Lida Zhu

Integration of the CAD/PDM/ERP System Based on Collaborative Design

The increasing requirement and product complexity need a new design method for the global market. The collaborative design is an important style for the requirement. The CAD system for design is connected with the Product data management (PDM) and enterprise resource planning (ERP) system for management. PDM can support the management of engineering data and the product development. A methodology for the PDM/ERP/CAD integration is proposed. Firstly, the interest of integration of PDM/ERP/CAD is introduced. Then the UML-based methodology is applied for the product data integration model. The PDM structure model diagram and the class model diagram are introduced. Workflow method for the method is introduced. By workflow method, the data publican is realized by the trigger. The data among systems can be visited and exchanged by the methodology. As a result, the design and management models are modified, simultaneously and maintained consistently. The methodology is applied for a system by means of an example, which achieves a good result.

Applications of virtual reality in turn-milling centre

Virtual reality (VR) is a high-end human computer interface that strives to immerse the designers and users completely in a virtual interactive environment for a simulation of real world. In order to meet the requirements of market competition, VR technologies can not only reduce effectively the time and cost, but also optimize complex products in the design process. PVAS (Products Virtual Analysis System) is developed in the paper. The system can realize three main functions. Firstly, products are displayed for the designers and users with stereo glasses. Secondly, products performance is analyzed and optimized in virtual environment. Thirdly, virtual machining and virtual assembly are realized. At present, the translation of data form CAD to virtual reality is often unidirectional and unsatisfactory. Since the limitation is the different data formats used for CAD and VR, two different approaches are proposed in the paper. Finally, the paper takes virtual reality applications in turn-milling centre an example. Using three-dimensional computer graphics, interactive devices, and stereo glasses, turn-milling centre machining simulation can be realized in a virtual world as if it were in the real world. Therefore the method that complex products based on VR are analyzed is significant and has application value.

Prediction of Three-Dimensional Milling Forces Based on Finite Element

The model of milling force is mainly proposed to predict and analyze the cutting process based on finite element method in this paper. Firstly, milling finite element model is given based on orthogonal cutting principle, and then the influence laws of cutting parameters on chip formation are analyzed by using different simulation parameters. In addition, the three-dimensional milling forces are obtained from finite element models. Finally, the values of milling force by the milling experiment are also compared and analyzed with the simulation values to verify the feasibility and reasonability. It can be shown that milling forces match well between simulation and experiment results, which can provide many good basic data and analysis methods to optimize the machining parameters, reduce tool wear, and improve the workpiece surface roughness and adapt to the programming strategy of high speed machining.

Research on Virtual NC Technique in Turning and Milling Process

A virtual machining system based on virtual manufacturing technique and NC machining technique for turn-milling center is developed in this paper, which can realize all processes from the establishment of NC procedure to machining simulation. On the platform of visual C++, the virtual machining environment is built by OpenGL technique, and the structure of machining simulation system and its function are proposed. According to turn-milling center characteristic, the mathematical models about turning and milling are respectively built in virtual NC machining process. The geometric simulation and physical simulation are realized on the basis of the models by C++ language. The research demonstrates that the simulations are handled to complete the virtual machining of the product by checking machining ability, rationality of design, prediction manufacture circle, and promptly modifying design. The method offers the theoretical foundation and reference value of practical application for structure design of turn-milling centre.

Dynamics Modeling and Co-simulation of Rigid-flexible Coupling System of 3-TPT Parallel Robot

A co-simulation method for rigid-flexible coupling system is proposed in this paper, it is simple and easily carried out. In order to solve the dynamics of 3-TPT parallel robot more accurately, its three driven links are regard as flexible bodies and the other parts are rigid bodies to form the rigid-flexible coupling system, and the dynamics equation of the coupling system is educed by Lagranges equation, but it is very complex and difficult to educe number solution, so the co-simulation method using ADAMS and ANSYS is put forward, which the dynamics analysis is fulfilled in ADAMS and stress analysis in ANSYS. The concrete steps are also introduced. In order to observe the simulation results better, the simulation results are compared with rigid system, and the results show that, the forces applied on flexible bodies appear high nonlinear, and with the driven links are close to their extreme, the nonlinear is more obvious and the forces are bigger. This state is closer to the truth, so the simulation results are more authentic and can reflect actual dynamics characteristic of 3-TPT parallel robot.

