Abstract
The guest editors are honoured to present this Special Issue on Computational Numerical Control (CNC) Machining. The majority of the papers were authored by invited experts who have presented their latest research at the 2nd International Symposium on Computational Numerical Control Machining held on 9–10 April 2013, Nanjing, China. The symposium gathered researchers from Chinese and international leading research groups working in the specialized field of CNC technologies in machining. A number of world-leading researchers in this field, who albeit did not attend the symposium, were also invited to submit papers to the Special Issue to report their latest research results. All papers were written from scratch and reviewed by three reviewers following the standard criteria and review process of the Journal of Engineering Manufacture.
In order to give an overview of the contextual background, the guest editors conducted a review of the main aspects of the theories and technologies in this field, which is presented as the first paper titled ‘From computer-aided to intelligent machining: Recent advances in computer numerical control machining research’. The rest of the papers are briefly introduced below.
Huang et al., in their paper ‘Generation of spherical non-uniform rational basis spline curves and its application in five-axis machining’, present a De Boor-algorithm-based method to avoid interference and obtain smooth toolpaths simultaneously, by adjusting fewer directions.
Li et al., in their paper ‘Interpolation using non-uniform rational B-spline for the smooth milling of ruled-surface impeller blades’, present a three-order spherical non-uniform rational basis spline (NURBS) curve interpolation algorithm for ruled surface blades, in order to realize a smooth interpolation and high-accuracy machining, by effectively coordinating the hub and shoulder curves.
Zhao et al., in their paper ‘Look-ahead interpolation of short line segments using B-spline curve fitting of dominant points’, present a real-time system consisting of spline fitting, feed-rate scheduling and parametric interpolation modules to obtain smooth toolpath and feed-rate profile simultaneously.
Min and Gao, in their paper ‘Iso-scallop tool-path generation of five-axis computer numerically controlled machining for cyclide splines’, present effective algorithms to generate optimal tool orientations by making the contact order between the cyclide patch and the cutter envelope surface as high as possible.
Xu et al., in their paper ‘A five-axis tool length compensation method using the numerical control program with macro variable’, address how to respond to changes in tool length during real-time machining, by establishing a kinematics model of the machine tool and a compensation method based on post-processing for five-axis machine tools with dual rotary heads or with a rotary head and table.
Yanlong et al., in their paper ‘A point-based variation propagation model for multi-pass machining process’, present the relationships between different machining passes and a method by which the workpiece deviation generated in the previous pass can be applied to the next pass, thus ensuring timely adjustment of machining strategy with dynamic information.
Du et al., in their paper ‘Automatic robotic polishing on titanium alloy parts with compliant force/position control’, present an adaptive force controller, which is able to imitate manual polishing operation and prevent undesirable vibrations and mechanical collisions. Online self-learning capabilities have also been developed to automatically generate new basic trajectories from previous ones.
Bharathi and Dong, in their paper ‘Feedrate optimization and trajectory control for micro/nanopositioning systems with confined contouring accuracy’, present a framework for abstracting the dynamic capabilities of the piezo-actuated nano-positioning systems, to generate an optimal trajectory for a particular toolpath while satisfying all the process-related requirements.
Liu et al., in their paper ‘A dynamic feature–based operation planning method for 2.5-axis numerical control machining of complex structural parts’, present a new feature concept to represent the status of interim features including the unexpected wrong machining effects such as undercut and overcut conditions during machining. Accurate and optimal machining strategies can be planned and programmed in response to the changes in features during machining.
Su and Wang, in their paper ‘Latest development of a new standard for the testing of five-axis machine tools using an S-shaped test piece’, introduce a new standard initiated by main industrial users of machine tools, which has been recently accepted by the International Organization for Standardization (ISO). The advantages and disadvantages of the new standard and new efforts made to simplify the definition, reduce the testing workload and improve the measurement accuracy were also reported.
Huang, et al., in their paper ‘An effective numerical control machining process reuse approach by merging feature similarity assessment and data mining for computer-aided manufacturing models’, present a novel approach to effectively reuse the existing numerical control (NC) machining codes and parameters in previous manufacturing information models. The machining know-how database can be generated accordingly.
Zhang et al., in their paper ‘A meta-model of computer numerical controlled part programming languages’, present a meta-model to overcome the major barriers to the interoperability between CNC machines and computer-aided (CAx) systems caused by the use of different programming languages. The meta-model would also enable the process knowledge in existing part programmes to be easily reused.
Liu and Li, in their paper ‘Granulation-based resource classification in Cloud Manufacturing’, present a multi-level resource virtualization framework for manufacturing cloud services encapsulation, which are flexibly composed to respond business opportunities.