This method of production has been successfully used for over a hundred years to produce thousands of parts for multiple industries. Each of the parts is an exact replica with very few flaws or deformities. Since the process is extremely effective, low cost, and productive, it has remained as a central process in auto parts production.
Glass molding follows a very similar method in the production of specialized glass parts. The material that is pressed in glass molding is a sheet of pure, clean, and clear glass that is pressured into a mold that is very similar to the ones used to make automotive parts.
The sheets of glass used in the glass molding process are blanks, or floated glass. The floating process was invented to produce flawless sheets of glass free of any imperfections or scars. As with glassblowing, the process begins with molten glass, which is poured over a thin layer of molten metal. The resulting product is glass with a very smooth surface making it perfect for molding. Once the floated glass cools, it is cut into workable sheets, or blanks.
The molding process begins with the blank, the top of the mold, and the bottom of the mold. The blank is secured to the bottom of the mold. The top of the mold is rested over the bottom of the mold and the blank without touching either one. The three parts are heated sufficiently to make the blank pliable and malleable. Once it reaches the appropriate temperature, the top of the mold is slowly lowered and pressed against the blank forcing it into the shape of the bottom of the mold. The success of the process depends a great deal on careful monitoring to ensure that the blank does not get overheated and liquify.
Once the appropriate thickness of the blank is reached, the downward movement of the top of the mold stops, and the three parts are set aside to cool. The length of the cooling time varies depending on the type of part and the thickness of the glass. Once cooling is completed, the flawless part is removed from the mold and does not require any finishing or fabricating.
Glass molding has become popular because of the quality of the parts it produces. The key to its success is the flawlessness of the blank from the floating process. That single step produces a product that is completely ready for distribution. The final product has the highest quality with the lowest possible cost. In most cases, when the part is removed from the mold, it is given a finishing coat with a clear polymer or thin metal alloy.