Three-point method with three gap-detectors has been known effective for measuring the accurate profile excluding the influence of motion errors of machine. As a first step for the research and development of the three-point method to measure the accurate profile on machine tools, the followings are discussed in this paper; (1) a technique to measure the diameter of a roll by the three-point method, (2) evaluating errors due to the arrangement and the random noise of the three gap-detectors, and (3) the measurement result on the diameter of a roll (φ620mm) whose repeatable accuracy was ±3 μm.
This paper presents a method for measuring tool wear parameters based on two dimensional image information. The tool wear images were obtained from an ITV camera with magnifying and lightening devices, and were analyzed using image processing techniques such as thresholding, noise filtering and boundary tracing. Thresholding was used to transform the captured gray scale image into a binary image for rapid sequential image processing. The threshold level was determined using a novel technique in which the brightness histograms of two concentric windows containing the tool wear image were compared. The use of noise filtering and boundary tracing to reduce the measuring errors was explored. Performance tests of the measurement precision and processing speed revealed that the direct method was highly effective in intermittent tool wear monitoring.
The adhered oil film transfers from one specimen surface to another when the contact occurs between surfaces with and without very thin oil film. A transferred oil spot is in fact a real contact surface. In this paper, the real contact area and the pressure distribution of the contact surface are measured by detecting the distribution of the transferred oil film using the reflection of light irradiated onto the contact surface. The measuring device developed in this study is shown, along with the pressure distribution measured in the contact of lapped, ground, blasted surfaces and so on.
In this paper, we propose a new optical measuring method which can be applied to in-process measurement of root mean square roughness (Rrms) of ultra-fine finished surface with an accuracy of sub-nanometer. The principle of our method is based on the Fraunhofer diffraction theory with taking account of Gaussian laser beam propagation. The automated random micro-roughness measuring system is developed based on the principle. Practically, the optical parts composing optical system in which laser beam propagates are taken as the diffractive and scattering body, so the systematic error which is defined as optical system roughness is occurred. In order to enable more accurate measurement by eliminating this error, calibration method based on theoretical analysis is introduced. This method is performed by using a reference surface of which surface roughness is measured by using the traditional stylus method with high reliability. The measurements of the ultra-fine polished silicon wafers with the micro-roughness of sub-nanometer order are carried out by using the developed measuring system of which optical system roughness is calibrated. And the silicon wafers are measured by using the ZYGO profiling instrument for checking surface roughnesses. It is shown that the developed measuring sensor which is calibrated is valid for measuring random micro-roughness within a nanometer.
We develop a multi-dimension interferometer of which function is that not only carriage moving position but pitch and yaw motions can be measured respectively and simultaneously. Here we describe the principle, functions, linearity and construction elements of this interferometer. Using this interferometer system, we try to measure the performance of the monolithic parallel spring. We get these results: linearity of this interferometer is within 0.2nm, measurement repeatability of pitch and yaw motions is within 1nm, when the position of this spring is 35 μm.
An actuator with three degrees of rotational freedom has been developed as a component of micro machines. This actuator consists of a rotor and several drive units which moving tips are attached with the rotor. Each drive unit has a trass structure composed of three piezoelectric actuators. The rotor is driven by frictional force generated between the rotor and the drive unit and can rotate in three directions with cooperative motion of the drive units. In this paper, the principle of this actuator is presented. Next, a position control method which realizes cooperative motion of three piezoelectric actuators, for the drive unit is proposed. Then, the dynamical simulation results of the drive unit and some experimental results are shown. These experimental results show that the drive unit can generate the desired elliptical trajectory with the proposed cooperative control method.
The purpose of the study is to measure axisymmetrical aspherical form, by using a contact type form measuring equipment and to evaluate three dimensional form deviations. In the previous paper, the following process of the measurment was described; (1) Sectional curves along concentric circles and diameters are measured. (2) These sectional curves are combined on cross points by the least square method to compensate measuring errors due to tilts and lifts of a specimen. (3) A curved surface is generated by interpolation from sectional curves. The system to measure axisymmetrical form by using the above method was composed of a contact type form measuring equipment, a rotary table and so on. Measurement accuracy of the system was confirmed to be about 110 nm. In this paper, the other two methods based on the above method are described and are compared with the above method theoretically and experimentally. In some experiments, a glass mold, a molding and a ground lens are selected as specimens which have aspherical form.
To characterize a Si real surface, the effects from native oxide is inevitable. This paper describes the evaluation of the native oxide on Si wafer by photo-reflectance spectra. Photo-reflectance of Si real surface is mainly affected by two effects from the oxide. The one is multiple-reflecting effect in the oxide layer, and the other is the spectral change of the refractive index caused by the strain in Si substrate near the oxide. Differential reflectance (D. R.) spectrum, proposed in the previous paper, is a highly sensitive method for measuring photo-reflectance spectrum. Its high sensitivity enables to separate the two effects of oxide: the thickness of the oxide and the magnitude of the strain are determined by fitting two slopes of D. R. spectrum at two photo-reflectance spectrum peak points (3.4 eV and 4.5 eV). The magnitudes of the measured D. R. spectra of native oxidized surfaces are of the order of 1% to 0.1%. By analyzing the experimental spectra, the thickness of the native oxide and the strain in Si of as-received sample are determined to 2.2 nm and 9.0×10-4 respectively, those of the sample oxidized after removal of the initial oxide are also determined to 1.5 nm and 1.4×10-4 respectively.
