Integrated preform molding, cooling system developedIntegrated preform molding, cooling system developed

A new venture established by injection machine supplier MIR and moldmaker Cantoni is marketing a 2800-kN pet preform molding system based on MIR’s RMP toggle machine with an oversized injection unit, and using a mold that does both preform molding and cooling, so that no robot cooling station is required.

Maximum preform cavitation is 16 for containers from 0.5 to 20 L, and the system has a top output of about 40,000 1.5-L preforms/h. Preform size can be altered by changing mold inserts. In a recent demonstration, MIR ran the machine on a 12-s cycle.

When the mold opens on a conventional pet preform machine, a robot extracts the preforms to a cooling station. In the MIR/Cantoni machine, there are two sets of cores, side by side, and three sets of cavities. The central set of cavities is used for molding the preforms, and the two outer sets are for cooling. Once the preforms are molded they are retained on the cores when the mold opens and the cores move either to the left or right. The mold closes, and while a new set of preforms is injected, the first set is cooled. When the mold opens again, the first set of preforms falls onto a conveyor without damage. Cantoni says a similar principle can be used to blow mold bottles. In this process, the preforms are blown in the second stage, rather than cooled.

A similar system has also been developed by Portuguese moldmaker Plasdan, which says it is ready to debut a mold system that will enable preform injection, stretch, and blow molding on a conventional injection machine. It has not released details, and it is yet to be clear how it differs from a system developed by SysTec Engineering, Bad Urach, Germany, almost six years ago (Sept 97 mpi, 29).

MIR says the preform molding system will be priced competitively with even the most inexpensive Chinese injection molding systems.