Research On The Physical Simulation Modeling And Virtual Machining Of CNC Turning System

Computer simulation technology becomes more and more popular in manufacturing in 21 Century to meet the need of agile manufacturing and green manufacturing. Therefore, a lot of researchers focus on modeling and simulation of virtual manufacturing.Dynamic cutting force is a basic parameter and it directly influences relative displacement between tool and workpiece, tool wear and surface quality in turning operation. Therefore, simulation model of dynamic cutting force is an important part of machining physical simulation research. Cutting force models commonly used are empiristic equations. These equations are often based on statistical analysis of machining data, obtained via changing one or more machining parameters, whilst fixing others. But a complete turning process and nature of force can not be accurately described by means of these models. In this paper, change value of dynamic cutting force model based on time series analysis is presented through extracting feature value of force (maximum value and minimum value per second) on the basis of cutting experiments. Cutting process can be completely described by using the model, which is a research platform for constructing other models which there are close relationship with cutting force.Tool wear prediction model, cutting force simulation model and chip formation prediction model are presented by means of theory of artificial neural network. Input variables of neural network are cutting force, tool wear, cutting speed, feed rate and cutting depth, etc. After the training process is finished, the neural network becomes a knowledge-based tool wear and chip formation system and estimates the tool wear and chip formation. Results showed that tool wear, cutting force and chip formation can be accurately estimated by using neural network in unknown cutting conditions.The multi-goal intelligent optimizing mathematic model of turning parameters is presented by means of Genetic Algorithms. In this work, two objective functions, i.e. minimum production cost and minimum production time, have been considered for turning operation. Furthermore, optimization simulation model, which combines NC graphics verification with optimization estimation, is proposed through integrating optimizing mathematic model into CNC simulation system. As tools to optimize the production activities, the production efficiency is improved via simulation prior to thestart of actual production.Virtual manufacturing is a computer-based system that integrated machining activities dealing with models and simulations instead of physical objects and operations in real world. Aimed at feature of turning operation, a real-time machining modeling method that is combined feature modeling algorithm with dynamic area division method for simulating material removal process is presented in this paper. Meanwhile, a new method, called self-adaption quadtree area division algorithm in Z direction, is proposed to enhance the efficiency of milling simulation. The most significant benefits of suggested algorithm are its improved accuracy and reliability in simulation. The core of algorithm is that workpiece model is divided equally into four parts according to self-adaption quadtree area division algorithm in the precondition of cutting process and change in Z direction. By analyzing simulated results, it is shown that high realistic dynamic image may be produced fluently in the virtual machining environment.The virtual cutting process model, which is combined dynamic cutting force and tool wear and optimization estimation, is established in this paper. On the basis of physical simulation model, the integration modeling system of virtual machining simulation optimization is developed and the integration of real machining and virtual machining based on agile manufacturing is realized.