Reducing the electric power consumption in NC machine tools is strongly demanded in these years, because the NC machine tools are one of the main facilities in the manufacturing field. Thus measuring tests of the power consumption in an NC machine tool for all components were measured in other studies up to now. This study focused onto the power consumption of feed drive systems. In this study, electric power consumption of an actual 5-axis vertical type machining center consists of X, Y, Z, B and C axes is measured. In order to investigate the electric power consumption of feed drive systems, currency and voltage of servo amplifiers are measured. At first, the measuring tests of each axis are carried out under various feed rate. As the results of the measurements, it is clarified that the power consumption depends on the motion velocity and torque. In addition, acceleration-deceleration parameters and servo gains are also changed to investigate the influences of the parameters. These parameters have big influences on the power consumption during the acceleration-deceleration process. The results of this study show that the electric power consumption might be reduced by changing the motion and parameters of the axes.
The stereo measurement has been used to identify the positions of a target object. In a general way of the stereo measurement by single robot, multiple cameras are used in which their position and posture are fixed. However, it is difficult to detect the object which is occluded by other objects, and is moving over a wide range. In this paper, we propose a novel method for measuring a mobile robot's relative position and posture. For the stereo measurement, it is required for robots to measure precisely informations about the distance between cameras, as well as the relative posture of the cameras. To hold their positional and posture informations, the robot was equipped with three identification markers and share the images taken by another robot. To confirm the effectiveness of the proposed method, we experiments the stereo measurement by real two robots on uneven floor.
In this paper, we consider a continuously variable transmission (CVT). The conventional continuously variable transmissions (CVTs) are mainly classified as belt-type CVTs or toroidal CVTs. Each CVT is basically composed of several friction parts, friction wheels and other mechanical components. Because these conventional CVTs use friction force, their energy transfer efficiency might be inferior. Especially, the conventional toroidal CVTs require precise processing in shaping and surface processing since two rollers are being pushed by strong compression power. Consequently, we propose a new structural CVT in this paper. The proposed CVT consists of a couple of quadric crank chains and one-way clutches. Two identical quadric crank chains are placed symmetrically in the mechanism. Since the proposed method is not based on friction conduction, it provides a mechanism that creates no noise, is durable, and offers high transmission efficiency.
The demand of more accurate and durable cutting edge has increased for high-performance cutlery such as razor blades and surgical knives. A plasma nitriding with high density plasma can be achieved by installing a hollow cathode, and the cutlery surface can be cleaned, etched, heated up and nitrided effectively, which would decrease the surface damage and increase the surface hardness of stainless steel. In this study, the durability and cutting performance of stainless steel cutlery treated by plasma nitriding were investigated in order to evaluate the applicability of plasma nitriding to the surface treatment of cutting edge. The experimental results made it clear that the durability of cutting edge could be improved by the plasma nitriding, since the wear of cutting edge decreased with increasing the process time and temperature.
Recently, the demand for low carbon free-cutting steel that contains no lead has increased. However, no lead steel occasionally produces built-up edge (BUE) that makes machined surface worse during cutting. Therefore, the control of the BUE particularly becomes the important problem to be solved in case of cutting the low carbon steel. This study discusses both BUE generation and omission of low carbon steel SM490A by the use of reaction kinetics in state transitions and linear damage mechanics. As a result, the omission cycle time of BUE can be predicted in the material with a simulation based on the generation and omission mechanism. The result will become the knowledge of the control of BUE for the low carbon free-cutting steel.
The production and development of a new work material and tool material, model for predicting the frictional force component in order to estimate the machinability have been proposed.2) The proposed model has a frictional force, which estimated the opinion slippage caused by the interface on a specific site of the tool rake surface, and the workpiece is chemically bonded to the movement area that is not bound conforming to dislocation. However, the frictional force of the model, the influence of temperature in the two-dimensional surface of the tool rake is not considered. This study constructed a model to for considering the frictional force from the jump probability of the workpiece in the rake surface taking temperature effects into account.
Machining is often performed by a machining center using various cutting tools and end-milling conditions for different shapes and materials. Recent improvements in CAM system make it easier for even unskilled engineers to generate NC programs. In the NC program, the end-milling conditions are decided by engineers. However, engineers need to decide the order of the process, cutting tool selection, and the end-milling conditions on the basis of their expertise and background knowledge because the CAM system cannot automatically decide them. Data-mining methods were attracted attention to support decisions about end-milling conditions. Our aim was to extract new knowledge by applying data-mining techniques to a tool catalog. We used both hierarchical and non-hierarchical clustering methods and also principal component regression. We focused on the shape element of catalog data and we visually clustered ball end-mills from the viewpoint of tool shape, which here meant the ratio of dimensions, by using the k-means method. Expressions for calculating end-milling conditions were derived from response surface method. We conducted end-milling experiments to validate the availability of calculated values.