In plastic injection molding there is ideally no irregular filling in the molded products. Since filling irregularity must be evaluated by the physical characteristics and internal state of the molded products, characteristics that reflect the internal state properly must be measured. In this study to evaluate the uniformity of mold filling patterns with polycarbonate, a transparent resin, we measured the RGB optical density values of light transmitted through a polarizing plate, and compared uniformity of the transmitted density by parameter design techniques, using molding conditions as factors and analyzing the results by the MT method. Evaluation of transmission density through the polarizing plate was able to detect filling irregularities and transmission variations more sensitively than evaluation of transmission density without the polarizing plate.
Due to recent escalation of the new-model development race and diversifying customer needs, the automobile industry faces an increasingly severe environment,in which various measures are being taken to achieve goals in relation of quality level, cost, and development time. For stamped parts, appearance is one of the quality issues. The present practice has been a continuing series of stopgap measures to deal with defects as they occur. To change this situation by applying quality engineering, an attempt was made to establish a robust stamping method that could solve appearance quality problems even without advance CAE validation, and could be applied to any type of vehicle(any part shape). A problem of surface distortion that sometimes appears in front fenders was addressed and an optimal die design and stamping method were found which minimized distortion in parts for any type of vehicle from the initial stampillg with a new die.
An evaluation method that yielded a quantitative index of usability was demonstrated in the previous paper, but if the discovery that the level of usability is low is made at a stage when the design work has been finished, it is difficult at that point to implement a fundamental solution. This led to the idea that if usability could be evaluated in the planning stage, that is, in the first stage of
The increasing use of integrated switches in today's cars requires switch lamps that can produce an even glow, When a point source of light such as an LED or a light bulb is used to illuminate the surface of a product, a transparent plastic molded part called a light guide is used. A microscopic relief pattern transferred onto the surface the light guide. diffuses light so that the light is emitted evenly from the whole surface, playing the same role as the light guide plates in TV and PC monitors. The purpose of this study was to optimize the molding conditions for fabricating light guides by injection molding. Molding conditions were evaluated by a transferability evaluation method in which the microscopic shapes transferred onto the surface of the molded product were measured. There were, however, several tens of thousands of microscopic shapes on the surface of the molded part. This necessitated a pinpoint evaluation in which the shapes were measured at only a few points on the surface. Therefore, on the assumption that degradation of transferability would impair the functionality of the light guide, the molding conditions were also optimized by using luminance uniformity, which is the functionality of the light guide, as an evaluation scale for evaluating transferability over the whole molded part. As a result, gain was obtained in the transferability evaluation that measured microscopic shapes on the surface of the molded part, but reproducibility could not be obtained in the functionality evaluation.
For construction machines, reducing transmission noise and ensuring durability are important issues. Gears have a particularly great effect on noise and durability problems. There is a need to reduce noise, improve durability, and evaluate the results properly in a short period of time, but with current evaluation methods, evaluating durability is a lengthy process and it is difficult to improve durability and reduce noise at the same time. In this study, an experiment and evaluation focused on the generic function of the transmission power train were performed by measuring the electric power consumed by the transmission driving motor, using quality engineering methods. As a result, the effects of different design factors were found in a short time, and under restricted conditions, the noise level was also reduced.
As a basis for establishing an off-line design method for an inverting spring used fbr pushbutton switches in electronic devices, a functional evaluation methodology in which the standardized S/N ratio was applied to the results of a numerical simulation of the force-stroke characteristic of the inverting spring was studied. A direct product array in which 1% internal noise was added to the control factor levels of the inner orthogonal array was allocated and a functional evaluation of the force-stroke curve was carried out using the standardized S/N ratio. By proper selection of control factor levels, a combination of control factors was found that reduced variations in the force-stroke curve due to internal noise. When the mean values of the force-stroke curve obtained from the outer orthogonal array allocation were used as standard conditions, reproducibility of the gain was improved as compared with the use of the force-stroke curve of the inner orthogonal array allocation as the standard condition. The optimum condition obtained from the evaluation by the standardized S/N ratio was then taken into consideration in tuning to the actual force-stroke curve,resulting in a combination of control factor levels that nearly matched the actual force-stroke curve.