Page 99 - 《橡塑技术与装备》英文版2026年3期

PRODUCT AND DESIGN

To precisely maintain uniform temperature distribution of the avoiding uneven wall thickness and eccentricity. Since this
pipe billet, this is not only the key to the forming technology extrusion pipe head does not have a structure that allows the
of the orientation process but also the key to avoiding uneven orientation stretching device to move forward or backward, the
wall thickness and eccentricity. Therefore, the processing heated pipe billet cannot be uniformly heated at the optimal
temperature control during pipe billet stretching must be evenly orientation stretching position, making it difficult to ensure the
distributed. Only in this way can the pipe billet achieve biaxial uniformity of overall expansion of the pipe billet. This results
stretching along the biaxial stretching device and improve the in issues such as uneven wall thickness and easy deformation
overall performance of the pipe. To this end, an extrusion pipe of the pipe body after stretching, leading to a decline in the
head structure using a worm gear traction biaxial orientation performance of the oriented and stretched pipe and seriously
stretching device has been designed. affecting its service strength. Additionally, if the temperature
control is improper during production, the pipe billet is
1 Analysis of the molding process of stretched at a lower temperature, increasing the traction resistance
extrusion die head for pipe materials of the material as it passes through the orientation stretching
The manufacturing method of the biaxial orientation device, leading to unstable production and even downtime. In
stretching process typically involves placing a long steel this case, it is necessary to adjust the length of the steel wire rope
wire rope inside the extrusion pipe head, with one end fixed and restart production. This affects production efficiency, results
at the center of the extruder head mandrel and the other in scrap, and increases the cost of forming pipes. Therefore, in
end fixed at the center of the expansion head of the biaxial response to issues such as uneven heating and low strength of the
orientation stretching device. This technique is often a two-step formed pipes in the online production of the orientation stretching
process, where the extruded pipe billet is first cooled to room device, an extrusion pipe head utilizing a turbine-driven biaxial
temperature and then heated to the stretching temperature. orientation stretching device has been designed, allowing the
However, this method poses certain technical challenges in orientation stretching device to flexibly adjust its position and
terms of the stability of stretching and heating during actual move forward or backward during online production.
production. Specifically, after the pipe billet is cooled and The structural feature lies in that an output shaft
solidified, it is pulled into the heating device by the first tractor connected to a worm gear is arranged between the diverter
for secondary heating. After being heated to a highly elastic cone and the hollow mandrel inside the extrusion tube head.
state, the pipe billet is subjected to bidirectional stretching One end of the output shaft is fixedly connected to a steel
through an expansion mold. Since the position of the secondary wire rope through threads, and the other end of the steel wire
heating device for continuously formed pipes is generally fixed rope is connected to an orientation stretching device. The
after installation on the production line, and the position of orientation stretching device is driven by the handle of the
the orientation stretching device is also fixed after adjustment worm gear, with the output shaft winding around the steel wire
before production, the orientation stretching device cannot rope to pull the orientation stretching device to move back and
move forward or backward during online production, limiting forth. By adjusting the position of the orientation stretching
the uniformity of heating of the pipe billet. device online, the tube billet can be heated at an ideal heating
As a result, precise and uniform heating of the pipe billet temperature, ensuring the uniformity of the overall expansion
cannot be achieved, and only heaters can be used to adjust the of the tube billet. At the same time, the entire extrusion tube
temperature to suit the heating degree of the pipe billet. This head structure is designed to be simple, without the need
process adjustment is complex, and the pipe billet cannot be to stop the machine to adjust the position of the orientation
heated uniformly in a timely manner, affecting the stability stretching device, reducing scrap, time, and labor costs. In
of orientation stretching and making it difficult to control the addition, traditional plastic tube extrusion heads generally use
pipe billet during orientation stretching. This is both crucial a solid mandrel and diverter cone structure, which is relatively
for the forming technology of the orientation process and for bulky, time-consuming and laborious to disassemble and assemble,

Vol.52，2026 ·53·