The P-map method - a new 3-D shape modeling method is proposed in this paper. The P-map method has many good properties for a 3-D CAD/CAM system ; it needs small memory, short processing time and has high precision of shape representing which are harmonized with each other. Based on the P-map method, we have developed a CAD/CAM system called PHP-CAD/ CAM (PHP = Personal High Performance) using a 16-bit micro-computer. This paper describes the concept and the properties of the P-map method. In order to generate tool paths with high speed and high precision, a tool's touch-point theorem is also proposed. Based on the P-map method and the theorem, a new tool path generating algorithm has been developed.
Behavior of tool system which consists of one degree of freedom mass-spring system is characterized by repetitive steady-state motion for impact working like as hammering, punch-ing and press. The self-excitation is applied to improve motional stability for the workings. The tool motion don't have an effect on fine variation of working condition by means of the self-excitation which makes to act pull up and down excitation forces between pre-setted switch on and off positions, respectively. Then, the steady-state repetitive working motion is absolutely stable over the all drive condition. In the case that the pull up force cut time comes nearer at working start time and switch on time of the pull down force comes nearer at time of leave from a workpiece, the both force levels required for an arbitrarily decided initial working velocity approach to the minimum values. If switch on time of the pull down force comes near by the center of period of the motion, the required force level has the minimum value regardless of addition of the pull up force in the light damping.
It is important to estimate the rotational vibration of a pair of spur gears when the tooth profile error is given. The effect of the amplitude and the phase angle of each harmonic component of tooth pofile error to the amplitude of vibration is discussed in this paper. The amplitude-rotational speed characteristics of vibration are numerically obtained by using the finite difference method. We found that each resonance amplitude of vibration is the function of the amplitude and phase angle of each harmonic component of tooth profile error. The linear approximated formula between the each resonance component of vibration and the each harmonic component of the tooth profile error is proposed. We apllied this linear approximated formula to estimate the vibration of actual tooth profile error of gears which are made by various processing method. The estimated results agreed with the detailed-calculation results.
Several important items such as fiber orientation and hardness, relating to strength of short glass-fiber reinforced nylon (GRP) thread, are investigated over the section of GRP thread profile after hot and ultrasonic indentation forming. It is observed from SEM photograghs that the fibers at crest are aligned quite differently from the thread profiles formed with two methods, while those at root are aligned similarly along with the surface. The hardnesses along the centerlines of crest and root, measured by Micro-Vickers Hardness Measuring Instrument, tend to be lower than those of base material only at surface. Compared with hot indentation forming, it is found that not only indentation force F1 but also die temperature (forming temperature) Td, appears lower for ultrasonic indentation forming. It is also observed the flaw remains inside of the thread profile for hot indentation forming even if the die temperature is elevated to a quite high point.
The cooling action of grinding fluid is expected to improve the accuracy and quality of finished surfaces and to enhance the grinding efficiency. However the exact value of the local heat transfer coefficient at the wheel to workpiece contact zone, α, has hardly been known. In this paper, a new method for measuring α in the vicinity of the contact zone is proposed. The error introduced in this method is estimated by using a finite element method, and the factor for correcting the measured value is derived. Thereby the distribution of α is measured in some conditions of supplying grinding fluid, and following results are obtained : (1) α increases with the decrease of the gap distance between wheel and workpiece, L G, however it becomes almost constant in the range Δ G <50μm. (2) α marks the peak value at the center of the contact zone and it sharply declines around this point. (3) α increases with the velocity of grinding fluid, but after it attains about 120 kW/m2K it becomes constant.
In the drilling process using twist drill, point shape of drill is closely related with machining characteristics. Especially, it is generally known that chisel edge angle has an influence on machining characteristics such as machining accuracy. The cause of the roundness error of machined hole is wandering of drill. There were many studies about wandering motion of drill, and most of these studies analyzed mechanism of wandering by detecting the motion of drill point. However, there were few research works on the relation between wandering and shape of drill point. Therefore, wandering behavior was examined with different angle of chisel edge, and moreover the mechanism of start of wandering and change of wandering motion were observed. Results obtained are as follows : (1) Wandering starts when major cutting edge starts to cut. (2) The larger the chisel edge angle is, the larger the wandering motion is. (3) In the case that chisel edge angle is less than 115deg. wandering becomes small and circular motion. (4) With increase of the chisel edge angle from 115deg. to 137deg. wandering changes from polygonal to triangular.
