Research on Fault Knowledge Base Technology of High-End CNC Machining System

2011 ◽  
Vol 308-310 ◽  
pp. 35-40
Author(s):  
Xiao Li Xu ◽  
Bin Ren ◽  
Yun Bo Zuo ◽  
Guo Xin Wu

In the high-end CNC machining process, the stability and reliability of the running state of the machining system directly affects the machining accuracy and work-piece quality. In order to effectively ensure the reliable, stable, safe operation of the high-end CNC machining system, the fault knowledge base technology construction for the cutting tool system is carried out. It focuses on the high-end CNC machine tools, and build the condition monitoring system test platform with cutting tool system as the core; the fault sample acquisition method based on the rough set theory is proposed; a knowledge base model construction technology is conducted; and the network-based sample acquisition test platform is established, so as to provide users with data information on the operation of cutting tool system, and provide the key test techniques for the generation mechanism of the dynamic performance and wear condition of the operation of cutting tool system and for the analysis of the intrinsic correlation between the characteristic parameters and wear condition of cutting tools.

Author(s):  
Xiao-Jin Wan ◽  
Cai-Hua Xiong ◽  
Lin Hua

In machining process, machining accuracy of part mainly depends on the position and orientation of the cutting tool with respect to the workpiece which is influenced by errors of machine tools and cutter-workpiece-fixture system. A systematic modeling method is presented to integrate the two types of error sources into the deviation of the cutting tool relative to the workpiece which determines the accuracy of the machining system. For the purpose of minimizing the machining error, an adjustment strategy of tool path is proposed on the basis of the generation principle of the cutter location source file (CLSF) in modern computer aided manufacturing (CAM) system by means of the prediction deviation, namely, the deviation of the cutting tool relative to the workpiece in computer numerical control (CNC) machining operation. The resulting errors are introduced as adjustment values to adjust the nominal tool path points from cutter location source file from commercial CAM system prior to machining. Finally, this paper demonstrates the effectiveness of the prediction model and the adjustment technique by two study cases.


Author(s):  
P Vichare ◽  
A Nassehi ◽  
S Newman

The capability of any manufacturing system primarily depends on its available machine tools. Thus machine tool representation is a vital part of modelling any manufacturing system. With the rapid advances in computerized numerically controlled (CNC) machines, machine tool representation has become a more challenging task than ever before. Today's CNC machine tools are more than just automated manufacturing machines, as they can be considered multi-purpose, multi-tasking, and hybrid machining centres. This paper presents a versatile methodology for representing such state-of-the-art CNC machining system resources. A machine tool model is a conceptual representation of the real machine tool and provides a logical framework for representing its functionality in the manufacturing system. There are several commercial modelling tools available in the market for modelling machine tools. However, there is no common methodology among them to represent the wide diversity of machine tool configurations. These modelling tools are either machine vendor specific or limited in their scope to represent machine tool capability. In addition, the current information models of STEP-NC, namely ISO 14649, can only describe machining operations, technologies, cutting tools, and product geometries. However, they do not support the representation of machine tools. The proposed unified manufacturing resource model (UMRM) has a data model which can fill this gap by providing machine specific data in the form of an EXPRESS schema and act as a complementary part to the STEP-NC standard to represent various machine tools in a standardized form. UMRM is flexible enough to represent any type of CNC machining centre. This machine tool representation can be utilized to represent machine tool functionality and consequential process capabilities for allocating resources for process planning and machining.


2013 ◽  
Vol 579-580 ◽  
pp. 276-282 ◽  
Author(s):  
Zhi Yan Ma ◽  
Guang You Yang ◽  
Xu Wu Su

Based on Virtual Numerical Control machining system (VNC), a new method of Augmented Numerical Control machining system (ANC) which aims at the realization of NC machining process simulation in real machining environment is put forward. The System inputs continuous video images of real NC processing environment through camera to identify and locate the major machining and positioning parts of real machine in the image stream. And the virtual parts of VNC will be matched to the corresponding real ones of real machining system to achieve the registration of ANC. The NC system drives the virtual machining models for processing through a real machine. On the other hand, the actual running information of CNC machine are imported into the ANC system to drive some models of process variables such as cutting force, material removal rate, chip shape, tool temperature, cutting tool wear. ANC provides the platform to integrate the geometry and physical simulation based on actual information from real CNC machining environment.


2016 ◽  
Vol 693 ◽  
pp. 1704-1710
Author(s):  
Ting Ting Guo ◽  
Xian Ying Feng ◽  
Teng Jiao Sun

Taking the CY4105 crankshaft mould as the research target, this paper introduced the CNC machining method based on CAD/CAM technique. At first, structure of the mould was introduced. Then, machining method was introduced, including blank setting method, cutting tool selection, machining method selection and technological parameters setting method. After that, generation method of the mould machining programs was introduced, including tool path and G codes generation. At last, the mould was machined by a vertical machining center, and the results show that the machining accuracy is high.


