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The Importance of Temperature Control in Rubber Extruders

Time：

2021-05-31

Currently, temperature control in rubber extruders typically operates as a closed-loop system, following a sequence of measurement, adjustment, and set-point regulation. Specifically, the temperature of the controlled process is accurately measured, the deviation from the desired setpoint is determined, and the control action is adjusted to maintain the process temperature within a specified range. The screw of a rubber extruder consists of two main sections: the threaded portion, which serves as the working zone, and the section connected to the drive mechanism. Screws are classified into three types: single-start, double-start, and compound screws. Single-start screws are commonly used for gel filtration, while double-start screws are preferred for extrusion molding, ensuring uniform material discharge. The feed end of a compound screw features a single-start thread configuration, facilitating easier material feeding.

Currently, temperature control in rubber extruders is typically implemented as a closed-loop system, following a sequence that includes measurement, control action, and setpoint regulation. In other words, it is necessary to accurately measure the temperature of the controlled object, determine the deviation from the setpoint, and adjust the control action to maintain the temperature at a specified level.

The screw of a rubber extruder consists of a threaded section—i.e., the working zone—and a portion that connects to the drive mechanism. Threads are classified into three types: single-start threads, double-start threads, and multi-start threads. Single-head dies are typically used for gel filtration, while double-head dies are commonly employed in extruders for shaping, ensuring uniform material discharge. The feed end of the composite screw features a single-start thread (for easy material feeding), while the discharge end has a double-start thread, ensuring uniform discharge and superior product quality.

As the use of rubber extruders continues to expand and extrusion theory advances, the variety of screw and thread configurations has grown considerably, including designs with primary–secondary threads, those featuring mixing sections, and split‑flow baffle types, among others.

The Importance of Temperature Control in Rubber Extruders

With the advent and widespread adoption of cold-feed extruders, the application scope of hot-feed extruders has gradually narrowed. . Rubber extruders have evolved from hot-feed to cold-feed designs. In cold-feed extruders, the rubber compound is both cold and rigid, and such cold, hard compounds must meet their extrusion process requirements entirely within the extruder itself. From cold to hot, from hard to soft, and from non‑uniform to uniform, this process undergoes distinct stages of transformation, with each stage influencing the others. With all other operating conditions held constant, the temperature in each section of the extruder plays a decisive role during extrusion. If the temperatures in these sections vary, the extrusion rate, extrusion temperature, and expansion ratio will all change, leading to instability in the extrusion process and severely compromising the quality of the semi‑finished product.