An expansion joint, also known as a compensator, is a device installed in a piping system to absorb thermal expansion and contraction or other types of displacement. Expansion joints can be molded in a variety of ways depending on the material and application. Here are some common expansion joint forming methods:
Roll forming：
Suitable for manufacturing large diameter expansion joints.
The material is continuously rolled to form the desired corrugated shape.
Stamping：
Fits smaller parts and thicknesses.
The flat sheet material is shaped into a corrugated shape using a punch press and a die.
Hydroforming：
Liquid pressure is applied inside the tube blank to expand it to form ripples inside the mold.
This method is particularly suitable for the manufacture of annular bellows, which can form bellows with a wall thickness of 0.08 to 4 mm.
Hydroforming is capable of providing a more even pressure distribution, resulting in higher quality corrugations.
Multiwave molding method：
Using a liquid as a molding medium, this was carried out in a split mold.
It is especially suitable for the manufacture of medium and small diameter expansion joints, and has the advantages of fast forming speed, saving materials and simple processing.
Each molding method has its specific application scenarios and advantages, and which method to choose depends on the size of the expansion joint, the material, the working environment, and the requirements of cost and performance. In actual production, several different molding techniques may be used in combination to achieve optimal product quality and economic benefits.