【正文】
by the principle of the machining process , we also can be learned to ensure the accuracy of precision machining plane than to ensure the hole easily. So the process after the first surface of the hole is to follow the principles of this design . And hole machining plane and a clear division became roughing and finishing in two stages , in order to ensure that the processing precision. After processing the steel sheet during the spring lug , the reference selection process for the first rough selection basis , select fine basis . Therefore, after analysis of the parts we know , we have chosen benchmark crude cylindrical end face of the leaf spring is a big lug , and fine benchmark process we chose two large cylindrical holes and leaf spring lug end face of the future . Its main processing arrangement is the first step in the process for machining the face in the process of hole machining , specifically after the first leaf spring lug large cylindrical end face each other benchmark machined end face , then face orientation process machined hole . In addition to individual processes , in general, are used to locate holes in the face and the subsequent process step, in order