Extensional shear generally has been associated only with twin-screw extruders. However, I am now convinced it can be done with a single moving force (screw) by changing the geometry of the flow field perpendicular to the direction of flow.

Material cost is the largest cost factor in most extruded commodity products, so processors should be motivated to reduce these expenses.

Extrusion processors typically run a number of different products and resins.

Wear that occurs as a result of metal-to-metal contact in extruders is quite common.

The HHT (high heat transfer) cooling screw from Rauwendaal Extrusion Engineering Inc. in Auburn, Calif., has recently been modified with a flight configuration designed specifically for PLA foam.

Determining the optimum barrel-temperature profile is one of the most important tasks in extrusion.

 Gels are a common quality problem in extrusion of clear film and tubing less than 0.005 in. thick.

NPE will show higher outputs of practically everything, as advances in grooved feeds, servo drives, screw torque, mixing screws, dies, and downstream cooling, cutting, and handling make everything run faster.

While twin-screws get most of the glory, a quiet revolution has been taking place in single-screw compounding. In the past six to 12 months, some half-dozen new dispersive mixing elements have gone into commercial production, and more are on the way.