Encyclopedia of Glass Science, Technology, History, and Culture. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
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Жанр произведения: Техническая литература
Год издания: 0
isbn: 9781118799499
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Glass Composition

      For cost reasons, glass containers are made out of soda‐lime‐silica glass whenever special constraints do not apply. An exception is, for instance, laboratory ware for which borosilicate glass is used instead (Chapter 7.7). Even though the forming process needs to be adapted to account for the specific properties of each glass type, the principles at work are similar for given kinds of containers. Three different forming processes are applied, namely BB, PB, and NNPB. Their main differences concern blank‐side forming where the parison is made, the subsequent forming steps to make the final container being identical. As a matter of fact, many containers can be produced with more than one process so that there is much overlap between them in terms of product range.

      3.2 Blow & Blow Process

      In the current IS‐machines, the loading speed of the gob is often so high that the finish is already formed at the gob‐loading step, which would make the settle‐blow unnecessary for the finish forming. This step is nonetheless maintained in the process to guarantee a constant heat transfer between the glass and the blank, from cycle to cycle, before counter‐blow. During settle‐blow, a vacuum can be applied through cavities in the molds to support the parison and finish forming. Some modern BB IS‐machines work without a funnel. They control the switch between settle‐blow and counter‐blow by a valve in the baffle to exhaust the compressed air that is used for settle‐blow.

      After settle‐blow, the baffle is quickly lifted, the funnel is removed, and the baffle settles again and closes the blank‐mold completely. A counter‐blow is applied from the down side through the formed finish, blowing the glass fully into the mold shape and forming the parison (Figure 3c).

(a–d) Schematic illustration of the blow & blow process, blank-side.

      After the parison has been formed, the baffle is removed (Figure 3d), the mold opens, and the parison is transferred via the invert mechanism to the blow‐side.

      After the container has been released by the blow‐mold, a take‐out grips it by its finish (Figure 4d) and places it over a dead‐plate through which air is blown from below to cool it further. Finally the container is transferred via a pusher onto a conveyor belt.

      3.3 Press & Blow Process

(a–d) Schematic illustration of forming the final container at the blow-side.

      3.4 Narrow‐Neck & Blow Process

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