Track Code2016-010
Short DescriptionNone
Posted DateMay 8, 2017 1:44 PM


David Kazmer


Rajnish Kaushik


Plasticating screws are used in virtually all plastics manufacturing processes, including extrusion, blow molding, thermoforming, and injection molding that convert the polymer resin to the finished product. Moreover, extrusion is used not only in the conversion of feedstock to finished goods (tubing, sheet, film, profiles, etc.), but it is also used in compounding, polymerization, and other processes for creation of the feedstock materials. Existing screw designs are deficient with respect to the conveyance and melting of pelletized feedstock.


The invention describes designs and associated analysis methods which provide for division of the feed channels into multiple channels that more optimally process each piece of the feedstock material to provide improved dispersion and uniformity of the output product. Each of these channels may subsequently be divided into multiple channels that meter the processed material with improved temperature consistency and reduced energy consumption. As a result, the screw may be designed to avoid large agglomerations of pellets and other stagnant material zones that lead to prolonged material residence times. The invention’s use of multiple channels thus provides a means for quickly and efficiently processing the feedstock material while also reducing fluctuations in flow rates and pressures of the processed material.

The technology includes not only claimed designs but also methods for numerical simulation and manufacturing automation that support rapid application development of screws targeted to specific materials and performance objectives including flow rate, pressure, and consistency.


There are two envisioned product platforms:

1.      Fractal feed screws for single-screw extrusion and related processes such as injection molding and blow molding and thermoforming, and

2.      Fractal feed screws for twin-screw extrusion directed to reactive processing and compounding and other processes.

Such designs can be used for diverse set of applications like extrusion, molding, thermoforming, polymerization, compounding etc.

Competitive Advantages

The technology has been deployed with full-scale validation on an instrumented extruder having a screw diameter of 38 mm and an output rate of 50 kg/hr. Processing and product quality data indicate competitive advantages including:

  •  Shorter screw designs, thereby reducing the size, cost, and complexity of machinery.
  •  Lower residence times, thereby reducing any degradation of the material properties.
  • More efficient and uniform processing, avoiding the need for active cooling.
  • Precise control of the processing history, to improve consistency and dispersion.
  • Higher quality production with reduced machinery, processing, and energy costs.

About the inventor

Professor David Kazmer is Chair of the Department of Plastics Engineering at UMass Lowell. He has a doctoral degree from Stanford University’s Design Division and is an inventor or co-inventor of 25 issued utility patents related to plastics processing. This invention addresses significant problems observed in industry, including his prior experiences at some of the companies. The underlying analysis and design automation builds on related research including 1) axiomatic and robust design, 2) constitutive modeling for polymer stress relaxation behavior from creeping solids to non-Newtonian flow of polymer melts, 3) on-line instrumentation and real-time simulation of 3D printing, and 4) multivariate sensors for in-situ characterization of shrinkage, viscosity, pressure, temperature, and (most recently) particle tracking. 


pending Worldwide



Rajnish Kaushik

Office of Technology Commercialization (OTC)

University of Massachusetts Lowell, 600 Suffolk Street, 2nd Floor, Lowell, MA 01854