Despite the fact that beverage containers come in an almost unending variety of shapes, sizes and colors, the profile of a champagne bottle is easily recognizable from a distance. Even the heft of the container is part of its perceived quality. Other bottle shapes are also closely associated with specific beverages or brands. So changing a bottle’s shape to reduce weight and materials treads into sensitive territory. Given that, when it comes to making these changes, Brajer and his R&D team consider the subjective aesthetic factors. But they do so while relying on objective engineering tools.
Internal pressure loading is one of the most common causes of breakage for carbonated beverage containers. But it is not the only one. As bottles move from the glass-making mold to the bottling assembly line and then finally to the store shelf, they are filled, capped, stacked and transported. This subjects them to a variety of loading scenarios including thermal stress (from hot liquids), impact, squeezing and compression. Basically, the life of a glass bottle can be a precarious one.
The primary method for making narrow-necked bottles—for champagne, hard cider, or wine—is a blow-and-blow process (as opposed to a press-and-blow method primarily used for wide-mouthed jars). Employing this technique, molten glass at 1500º C, straight from the furnace, is first cooled to 1100º C in a forming machine and then cut into “gobs” (small bottle-sized amounts). Compressed air is used to blow a cavity into the hot semi-liquid material creating an intermediate shape in the forming machine. A second jet of air gives its final shape to the bottle in the blow mold. An annealing process is utilized to give the glass additional strength.
by Chris Hardee, edited by Evan Yares/Senior Editor & Analyst, Software (May.10, 2013)