2014 ◽  
Vol 1030-1032 ◽  
pp. 1305-1308
Author(s):  
Shi Chao Li ◽  
Song Lin Wu ◽  
Yan Kun Liang

It is a general processing technology that multi-axis NC machine tools is used for machining impeller at present. In order to improve the machining accuracy of the five-axis NC machine tools, the paper analyzes the computing interpolation error of the Multi-axis CNC system in detail. Some of the measures of tools selection have been proposed in purpose of diminishing the accumulative error of the system. The paper also establishes the optimized objective function to optimize the process parameters of the CNC machining based on the material removal rate. All these measures will improve the machining efficiency significantly and increase the stationary of the machining process.


Author(s):  
Yong Li ◽  
Hao Tong ◽  
Jing Cui ◽  
Yang Wang

In electro discharge machining (EDM) for 3D micro structures, the electrode wear is serious and it needs to be compensated in process. To obtain a better balance of the machining accuracy and efficiency, a servo scanning EDM method is proposed for 3D micro structures, in which the electrode wear is compensated on real-time by controlling the discharge gap constant. It is supposed reasonably that the machining depth of each layer in servo scanning EDM is consistent if discharge gap is kept preferably. The servo scanning EDM strategies include the model design by Pro/Engineer (Pro/E), the plan and simulation of scanning path, and the machining process. The 3D micro structures are machined by scanning layer-by-layer under servo control of the electrode with monitoring discharge gap signal. The CAM, gap servo control, and real-time electrode wear compensating are integrated into the machining system. The evaluation experiments of servo scanning EDM and the typical machining experiments of 3D micro structures have been carried out. The machining results show that the electro discharge in the servo scanning EDM is more stable. Servo scanning micro EDM is propitious to improve machining accuracy and efficiency in 3D micro structures.


2020 ◽  
Author(s):  
Mohsen Soori ◽  
Mohammed Asmael

Abstract To enhance accuracy as well as efficiency in process of machining operations, the virtual machining systems are developed. Free from surfaces of sophisticated parts such as turbine blades, airfoils, impellers, and aircraft components are produced by using the 5-axis CNC machine tools which can be analyzed and developed by using virtual machining systems. The machining operations of thin walled structures such as impeller blades are with deflection errors due to cutting forces and cutting temperatures. The flexibility of thin walled impeller blades can cause machining defects such as overcut or undercut. So, the desired accuracy in the machined impeller blades can be achieved by decreasing the deflection error in the machining operations. To minimize the deflection of machined impeller blades, optimized machining parameters can be obtained. An application of virtual machining system in predicting and minimizing the deflection errors of 5-Axis CNC machining operations of impeller blades is presented in the study to increase accuracy and efficiency in process of part production. The finite element analysis is applied to obtain the deflection error in machined impeller blades. In order to minimize the deflection error of impeller blades in the machining operations, the optimization methodology based on the Genetic algorithm is applied. The impeller is machined by using the 5-axis CNC machine tool in order to validate the developed virtual machining system in the study. Then, the machined impeller is measured by using the CMM machines to obtain the deflection error. As a result, the deflection error of in machining operations of impeller by using 5-Axis CNC machine tools can be decreased in order to enhance accuracy and efficiency of part manufacturing.


Author(s):  
Mohammad Arafat ◽  
◽  
Rasidi Ibrahim ◽  
Muhammad Agung Hambali ◽  
◽  
...  

In ultrasonic vibration-assisted turning (UVAT), vibration is one of the critical factors that causes noise during machining and affects cutting tool life, machining accuracy and workpiece surface quality. Vibration generated by piezoelectric actuators tends to transmit undesired vibration on the edge of the cutting tool and tool post. This situation hinders the maximization of vibration energy usage in the cutting tool. Thus, this paper investigated the vibration performance in the cutting tool by adding an isolator pad as damping element in the static zone of a tool holder to reduce the resonance generated during the machining process. The static, vibration and surface roughness analysis has been performed to determine the impact of damping on the machining performance. The results revealed a significant improvement in surface roughness where the best Ra for UVAT was 0.38 μm. In addition, vibration and static analysis showed the application of isolator pad capable of reducing 80% of energy loses and a supporter to increase the displacement, respectively. Ultimately this innovative solution can play an important role in improving UVAT performance.


2016 ◽  
Vol 836-837 ◽  
pp. 296-303
Author(s):  
Dong Sheng Liu ◽  
Ming Luo ◽  
Ding Hua Zhang

Thin-walled workpieces are widely used in the aerospace manufacturing industry in order to reduce the weight of structure and improve working efficiency. However, vibration is easy to occur in machining of thin-walled structures due to its low stiffness. Machining vibration will result in lower machining accuracy as well as machining efficiency. In order to reduce the machining vibrations of thin-wall workpieces, commonly used method is to select proper machining parameters according to the chatter stability lobes, which is generated according to the machining system parameters. However, this method requires exact system parameters to be determined, which are always changing in the machining process. In this paper, a special designed fixture with damping materials for the thin-walled workpiece is presented based on the machining vibration control theory, and analysis of the effect of vibration suppressing is obtained through the contrast of vibration tests of milling the thin-walled workpiece on the damping clamp. The damping material is used to consume vibration energy and provide support for thin-walled structure. Machining test was carried out for thin-walled structure machining to validate the effectiveness of the proposed method.


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