In cylindrical plunge grinding, the dimensional accuracy of a workpiece is reduced due to its thermal deformation. Therefore, it is necessary to simulate the thermal deformation of a workpiece during grinding in order to obtain high accuracy. To calculate the thermal deformation of a workpiece, we propose a new simulation method. In this method, the thermal deformation of a workpiece is calculated with the tangential grinding force that can be estimated easily from the measured power consumption of the wheel motor. Grinding experiments were carried out in several grinding conditions to verify the proposed method. Good agreement was achieved between the simulated thermal deformation of the workpiece and the experimental results in each grinding condition.
The mechanics of “chip-guiding cutting” with grooved tools are investigated in the present study. The chip-guiding cutting has been proposed by the authors to realize continuous chip disposal. It has been clarified in the previous study that chips can be guided successfully into desired directions with the grooved round-nose tools, but the mechanics of the new cutting process with the guide grooves has not been clarified. Fundamental chip-guiding cutting experiments are carried out with grooved straight-edge tools in this study. An analytical model for the chip-guiding cutting process is developed. Effects of the chip-guiding on the process parameters such as cutting forces are investigated accurately by the proposed model and validated by cutting experiment. Both experimental and analytical results unveil that chip flow direction can be controlled by chip-guiding forces generated by the side-walls of the groove structure engraved on the rake face. It is shown that as the chip flow direction can be altered to the various guide directions from the original one, and the proposed model predicts that as the guiding force increases, shear angle decreases and thus resultant cutting force is increased only slightly. Therefore, when the guide direction is not dramatically different from the original chip flow direction, the resultant cutting force is not increased significantly, which make the process favorable. These results support the fact that proposed model captures the critical cutting mechanics accurately.
It is difficult to fabricate a nonwarped substrate, because a thin wafer cannot be fixed without deformation occuring. To resolve this matter, a silicon-carbide-ceramics freezing pin chuck has been developed. This paper describes the structure and cooling characteritics of a prototype freezing pin chuck, the uniform application method of fleezing requid on pin tops, applicability of polishing and low-temperature polishing. The prototype freezing pin chuck has double spiral flow channels built inside. These structure enable to cool down a quartz glass surface less than 5°C where frozen liquid does not melt till the polishing temperature of 30°C. The newly devised application method can form uniform droplets with the height of about 160μm on the whole chuck by blowing mist in the upper and oblique direction. When the quartz glass surface is cooled less than 5°C and the coolant fills spaces between pins, it becomes possible to polish a quartz glass for 60 min with cerium slurry under the pressure of 4.8kPa and the revolution speed of 50 min-1. In addition, it was shown that the low-temperature polishing less than 10°C with the cerium slurry has the performance of the same removal rate as that at the ordinary temperature. Accordingly, the matter of peeling of a wafer due to polishing heat was resolved without reducing the removal rate.
As a method to reduce electric power, a light source called Field Emission Lamp (FEL) is developed. The power consumption of FEL is one tenth of incandescent lamp and this lamp can be manufactured at low cost. We developed a white FEL by blending RGB phosphor powder while taking advantage of the characteristic emitting color of FEL. We made a prototype of the white FEL light source with the same structure as stop lamps. The prototype demonstrated the luminance of 42,700cd/m2 at 1.56W energy consumption. Based on this, we developed a compact and high-intensity light source structure for headlamps that satisfies light distribution requirements. We newly designed a reflector and modified the lamp structure. The I-V characteristic curve and electronic field simulations showed the improved capacity of electronic emission and reduced load to the supply circuit.
Hydrostatic bearing has advantages of high accuracy and high speed as a guideway of grinder for cam shaft and crank shaft. Reduction in number of bearing pockets is effective for manufacturing cost of the guide way. In our previous work, a numerical analysis based on Reynolds equation, which considers non-linearity of oil flow at restrictor, elastic deformation of plumbing and volumetric strain of air bubble in oil, is proposed for development of a hydrostatic bearing with self-controlled restrictor using a diaphragm. Important parameters for static stiffness of hydrostatic bearing are revealed by the simulation. The developed bearing has achieved three times higher stiffness in static response than that of the conventional bearing with orifice restrictor. In this research, a linear motion stage with less bearing pockets than those of conventional guideway is developed by employment of hydrostatic bearing with self-controlled restrictor. The developed guideway has achieved one-third of bearing area, compared with those of conventional guideway. Furthermore, flow rate of bearing oil has achieved one-third, compared with that of conventional one. According to the evaluation of static response, compliance and motion characteristics, the developed linear motion stage has demonstrated same performance as a guideway used hydrostatic bearing with orifice restrictor.
There are a number of useful fluid flow analysis methods that support designers to design flow channels of engineering products or to design flow channels used in manufacturing processes. It is important to derive better design by the iteration of evaluation and refinement of the design proposal so that the resulting product could achieve the required performance. However, most of the conventional methods are not so efficient that the evaluation and refinement cannot be executed enough. In order to make the evaluation part of the iteration process efficient , our previous paper presented a highly efficient fluid flow analysis method that adopted smoothed particle hydrodynamics (SPH) method, and that accelerated its calculation using graphics processing unit (GPU). Furthermore, in order to support designers more efficiently, this paper presents a new method for flow channel design based on form deformation techniques integrated with the analysis method, which enables the modeling of flow channel shape during simulating the flow behavior in it. In order to confirm the usefulness of the method, it is applied to an example of runner design of die-casting during casting flow simulation.
Individual products have a variety of states depending on their life cycle histories even if they are produced from the same design information, which represents their nominal information specified by designers. We call a specific state of an individual product as “entity information,” as opposed to the nominal information. To utilize resources of products efficiently throughout the entire life cycle, this paper proposes a method for modeling both nominal information of a product life cycle and the entity information at its design stage. This method represents the nominal information with hierarchical product structure model and life cycle flow model, which we have already proposed in our previous study. In this paper, we propose a model of the entity information, which we call “Entity Information Model.” Entity Information Model represents states of individual entities and the changes of the number of the entities in each life cycle process such as maintenance, collection, and end-of-life processes by recording life cycle histories of individual entities. Entity Information Model is created by using life cycle simulation technique. A case study of a smart phone is illustrated for demonstrating the feasibility of the proposed method.
We produced transparent models that visualize the internal structure of original objects, utilizing latest 3D imaging devices such as X-Ray CT, engineering software and processing technique. Whereas the models produced with a 3D printer usually have several shortcomings, including cloudiness in vertical direction and limitations in size, material and durability, the new method enables us to produce a low-cost, high-quality transparent models by effectively coordinating each step in the procedure. As an example application of this method, we produced transparent models that visualized internal shapes of garden hoses and conducted an experiment and evaluation using them. These transparent models are effective for the observation of internal phenomena and state. Thus, this method of reverse engineering has great potential applications in the areas of industrial products, medicine and education.