The impact drive mechanism (IDM) moves utilizing impulsive force caused by rapid deformations ofpiezoelectric elements and friction. Most of the devices utilizing impulsive force and friction move on a dry base. However, it was found that the IDM could move on a lubricated base through several experiments. In this paper, the movement performances of the IDM on lubricated bases are investigated. The movement on lubricated bases and that in oil are as fine as that on a dry base. The IDM moves in experiments in the same way as calculated by assuming on the dry base. The standard deviation of the movement on the lubricated bases is smaller than that on the dry base. Considering the small distribution of the movement and the antirust of the equipment, it is useful for the devices utilizing impulsive force to drive under the boundary lubrication.
This paper describes new equations for calculating grinding forces and the new measuring system in centerless infeed grinding. In the equations, there are some unknown parameters which must be measured experimentally. For getting the values, such as forces on blade and stopper, angular velocity and acceleration of workpiece, a 3-component dynamometer and non-contact workpiece velocity sensor were mounted on the grinding machine. From this measuring system, normal and tangential grinding forces at grinding point were measured in centerless grinding of a ferrite workpiece with a diamond wheel. These values agreed well with the grinding forces from a conventional measurement in cylindrical grinding, and it was found that the measuring system for centerless grinding has satisfied performance.
Micro photoforming is considered to be a useful and promising technique for manufacturing microstructures or micromechanisms. But the materials used in usual photoforming methods are restricted to UV photohardenable resins, and their properties are usually found unsatisfactory. In this paper, the authors proposed a new application of micro photoforming for manufacturing ceramic microstructures. According to the proposal, a liquid mixture, which is made by blending a photohardenable resin and ceramic powders, is used to photoform microstructures in the green state. The resin in the microstructures can be burnt out by so called deresining at appropriate temperature between 450°C and 600°C, and finally the ceramic microstructures can be obtained after sintering at higher temperature. In this paper, the authors also describe the instrumentation for micro photoforming, report some fundamental results that show the promising feasibility of micro photoforming for making three dimensional microstructures in the green state.
An experimental optical sensor is developed to realize the mixed method in the measurements of roundness and rotational errors. The sensor has two probes, which can detect the displacement and angle at two points on the measured surface simultaneously. The angular distance between the probes is set to 45° according to the result of simulations. The displacement meter utilizes an imaging-formation system and the angle meter utilizes the principle of autocollimation. According to the calibration results, the resolution of the displacement meter and angle meter is 0.1 μm and 0.6s, respectively. To improve the performance of the optical sensor, an optical fiber system for power transmission is used to divide the light from a LD into two beams, which are utilized as the light sources of the two probes. The effectiveness of the fiber system is investigated by measuring the intensity distribution and its stability at the fiber output. The experimental results confirm that the output beams of the fiber system demonstrates fairly good performance. A measurement system is also constructed to realize the measurements of roundness and rotational errors by using the optical sensor. The stability of the profile measurements of the system is confirmed to be 0.05μm. The measurement results show that the mixed method can separate the roundness and the rotational errors clearly. The effectiveness of the mix method that can accurately measure high frequency components is also verified.
This paper deals with improving the DBB test, a method of measuring and diagnosing motion errors of the feed drive system of NC machine tools. Recently the evaluation of the machine's accuracy by measuring circular interpolation motion as the DBB test has been widely accepted. In this study, the method of simultaneously sampling errors ΔR of the traditional DBB test with scale feedback values of closed-loop machine is contrived. With this method servo errors that appears in scale feedback value are eliminated from motion error traces measured by the DBB test, making error origin diagnosis easier and more accurate.
The continued demand by the integrated circuit industry for higher device densities has placed requirements on the photolithographic manufacturing system for high accurate photomasks. To obtain the desired photomasks, decrease of pattern distortions due to bending of a photomask-substrate, as well as positioning accuracy of electron beam, is needed. In the case of unforced support, for example, this bending is caused by its own weight and by strains between the structured coating and the substrate. This paper shows that, in the condition of cylindrical bending substrate with simply supported edges, adequate bending moments in its supporting points minimizes the pattern distortions and linear gain correction in writing positions makes same effect to them. This paper also shows the examples of substrate flatness supported in a 8 supports holder, minimizing the substrate bending by additional bending moments in its supporting points.
This paper describes a head-arm in which thermal deformation is eliminated for a large-capacity magnetic disk storage system. This study uses two methods: measurement by holographic interferometry and calculation by finite element method (FEM). The head-arm is a laminated structure composed of aluminum, adhesive and a flexible printed circuit (FPC). By inserting stainless steel in the adhesive layer, thermal deformation can be eliminated. When the stainless steel is 16 μm thick, thermal deformation is reduced to one third of the older head-arm. The stainless steel must be 22-26 μm thick for deformation in the head-arm to be completely eliminated. In addition, the influence of FPC and IC chips on the head-arm is investigated.
This paper treats the expert computer system for selecting barrel finishing operations. The barrel finishing data concerning the barrel machines, the features of workpieces and the finishing conditions, such as the selecting of media and compounds are classified to construct the expert system on the rule base and frame base learning system. The expert system composed of both production system and frame system is developed. The production system of two stages is introduced in the system. The preferable barrel machines can be selected by the first stage system, and the preferable finishing conditions, such as, the selection of media and compounds are decided by the second system. The combination of more than two barrel finishing conditions can be also decided by the system. It is found that the preferable barrel finishing conditions can be obtained by using the expert computer system which is developed in the study, and the verification results coincide fairly well with the experimental results.