Research On Micro-displacement To Achieve Detection Of External Screwthread Based On Linear CCD

According to the development of the testing and measuring technology and the requirement of the project, a non-contact method for displacement of the external screw thread is proposed based on a linear CCD. We fabricated the thread detection system using optoelectric technology with the optica grating displacement sensor, application of computer and the fine mechanic technology.Firstly, we introduced the basic principles and working methods. Then we interpreted the CCD time sequence driven by the FPGA and designed the analog to digital converter circuit. We also briefly introduced the principles of the optical grating displacement detection and the step motor sub-driver technology. The processing method of the controlling computer software was also interpreted. The origins of the error and the method to improve it were also given. At last, we analyzed the error in the experiment results.It is proved that the measuring system of the external screw thread is a fast, effective method to measure parameters of the screw pitch, the tooth depth, the addendum angle , the screw thread taper and the results can meet the requirement of the project.