Quick Did You Know: The actual design of the screw, and not metallurgy, become more important the larger the diameter of the screw. They have more effect on the melt process than the heater bands in some cases. Consequently, the design of smaller Single Screw Extruder Screw Barrel involves more wear-related material decisions, of which the conversation then becomes a metallurgy or coating issue.
Generally speaking the ratio of importance in the selection between the screw and barrel should fall more so on the screw and non-return design/selection and metallurgy.
So if you are still keeping score, the need to select the right screw and barrel is critical for any application. However, when should this critical component be clarified in the commercial conversation? In reality, it isn’t discussed as early as it should be in the build-up for a brand new machine. It is not likely that you’ll find it at the top of a new machine conversation, but it should follow close behind.
More often than not, you’ll find that the topic of screw and barrels is discussed in an aftermarket setting. Even after a machine has been running for a long period of time, many molders forget to look at newer or improved screw and barrel technology. Continual improvements in screw and barrel sizing, coatings and metallurgy have shown to improve efficiency, performance and general material handling versus potential cost and changes related to the clamp end.