Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 118

Rotational forming machines are nowadays used only in some rare cases. The principles of glass‐container forming will thus be described for IS‐machines, with which almost glass containers are made. Derivatives of the IS‐machine such as the Emhart RIS and Heye H 1–2 machines have been developed in the past but are hardly in use any longer [9]. They work with two molds on the blow‐side forming, which are loaded alternately. This approach is advantageous in terms of longer reheat and more homogeneous glass thickness distribution but is much more complicated, expensive, and prone to jamming.

In a narrow sense, IS‐machines consist of a gob‐distributor and delivery equipment, blank‐side forming, invert, blow‐side forming, and take‐out and have several identical sections aligned in a row (Figure 1). The only differences between sections are the individual delivery (as different distances from gob‐cut to mold need to be overcome) and the distance of the section to the annealing lehr. The differences in delivery distances cause different gob speeds and different gob arrival‐times at loading and thus require different section‐timings. The differences in distance to the annealing lehr may cause different containers temperatures at the hot‐end coating and at lehr entrance. When entering the lehr, there is, for example, a difference of 50 K or more in surface temperature between containers from section 1 and from section 12, which are the farthest from the annealing zone.

The IS‐machines in principle can be adapted to all three forming processes that have been mentioned earlier. To a certain extent the machines can be converted between a triple‐gob setup to a quad‐gob setup or, given another machine construction, from a triple‐gob setup into a double‐gob setup. How widely a machine can be adapted depends on different parameters, especially on the inner‐section distance, which describes the possible center distances of the molds to each other within one section. The type of setup to be used depends on different parameters such as the size and weight of the container to be produced, desired machine speed, and portfolio of the respective glass‐manufacturing plant.