Studies boost prospects for high-speed extrusion

A study conducted by Davis-Standard LLC (D-S) and presented at the Society of Plastics Engineers ANTEC 2012 meeting in 2012 April by John Christiano, D-S's v.p. of processing technology, has revealed that a properly designed high-speed, single-screw extruder (HSSSE) can significantly boost the processing capability of a small-diameter. The extruder used for the study was a 2.5-in., 40:1 LID extruder equipped with a 500-hp motor. Screw speeds up to 1200 rpm were evaluated. D-S's Thermatic Temperature Control system was used to control the barrel temperatures and measure the heat flux in each zone of the extruder. Eight pressure transducers were located along the barrel at approximately S D increments to measure axial pressure generation along the screw. The HIPS sheet grade was processed within the design parameters at up to 2425 lb/hr. D-S contends that higher output rates are possible with further screw-design optimization to improve melting and mixing. The thermal process stability remained in the desired range.