At a joint Japan-United States conference held at North Carolina State University in Raleigh, North Carolina, U. S. A., on November 14 and 15, 1985, a proposal was presented to the Americans suggesting the formation of a Society that would include in its charter a liaison with the Japan Society of Precision Engineering. The Americans present appointed an informal organizing committee with a directive to determine the interest in such a Society and to propose a method for its formation if sufficient interest was found. The committee drafted and circulated a questionnaire. The results indicated sufficient interest to form a new, independent American Society of precision Engineering. A non-profit corporation has been established and the first conference was organized and held on November 5, 6 and 7, 1986, in Dallas, Texas. Concurrently, an invitation for applications for charter membership was circulated which has resulted in approximately one hundred charter members. The informal organizing committee disbanded at the Dallas Conference and was replaced by an elected interim Board of Directors. Another conference is scheduled for November 4, 5, and 6, 1987, in Columbus, Ohio, at which time it is planned to elect a permanent Board and officers and adopt a constitution.
The ability to withstand corrosion and high temperature oxidation of the surface layer of workpiece produced by the electrical discharge machining has been studied. Electrical discharge machining was performed in hydrocarbon oil using copper and semi-metal silicon electrode on workpieces of carbon steel, aluminum, 13 chromium steel and SUS 304 stainless steel. In order to examine the machined surface characteristic, the susceptibility to corrosion or high temperature oxidation of the surface was evaluated. It has been revealed that the machined surfaces of SUS 304 stainless steel and 13 chromium steel produced by using of silicon electrode have remarkable corrosion and high temperature oxidation resistance respectively, while the behaviors of the machined surfaces of carbon steel workpiece produced by copper or silicon electrode were all similar to that of the carbon steel. Surface layers having remarkable corrosion or high temperature oxidation resistance were investigated by the electron-beam probe microanalyser and electron diffraction. The results showed that the surface region is implanted with silicon in the range of about 3 μm deep, and that an amorphous phase is produced on the machined surface of SUS 304 stainless steel. It was found, furthermore, that no damage of the surface layer occurred by cyclic plastic deformation or rapid heating and cooling.
In order to get a good cutting condition for machining cast-iron rolls with carbide tools, tool life tests of various rolls such as chilled, ductile, grain and adamite rolls are examined experimentally with carbide tools. The relation between the mean free path of Co-phase and a grain size diameter in microstructure of carbide tool and the tool life is investigated. The main results are as follows : (1) The shorter the length of mean free path is the longer tool life when the abrasive type wear works in machining cast-iron rolls. (2) For the estimation of optimum cutting speed (υ>1200), the nomogram is made by both the length of mean free path of carbide tools and the hardness of cast-iron roll. (3) The diagram of the relation between cutting speed and feed rate is made by the tool life tests in machining ductile-roll. If the length of mean free path of carbide tool and the roll hardness are measured, the optimum cutting condition for machining the ductile-roll is obtained by both the nomogram and the diagram. (4) The adaptability of carbide tool on the roll-cutting depends upon the length of mean free path of Co-phase and the mean grain size diameter of carbide particle. Therefore, these values are useful for the selection of roll-cutting condition.
In external cylindrical traverse grinding of a slender workpiece, intermittent grinding phenomenon that the workpiece is separated partially from the wheel during cutting can be frequently observed. According to the previous experimental investigation, this phenomenon is considerably influenced by the thermal deformation of the workpiece. In this paper, the intermittent grinding phenomenon is investigated analytically by using the difference method and the finite element method. The obtained results are as follows : (1) The analytical results show that rotating motion of the workpiece arises from its thermal deformation and results in the intermittent grinding phenomenon. (2) This phenomenon occurs for the workpiece with the length/diameter ratio more than twelve. (3) The deformation of the workpiece according the analysis is showed approximately agreement with the experimental result.
This paper describes a new spindle-finish type finishing apparatus and the finishing performance it provides when using magnetic abrasives of 0.15 mm in diameter in a magnetic field. The features of this maching process are : the finishing process is carried out with the application of magnetic force instead of the centrifugal force of finishing media in the conventional barrel-finishing process ; the finishing force of the magnetic abrasives is controlled by exciting current of a magnetic coil ; and surface finishing, deburring, and precision rounding-off of the workpiece are done simultaneously.
As the first approach to study on grit blasting, basic characteristics of grit blasted surface and surface layer are described, measuring such factors as average dent size, surface roughness, hardness distribution, harf width and surface residual stress. Grit blasting was performed on steel (C:0.45%) by centrifugal blasting machine. The results obtained from experiments are as follows : (1) Average diameter of dent is in proportion to size D and root of velocity V of grit. (2) Surface roughness is in proportion to D and V. (3) Maximum hardness on the blasted surface is about 15% more than that of shot peened and the depth of work hardened layer is 40-50% less than shot peened. (4) Residual stress on blasted surface is compressive and the value is 12-35% less than shot peened.
The mechanism of the cutting process in drilling by a twist drill has not well understood yet because a drill with a complex geometry of two cutting lips is used and it causes the dynamical interaction with some parts of a machine. In this paper some experiments were performed to investigate the influence of difference of rigidity of main spindle and difference of drill point styles to cutting process. As the result, there was not interaction between two lips under the usage of high rigid spindle but was in low rigid spindle. Drill walking and rifling phenomena occurred in case of low rigid spindle. It is found that comparing other points the spiral drill point has the ability of reduction of interaction between lips.
