Papers by Keyword: Machine Tool

Abstract: In this paper, a series of numerical control machine tool truncated failure data collect.The data are assumed to be two parameter weibull distribution and related parameters is obtained and relevant inspection and test of hypothesis, it is concluded that the mathematical model of batch of nc machine tool failure interval time distribution.Relevant indicators to determine the reliability of nc machine tools, machine tool's observations, Machine tool observations, point estimation and interval estimation index value provide a theoretical basis for the research on reliability of machine tool.

Abstract: In case of remanufacturing, from the point of view of static and dynamic stability the reusable structural elements are in a partially unknown condition. Before commencing the re-manufacturing process, the effects of reactions and moments occurred subsequent to the work processes and that of other disturbing factors upon the structural elements, during the previous exploitation cycles, should be known. Therefore, it is necessary to verify the static and dynamic stability of any machine tool before commencing the remanufacturing process.

Abstract: This paper deals with the possibility to replace the mineral oil with water in the hydrostatic units of machine tools. With this aim in view we try to make a technical-economic comparison between the hydrostatic drive that uses mineral oil in the range H38 - H46 and the drive with untreated water. Two simple units were taken for comparison, in principle, which use as hydraulic energy source one constant flow pump (q_P = 4 cm³) for the actuation of two consumers and one constant flow pump (q_P = 20 cm³) for making the hydrostatic suspension of the saddle of an AFP type machine.

Abstract: Error modeling and analysis can improve the manufacturing precision and the error compensation accuracy of machine tool. According to the surface of the parts topography information, this paper puts forward a kind of error model of machine tool based on cutter contacting point vector chain. Based on analyzing the cutter contacting point of one tool path which is on the surface of the parts, Based on analyzing action rules of a single cutter contacting point error, the cumulative rules of errors and calculation methods were introduced detailedly, and an application demonstration is given.

Abstract: Fixtures are used for orientation-positioning-tightening of workpieces during machining on machine tools. Multiple clamping fixtures are intended to clamp several workpieces for simultaneous or successive machining. Multiple clamping is characterized by a series of economical advantages, due to the reduction of total machining time. These advantages are more important once the number of workpieces is higher or if the machining is made with compound tools. Due to the complexity, overall size and the high number of components, the multiple clamping fixtures have diminished accuracy than simple fixture due to elastic and contact deformations of fixtures housing, of supports etc. Also, multiple clamping fixtures present diminished rigidity and dynamic stability. From the analysis of the specialized literature results that there are a few paper on the subject of multiple clamping. In the paper there are presented the causes that can lead to the diminish of the accuracy of multiple fixture. The modalities for the determination of fixtures precision are presented, also, for the parallel and serial multiple clamping fixtures.

Abstract: In previous study, the quantitative measurement method of contact stiffness of the joint considering real contact area is developed by experimental approach. However, the measurement of contact stiffness needs special device and skillful measuring technique. Therefore, in this paper, simplified calculation method with material properties and profile data of surface roughness obtained by profilometer is considered. As a result, real contact area, contact stiffness and contact spring stiffness calculated from specific wavelength of rough surface are near agreement with experimental value. Hence, it is revealed that there is dominant configuration in surface roughness.

Abstract: Recently, there has been an increasing demand for miniaturization and multi-functionalization of electronic equipments due to the developments in information technology (IT). Thus, the miniaturization of printed wiring boards (PWBs) and fabrication of highly dense electrical circuit layers are needed to realize the miniaturization and densification of the semiconductor package PWBs. Micro-drilling technology has been attracing attention to machine the electronic micro-through holes with an ultra-high-speed spindle, more than 160 krpm. However, problems have emerged; the drill tool bends and suffers breakage in the drilling process and the heat damage around the drilled hole after a drilling process occurs due to the increase in the drilling aspect ratio between hole depth and diameter. In general, a step feed drilling method is considered an effective way to solve these problems. However, short stroke alternating motion in the spindle axis is needed to do the step drilling process and its motion causes various kinds of vibration. We constructed a machine tool with a novel counter balance mechanism in the spindle driving Z-axis and investigated a model to estimate a proper balance mass for the step drilling process. We compared the frequency response results from a proposed model with the experimental ones, and discussed a control on vibration due to the counter balance mechanism. The results demonstrate that a proposed vibration proof method was found to reduce the vibration in high-speed step-micro-drilling motion and to improve the drilled hole quality and the efficiency of micro-drilling process in the PWB manufacturing fields.

Abstract: In this paper, the kinematics of 5-UPS parallel machine tool is analyzed, and a kinematic analysis method combining kinematic analysis and computer kinematics software is proposed. Under the premise that the parallel machine tool sector parameters is known, firstly we use the vector method to establish a mathematical model of inverse kinematics, and in accordance with a U-shaped processing trajectory the inverse solution is calculated; Secondly, three-dimensional model of the parallel machine tool is modeled in Adams, and kinematic constraints are set correctly; Finally, the inverse kinematics solution of the mathematical model is used as the Adams drive input, then the positive solutions is carried out. Compared through the Adams simulation results with U-machining path, it is verified that the inverse solution of the mathematical model and parallel machine tool bodies both are correct, it has certain significance for Parallel machine tools and other parallel robot kinematics analysis.

Abstract: Coordinate Measuring Machines (CMM's) have attributes to provide results with accuracy and repeatability in measurements, so they are considered equipment with potential for application in industrial environments, specifically in inspection processes. However, as in a machine tools the knowledge of the errors in CMM is needed and allows applying techniques of error compensation. This study aimed to develop a mathematical model of the kinematic errors of a bridge type CMM in "X", "Y" and "Z" directions. Modeling of the errors was accomplished using coordinate transformations applied to the rigid body kinematics; the method of the homogeneous transformation was used for the development of the model. The position and angular errors for the three axes of CMM, in addition to errors related to the absence of orthogonality between them were equated. This study allowed to conclude that modeling of errors applied to CMM allied to calibration is able to evaluate the metrological performance of equipment with displacement on guides, thus is possible to use this technique as error budget analysis in machines.

Abstract: Besides the energy efficiency approach to reduce energy demands of production systems there are also other possibilities to decrease the energy related operating costs. Amongst others avoiding long-term peak loads represents a common measure. In possible future cases a flexible energy demand of factories can also be refunded by the energy provider within new tariff structures. This paper shows the potentials of production systems to alternate their energy demand within productive state, which is also referred to as technical energy flexibility. The focus is on machines of sensitive main processes, where an influence on the energy demand could induce distinct negative effects on the product quality. It is shown how and to which extent the energy demand of production systems can be controlled without negative effects.