Dressing of the grinding worm and initial grinding. A grinding experiment is performed on YK7340A CNC gear grinding machine with five degrees of freedom (QCMTT). Here, a face gear with parameters listed in Table 1 is used. The material of the face gear is 17CrNiMo6, and the hardness of the tooth flank is HRC62 after cemented quenching. In order to manufacture the worm with modified high precision tooth profile, the most important consideration is how to develop the profile of the grinding wheel in the worm grinding process. It is the essential requirement for the development of grinding machine for the worm.