or softwood residuals into wood fibers, combining it with wax and a resin binder, and forming it into panels by applying high temperature and pressure. MDF is generally more dense than plywood, and is great for machining on the Shopbot because of its uniformity. Sometimes used for making large positive molds for vacuum forming, negative molds for casting, or larger looks-like feels-like models by laminating sheets together and machining away excess.