This paper reports on fabrication technologies for package parts of Josephson chips, and the mechanical & electrical characteristics of model packaging system measured in liquid helium. Solder bonding technology is applied to connect the pinned substrate & chip mounted substrate, and it has become possible to line up and connect the substrates pattern pitches as fine as 100 μm. In order to connect I/O cable and patterned substrate, a flat cable is applied, and Cu ball bonding technology is developed. By pressing the cable onto the Cu balls which are solder bonded on the patterned substrate, a stable connection can be obtained in liquid helium. Using these packaging parts, a model packaging system is constructed on a molybdenum holder. The mechanical & electrical characteristics are evaluated on the system. The results are as follows : The system operated successfully in liquid helium, and series connection was possible. The model system showed the stable connection in heat cycles. The DC resistance of the fillets, micro-connectors, and flat cable connectors measured in liquid helium was sufficiently small for practical use. Through these development, high-density packaging technologies are developed, and a model packaging system for Josephson chips can be realized.
When polymers are compared with metals, they have a distinctive characteristic, or viscosity. This paper describes the numerical analysis of cutting process of polyvinyl chloride (PVC) as a viscoelastic, plastic material. In this analysis, the mechanical behavior of the polymer is expressed by a simple model, which consists of three parameter solid and plastic element connected in series. Besides its material properties such as coefficients of viscoelasticity and flow stress characteristic reported in the previous papers, the variations of elastic moduli with temperature and stress were obtained empirically, and the friction characteristic on the rake face was found to be similar to those in machining of metals. Using these properties, the steady state cutting process was simulated by the repeated revisions of strain, strain rate, temperature and yield stress of finite elements and flow lines. The results obtained are high shear angle, thin plastic zone and peculiar temperature distribution where temperature at the free chip surface is much higher than at the rake face, which are apparently different from those in metal cutting simulations. Chip springback after quick stop of machining were further simulated. The large scale springback, which is obseved in experiment, was also realized in this simulation and it is concluded that the temperature dependence of elastic moduli exerts a strong influence upon the behaviour of PVC.
The thermo-couple method, which is one of measuring methods of grinding wheel surface topography, is analyzed theoretically and experimentally by using a statistical approach. The theoretical analysis is made on the number Cm of effective cutting edges per unit wheel surface area, and the following effects on Cm are discussed ; (a) grinding conditions, (b) shape dispersion of grain cutting edges, (c) positional distribution pattern of grain cutting edges, (d) elastic and plastic behaviors between grain and workpiece. The experiments are carried out for three different sizes of constantan wire under the condition of surface plunge grinding, and the relationships between the number Nm of thermo-electric pulses and the following two factors are discussed ; (a) grinding conditions, (b) width of thermo-couple hot junction. The experimental number Nm shows a good agreement in a qualitative sense to the theoretical one.
This paper presents how to make a solid model of the fillet volume which surrounds the intersection line between two quadratic surfaces. In order to be able to handle the fillet volume in CSG representation method for geometric modeling, Sweep Operation is applied to generate fillet volume. The outline is described below : Two primitive solids with quadratic surfaces, such as cylinder, cone or sphere, are given in a condition of being connected to each other, then their intersection lines are led analytically. 2-D fillet pattern, defined on a sectional plane which crosses the intersection line, is swept along the intersection line. Swept Volume consists of a set of space points which are inside or on the fillet patterns from start to end of sweep. Fillet Volume is generated as a result of swept volume, and can be handled the same as the primitive solids. The algorithm of this work has been implemented in the CAD/CAM system TIPS-1. According to experimental results, it became clear that the work was effective for geometric modeling of an object constructed by quadratic surfaces and fillet volume.
In three dimensional solid modeling, there are mainly two types of modeling, CSG (Constructive Solid Geometry) and B-Reps (Boundary Representations). CSG is a human oriented model because it is constructed by combination of primitives. B-Reps is an application oriented model but if designer try to construct 3D shapes by B-Reps directly, many difficulties arise. So it is the best way that the designer makes shapes by CSG, and B-Reps is automatically generated from CSG for computer processing. This paper proposes a method of automatic generation of B-Reps model from CSG model in an analytical way. It is not aprroximate ones but the exact quadratic surfaces are treated. And intersectional curves are derived by an exact analytical method among these surfaces. For getting shape edges from intersect curves, it is shown how to use the CSG structure and how to treat the co-lying surface problems. After creating all geometrical information of B-Reps, topological information of B-Reps is constructed by determining the coordinates of both terminal points of edges and by checking the information of two surfaces to which each edge belongs. To demonstrate this method, the CSG-B-Reps conversion system EAGLE is made, and many experiments are executed.
This paper firstly describes that the 3rd-order autocorrelation function for a picture of heaped chips is useful for identifying the feature on the shape of a separate chip. It has been actually shown that, for typical five kinds of chips with curled (bigger), curled (smaller), spiral (slim), spiral (thick) and powdery shapes, the 3rd-order autocorrelation function could extract the feature of each type of chips. In the experiment for each 10 sample images of the five kinds of chips, 49 samples in those 50 samples above-mentioned have been successfully identified. Lastly, a hardware for calculating the 3rd-order autocorrelation function is shown.
A real-time method is developed for measuring 3-dimensional profiles from fringe patterns generated by moiré-topography or a deformed grating method. This paper presents theoretically relationship between object shapes and phases of fringes. It also describes the construction of an experimental system which uses a Digital Phase-Locked Loop (DPLL) circuit. Furthermore, experimental results that confirm the DPLL circuit's performance are reported. In the system, a video-camera scans the fringe patterns across the array of fringe stripes. The video signal has a sine-wave form. The low frequency component of the wave is eliminated by a high-pass filter and its output is digitized by an A/D converter. The phase restoration of the digital signal is performed by the DPLL circuit. The obtained phase signal is proportional to relative distance between the camera and the object. Then the phase signal is converted into analog signal by a D/A converter and the results are displayed as gray-level images on a CRT monitor and also as perspective diagrams on an oscilloscope. An exact profile of the object can be obtained at the video-rate with this method.