Heavy-duty Machine Tool Research Articles

Thermal Deformation Finite Element Analysis for the Ram of Heavy-Duty CNC Machine Tools

The thermal deformation of ram system in a heavy-duty CNC milling-boring machine tool has a serious effect on its accurateness. This paper analyses quantificationally the temperature field and deformation field of the ram system, and gives the ram’s heat sources, calculating quantity of heat and transferring type of heat. And then a finite element analysis is performed, the analyzing results provide basic theoretical data for thermal error compensation in machine tools.

Prediction of machining accuracy degradation of machine tools

Abstract Machine tool has to maintain its accuracy for quality control of products. After a long period of cutting operations, obvious wear will occur on the contact surfaces of the slide and the guideway. Such a wear will degrade the accuracy of machine tool due to the increase of Abbe errors. This research proposes a mathematical model so that, at given cutting forces and parameters of the slide-guideway, it is able to calculate the geometric errors of the slide due to contact deformation caused by the wear of the guideway and then predict the positioning errors after a long-term operation. Cutting forces applied to the worktable will cause reaction forces on contact surfaces between the slide and the guideway. Such reaction forces can be solved by static equilibrium equations of deformed free-body diagram of the slide. The induced abrasive wear can then be estimated. A simulation study on a heavy duty machine tool with slide-guideway will show the magnitude of wear on the sliding surface and the consequently caused geometric errors of the moving axis. Experimental tests show that, if modifying the wear coefficient to a function of sliding distance, the analytical result is in good agreement with the experimental result.

Research on the Vibration Attenuation of Heavy-Duty Machine Tool Based on Non-Obstructive Particle Damping (NOPD)

In this paper, the possibility of applying non-obstructive particle damping (NOPD) into the vibration attenuation for heavy-duty machine tool was analyzed and the experimental study on the characteristics of damping vibration attenuation was then carried out. First, the finite-element model for heavy planer type milling machine was built and then the stress state excited by the cutting force in the presence of the holes for filling particles located in the stand column was calculated. Secondly, based on the experiment, the acceleration time-domain waveform and the frequency response function (FRF) between NOPD application and the traditional solid cast-iron column of the planer type milling machine were obtained. Finally it is indicated that NOPD can effectively reduce the amplitude of vibration of heave-duty machine tool and has a good damping effect. Meanwhile, it has some additional effects, such as cost reduction, energy conservation and emission reduction.

Reconstructing NC Program-Based Geometrical Error Compensation for Heavy-Duty NC Machine Tool

Heavy-duty NC machine tool is difficult and costly to evidently improve their precision via manufacturing technology only. It is proved being an effective approach to improve machine tool manufacturing precision based on software error compensation. In this paper, an error compensation algorithm based on reconstructing NC program is discussed. Following comprehensive discussion on basic algorithm of positioning error compensation in detail, linear interpolation and circular interpolation movement error compensation algorithm are further sketched in brief. To decrease the machining error, NC program is reconstructed before actual machining. The experiment results show that error compensation methods based on reconstructing NC program can improve profile accuracy of heavy-duty NC machine tools obviously.

Temperature Variables Selection for Thermal Error Modeling of Heavy-Duty CNC Milling-Boring Machine Tools

One of the difficult issues in thermal error modeling is to select appropriate temperature variables. In this paper, two selection strategies are introduced to overcome this difficulty. After measuring the temperatures and thermal errors of a heavy-duty CNC milling-boring machine tool by a laser tracker, four temperature variables which are the foundation of thermal error modeling are selected for each feed axis from fifteen temperature variables according to major factor strategy and non-interrelated strategy.

Stiffness Study of Swing Chainon Heavy Duty Deflection Angle Milling Head

Heavy duty deflection angle milling head is the core functional unit of heavy-duty gantry CNC machine tools. Stiffness of swing chain system is one of the important factors that determines accuracy of heavy duty deflection angle milling head. In order to improve dynamic performance and mechanical precision, the gear pair and support system of the swing chain are studied in the paper. Based on the deformation compatibility condition and the superposition theorem, the torsional deformation and stiffness of each part are analyzed, and considered the deformation of workpieces and supporting system and the interaction of them. The vulnerable segment is found out in the paper, which is valuable to amend and improve the design of milling head. At last, the curves of the relation between the swing chain stiffness and the gear parameters and bearing preload are charted, which provide the theory and technical support for digital design, optimization of the milling head and the basis for the similar driving system stiffness calculation.

Application Research on New BOM Model and Algorithm Base on Path Correlation

This paper summarizes and analyzes several construction methods of a list of common materials, proposes a new type of path-based BOM construction methods, improve BOM arithmetic to achieve BOM traversal algorithm. The BOM structure and its traversal algorithm are applied to data management platform of heavy-duty machine tool, which improve the operational efficiency of data management platform.