In recent years, production volume of five axis machining center (5-MC) is increasing. However, processing accuracy of 5-MC are inferior to usual three axis machine tools. Because, the structure of 5-MC is complicate, and have a lot of geometric deviations. Geometric deviation is the geometric error of relationship between each axis of 5-MC and it affect the positioning error of spindle. The valuation method of geometric deviation is standardized. But, setup of standardized method is difficult and requires much time. And these cannot valuate all geometric deviation. In this study, the estimation method that can measure all geometric deviations by one setup is developed. The developed estimation method is based on least-squares estimation of system identification. And, the relevance of the proposed estimation method is verified on the simulation. As the result, geometric deviation is not estimated high accuracy. But, accuracy of 5-MC is increase by calibrated using the estimated geometric deviation.
3D measurement system using stereo images is an important issue in many applications. As the applications are non contact measurement and positioning of the robot. In 3D measurement using a stereo camera, the camera calibration is required. The camera calibration work is to determine experimentally the extrinsic and intrinsic parameters of the two cameras. This task is time consuming and it is necessary to measure many known points. In this paper, a new method to reconstruct 3D data using cross ratio measurement in stereo images is proposed. In the method, it is not necessary to calibrate the extrinsic and intrinsic camera parameters, and a standard scale suitable for this measurement method is presented. In the method proposed here, it is not necessary to fix the cameras when in the same frame, the object to be measured and the standard scale are projected.
An appearance inspection is one of the most suitable applications of a laser rangefinder. In such a field, many products are designed by 3-D CAD. Therefore, the appearance inspection of products validates the deviation between the designed 3-D data and the measured 3-D data. There are a lot of products of specular objects with shiny surface such as polished metals and plastic materials. However, conventional triangulation-based rangefinders are known to be difficult to apply to the 3-D shape measurement of such shiny objects. In this study, we propose an advanced laser rangefinder to be able to obtain the 3-D shape of specular objects and apply the rangefinder to an appearance inspection system.
This paper presents a vibration control using a variable notch filter to suppress mechanical vibrations due to angular transmission errors (ATEs) in harmonic drive gearings (HDGs). Mechanisms including HDGs excite resonant vibrations due to ATEs, especially in the condition that the frequency of synchronous components of ATE correspond to the ones of critical mechanical resonant vibration. In the proposed approach, therefore, a variable notch filter with free parameters of frequency and damping is designed to suppress the resonant vibrations during transient response, considering the sensitivity characteristics of the feedback system. The proposed control has been verified by numerical simulations and experiments for a uni-link robot arm.
In this paper we discuss influence of Dilute NaCl-electrolyzed reducing water (ER water) on the surface of high carbon steel. First, the characteristics of dilute NaCl ER water and pure water for the comparative experiment was described. Next, the high carbon steel test pieces reviewed about the surface change such as the corrosion by the immersion processing to dilute NaCl ER water and pure water. The results show that pure water corrodes to the high carbon steel surface but dilute NaCl ER water doesn't corrode. Also, when doing immersion to dilute NaCl ER water, the alien substance which contains sodium mainly occurs. Moreover, when dry with drying oven after processing an immersion with dilute ER water, alien substance occurs much, but with the centrifuge, the occurrence of alien substance can reduce. The study indicates that dilute NaCl ER water can be applied to the surface treatment and washing of high carbon steel.
In the 1st part of this investigation, cutting speed and geometric quantities such as the tool-workpiece contact region, undeformed chip thickness along the cutting edge and the area of cutting cross-section in slot milling in which the tool is tilted by one or two axes were analyzed, and variations of these quantities according to the tool tilting angle were shown. Cutting forces under various tool tilting angles were predicted by using a cutting model proposed in a previous paper, and relationships between the tool attitude and the cutting forces, abovementioned geometric quantities and cutting speed were systematically discussed. In this paper, differences in these quantities according to the direction of pick-feed are compared in milling using various attitudes. It is found that when two tilting angles are specified by positive angles and a pick feed is applied in the negative direction, change of cutting forces during milling are reduced and a large cutting speed is obtained. Tool deflection generated in the abovementioned milling process is also analyzed using the predicted cutting force data and a finite element model of a ball end mill. As a preliminary result, it is shown that tool deflection and the tool axis trajectory vary considerably according to the direction in which pick feed is applied.
The influence of surface morphology of TiAlN/SiN multilayer, TiAlN and SiN monolayer coatings on their friction behaviors was investigated under dry and water boundary lubrication conditions. The TiAlN/SiN multilayer and TiAlN monolayer coatings were prepared on cemented carbide tool and silicon wafer substrates by reactive DC magnetronsputtering deposition. Tribological properties of the coatings were evaluated by high-frequency linear-oscillation friction testing. The morphology and microstructure of the coatings was observed by atomic force microscopy (AFM) in the dynamic friction mode (DFM) and transmission electron microscopy (TEM) for the investigation of the relation between the topography and mechanical properties of the TiAlN/SiN coatings. The grain diameter and roughness of the TiAlN/SiN are smaller than those of the TiAlN. As a result, the TiAlN/SiN shows higher hardness and better wear-resistant propertiescompared with the TiAlN and it shows a frictional coefficient as low as μ=0.38 under the water boundary lubrication. It is considered that the introduction of the SiN layer contributed to the decrease in the grain diameter of TiAlN and the improvement of surface roughness. The grain diameter and surface roughness can be decreased by changing substrate rotation speed.
Ultraprecision machine tools can exert its performance together with CAD/CAM system. However, CAM systems generally focus on NC data generation. Consequently, operators have to make the process planning by considering the features of machine tools, cutting tools and workpieces. The process planning, which calculates suitable cutting conditions and generates tool paths, is more important when micro-parts are fabricated. Moreover, the setting error may cause the interference between the cutting tool and the workpiece and result in the low machining accuracy. Therefore, this study deals with the development of CAM system in ultraprecision micromachining to generate tool paths by considering high-aspect-ratio structures and to assist operators in setting operation. The effectiveness of the developed system is experimentally confirmed.