It is well known that acoustic emission (AE) is the emission of elastic stress waves resulting from the deformation and fracture of materials. This paper describes the characteristics of AE signals which generated by friction and wear phenomena. The experiments carried out changed the finishing method of plate specimens for produce a typical wear mode. In addition, tensile tests carried out for study of the AE signal. The main results of experiments are summarized as follows : (1) In the friction and wear experiments, AE frequency range is very wide (0.02 to 1.5 MHz). (2) In the friction without wear, AE waves are only low frequency spectrum of below 500 kHz. (3) AE waves resulting from wear are characterized by the high frequency spectrum range (0.5 to 1.5MHz).
A method of atomic scale cutting in a computer has been developed based on the nonlinear finite element formulation which regards atoms and atomic interaction as nodes and elements, respectively. This method can handle discontinuous phenomena due to instantaneous propagation of dislocation in a workpiece during cutting. Experiments carried out using two kinds of assumed interactive potential energy between tool and workpiece atoms have revealed that the process of chip formation as well as the stress distribution on the tool face during cutting is strongly dependent on the type of interaction energy between the tool and workpiece, while the size effect for the specific cutting coefficient and the discontinuity of cutting force variation during cutting are common in both types of potential energy. The experiments have also shown that the intermittent drop of the potential energy accumulated in the workpiece during cutting is the result of heat generation associated with plastic deformation of the workpiece, while the heat generation causes impulsive temperature rise on the tool face repeatedly during cutting.
The purpose of this study is to establish the evaluation method for thermal stress fracture reliability of ceramic components by means of laser heating. To elucidate the thermal shock cracking induced by laser heating, the stress distribution and the thermal stress intensity factor are first analyzed using finite element method, then laser thermal shock experiments are conducted on partially stabilized zirconia. It is found in the analysis that the minimum principal stress direction is radial near the surface outside the beam radius, and the maximum value in the thermal stress intensity factor appears at the position of 1.5-1.8 times outside by the beam radius. The thermal stress intensity factor monotonously increases in heating process, while it decreases in cooling process. The thermal stress intensity factor also tends to decrease after a certain peak value with increase in the crack length. The crack is observed to form and grow in the radial direction and it is also observed to arrest after a certain growth. The observed behavior of thermal shock cracking is coincided with analytical results.
The three components of the outer-blade slicing force are discussed analytically, assuming that the shape of the grain cutting edge is approximately a circular cone with the tip angle 2 γ, and investigated experimentally. This paper puts a special emphasis on the effect of the asymmetric wear of the blade onto the component Fz acting in the direction of the wheel axis, which causes an elastic deformation of blade. The results are summarized as follows. (1) The component Fz is in proportion to the following values : specific grinding force; work thickness; tan γ; asymmetric wear coefficient. Furthermore, it is in inverse proportion to the wheel speed. (2) In a practical cutting, component Fz increases gradually from start of the cutting process to its end, which is caused by the change of the apparent asymmetric wear due to the elastic deformation of the blade.
A numerical simulation approach for the evaluation of temperature distribution analysis in multi-layer thin film structures during laser irradiation, such as the laser patterning of a-Si solar cells and the laser annealing of silicon on insulator (SOI) device, is introduced. In order to analyze more correctly and realistically, temperature dependence of material constants for each layer and latent heat during phase change has been taken into account, and the motions of heat conduction during laser irradiation have been made clear by solving the three dimensional non-linear and transitive heat conduction equations using the finite difference method. Results have been compared with experiments, and it has been confirmed that the numerical simulation approach was very useful for laser processing.
The effects of tufftriding and sulphonitriding treatments on the life of hot die steel have been investigated. The thermal fatigue test, erosion test, X-ray probe microanalyses and optical microscopy of hot die steel samples were carried out after tufftriding and sulphonitriding treatments. It was found in the thermal fatigue test that the number of cracks per unit area of tufftrided and sulphonitrided samples markedly smaller than those of ordinary SKD61 sample. For the tufftrided sample, the high concentration region of nitrogen, i.e., Fe2-3N compound layer, disappeared and became a diffusion layer after the test. For the sulphonitrided sample, the surface layer was contained oxide and nitride, and the nitride was disappeared after the thermal fatigue test. In the erosion test, the sulphonitrided sample showed the most excellent erosion resistance, i.e., 10 times of the tufftrided sample and 30 times of the ordinary SKD61 sample.
This paper presents the deformation characteristics of honing head in order to improve the accuracy in honed hole diameter of in-process automatic sizing in honing. Thermal deformation by the warmed honing oil or by the heat generated during machining is experimentally examined. Elastic deformation by honing force is numerically and experimentally analysed. The results indicate that the thermal deformation of honing head shows nearly iso-thermal expansion. The elastic deformation of honing head is precisely obtained by F. E. M. calculation. Torque component of honing force is the main factor which has a strong influence on the elastic deformation. Thrust component of honing force has very little influence on the deformation.