Excessive runout in a rubber covered roller is usually related to the metal core, rubber covering process and final grinding. If the shaft core has poor concentricity or deformation, the finished roller will be difficult to control even after covering.
Uneven rubber thickness, unstable vulcanization and insufficient machining allowance can also create dimensional deviation. After covering, precision grinding is required to control diameter, roundness and surface finish.
For equipment that requires stable feeding, pressing or transmission, runout should be confirmed together with hardness, bearing position, shaft tolerance and operating speed. A controlled process helps reduce vibration, uneven wear and installation adjustment time.