# A Novel Optimization Design Method of Form Ginding Wheel for Screw Rotor
Recent research on spiral bevels and screw surfaces has examined the influence of machine settings and installation parameters on machining errors, and several authors have proposed error compensation methods [PERSON] _et al._ (2010); [PERSON] _et al._ (2010); [PERSON] _et al._ (2010). These researchers have attempted to control the installation parameters such that the target for improving machining accuracy could be reached. These models can improve the profile accuracy in screw surface machining to some extent; unfortunately, these studies have examined the influence of installation parameters on profile errors with the assumption that the wheel profile is known. The selection method of installation parameters is not involved in the form tool design stage. A novel tilt form grinding method was presented by [PERSON] and [PERSON] [PERSON] and [PERSON] (2010) to address the difficulties in concave profile grinding. By using their proposed machine arrangement and installation parameters, a concave rotor profile can be ground without undercutting or secondary enveloping. [PERSON] and [PERSON] [PERSON] and [PERSON] (2011) used envelope theory to design a screw rotor cutter by including an installation parameter design method. However, it can only be used to select the installation parameters regarding the polylines of the rotor profile; in addition, they did not report on the selection method that they used for the installation parameters for smooth curves. Regrettably, none of these methods can be used to determine the installation parameters for the form cutter for smooth screw profiles. The use of improper installation parameters will reduce the profile precision and grinding performance of the form cutter, and the machining precision of the screw rotor will also suffer. In industrial applications, the screw rotor profile is usually a smooth curve consisting of data points from either design software or measurements. Therefore, it is essential to obtain the correct installation parameters according to these discrete data. In this way, the high precision and good grinding performance of the form grinding wheel can be addressed. In this paper, a novel optimization design method of installation parameters has been proposed. With this method, the dressing and grinding performance of the grinding wheel can be predicted during the design stage, such that improvements in machining accuracy and screw rotor efficiency may be achieved. The remainder of this paper is organized as follows. First, the form cutter design method and the form grinding principle are introduced, which together provide a basis for the subsequent procedures. Then, a parameterized program is designed based on space engagement theory and the coordinate transformation between the screw rotor and the grinding wheel. Subsequently, the characteristics of the contact line and profile features of wheel grinding under different installation parameters are investigated, providing basis for the selection of installation parameters. Finally, grinding experiments are conducted on a profile grinding machine; then, the experimental data are analyzed by comparing them with the theoretical results to demonstrate the effectiveness of the proposed method.