FEEDING THE PROCESS--How seemingly insignificant forces can influence a fabrication process

摘要

THE process of advancing or feeding a tube during a forming process seems straightforward: Don't lose track of the length of tube advanced and you have it made. Quite often, though, it is not that simple. For example, in a roll bending process, the weight of the tube itself downstream of the bending process can influence the radius being formed. Needless to say, this is one of many seemingly insignificant forces that can produce unwanted results. Roll benders come in numerous types, but they all work the same way--they make large-radius bends while the tube rolls through a set of three roll dies. As the tube passes through these roll dies, its center of gravity changes continuously. Depending on the radius the bender is attempting to make, the actual radius formed can be influenced by the changing center of gravity. In short, the tube's weight produces a torque or twist that affects the section being bent at that moment in time.