Development of a Die Shoulder Force Transducer for Sheet Metal Forming Research

Abstract

A force transducer has been developed for measuring the tension in a strip of sheet metal as it passes over a die shoulder. This transducer is primarily a research tool. The die shoulder portion of the transducer can be selectively fixed or permitted to roll by contact with the moving strip. Applications of this force transducer are to measure pull force, drawbead restraining force, calculate the average coefficient of friction over the die shoulder, and quantify bending effects. Described in this paper is the development of the force transducer. It is a design based on four webs with strain gages as the transduction elements. It has been built, calibrated, and shown to accurately measure sheet tension in a strip test apparatus before and after the portion simulating the die shoulder. Friction and bending effects are studied from the sheet tensions.