John Deere, a leading global manufacturer of forestry equipment, has achieved optimum driver protection against falling branches combined with a good 360-degree view for safety by using polycarbonate glazing solutions from Bayer MaterialScience in the drivers' cabs of its new E-Series of vehicles for felling timber. The cabs of the harvesters and forwarders are fitted with a total of five large panels made of solid sheets of polycarbonate glazing of Makrolon® GP 099 grade from Bayer Sheet Europe GmbH. This glazing is used in automotive applications because of its design flexibility and the potential it offers for function integration and weight reduction. In addition, rather than being flat as in previous cabs, the sheets were curved for a more attractive design and to provide a better all-round view. Due to its high impact resistance and strength, the solid, 12-millimeter-thick polycarbonate sheets prevent falling objects such as thick branches, stones or broken wire cables from winches penetrating the cab and injuring the driver. In doing so, they comply with a set of requirements that are among the strictest in the field of vehicle occupant protection. In contrast to glass and laminated glass, the polycarbonate sheets do not splinter and break when subjected to loads.
The large polycarbonate sheets also play their part in ensuring that the driver has a clear view of what's going on as the new E-series vehicles rotate freely. The sheet for the front window, for example, is 1,576 millimeters long and up to 1,128 millimeters wide. Despite their thickness, the optical quality of the sheets is said to be excellent. This comprehensive expertise is part of BayVision®, the competence brand for polycarbonate vehicle glazing of Bayer MaterialScience.
The important task here was to extrude the sheets in a way which would have no streaks that could interfere with driver's vision. In addition, the sheets were formed, coated and trimmed, and an adhesive primer is applied to the edges at KRD Sicherheitstechnik GmbH using their special thermoforming process to achieve high optical quality sheets. The sheets were then given a hard coat based on the polysiloxane topcoat Momentive AS 4000 from Momentive Performance Materials GmbH in Leverkusen for offering sheets scratch- and weather-resistant properties very similar to those of glass.