Improvement of an unwinding machine electric drive on a high-strength rebar production line

摘要

Improvement of electric drive's control systems on rebar production lines is one of the key factors that lead to the rebar quality increasing and imperfect product percentage reducing. Known technical implementations for the drives were made without consideration of the effect of their parameters to the rebar quality, particularly to the depths of notches on it. The objectives of this work are to analyze how the lines' electric drives affect the depths of notches, and based on the analysis the development of the electric drives control systems which should decrease imperfect product percentage caused by the depths of notches deviation from desired values. Solutions to the objectives were based on analytical methods for solving algebraic problems, computer modeling methods and statistical processing of the data concerning depths of notches, and the line's electric drives' load torques variations. Novelty of the paper is in proposing new technological requirements to the unwinding machine electric drive, development of a calculation method for the wire tension effect to the rebar depths of notches, unwinding machine electric drive's breaking torque alteration method with the view of wire tension stabilization on a specified level at the inlet of profile stand. As a result of industrial tests of the developed unwinding machine electric drive control system on an active production line there was obtained decrease in rebar percentage that has depths of notches out of allowable range from 7.2 % to 1.1 %.