Whereas injection molding and air-blowing processes were used on different machine designs up to now, BOY now combines both processes on a BOY injection molding machine. With the support of the European Regional Development Fund and the State of Rhineland-Palatinate, the development of this combined process was completed. As a pilot project, small bottles for eye drops were manufactured on a BOY 60 E in clean room design.
In the first step, four preforms are injection molded, rotated 180 degrees around an index plate and then inflated with compressed air to produce the finished bottle contour in the same mold. The finished eye drop bottles are packaged directly after demolding in the clean mold area of the clamping unit and carried off by a conveyor belt.
Air-blowing on an injection molding machine is suitable for smaller hollow bodies, such as cosmetics, food or pharmaceutical bottles. The cost of the production machine – in this case a BOY injection molding machine – is significantly below the cost of a pure injection molding machine. One benefit of air-blowing is the possibility of manufacturing even more complex contours at the bottle neck extremely precisely, which is only possible to a limited extent in traditional blow mold processes.
Using a manifold system developed specifically for this application, the preforms are injected without sprue so that no waste is produced in bottle production. Unlike with blow molds, the bottle is finished at the end of the blowing process. No material used to seal the mould body needs to be cut and removed.