ORIGINAL ARTICLE Design and implementation of an open CNC core at the shop floor level Tianliang Hu & Chengrui Zhang & Riliang Liu & Peng Li Received: 28 September 2007 / Accepted: 19 December 2007 / Published online: 5 February 2008 # Springer-Verlag London Limited 2008 Abstract In this paper, a new CNC core design method, the function-separated design (FSD) method, is proposed to increase the modularity and reconfigurability of CNC systems, simplify the CNC development process, as well as gain a secondary development ability to allow customers or third parties to add or modify NC functions at the shop floor level. With the FSD method, a new CNC core structure is built. In this structure, the CNC core is composed of three main components: engine machine interface, event processor (EP), and system description data (SDD). The engine machine interface provides an interface to machine tools through the parameter settings via a human machine interface (HMI). The EP and SDD are the most important parts. The SDD stores the control rules and modularized NC functions. It is designed as the relatively separated part inside the CNC core. It can also be modified according to the specification changes to access the functions of the CNC core at the shop floor level. To ease the modification of the SDD on the shop floor, the Statechart modeling tool is used to generate a CNC function model; meanwhile, an SDD generator is developed to convert this model into the SDD. The EP is driven by events from the event generator and processes these events by referring to the SDD. The EP always remains the same. With such a structure, the control rules and NC functions of a CNC core can be redesigned or upgraded easily. A case study for implementing a non-circular piston-turning system verifies the feasibility of the proposed design method at the shop floor level. Keywords CNC core . Function-separated design . Statechart . Event processor . System description data 1 Introduction As the brain of machine tools, CNC has been widely used since its introduction in the early 1950s and plays a very important role in modern industry. In order to fulfill the rapid development of manufacturing technology and industry requirements, conventional CNC systems still have many drawbacks, which have become bottlenecks of CNC system development. The major limitations are summarized as below [1]: – First, conventional CNC systems have low reconfigur- ability. They are based on specific hardware maintained by different CNC providers. Meanwhile, the function components of its software are not relatively separated and cannot be reconfigured after the CNC systems are built. The closed hardware and software architecture makes it like a black box to the customers, as well as the third parties (such as machine tool companies). This makes it impossible to reconfigure the hardware and software to meet different control requirements. It also causes compatibility problems between different CNC companies and even between different products of a same company. – Second, it is not easy to carry out secondary develop- ment for conventional CNC systems. Currently, special control functions are frequently requested for special machine tools with new machining methods. It is very hard to integrate all functions together into a general- purpose CNC system at the very beginning when the CNC system is built. Int J Adv Manuf Technol (2009) 40:541–552 DOI 10.1007/s00170-007-1365-5 T. Hu (*) : C. Zhang : R. Liu : P. Li School of Mechanical Engineering, Shandong University, Jinan 250061, People’ s Republic of China e-mail: tianliang.hu@hotmail.com