In order to resolve the practical problem about measuring hobs with bigger modulus, a new method is put forward by which the circular adjacent pitch error and accumulated pitch error of hobs can be measured on the grinder.

Accumulated error control technique applied in small mass production of piece;

This paper introduces the principle of the 3D Optix laser scanner briefly,discusses the method of improving the data accuracy in single piece measurement and reducing the accumulated error of spliced joint in multi-pieces measurement with an applied example.

Firstly,the nonlinear problem and the cause of accumulated error for inertial strapdown attitude solution were analyzed.

With the purpose to reduce influence of accumulative error from the recurrence formula of residual stress measured with magnetic stress meter on the calculation result,based on the consideration that the stress at a same measuring point has no relation to the measuring order,the author proposed an improved calculation method for the work piece with free boundaries on both ends.