Results 1 - 10 of 1997
Results 1 - 10 of 1997. Search took: 0.024 seconds
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[en] A long milling tool with a hollow shank is considered. A special chamber in the shank accommodates the compensation material. This design ensures that the tool is self-balancing. That reduces its vibrational amplitude and increases the productivity in high-speed machining.
[en] The dynamic characteristics of the torsional system in a lathe gearbox are analyzed. The forms of vibration of the torsional system are identified, and the amplitude–frequency characteristics of the gearbox’s dynamic pliability are determined. The resonant peaks at the eigenfrequencies are considered.
[en] Management in general can be interpreted as a rule for controlling the number of people to achieve the goals desired. Management of maintenance activities can be developed from the above definition by describing the activities of the universal dividing head treatment at Holke milling machine. The equipment is a major tool in the milling machine used to manufacture a wide range of very precise grooves, the hole and diameter should have the same distance, and the even and uneven distribution. The tool was damaged and cannot be functioned. The bearing of fulcrum axle was crushed and the screw shaft was worn out due to aging. Therefore, maintenance activity was carried out by replacing of bearing. Function test was then made, and the result shows that the universal dividing head can function well. (author)
[en] Los Angeles machine is used both for mining process and for standard testing covering strength of materials. As the present work is focused on the latter application, an improvement in the estimation procedure for the resistance percentage of small-size coarse aggregate is presented. More precisely, is proposed a pattern identification strategy of the vibratory signal for estimating the resistance percentage using a simplified chaotic model and the continuous wavelet transform.
[en] For conventional CNC lathes, clamp device was located mainly by bonding the end surface of soft mechanical claw to the positioning surface (machining plane) of workpiece inner hole, and then the measuring surface (measuring plane) was measured to achieve accurate positioning of the test through the dial indicator. But this method had following defects: (1) The machining and the measuring benchmark were not on the same surface, which was not conducive to the improvement of the machining accuracy; (2) The measuring process time of the dial indicator was too long to be conducive to efficiency. In order to ensure consistency of product size and improve the efficiency of the workpiece clamping, a set of workpiece fast axial positioning device was designed. The structure of a mechanical soft claw in this device was redesigned. The detection system and pneumatic system were into the device to achieve automatic detection of the workpiece positioning surface and rapid display of test results. The advantages of this device were as follows: (1) The machining and the measuring benchmark were on the same surface of the workpiece to ensure the accuracy of the positioning and improve the machining accuracy; (2) Automatic detection could improve efficiency, eliminate human error arising from dial indicator test, ensure the processing quality, and be conducive to mass production. The statistical results of the first year after this device put into operation were: (1) The size of the workpiece processing meet the technical requirements, no bad parts occurred and processing quality was reliable; (2) The average fixturing time of one workpiece was reduced from 30 s to 10 s, which improved the production efficiency. The use of this device meet the needs of mass production of the workpiece. (author)
[en] The intelligent material, so-called magnetorheological (MR) fluid, is utilized to control turning vibration. According to the structure of a common lathe CA6140, a shear MR damper is conceived by designing its structure and magnetic circuit. The vibration suppression effect of the damper is proved with dynamic analysis and simulation. Further, the magnetic circuit of the damper is optimized with the ANSYS parametric design language (APDL). In the optimization course, the area of the magnetic circuit and the damping force are considered. After optimization, the damper’s structure and its efficiency of electrical energy consumption are improved. Additionally, a comparative study on damping forces acquired from the initial and optimal design is conducted. A prototype of the developed MR damper is fabricated and magnetic tests are performed to measure the magnetic flux intensities and the residual magnetism in four damping gaps. Then, the testing results are compared with the simulated results. Finally, the suppressing vibration experimental system is set up and cylindrical turning experiments are performed to investigate the working performance of the MR damper. (paper)
[en] Volumetric verification is becoming increasingly accepted as a suitable technique with which to improve machine tool accuracy. In the same way, the use of laser trackers to obtain machine error information using the new Active Target motorised retro-reflector allows the verification of all types of machine tool throughout their workspaces. Non-linear optimisation methods and machine tool kinematic models are the mainstays of this technique. Whereas the latter provide the relationship between the nominal coordinates, the geometric errors of the machine and laser tracker measurement, the former reduces the combined influence of geometric errors by obtaining their approximation functions. However, within these two procedures, several factors affect the scope of the produced verification results. The present paper focuses on the analysis of the adequacy of commercial measurement techniques using laser trackers and the new motorised retro-reflector in a real milling machine. An examination is also made regarding the influence of the optimisation sequence defined by the identification strategy, as well as the impact of the number of measured points in relation to the employed regression functions. (paper)