Coextrusion trumps metal and fibreglass down on the farm
By Barry Copping
Posted 12 October 2012
Polycarbonate/ABS bonnet and bumper unit promises better toughness and weatherability
Coextruded Lexan and Cycoloy resins from Sabic’s Innovative Plastics business have been used for a tough new bonnet assembly for a heavy-duty agricultural sprayer.
The product was developed to overcome performance issues associated with fibreglass composites and metal, such as cracking or fading from exposure to high temperatures, aggressive chemicals and ultraviolet (UV) light.
The project was a collaboration between Mooresville, Indiana-based sprayer builder Equipment Technologies (ET), Allen Extruders, a supplier of custom thermoplastic sheet, and AMD Plastics who designed the bonnet assembly and produce it.
The new custom-coloured bonnet, measuring 237 x 126 x 143cm, is used in all three of ET’s Apache sprayer models. It is cited as an example of significant cost advantages from thermoforming a large part as against injection moulding it. The bonnet is integrated with the sprayer bumper, and is claimed help ET reduce warranty claims through better durability. The finishing and painting required with metal are eliminated.
Lexan SLX polycarbonate (PC) resin forms the pre-coloured cap layer in Allen Extruders’ Alextra-MV sheet. The Cycoloy substrate is a blend of PC and acrylonitrile-butadiene-styrene (ABS). Excellent impact resistance and weatherability are claimed for the combination, and its heat deflection capability is said to be particularly important as manufacturers seek to comply with Tier 4 interim and final US Environmental Protection Agency (EPA) heat emission standards. A weight saving of 63.5kg over previous fibreglass bonnets is claimed.
ET’s lead engineer Chad Ringer says: “As the trend toward mega-farms increases and more farmers turn to self-propelled agricultural sprayers to replace pull-behind models, the Apache sprayer is a logical choice, especially given its lighter weight and increased durability. We are already seeing increased sales, and the new design of the Apache bonnet has generated positive feedback from our customers. Clearly, our collaboration with Sabic, AMD, and Allen Extruders made this product the resounding success that it is.”
Mike Ringquist, sales manager with Allen Extruders adds: “The ‘MV’ in the name of our Alextra-MV sheet signifies that this is our ‘most versatile’ material, with many applications in heavy trucks and recreational vehicles as well as agricultural equipment. We were very pleased to work with Sabic, AMD Plastics and Equipment Technologies to help create a new sprayer bonnet with major performance and aesthetic improvements over fibreglass.”
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