1概述六十年代初，浙江省轻工机械厂从日本引进一台龙门刨、铣联合机床，经过20多年运行，机械性能仍能保持原进口状态。唯电气控制系统使用寿命已到，大部分元器件老化，故障不断，尤其是大量的继电接触器，日本标准和我国标准不一致，损坏后不能得到相应配套，进口价格又较贵 1 Overview In the early 1960s, Zhejiang Light Industry Machinery Factory imported a gantry planer and milling machine from Japan. After more than 20 years of operation, its mechanical properties can still maintain its original import status. Only the life of the electrical control system has arrived, most of the components aging, continuous failure, especially a large number of relay contacts, Japanese standards and our standards are inconsistent, can not be damaged after the corresponding package, the import price is more expensive