While the processes of injection moulding and air-blowing are normally undertaken on different machines, German injection moulding machine maker Dr Boy has combined both processes on a Boy injection moulding machine.
The company says it undertook the project with the support of the European Regional Development Fund and the State of Rhineland-Palatinate. 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 moulded, rotated 180 degrees around an index plate and then inflated with compressed air to produce the finished bottle contour in the same mould. The finished eye drop bottles are packaged directly after demoulding in the clean mould area of the clamping unit and carried off by a conveyor belt.
Air-blowing on an injection moulding machine is suitable for smaller hollow bodies, such as cosmetics, food or pharmaceutical bottles.
Boy also says the cost of the machine used is significantly below the cost of a just a injection moulding machine. One benefit of air-blowing is the possibility of manufacturing more complex contours at the bottle neck with precision, which is only possible to a limited extent in traditional blow moulding processes, says the German machine maker.
Using a manifold system developed specifically for this application, the preforms are injected without sprues so that no waste is produced in bottle production. Unlike using blow moulds, the bottle is finished at the end of the blowing process. Another advantage is that material used to seal the mould body does not need to be cut and removed.
Dr Boy specialises in the manufacture of compact injection moulding machines with clamping forces up to 1,000 kN, said to be energy-saving and therefore highly economical. Since the privately-owned company was founded in 1968, it has delivered more than 45,000 injection moulding machines worldwide.