In the process of pipe bending very high accuracy is a necessity, especially in the sectors where long uninterrupted and precisely shaped pipes are required. Wiper dies are one of the elements that account for such precision. In this article, we define what wiper die is, how it is used and its importance in the pipe bending process.
Wiper Die: What Is It?
A wiper die is a device built in pipe bending machine. The primary role of such a device is to avoid the inner pipe from being folded, ruffled or deformed when bent. The wiper die is placed immediately after the mandrel and along the out of the pipe. This, allows the wiper die to support the pipe material as it bends preventing any wrinkling.
Operation and Principle of a Wiper Die
The bending of the pipe causes some compressive forces to act on the pipe’s inner side which may cause bending or even wrinkling of the material. That is in the way of mere edges affected by the bending process while the reinforced structures hold the pipe’s hollow in its shape and thus prohibits the occurrences of creases. In most cases, the wiper die is fitted just behind the mandrel, and it operates along with the pipe while it is curving. Because of this location, the die is capable of contacting the pipe’s surface throughout the process, which limits the amount of deformation sustained.
The geometric characteristics of a wiper die depend on the diameter and wall thickness of the pipe. Wiper dies are effective and designed to have a long service life and very little wearing out as they are usually constructed from specially designed alloys with tip hardening. The manufacture of wiper dies needs to be selected according to the bending pipes and their materials as well as bending pressures.