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.
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. The gob, now a parison, is then flipped into a corresponding final mould where it is blown again, to form the interior side of the glass container. Glass bottles of varying neck thickness can be made using blow-and-blow formation.