Papers by Keyword: CNC Machine Tool

Abstract: The uncertainty of mechanical system performance is strongly influenced by the properties of system components such as mass, stiffness-damping coefficient, and friction coefficient. Based on computational simulations, the system performance under uncertainty conditions can be estimated. However, the nonlinear dynamic behavior of friction is difficult to simulate in numerical simulations, this research is therefore employed a smooth stick-slip friction force model instead of the Coulomb friction force model. Monte Carlo simulation (MCS) combined with multibody dynamic (MBD) simulation is proposed to evaluate the uncertainty characteristics of the system components and stick-slip friction force between two contacting bodies. Numerical simulations applied the proposed method were performed to consider the effects of uncertainty of friction coefficient on the machining accuracy of a three axes CNC (Computer Numerical Control) machine tool.

Abstract: In this paper, an online inspection system is developed based on TDNC-H8 open CNC system. The system includes motion control, program management, the preservation and processing of the result and other functions. To check the rationality of inspection route, optimize and modify the inspection program, avoid accidental collision, online inspection simulation function is developed with Visual C++ programming tool and OpenGL graphics library.

Abstract: In this paper are proposed two new approaches to maintenance strategies for Computer Numerical Control (CNC) machine tools. The analysis is done for different families of CNC machine tools from S.C. Elmet Bacau, a company specialized in aviation. In maintenance actions applied to CNC machine tools is very important to know the evolution of defects and critical state of electrical and mechanical components. The results of this analysis concludes that maintenance actions can be judged by the developing time period diagram, between failure appearance and interruptions in operation. It is also analyzed the financial impact, revealed from known maintenance strategies adopted on CNC machine tools, resulting in a positive approach of condition based maintenance.

Abstract: Modern CNC machine tools constitute advanced mechatronic systems. Numerous works are undertaken on the development of new intelligent control systems for CNC machine tools [1–5] equipped with unique diagnostic systems. One of the development directions of CNC control systems is exploring new forms and techniques of operator-machine communication as well as new, simpler machine tool programming procedures. Nowadays, there are many techniques for programming CNC machine tools [6], [7]. These techniques have taken a variety of forms both due to historical limits of technology and various environmental requirements. Despite the existence of complex control systems for operation and programming CNC machine tools or CAD/CAM systems facilitating the generation of a machining strategy for complicated elements, there is a demand for machine tools that are easier to operate, and therefore do not require advanced programming skills for operation.

Abstract: The main goal of the kinematic feed chains used on numerically controlled machine tools is to ensure the relative position between the manufactured part and the cutting tool tip with a high accuracy. Therefore, the positioning precision is a major performance criterion for CNC machine tools. The guidance system of the machine table, together with the actuation system and the closed-loop control system, represents a key factor in manufacturing high precision machine tools. Mounting and alignment errors of guideways, both in vertical and horizontal directions, directly affect the table positioning precision and implicitly, the manufacturing precision of the machine tool. Guideways misalignment also generates stresses, plays and excessive run-out. The present paper contains a method of experimental analysis regarding the influence of guideways alignment errors on the positioning precision of the kinematic feed chains, which takes into account the alignment of the two guide rails, both in vertical and horizontal plans. The feed axis used in the experimental setup is closed-loop controlled, making use of an indirect position measurement system.

Abstract: This paper aims to implement an OMM (on-machine measurement) system using a touch trigger probe installed on the spindle of the milling machine with Fanuc 0i-mc CNC system. The CNC used in the milling machine is Fanuc 0i-mc system. The hardware system configuration for OMM and its software were both presented. The software is composed of several modules, and the most significant one is for generating measurement program based on CAD model of workpiece. This paper mainly presents the specific construction of the measurement macro for Fanuc system.

Abstract: Since numerous parts and various faults of CNC machine tool, the mapping model is proposed to represent the complex relationship between faults. Then some matrices are used to process the mappings model. Finally, the priority of the fault sources is sorted by the fault localization algorithm based on the matrix above. Besides, the case of ram feed system of CNC boring machine tools FB260 illustrates the performance of mapping model based on fault diagnosis.

Abstract: According to the communication principle of 840D numerical control (NC) system and internal data structure, the PLC program is developed to make 840D system state data transmit to the PC with the MPI channels; production status data real-time monitoring system based on 840D NC machine tools is developed, meanwhile, the monitoring and data management for NC machine tool production process status is realized.

Abstract: Gravity has huge impact on the accuracy of heavy-duty machine tools. To investigate errors caused by gravity, it is essential to figure out the most influential factor. This paper presents a geometric error modeling for heavy-duty CNC machine tools. Regarding a machine tool as a rigid multi-body system (MBS), the geometric error model has been established by utilizing kinematics chain and homogeneous transfer matrix (HTM). By analyzing the Jacobi matrix, the influence of all the geometric error parameters has been calculated to find out the key geometric error that affect the accuracy most. It is revealed that gravity of beam and tool affect the accuracy of the machine tool most through the ANSYS simulation. It supports a theoretical basis for the further research on error compensation of the key component of a machine tool.

Abstract: To study the influence law of Geogrid’s effects on the stiffness of grave cushion, cushions of nine different kinds are designed and are carried out static load test of model respectively. The effects of different thickness of cushion layer , different geogrid layers and different laying position of gravel cushion layer on gravel cushion and reinforced grave cushion modulus of deformation are analyzed through the experimental results. Results show that ,under other fixed condition ,modulus of deformation of grave cushion is bigger than that of pure grave cushion layer, and the modulus of deformation of thinner layer of grave cushion is increased much higher; modulus of deformation of the gravel cushion layer of geogrid is increased along with the thinner layer, added gravel cushion layers of geogrid and the move up of the position; the effects of the location of geogrids on cushion modulus of deformation decreases with the increase of the grating layer. Research results provide a referential basis for the optimization design for reinforcement pads in composite foundations.