Rubber extruder Brief History of Development: The rubber extruder originated in the 18th century. In 1795, a manual piston‑type press manufactured in Britain for producing seamless lead pipes is regarded as the world’s first extruder. Since then, during the first half of the 20th century, rubber extruders were primarily used to manufacture lead pipes, process pasta and other food products, and serve the brick and ceramics industries.

In the evolution of rubber extrusion as a manufacturing process, a well-documented instance dates back to a patent filed in 1845 for producing goutebo adhesive thread using an extruder. The extruder was subsequently refined by H. Bewlgy of Goodwave and, in 1851, employed to coat the copper conductors of a submarine cable between Dover and Calais. Over the following quarter-century, extrusion technology grew increasingly significant, with electrically powered extruders gradually supplanting earlier manual models. Early mechanically operated plunger-type extruders produced thousands of kilometers of insulated wires and cables, firmly establishing extrusion as the standard method for cable manufacturing. The earliest cable‑extrusion machines—whether manual, mechanical, or hydraulic—were all of the plunger design. In this process, a plunger forced heated rubber compound into a die surrounding the copper conductor; the compound was then extruded through the die, coating the conductor and forming an insulating layer.

Spiral type, which appeared in 1870. Rubber extruder It is a hot-feed extruder. It is used to feed rubber that has undergone thermal refining, requiring uniform, stable, and steady feeding while maintaining a material temperature of 50–70°C. The screw is short with deep flight grooves, resulting in less-than-ideal homogenization. Since the 1970s, the length-to-diameter ratio has been reduced. Due to its continuous operation, simple handling, and high production efficiency, as well as the stable shape of the extruded products, hot-feed extruders remain widely employed in many manufacturing processes. They are suitable for extruding various tread compounds and different types of rubber in tire production, and are also used for extruding and shaping rubber hoses, cables, and other rubber products.

Conventional cold-feed extrusion Rubber extruder Emerging in the 1940s, it began to gain widespread adoption and became the mainstream technology by the 1980s. By the early 1990s, products manufactured using cold-feed extruders in developed countries such as Europe and North America accounted for 95% of total output. Extruders include single-screw extruders, barrier‑transfer mixing screw extruders, pin‑screw extruders, and multi‑channel transfer‑mixing screw extruders.

From the perspective of equipment design, both cold-feed and hot-feed extruders typically feature relatively long barrel lengths with length-to-diameter ratios ranging from 8 to 20, and shallow screw channels. Due to their extended bodies, multifunctional capabilities, and lower feed temperatures, these machines consume significantly more power—roughly two to four times that of comparable hot-feed extruders. For example, a 250‑mm‑diameter cold-feed extruder manufactured by Bühler in Germany has a rated power of 500 kW, whereas a similarly sized hot-feed extruder delivers only 105 kW; however, its production capacity is lower than that of the hot-feed unit. The introduction of cold-feed extruders has streamlined production processes: rubber no longer requires thermal refining, and products can be formed directly by feeding room‑temperature rubber into the extruder. This technology can fully replace traditional hot-feed extruders, eliminate the need for plastic thermal refining, simplify manufacturing workflows, and enable higher die pressures, thereby enhancing the quality of extruded products. As a result, cold-feed extruders have found widespread application in the production of certain types of goods.

However, to achieve superior plasticization of composite materials, a screw design featuring both primary and auxiliary threads has been developed. This configuration affects the extrusion yield and requires substantial drive power, thereby limiting its applicability in certain production processes. The single‑screw cold‑feed extruder emerged in the 1970s; its main thread is a conventional helical groove, with the secondary thread designed such that there is a specific height difference between the two. The secondary thread features varying heights along its length, allowing rubber to be conveyed forward only through narrow gaps. This effectively eliminates the “dead zones” commonly found in conventional screw grooves, enhancing plasticization and mixing performance. Nevertheless, the resulting mixture exhibits uneven quality and consumes significant energy.