Planetary gear trains (PGTs) are widely used in various kinds of machines owing to its advantages, such as high gear ratio, compactness, light weight, and high-load capacity. Needs for PGT especially as a differential device are getting bigger and bigger such as in the human friendly robot and assisting suite. Although there are many studies about PGTs, experimental studies are few, and also almost all studies are dealing steady conditions in ordinary simple usage for reduction. Therefore in this study, transient conditions in starting up are dealt, and the motion of planet gear, which is hidden in ordinary PGT, is directly observed by high-speed camera on novel PGT named U/2K-HV equipping clear acrylic carrier.
Software datums that separate a surface profile from straightness error motion of a scanning sensor are well-known for the straightness profile measurement. Though sequential two point method is often used, it's not useful for many sampling points. When number of sampling point is increased, influence of error propagation of sequential two-point method is increased. In this paper, some combination methods, based on the average criteria, the generalized two-point method criteria and the least squares criteria, are discussed, assuming that a measured profile is a non-periodic function. Simulation results show that the combination method based on the least squares criteria is suitable as the combination of the some large sensor interval sequential methods.
In this paper, the authors propose a phase analysis method of an interferometric pattern generated for the optical axis direction using three-beam interferometry. Authors perform shape measurement using the proposed method. In three-beam interferometry, the fringe pattern along the optical axis direction appears by superimposing each two-beam interference fringe. Therefore, the power distribution of the fringe pattern appears along the optical axis direction. This method enables us to directly obtain shape and displacement using the interferometric pattern. Our method intended for wide application with 3D shape measurements and out-of-plane displacement measurements for the inspection and maintenance of large constructions. As the first step of developing a device for 3D shape and displacement measurement, in this paper, simulation and an experiment were used to confirm that interferometric pattern for optical axis directional appeared. Further, slope of object was measured from the phase shift of optical axis directional pattern.
Curved hole drilling technique for a titanium alloy was needed for a efficient flow path such as water jet nozzle because of its light weight and high corrosion resistance. In this paper, EDM characteristics for titanium alloy workpiece using a copper-tungsten ball electrode with 7.0 mm in diameter were experimentally investigated. While drilling titanium alloy using a suspended ball electrode, the workpiece needs to be vibrated using a vibrator for stable machining performance. Under almost EDM conditions, the removal rate using the suspended ball electrode with workpiece vibration was significantly higher than that using a fixed rod electrode. Furthermore, the electrode wear rate using the suspended ball electrode was lower than that using the rod electrode. While titanium carbide was formed on the machined workpiece surface using the rod electrode, the surface using the suspended ball electrode did not form such phase. Additionally, the possibility to machine a curved hole in the titanium alloy using the suspended ball electrode was investigated. The results indicated that bended holes with various angles such as 15°, 30°, and 45° could be machined successfully by tilting the workpiece.
This study aimed to improve the efficiency of mold processing with high-speed milling and to collect basic data on high-speed milling. In this work, we used a milling machine with maximum cutting speed of 160,000 min-1 and maximum feed speed of 15,000 mm/min along with a small diameter end mill to examine tool wear and machining characteristics when the product of axial depth of cut and pick feed as well as the removal rate were constant. We further compared machining efficiencies for surface and side grinding. The results showed that in high-speed milling, tool wear and surface roughness obtained in face cutting were lesser than that obtained in side cutting; thus, surface grinding was more effective.
This study describes a method to determine a 5-axis tool path in a CNC machine tool. In general, the tool path is determined by two steps: main and post processor. First, positions and postures of the tool are determined in the main processor. After that, travel amount of each axis is calculated based on form shaping theory in the post processor. Therefore, it is difficult to determine especially tool postures considering the axis travel amount in the conventional CAM. In order to solve this problem, this study proposes extended C-space, which is generated from form shaping surfaces defined by the form shaping function analogically, and several strategical constraints can be added to the axis travel amount. This paper describes two strategies as implementation examples of extended C-space. One is minimization strategy of angle change in rotation axes, and the other is minimization strategy of power consumption in all axes. Finally, these effectiveness are confirmed by machining.