MUNICH — BMW AG has chosen a plastic material-handling system from Piovan SpA for making its new BMW i3 electric and BMW i8 plug-in hybrid vehicles.
BMW needed a system for conveying, drying and blending plastic materials that was energy efficient, easy to use and sustainable. While setting up its new plant in Leipzig, Germany, Munich-based BMW tested systems from five major suppliers of auxiliary equipment, eventually choosing the Modula system from Santa Maria di Sala, Italy-based Piovan.
Modula is an auto-adaptive and energy-efficient drying system with multiple-hopper assembly. Piovan launched the system in late 2010, and recently received a patent.
The materials used by BMW are mainly blends with a polycarbonate or polypropylene base, including PP/ethylene propylene diene monomer and PP/styrene acrylonitrile. The plastic parts for the cars are injection molded and immediately transferred to the painting lines. Silicone particles are banned from the paint lines to prevent contamination. BMW chose the Modula system, in part, because it has no silicone components or parts.
Two sets of Modula were supplied, each configured with a single dry-air generator and seven drying hoppers with volumes ranging from 600 to 1,000 liters.
Hygroscopic plastic drying is performed to reduce moisture content. Hot, dry air is circulated inside a drying hopper. In this multiple-material setup, a central unit generates dry air that is then distributed to a series of hoppers through a duct system. Each hopper requires specific conditions (dry air flow, temperature, pressure) depending on the different material characteristics: polymer type, initial moisture level, required moisture level, hourly material consumption and granule size.
Modula is available for medium and large capacity applications (200 to 2,000 kilograms per hour) and, the company claims, provides savings of up to 50 percent over ordinary centralized drying systems of equivalent capacity.