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The article discusses how to troubleshoot the twin-screw process in plastic molding to achieve high quality homogenous melt without degradation. Also cited are the key role of twin-screw extruders (TSE) in mixing polymers with additives, modifiers and additives to achieve the designed performance characteristics, and how to achieve good quality distributive and dispersive mixing.

The article offers information on the WEX 2021, the Web Exhibition presented in June 2021 by ST BlowMoulding which presented machine developments and advances in productivity, energy efficiency, ergonomics and safety. Topics include background of ST BlowMoulding, the model ISIT 1320 Duo machine as the highlight of the Exhibition, and key focus of virtual presentations by ST BlowMoulding experts.

The article focuses on the introduction of collaborative robots or cobots as a concept for automation. It says that collaborative industrial robots are defined by Institute for Occupational Safety and Health (IFA) in Germany as complex machines, which work wit human beings in terms of work process. It mentions the suppliers of cobots including Rethink Robotics, Universal Robots, and Fanuc America. Moreover, the Baxter collaborative robot is discussed.

The article provides suggestions to molders on how to improve quality and productivity with advanced screw design. Topics discussed include common molding/part problem that melt non-uniformity that does not cause or exacerbate, what it takes to get melt uniformity, and experience of Mike Sepe, a noted materials expert and fellow "Plastics Technology" columnist, when he purchased melt-uniformity screws.

The article explores the optimization of barrel temperature for barrier screws. Considered as high performance screws, barrier screws require finer tuning of barrel-temperature zone profiles. Examining the heater-zone layout and how the zones are placed in relation to various sections of the screw will help identify the proper zone settings. Barrel-zone temperatures are particularly recommended for barrier screws and will condition the resin in the least stressful manner.

The article discusses how to find single-screw performance with the help of a hand-held calculator and some basic equations. Performance can be measured using the drag flow equation for a screw having a standard-pitch metering section. If the actual output is very close to the calculated drag flow, the screw is said to have a balanced design. When there is head pressure on the screw, the output is generally less than the drag flow.

The article deals with the problems that may result from large extrusion screws being run too slowly. Topics discussed include the role of extrusion screws in the processing of polymers, the differences between viscous dissipation and heat conduction in relation to melting polymers and the steps that can be taken to address problems related with screws running on speeds that are lower than the level they are designed for, including using a screw with shallower channels and extending the barrel.

The article discusses wedging and misalignment as the main causes of screw wear. It offers advice on how to correctly diagnose screw wear including the inadequate melting as the cause of wedging, screw bending as the cause of misalignment, and the difference in forces and patterns created such as the burr produced. Also discussed are the causes of galling.

Evaluates a barrier element for corotating twin-screw compounding extruders from Extricom GmbH. Position of its barrier segment; Effect of offsetting the elements.