Eddy Current Nondestructive Testing Sorter Design And Development

In the production process, we need to judge whether the workpieces are qualified through real-time test, in order to eliminate the unqualified workpieces. But the destructive testing methods are inefficient and not reliable, which can not meet the requirements of the real-time sorting. So the nondestructive testing methods are required.Eddy current testing is one of the nondestructive testing methods which are used widely in the quality control of the metal workpieces, and eddy current detector is an application of this technology. It has the advantage of high speed detection. While the current eddy current testing instruments mostly have the shortage of single frequency excite signal, low detect speed and instrument size large.Aim at this actuality, the design scheme of a new eddy current detector is put forward in this thesis. Firstly, a frequency adjustable signal generator which based on DDS technology is designed and the problems caused by single frequency of the excite signal are solved. Secondly, the eddy current sensor for cylindrical metal workpieces and the hardware circuit of the eddy current detector is detailedly designed. Thirdly, a Niosâ…¡processor system is generated and the software based on this system is developed. The software and hardware system is realized in just one FPGA chip and the size of the instruments is reduced obviously. Finally, the system hardware and software are debugged and the function of the eddy current detector is test.