Co-simulation of rigid-flexible coupling system for turn-milling center

Aiming at the problems of selection for motor parameters and mechanism design of the turn-milling centre, the model of the machining centre is simulated kinematically and dynamically by virtual prototyping technology. A 3D model of the machining centre is developed by UG software, and the assembly model is transformed into ADAMS to form a virtual prototype simulation model based on multi-body dynamics. In order to get more accurately the dynamics of turn-milling centre in the simulation process, the co-simulation method using ADAMS and ANSYS is put forward in the paper, and its important components are regarded as flexible bodies and other parts are rigid bodies to form the rigid-flexible coupling system. The designers cannot only observe the three dimensional dynamic movements in the virtual circumstance by the method, but also forecast accurately and solve possible problems during design before the prototype is manufactured, assuring the feasibility of the motor selection and designs for mechanism framework and control system, shortening the period of the product design and reducing the cost of production.

Analysis of dynamic characteristic and structure optimisation for hybrid machine tool

A new method that the exciting vibration test is simulated to analyse the dynamic characteristic of hybrid machine tool is proposed. The principle of exciting vibration test on dynamic characteristic is researched, and the skeleton and design process of swept sine vibration test is also given. In order to obtain accurate simulation results, the rigid?flexible coupling system model of hybrid machine tool is built in ADAMS software, which forms the exciting vibration simulation model. The exciting force is loaded on the coupling vibration system and brings displacement response, and then the curves of displacement response are obtained. According to the simulation results, the weak parts are effectively optimised and the simulation is carried out again on the optimised structure; then the simulation results are ideal and the deformation of weak parts is also reduced. Therefore, the simulation method can effectively improve the dynamic characteristic of hybrid machine tool.

Dynamic Analysis and Design of the Spindle-Bearing System in Turn-milling Centre

In order to obtain the accurate dynamic characteristics of spindle-bearing system during the design stage, the spindle-bearing system with finite element model is simulated by virtual software, and a method which springs and damping units imitate bearing support is proposed in this paper. The proposed method can predict the regular pattern which bearing stiffness and bearing span affect natural frequency and harmonic response. The research demonstrates that the method predicts well the dynamic characteristics of the spindle-bearing system; therefore, it can be a reference for dynamic optimization design of spindle-bearing system in turn-milling center.

Research on machining simulation of turn-milling center based on DVR

In this paper, a simulation system for turn-milling center is designed by VRML and Java/JavaScript based on Distributed Virtual Reality (DVR). The system overcomes the disadvantages of traditional expensive CAD/CAM software and reduces the volume of the machine document which is convenient for transmission through the web. The system includes movement demonstration and machining simulation by inputting NC code. Customers can interact with the system by the control panel to have a deep understanding of the products. The system includes several characteristics: free installation, low-cost, high availability and good portability.

Analysis of dynamic performance simulation for turn-milling centre

In order to obtain the dynamic performance of turn-milling centre accurately, a co-simulation method for rigid-flexible coupling systems is proposed in this paper. It is very complex and difficult to deduce the solutions of the dynamic equation of coupling system; so the co-simulation method is fulfilled by integrating finite element analysis and multi-body simulation. The kinematics and dynamics of machining centre are simulated to achieve the selection for motor parameters and mechanism design based on virtual prototyping technology. The exciting vibration test in the rigid-flexible coupling system is realised by the method to get natural frequency and displacement responses, which are compared with the experiment. The designers can not only analyse dynamic performance in the machining process, but also accurately forecast and solve possible problems during design process, assuring the feasibility of the motor selection and designs for mechanism framework and control system, shortening the period of the product design and reducing the cost of production.