A New Hydraulic Tube Bending Machine and In-process Measurements

摘要

This research presents a new flexible bending machine and its practical applications. The proposed machine uses a new method. When tubes are fed into the fixed and mobile dies, they are bent by shifting the relative position of the mobile die. The bending radius is controlled by the relative distance and orientation between the mobile die and the tube. The bending angle is controlled by the length of the fed tube. This forming process has a big advantage. A change of the expected bending shape will need no change in the tooling system but only a new definition of the motion of the active die and the length of the fed tube. The active die movements are controlled by a six degrees of freedom (6-DOF) parallel kinematics (PKM) with hydraulic servo drive. Practical applications show that the bending machine can be applied to universal designed products, and automotive parts. To improve the accuracy of the bending machine, we proposed a new in-process measurement technique and device for correcting error of bending process. Optical sensors are used for measuring three-dimensional shape of bending tubes in real time. The optical sensor system using a laser scanning is suitable for the tube bender through basic experiments. It is experimentally verified to improve accuracy of the bending process.