| Davis-Standard Corp., USA, a Crompton business, has further developed its groove-feed extruder line to support a range of blown-film, blow-moulding, sheet, pipe and profile, as well as wire and cable applications. Advances in both groove-feed bushing and screw-design have allowed the company to provide processors with increased throughput and improved polymer homogenisation at reduced melt-temperatures. Groove feed extruders, available in 50 to 150mm 34:1 L/D sizes, include a wear-resistant, unitised groove-feed housing with a removable and replaceable groove-feed bushing. The bushing is available in multiple groove designs for processing a range of thermoplastic materials, including PP, PVC, polyolefins and various engineered resins. Aggressive, rectangular grooves are available for stiffer polyolefin materials, as well as milder, ratchet-style grooves for softer materials, such as flexible PVC.
On the feed-screw side, Davis-Standard�s patended DSB�-VI barrier-screw is specifically designed for high-throughputs and incorporates a dual-barrier with a variable lead-barrier flight. The DSB-VI minimises wear within the aggressive groove-feed environment and improves stability in head pressure and melt-temperature. Wider channels accommodate larger outputs and provide a 40% increase in melting capacity when compared to conventional barrier screws. In addition, this design features provisions to fit several mixing sections to the screw for the production of uniform melt properties to consistently disperse additives and polymer blends.
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