Most bottle manufacturing is an automated process, which enabled manufacturers to generate larger production runs than was previously possible. Glass production is broken down into two general categories: container production and sheet production. Bottle machining is part of glass container production.
The first stage of glass-container making is hot end processes, which typically employ high amounts of heat to produce and shape a glass container.
Once the stock has been fed into the furnace, temperatures inside can be as high as 1675℃. Next, one of two method forming methods is applied: press-and-blow or blow-and-blow.
Press-and-blow formation takes place in an individual section (IS) machine and is the more commonly used method in glass-container production. IS machines have between five and 20 sections, all identical, which can each carry out the glass-container forming process simultaneously and completely. The result is that five to 20 containers can be produced with one machine at the same time.
When the molten glass reaches between 1050 and 1200 degrees, then press-and-blow formation begins. Gob---a shearing blade is used to cut and shape the glass into a cylindrical shape. The cut gob falls, and using gravitational force, rolls through the appropriate passage to reach the mould.
Like press-and-blow formation, blow-and-blow takes place in an IS machine, where a gob is released during the plastic stage and moved along to the moulds. However, in blow-and-blow formation, the gob is forced into the blank mould using compressed air to push the gob into place. Glass bottles of varying neck thickness can be made using blow-and-blow formation.
After formation, bottles often undergo internal treatment, an important factor if the bottles are intended to hold alcohol or other degrading substances. Internal treatment can take place during formation or directly after, and typically involves treating the bottles with a gas mixture of fluorocarbon. Glass containers can also be treated externally, to strengthen the surface or reduce surface friction.
Once formation is complete, some bottles may suffer from stress as a result of unequal cooling rates. An annealing oven can be used to reheat and cool glass containers to rectify stress and make the bottle stronger.
At this stage in glass production, the bottles or glass containers are inspected and packaged. Packaging methods will vary from factory to factory depending on the specific type of bottle and the size of the production run.