Milking platforms: Composites transform New Zealand cow sheds

New Zealand is the world’s biggest exporter of cow’s milk. Waikato Milking Systems (Hamilton, New Zealand) has provided the country’s dairy industry with milking equipment for more than 30 years. With a 62 percent share of the domestic market, the company sees its future growth in exporting sustainable and environment-friendly technology. To that end, Waikato introduced its Centrus composite milking platform in 2009 and, since then, has installed 24 platforms at customer sites. A milking platform is a large, elevated and slowly rotating structure designed to streamline the milking process, enabling simultaneous milking of as many as 54 cows by one or two persons. One Waikato customer reports that with a Centrus platform, it can milk 650 cows in less than one hour.

Typically made with concrete, a 54-bail (cow enclosure) platform weighs 80 percent less when made with composites, yet it is strong enough to support the cows’ total weight of 32.4 tonnes/71,300 lb. A lighter platform means less friction-related wear on the platform’s mechanical drives. The composite requires less maintenance, cleans up easily and is not corroded by cow urine or cleaning chemicals.

Waikato procures its composite materials from Gurit UK (Isle of Wight, U.K., and Auckland, New Zealand) in the form of Gurit’s B3 SmartPac format. Each ply is CNC-machined to shape and size, clearly labeled, packed in the order to be used and accompanied by step-by-step fabrication guides. The SmartPac package saves time, ensures repeatability and streamlines new-staff training. “It eliminated the need for time-consuming hand cutting at our own ... facility,” says Josh Janmaat, Waikato’s composites division manager.

The platform deck sections are sandwich laminates, comprising Gurit’s recyclable G-PET structural foam core faced with double-bias and quadriaxial E-glass fabrics, and they are reinforced with a hybrid aramid/glass woven cloth. The layup is resin transfer molded (RTM Lite) with an RTM-compatible polyester resin. Cured and demolded deck sections are installed over a steel substructure. According to Janmaat, the composite platforms last 25 percent longer than traditional concrete platforms.