随着科学技术的飞速发展，机械制造技术发生了深刻的变化。传统的普通加工设备已很难适应市场竞争的高质量、高效率的要求，以数控技术为核心的现代制造技术是机械制造行业现代化的重要标志。微机控制的数控机床、数控加工中心的高精度以及适合加工复杂零件的性能，能够很好的满足当今市场竞争与工艺发展的需要。 中船重工旗下陕西柴油机厂为了适应市场的需要，提高竞争力，提出了对一台普通龙门铣床6M612进行数控化改造，全面提高这台铣床的性能。 基于对这台铣床的改造，本课题首先通过全面考察铣床的加工状况来初步确定改造方案，然后研究FANUC 0i数控系统的性能和特点，进一步地根据铣床6M612自身的特点并考虑通过改造后铣床要实现的性能来选择数控系统；深入地理解铣床PMC的结构和工作原理，并在此基础上设计本铣床改造的PMC系统；最后对改造后的铣床进行数控系统的连接和调试。 经过一年多相关技术人员的努力，通过对改造后的铣床进行反复调试和检测，使铣床的性能、精度、工艺参数等都满足了要求，并通过了最终验收。改造该铣床取得了显著的经济效益，与购买同功能的铣床相比至少可以节省60%的成本。并且，改造后的铣床在性能和加工质量等方面都有很大提高。现在，该数控铣床已经投入了生产。

Along with the very fast development of the scientific technology, many profound changes have been happened in the technology of machine manufacture. The traditional common processing equipments become hardly suit the requirement of the high quality and high efficiency of the market competition. Because in the core of numerical control technology,the present technology of manufacture is the important sign at the industry of machine manufacture. Numerical Control Machine Tool and Numerical Control Processing Center, which in the control of the microcomputer, have the high precision, and some capabilities, which can suit the processing of complex part. In order to adapt to market needs and enhance competition, Shanxi Diesel Engine Factory which is belong to the China Shipbuilding Company decided to transformate a common milling machine 6M612. Based on the transformation of the milling machine,through a full inspection of this milling machine,my subject confirmed the project of the transformation. And mainly research the FANUC 0i CNC system’s performance and characteristics. Then, selecting CNC system according to the characteristics of the milling 6M612. Depth understanding of the structure and working principle , designing the PMC system of milling. Finally, connect and debug the transformation of CNC milling machine. After more the a year relation technical staff’s effort, and through the repeat debugging and testing of this milling machine , the performance of milling machine, precision, process parameters had meet the requirements and passed the final checking.Transformation of the milling machine has made significant economic benefits. And compared to the new machine of the same function, the cost can be saved at least 60%. In addition, the performance and processing quality have greatly improved. Now, the CNC milling machine has been put into production.