Bending machine and its operation method

摘要

The present invention provides a bending machine that enables an angle measuring instrument to be compactly built into a mold for accurate processing. The present invention also provides an operation method besed on learning control which achieves accurate bending with this bending machine taking spring back into consideration. A bending machine carries out bending using lineraly extending an upper die 4 and a lower die 2, the upper die 4 having a built-in angle measuring instrument 9. The angle measuring instrument 9 is composed of a corner contacting member 12 with links and an inductive linear position detector 13 for measuring displacement of the corner contacting member 12. In operation for learning, the position of and a load on the upper die 4 and a bend angle are measured during a bending process and a bend angle after spring back is subsequently measured. Based on the interrelationship between the measured values, a next correction value is obtained for an adjustable position of the bending machine which controls the bend angle.