The flowchart illustrates the process by which glass containers are shaped. Overall, the procedure comprises nine sequential steps which can be grouped into four main stages: melting, moulding, tempering, and final quality inspection. Notably, this process is largely machine-driven and quite complex.
It all starts with glass pellets being melted in a furnace at a temperature of 105 Celsius. The molten glass is then placed into the first mold, where hot glass is pressed from above. Following this, the glass container is transferred to the next larger mold, where its walls are thinned out by blowing air inside.
Next comes tempering; only when the desired shape is achieved can glass containers be subject to a high temperature in a kiln (482 Celsius). After this, they are cooled progressively in a cooling chamber for 60 minutes to reach 25 Celcius. Once cooled, a worker inspects glass containers for any defects, choosing quality containers for packaging and discarding bad ones.