Jim Frankland President

Extrusion 28 Jan 2013

The Evolving Barrier Screw

There has been a gradual transition from the earlier Maillefer designs used in Europe to the Dray/Lawrence design using the parallel barrier design with an increased helix angle to accommodate wider channels.

processing tips 28 Dec 2012

Why I Still Like Analog Meters

They may not look as slick as their digital cousins, but I find them more helpful in identifying and troubleshooting extrusion problems.

Extrusion 28 Nov 2012

Screw Design Is a Matter of Balance

In order to achieve a balance between feeding, melting, and pumping it’s necessary to use proven calculations and/or tested empirical data in the design of each section.

Extrusion 26 Oct 2012

What Output Should You Expect?

You can get a rough estimate of the potential output if you know the drive horsepower of your machine and the thermal characteristics of one of the materials you’ll be running.

Extrusion Know How 29 Sep 2012

New Frontier for Single Screw R&D: Mixing & Melting by Extensional Shear

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.

Extrusion Know How 27 Aug 2012

The Power-Law Coefficient

By referring to the power-law coefficient, the effect of barrel override in the metering section of many screws can be explained and anticipated.

Extrusion Know How 30 Jul 2012

Mission (Nearly) Impossible: Estimating Extrusion Melt Temperature

Extrusion processors often ask screw designers to estimate the output and melt temperature of a new design in the works. Projected output of a new screw can usually be estimated fairly accurately. Melt-temperature estimate, however, is another story