Papers by Keyword: Geometric Simulation

Abstract: This paper presents process optimization for the five-axis milling based on the mechanics model explained in Part I. The process is optimized by varying the feed as the tool-workpiece engagements. The linear and angular feedrates are optimized by sequential quadratic programming. Sharp feedrate changes may result in undesired feed-marks on the finished surface. The adopted step is to update the the original CL file with optimized and filtered feedrate commands. The five-axis milling process is simulated in a virtual enviroment, and the resulting feedrate outputs are stored at each position along the tool path. The new feedrate profiles are shown to considerably reduce the machining time while avoiding process faults.

Abstract: Logarithmic spiral bevel gear is the spiral bevel gear whose tooth line is logarithmic spiral line. It helixes angle along the direction of tooth length equal everywhere. Due to the high-tooth spiral bevel gear has significant advantages of high transmission stability, these gear are more widely used in our country, especially in the transport sector. But compared to general spiral bevel gear, its complexity space meshing theory leads that it is different to process. In order to ensure that machining process is reasonable and achievable, we show that how to create tools, geometry and procedures and calculate the tool path simulation based on Siemens UG CAM.

Abstract: Virtual NC lathe machining simulation system is carried out with Visual C++ and Open Inventor software. The system possesses visible UI, interactive inputting workpiece and machining parameters, the integration of geometric simulation and physical simulation, all the simulation functions including real-time display machining process, tool moving, workpiece geometry shape change, the generation and movement of iron simulation, workpiece pressure shape change could be realized. Tool temperature analysis and stress & strain analysis are simulated in the cutting process by FEM. The simulation results show the high efficiency of the simulation algorithm, reasonable simulation results, lifelike. The practice and training could be replaced by the virtual one. The system is applied to verification of NC code, quality evaluation of machine operators, operators, CNC programming staff training and other functions.

Abstract: The paper presents a Web-based virtual machine tool system construction method. The key technologies required to build the system were analyzed. A simulation platform is built with ASP technology, and the geometric simulation is researched by using VRML, JavaScript, and JavaApplet. The physical simulation is researched by using Matlab Web Server, The object of the virtual machine tool simulation system is ultra-high speed grinding test bench. The developed system can realize virtual assembly, CNC code identification, material removal simulation, grinding force calculation and optimization.

Abstract: Collision detection is a critical problem in five-axis high speed machining. Using a combination of process simulation and collision detection based on image analysis, a rapid detection approach is developed. The geometric model provides the cut geometry for the collision detection and records a dynamic geometric information for in-process workpiece. For the precise collision detection, a strategy of image analysis method is developed in order to make the approach efficient and maintian a high detection precision. An example of five-axis machining propeller is studied to demonstrate the proposed approach. It has shown that the collision detection task can be achieved with a near real-time performance.

Abstract: In order to solve the problems existing in geometric simulation of cutting process, slice segmentation method was presented in this paper. The instantaneous shape of roughcasts which are cut can be represented by the characteristics set that can be obtained through proper slice of machined parts and the intersection calculation of cutter and machined parts. By using this method, the accurate result of intersection calculation can be accurate and be gotten rapidly. Besides, because this method is based on visual C++ and OpenGL, it can be isolated from the commercial software. The method is proved to be feasible by the cutting simulation example of cylinder gears and bevel gears.

Abstract: This paper presents process optimization for the five-axis milling based on the mechanics model explained in Part I. The process is optimized by varying the feed as the tool-workpiece engagements. The linear and angular feedrates are optimized by sequential quadratic programming. Sharp feedrate changes may result in undesired feed-marks on the finished surface. The adopted step is to update the the original CL file with optimized and filtered feedrate commands. The five-axis milling process is simulated in a virtual enviroment, and the resulting feedrate outputs are stored at each position along the tool path. The new feedrate profiles are shown to considerably reduce the machining time while avoiding process faults.

Abstract: In free-form surface machining, it is essential to optimize the feedrate in order to improve the machining efficiency. This work is the first of a two part paper on cutting force prediction and feedrate optimization for five-axis milling. Conservative cutting parameters have been mostly used since there was a lack of physical models and optimization tools. Part and tool deflections under high cutting forces may result in poor part quality. The extracted cutter workpiece engagements are used as input to a force prediction model. The predicted cutting forces are shown to be in reasonable agreement with those collection during a roughing operation on a dual blades part.

Abstract: The future development of the manufacturing is using VR technology to make the machining simulation before the actual machining process made. The machining simulation of Ultra High-speed Grinding Machine Tool is researched in this paper. Firstly, using UG/NX software and VRML, the geometric modeling of machine tool is modeled. Secondly, through using Java and Javascript language, the operation and display of machining process of ultra high-speed grinding are realized. The main technologies include NC codes compiling, collision detection and material removal. Thirdly, the example of machining simulation using virtual ultra high-speed grinding machine tool can be obtained in the paper. Compared to other CNC machining simulation methods, the method in the paper has reality display, rich features, a good man-machine interaction, etc., and it does not rely on expensive CAD/CAM software. The system files generated by the machining simulation have the small size and can be transferred on the network easily.

Abstract: 5-axis milling operations are used in industries such as aerospace, automotive and mold for free-form surface machining. In these process, surface quality and material removal rate are of very important. Conservative cutting parameters have been mostly used since there was a lack of physical models and optimization tools. Part and tool deflections under high cutting forces may result in unacceptable part quality. The overall goal of this research is the integration of geometric and mechanistic models for cutting process simulation and feedrate optimization. The extracted cutter workpiece engagements are used as input to a force prediction model. The model predictions for cutting forces and feedrate optimization are compared and verified by experimental results.