By using the experimental modal analysis, the uncoupling technique is so developed as to extract the frequency response function of a component from those of the assembly structure. First a numerical simulation for a mathematical model is used to proof the theory of uncoupling. Then the influence of noise contaminating the frequency response function is discussed for actual measurement consideration and it is found that the noise appears enhanced in the uncoupled results. A test of a simple structure is carried out to confirm the effectiveness of uncoupling technique then another example shows the importance how to idealise the connecting part between the component for accurate uncoupling.
This paper describes a mask-to-wafer alignment technique for submicron X-ray lithography which utilizes single and dual gratings. A single grating method is proposed to avoid the influence of lateral displacement on the gap detection signal. The single grating method utilizes a flat surface without a grating acting as the wafer mark. Both+1-order diffracted light beams, which are reflected from a mask grating and wafer surface, produce an interference signal. By using the linear part of this signal, a resolution of 0.02μm in the gap servo-control is achieved. Moreover, the envelope signal of the interference signal makes it possible to detect the absolute gap. Next, dual grating method with an intensity difference between +1-and 1-order diffracted light beams is applied to detect the lateral displacement. It is found that the lateral displacement signal is highly sensitive and stable when the gap has a specific value and the mask grating aperture ratio is slightly larger than 0.5. By combining the single and dual grating methods, an alignment value is achieved where the lateral displacement is detected within a resolution of 100 A and the gap is set to an accuracy of ±0.5μm.
On the system of this pyrometer, the infrared flux radiated from an object is accepted by an optical fiber and transmitted to an infrared detector through it. Therefore, the surface condition of the incidence face of the optical fiber is closely related to measurement accuracy of this I.R.P. In this study, the polishing method of optical fiber is investigated to produce the good surface of incidence face conveniently. The properties of surface finish of incidence face is checked by measuring the acceptance energy of the optical fiber. The results are as follows. In order to reduce a relative vibration between optical fiber and polishing tool, the optical fiber should be fixed firmly by means of inserting it into a fine stainless steel pipe and the low polishing speed should be chosen. The better surface finish is obtained under the condition of the lower infeed rate. GC and WA abrasive grains are recommended but SD grain is not suitable. The polishing procedure recommended is as follows: for rough finishing the abrasive papers of # 800 and # 1600 are used and for finishing the buff with GC 3000 grain. The polishing with the abrasive grain finer than #3000 has little effect on the acceptance energy of the fiber. Angular miss of incidence face, which is produced when it is polished, has a little influence on acceptance energy of the fiber.
In order to grind a leadscrew of high lead accuracy in the previous studies, it was difficult to install the standard scale on the thread grinder, and furthermore there were some problems about grinding operation in case of in-process control. It is the purpose of this study to realize a new control method for the thread grinder using laser feedback system, to obtain a leadscrew of high lead accuracy and to operate the grinder easily. As a result, the authors obtained a leadscrew of 800mm length which has mean cumulative error of 0.6μm and variance of 4.0μm.
A new measuring method which can estimate quantitatively the periodical fine surface roughness, for example the surface of magnetic memory disk and laser mirror finished by ultraprecision diamond tool machining is presented in this paper. This principle of measurement is based on Fraunhofer diffraction. Relations between the surface roughness and Fraunhofer diffraction patterns of diamond turning surfaces are discussed theoretically and experimentally. The results obtained are summarized as follows: A conventional equation which can accurately estimate the surface roughness of less than 200nm Rmax by measuring the intensity values of 0-3 order diffractions is derived from theoretical analysis based on Fraunhofer diffraction. From the measurements of surface roughness of various workpieces including a magnetic memory disk, it is found that this Fraunhofer diffraction method makes it possible to measure the surface roughness within 10% errors from 1nm to the maximum 200nm.
