Yongxian Liu

Numerical control machining simulation: a comprehensive survey

Since the first numerical control (NC) machine tool was created at Massachusetts Institute of Technology in the 1950s, productivity and quality of machined parts have been increased through using NC and later computer numerical control (CNC) machine tools. Like other computer programs, errors may occur in a CNC program, which may lead to scraps or even accidents. Therefore, NC programs need to be verified before actual machining commences. Computer-based NC machining simulation is an economic and safe verification method. So far, much research effort concerning NC machining simulation has been made. This paper aims to provide a comprehensive review of such research work and a clear understanding of the direction in the field. First, the definition, common errors, programming approaches and verification methods of NC programs are introduced. Then, the definitions of geometric and physical NC machining simulation are presented. Four categories of NC machining simulation methods are discussed. They are solid-based, object space-based, image space-based and Web-based NC machining simulations. Finally, future trends and concluding remarks are presented.

Service-oriented, cross-platform and high-level machining simulation

With the development of manufacturing, Web-based numerical control machining simulation has become an important part to realise networked manufacturing and make the training for operators easier. Although some research about it is available, most of them are based on G&M code that has inherent drawbacks such as vendor-specific nature, incomplete data, irreversible data conversions and lack of accuracy. These limitations hinder the development of a truthful simulation system; they are dependent on specific platform and have bad interoperability, which limits their use. Therefore, there is a requirement for high-level data model to be developed and utilised that can assist with accurate simulation for machining processes. In addition, there is also a need to take account of computer heterogeneous environment and online service. To solve these issues, this article proposes service-oriented, cross-platform and high-level machining simulation solution that utilises high-level data such as standard for the exchange of product data and standard for the exchange of product data-compliant numerical control in order to produce an informative and truthful simulation and utilises the proposed browser/server-based model–view–controller-communication-data pattern, Java and Web service technology in order to produce platform-independent and service-oriented machining simulation. The outcome of the research provides a better informed simulation environment, makes the training for operators easier and promotes the development of networked manufacturing.

Notice of Retraction Understanding the STEP-NC data model for computer numerical control

STandard for the Exchange of Product data-compliant Numerical Control (STEP-NC) is a new model of data transfer between CAD/CAM systems and CNC machines. It remedies the shortcomings of ISO 6983 by specifying machining processes rather than machine tool motion, using the object-oriented concept of Workingsteps. STEP-NC is being developed concurrently under two different subcommittees of ISO Technical Committee 184, Industrial automation systems and integration so that two different standards, ISO 14649 Data model for computerized numerical controllers and ISO 10303-238 Application interpreted model for computer numeric controllers are generated, both of which can be represented in 10303-21. In this paper, ISO 14649 NC program in Part 21 relative to Example 1 in the ISO 14649-11 is explained in detail so that people can easily understand the object-oriented data model and the advantages of ISO 14649 from the actual example other than abstract and unintelligible theory. Probably, more beginners can get some revelation so that STEP or STEP-NC can get more attention and their development will be faster.

Research on job shop scheduling aiming at Instant Customerisation

The characteristic of instant customerization (IC) production model and its job-shop scheduling problem is described. Considering the conventional algorithmspsila low efficiency of search especially global search, PSO-based to job shop scheduling problem of IC is presented. According to the characteristics of the problem, the PSO coding and optimization are studied to determine the way of coding and operation, which is more adaptable to job shop scheduling. The job shop scheduling part of the system is then programmed with the algorithm. Simulation results show that setting the suitable parameters can provide an suitable working sequence to adapt to the IC job-shop problem. At last, a suggestion about this problem is presented.

System modelling and control of an intelligent bionic leg

Intelligent bionic leg (IBL) controlled by magneto-rheological (MR) damper is an advanced prosthesis. This paper introduced the conception, research purpose and configuration of IBL. Kinematics model and dynamics model were deduced in detail and modified sigmoid model of MR damper was proposed. Then control model of IBL was discussed and combined control simulation was performed. The result indicates that IBL controlled by MR damper can track human normal gait well.

Fuzzy Comprehensive Evaluation Method of the Importance Ratings of Customers’ Requirements

This paper deals with customers’ requirements information based on fuzzy set theory, constructs fuzzy judgment matrix between customers’ requirements and technical performance of products, and determines product technical performance weighting through fuzzy analytic hierarchy process. At the same time, it constructs the market competitiveness evaluation matrix, uses entropy method to analysis the market competitiveness weighting, and determines the indexes weighting of market competitiveness. Directing at the risk of product innovation, this paper constructs the risk evaluation model and calculates the weighting of product innovation risk. Finally, combining with the weightings of product technical performance, market competitiveness, product innovation risk and customers’ requirements of subjective decision, the final importance ratings of customers’ requirements will be determined by the evaluation model with multiple weighting vector structure. And a case of comprehensive evaluation method of the importance ratings of customers’ requirements about the innovative design of numerical control machine is provided to verify the accuracy and feasibility of this evaluation method.

Vibration Analysis of a Certain Type of Aero-engine Turbine Blade Based on UG

This paper introduces the FEA method for a certain type of aero-engine turbine blade and makes a vibration characteristics analysis to this aero-engine turbine blade based on this method. The vibration characteristic of this aero-engine turbine blade is studied and the natural modal of the turbine blade is calculated based on UG software. The first six natural frequencies and mode shapes are given. According to the analysis results the dynamic characteristics of the blade are discussed. The analysis method and results in this paper can be used for further study on optimal design and vibration safety verification for the blade.

Machining simulation – a technical review and a proposed concept model

Machining simulation is a modern tool for safe and reliable machining operations. Geometric simulation is used to mimic the movement during the machining process. Physical simulation is used to discover the ‘sciences’ behind the machining processes, e.g. cutting force, vibration, surface finish, cutting temperature and tools worn. STEP-NC is a new data model for computer numerical control (CNC). It provides rich information for CNC machine tools. The architecture of the NC simulation system based on STEP-NC is proposed in the research, using IDEF0.

Analysis and control of dimensional precision in turning process

The aim of the present work is to evaluate dimensional precision in turning process. A new model of dimensional error taking into account of flank wear and spring back of machined surface of workpiece material was proposed. Flank wear land, tool nose radius and clearance angle are the crucial control parameters in this model. According to the proposed model, the dimensional error was calculated using flank wear land obtained from previous experimental results. The role of three control factors on determining dimensional error has been investigated. The calculation of dimensional error coupling with predict model of flank wear can realize the pre-estimation of dimensional precision in machining.

Research on Product Lifecycle Management system based on Teamcenter

Product lifecycle management is the main part of enterprise informationizaiton management, Teamcenter software is the leader in PLM solution field. Considering the actual demands about the informationization management in large, medium and small enterprises, three architectures of Teamcenter are illustrated, eight subsystems of Teamcenter are discussed in detail and its software as well as the other PLM softwares is introduced. And two cases are given.