Circumferential pressure measurement for microrolling process monitoring

Forming pressure distribution on the roll surface is one of the key parameters determining quality of product in microrolling process. Prior work has led to the design, characterization, and prototyping of a roll-embedded capacitive sensing method to measure pressure distribution on the roll surface on a single line, along the axis direction. This paper reports on research that has expanded the sensing capability to enable pressure distribution measurement along the circumference, thereby realizing two-dimensional measurement on the roll surface. A key element for the new technique is a two-dimensional pressure retrieval algorithm based on Landweber Iteration method, which calculates pressure distribution as a function of the capacitance measured. A finite element model was established to simulate the pressure variation along the roll circumference. An angular coverage of 36 degrees for each embedded sensor is identified by the simulation result. The effect of sensing embedding depth on sensor coverage is discussed in view of enabling in-process control of electrically-assisted microrolling.