A compact and high sensitive angle detector for the measurement of surface undulation is proposed. It was constructed for making a sampling time brief. The detector consists of a vessel holds mercury and an optical system. It detects an inclination of a vessel based on a surface of mercury. The experiment about the dynamic character and the drift made the sensitiveness of the detector clear. The calibration by the autocollimator was performed, and it was examined in comparison with autocollimator by measurement of the surface undulation. According to the result, it was confirmed that the detector is smaller than 75mm×75mm×65mm, has high accuracy less than 1" based on the drift data, ±3" based on the calibrated data, and needs a few seconds to get stability of output when the detector is set at the sampling point. At the measurement of the surface undulation, the result gained by the detector coincided with the result by autocollimator.
The study presents the measurement and analysis of transient cutting forces of a rotating tool such as milling cutter from the tool side by means of the improved optical data transmission device. The measured cutting forces by the device are confirmed to correspond to those from workpieces by use of a conventional dynamometer. After disengaging from workpieces, the tool vibrates in the first natural frequency. In addition, transient cutting forces in up-milling, downmilling and up-and-down-milling are found to dominantly contain the component of the first natural frequency, independent of cutting speed, feed rate and depth of cut.
This paper presents a measuring technique and a data-processing algorithm for conical taper parts. Applied in this research are the measuring method of radial deviation and the 10mm range digital transducer with 0.1μm resolution. The acquired data involve the tilting and eccentric errors. It is, however, very hard to remove these errors because the formulae for this problem become nonlinear. Then this paper proposes a newly developed algorithm iterating the linear regression formulae in the least square method. This algorithm is simplified and rationalized for a micro-computer processing.
This paper describes that the discriminant function utilized in the field of pattern recognition is quite able to depict the machinability response. For the shadowy goal given by the abstract expression like an easiness of chip disposal or a good surface finish as well as the definite goal given by the concrete expression like a 30-minute tool life, the discriminant function can classify the set of achievable cutting variables. Therefore, we can put it to use of the decision making of the desirable cutting variables.
In this paper the fundamental investigations are performed to measure the stresses at the cutting edge during metal cutting operation by using of the method of Caustics formed by reflected light ray from the metal surface. In standard method of Caustics the models made of the transparent material are used, but for the stress analysis in the cutting tool under the actual operating conditions it is needed to investigate the difference from using the transparent model by performing the experiments using the metallic model. Two dimensional problems are treated and the objects of study are half plane and wedge shaped plane loaded perpendicularly or obliquely. Specimens are made of aluminium plate of about 6 mm thickness. The Caustics patterns formed by the reflected light from the polished front surface were observed and those characteristics with the loading conditions are investigated in detail. On the other hand the computational patterns based on the optical theory are plotted. These two patterns are coincided accurately enough. Furthermore it was found that the presented results for the metallic specimens were similar to those of previous report for the transparent specimens under the same loading conditions.
Steady vibrations with small amplitude and low frequency usually remain in precision diamond machine tools even supported on air mounts, and inevitably deteriorate cut surfaces roughness. Analysing an enveloping curve of feed marks disturbed by such a steady vibration, the surface roughness is estimated as the function of both the ratio of vibration amplitude to theoretical roughness, and the phase lag of the vibration to work rotation. This makes it clear that the roughness can be reduced to 20-30% of the sum of the theoretical roughness and a vibration amplitude at optimal cutting conditions. The analytical results are proved in experiments cutting Al alloy with straight and round tools. The lathe used for the experiment was oscillated at 5.8Hz frequency, 0.03μmp-p relative amplitude between a tool and a workpiece, by the disturbance from the floor. These results show that straight tools are more effective for improving surface roughness than round ones, and provide a surface roughness within 0.01μmRmax during the above-mentioned vibration.
