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With globoidal indexing cam mechanism as the object of study, this paper introduces its operating principle, analyzes and calculates its main motion parameters. On the basis of theoretical study, the paper using structured program design method and Visual Basic 6.0 as developing tool analyzes main function modules, such as system parameters input, law of motion, kinematics analysis and pressure angle check, etc. The paper develops globoidal indexing cam mechanism CAD system in simple operation and describes application method of the system and design examples.

The performance of twin-screw compressor is mainly decided by profiles of the two rotors. The constitution of new rotor profiles is studied, meanwhile the key technology of generating rotor profiles are mainly studied in this paper. A new method based on forward and reverse direction for generating rotor profiles with meshing lines is proposed.

In this paper, a novel surface reconstruction method is presented to creat a composite surface with point data on surface obtained by CMM. In this method, the 3th non-uniform B-spline algorithm is proposed to reconstruct every single free-form surface on the whole composite surface, and the algorithm for surface blending is proposed to merge every single surface together to achieve the level of G1 continuity. Furthermore, in order to check and visualize the reconstruction model, a special closed-loop RE system is developd by VC++ to constantly guide to measure and reconstruct untill the model fits in with requirements. Examples are included to illustrate the approach.

In the traditional screw compressor rotors profile generation method, the process of cockamamie parameters adjustment and confirmatory will take a long time, so that the modified results can’t be estimated in advance. Based on freeform curve, two rotor profiles generation methods are presented in this paper. One method is positive, and the female and male rotor profiles are acquired by every profile segment defined with freeform curve; another one is reverse, and the rotor profiles are derived through the meshing line. The rotor profiles are fitted by freeform curve and the shape of rotor profile can be adjusted by moving the control points. Finally, the two methods are used to developed a system for designing quickly the rotor profiles.

Take spare parts from front cylinder head of compressor as an example, the essay analyze feature of parameter in snap ring grooves, measure dimension error of cone angle in snap ring grooves in method of comparative measurement, solve the problem that parameter of similar spare parts can not be measured, implement gauge detection of size of snap ring grooves in method of comparative measurement.