An Application of Iso-gum in the Method for Estimating the Dimensional Errors of Bent Parts

The current study addresses the accuracy of bend elements and global dimensions with tolerances based on an analytical method, where each deviation in part dimension is represented by type A and type B errors, as instructed by ISO-GUM. Meanwhile, a generic formula is presented to estimate the deviations in the global dimensions of interest in bent parts based on the deviations in the participating bend elements. The deviations in the bend elements formed in each operation are in turn estimated through an analytical simulation model. Therefore, the error propagation in consecutive bending operations using a specified process plan is simulated. Using such a top-down analytical approach, the errors of the global dimensions with tolerances were represented and estimated through the errors encountered for each operation. Finally, a procedure for estimating dimensional errors in bent parts is suggested and illustrated with an example to show the applicability of the method.