This paper deals with the forced removal of molten part in drilled hole by vapor pressure of backing material with low evaporating temperature. The following results were obtained by a thermal analysis and experiments. (1) The backing material with lower evaporating temperature than that of workpiece and with high thermal conductivity enables to remove molten part of workpiece by its vapor pressure. (2) The thermal properties of backing material for removing molten part in drilled hole can be analytically estimated for given workpiece. (3) The range of machining conditions to obtain clogless holes becomes much wider and amount of molten rock in both surfaces around hole is reduced by using backing material. (4) Backing material has the effect to increase outlet diameter of workpiece without changing inlet diameter. This effect is more remarkable in backing material with high thermal conductivity.
In order to suppress the chatter marks due to the tuning-fork mode vibration of surfacegrinding machines, which is caused by intermittent contact of the wheel and the workpieceduring grinding operation, several types of dynamic dampers are developed and their effectiveness is investigated experimentally. It was found that in all cases the amplitudes of the tuningfork mode vibrations decreased to about 1/5 of the values in original states and the chattermarks due to these vibrations were suppressed completely. It was confirmed that the proposedprocedure was fit for designing practical dynamic dampers for ordinary horizontal spindlereciprocating table type surface grinding machines.
It is necessary to develop the grinding and the polishing tools for finishing the free-form metal surface of a mold cavity automatically. In our previous paper, the dual-axis micro-grinding tool which can finish a cavity surface to a smooth surface of less than 2.5μmRmax has been reported. In this paper, a dual-axis polishing tool with a spherical elastic body which can finish the ground cavity surface to a mirror surface of less than 0.3μm Rmax was developed. This tool has the following properties: (1) The revolution ratio m of the polishing spindle to the main spindle influences both the cross loci and the cross angle of abrasive grains. (2) This tool which has a low polishing speed and reversal polishing motion like a hand work can automatically polish a mold cavity surface to a mirror surface of less than 0.3μm Rmax in every range of 0-90° inclination angle.
For the machining of both faces of thin cylindrical workpiece, it is used to do external grinding and internal grinding alternatively But considering the efficiency and the grinding rigidity, it is recommended to grind both external and internal faces at the same time In this paper, the mechanism of combined grinding method of shoe type centerless grinding and internal grinding is simulated. The influences of grinding conditions on correcting out of roundness in combined grinding have been analysed in the simulation and the results are as follows. The process of correcting out of roundness of internal face is influenced by the external correcting process It is recommended to take the angle 55° for front shoe and 5° for rear shoe to get high accuracy. In the case that the front shoe angle becomes even times of rear shoe angle the correcting process gets worse. High infeed rate of the wheel give good ability of correcting out of roundness but final out of roundness is small in the condition of low infeed rate and in the condition out of roundness in low frequency is removed easily.
This research is primarily aimed at the investigation of ultra precision cutting for the electroless nickel plating process. The electroless nickel plating process and subsequent heat treatment were adjust so that samples with three different phosphorus contents (5.5, 8.5 and 12.0 wt%); therefore, different microstructures and hardnesses were obtained. All samples were treated by the heat treatment conditions at 373, 473, 573 and 673K from 1to 3 hours. The conclusion drawn from this work is that electroless nickel plating for ultra precision cutting should contain at least an amorphous structure to obtain a high quality machined surface. Also, the nickel phosphorus plating material in heat treatment at 473K for 2hours is lightest damage for machined surface layer. The chip profile of ultra precision cutting appeared to have a lamellar structure for an amorphous structure
In plunge grinding processes of workpiece with varying radius of curvature, the radius ratio and speed ratio vary continuously during one revolution of workpiece. The plunge grinding process is investigated with a computer simulation method. Main conclusions obtained are as follow: (1) Under constant rotation ratio, both radius ratio and speed ratio become maximum at the same angle at which the second derivative of profile function becomes maximum. (2) Under constant rotation ratio, normal grinding force and surface roughness become larger in a position with higher speed ratio. (3) Under constant speed ratio, normal grinding force and surface roughness distribute almost constantly on the circumference of workpiece, but the variation ratio of residual stock and wheel wear rate become larger because of higher effect of radius ratio as compared with that under constant rotation ratio.