Research on S-gear design, manufacturing and measuring based on NC machining center

This article presents a method of design, manufacturing, and measuring S-gear. S-gear is a kind of gear whose tooth profile is an S-shaped curve. The sine (cosine) gear, cycloid gear, polynomial gear, and circular arc gear are all S-gears in essence. In the S-gear transmission, the concave surface of one gear and the convex surface of the other gear contact each other. Therefore, the power transmitted by S-gear is much larger than that of the convex-convex-contact involute gear. Some scholars have studied the characteristics of S-gear, but few have explored its manufacturing. In this article, the Numerical Control (NC) machining technology of S-gear is studied in detail for its industrial application. The polynomial curve is used to construct the tooth profile of the S-gear based on the Gear Meshing Theory. The mathematical model of polynomial S-gear is established, by which involute gear can be represented as a special S-gear. The steps of generating NC codes are described. Then, the S-gear sample is processed with an NC machining center. Finally, the sample is measured with a Coordinate Measuring Machine (CMM), and the measurement results show that the accuracy of the S-gear processed by the NC machining center reaches ISO6. This research provides a feasible approach for the design, manufacturing, and measuring of S-gear.

Fixture Planning of Valve-Body Part Based on Machining Capability of NC Machining Center

To solve the problem that fixture planning of the batch valve-body part of car, the NC machining process of the batch valve-body parts based on the normal vector is analyzed in this paper. The different fixture planning of the valve-body part based on the capabilities of three-axis and four-axis and five-axis NC machining center (MC) is discussed. According to the questions that the feature of different machined position holes and faces of valve-body part on three-axis NC machining center, the multi-piece fixture planning and multi-position rotational fixture planning are designed. The results indicate that the proposed fixture planning can improve the machining productivity, which based on cabapility of three-axis NC machining center (MC).