What is the working principle of the pipe shrinker machine?

As the core equipment for tube processing, the pipe shrinker machine achieves tube end diameter reduction through mechanical force and mold cooperation. Its working principle integrates power transmission, mold shaping and precise control to ensure the consistency and strength of tube shrinkage.

The power system is the core driving source of the pipe shrinker machine. The motor converts the speed into torque through the reducer (usually output torque 50-5000N・m, adapted to different pipe diameters), drives the spindle to rotate through the transmission shaft, and the conical mold connected to the front end of the spindle moves synchronously. The hydraulic pipe shrinker machine provides axial thrust (pressure can reach 10-30MPa) through the oil cylinder to push the mold to feed at a uniform speed along the axis of the tube. Compared with the mechanical type, it is easier to control the pressure size and is suitable for thin-walled tubes (thickness ≤2mm) processing to avoid excessive deformation and cracking.

The cooperation between the mold and the tube determines the shrinking accuracy. According to the material of the pipe (carbon steel, stainless steel, copper pipe, etc.), the mold with the corresponding hardness (HRC55-62) is selected. The inner hole of the mold is a stepped cone structure (taper 3°-15°). When the pipe is pushed to the entrance of the mold by the feeding mechanism, the rotating inner wall of the mold contacts the outer surface of the pipe, and the friction drives the pipe to rotate synchronously. At the same time, the axial pressure forces the metal of the pipe to flow along the cone surface of the mold to achieve diameter reduction (the reduction range is usually 10%-40% of the original pipe diameter).

The control system ensures accurate matching of parameters. The CNC pipe shrinker machine is equipped with a PLC control system, which can preset parameters such as the reduction length (error ±0.1mm), feed speed (5-30mm/s), and mold speed (100-500r/min). The photoelectric sensor monitors the position of the pipe in real time and automatically stops feeding when the preset reduction length is reached. For thick-walled pipes (thickness>3mm), the system will start the segmented reduction mode and gradually complete the reduction in 3-5 times to avoid excessive force at a single time causing wrinkles in the pipe.

Auxiliary devices improve processing stability. The feeding mechanism uses a V-shaped roller to clamp the pipe (the clamping force is adjustable) to ensure that the overlap between the pipe axis and the mold axis is ≤0.05mm during feeding; the cooling system sprays cutting fluid to the contact part between the mold and the pipe through the oil nozzle to reduce the friction temperature (controlled below 80℃) and prevent oxidation and discoloration of the pipe surface. After processing, the demoulding mechanism automatically pushes out the shrunken pipe to achieve continuous production.

From the size adaptation of metal pipes to the sealing requirements of pipeline connections, the pipe shrinker machine replaces the traditional manual shrinking in a mechanized way through the coordinated operation of "power-mold-control", which increases the processing efficiency by more than 5 times, and the tensile strength at the shrinking point remains more than 90% of the original pipe, becoming a key equipment in the field of pipe processing.