机加零件螺纹过程质量控制方法研究

Research on the Quality Control Method of Thread Machining Process

摘要: 本文对螺纹加工过程中采用螺纹量规进行质量控制，导致环规不能旋合到位出现误判的现象进行分析，利用C_p和CPK过程能力指数来对螺纹加工过程能力进行评价，在加工过程中使用螺纹千分尺对螺纹中径进行定量检测，并将其控制在公差带下限的30%附近，通过该措施使外螺纹加工过程能力C_p > 1.67、1.0 < CPK < 2.0，螺纹中径值的加工质量达到6σ水平，降低螺纹中径值在制造过程的误差的波动范围，提升过程控制能力。

Abstract: This paper analyzes the misjudgment phenomenon that occurs when thread ring gauges fail to be screwed into place due to the application of thread gauges for quality control during the thread machining process. It uses the process capability indices C_p and CPK to evaluate the thread machining process capability. In the machining process, a thread micrometer is adopted for quantitative detection of the thread pitch diameter, which is controlled at around 30% of the lower limit of the tolerance zone. Through this measure, the process capability of external thread machining is optimized to meet the criteria of C_p > 1.67 and 1.0 < CPK < 2.0. The machining quality of the thread pitch diameter is improved to a qualified level, the fluctuation range of errors in the thread pitch diameter during the manufacturing process is reduced, and the process control capability is enhanced.