A second experiment in the application of quality engineering to sweet-potato cultivation was carried out. The first experiment took two years: an L18 orthogonal array experiment was carried out in the first year and then a confirmatory experiment was carried out in the following year. In the second experiment, the confirmatory experiment was carried out under conditions prepared in advance so that the orthogonal array experiment and the confirmatory experiment could be carried out simultaneously, which enabled the whole experiment to be finished within one year. The sweet potatoes were evaluated by analysis of variance;calculations were performed to determine interaction effects among months of cultivation, the size of the harvested potatoes, and relevant control factors and noise factors. As a result, it was found that months of cultivation and potato size are closely related. Relationships between months of cultivation and potato size were derived for each control factor level, enabling cultivation conditions to be selected for harvesting sweet potatoes of any desired size.
When cutting a workpiece, it is common to use a cutting oil. The cutting oil is needed to cool, lubricate, and cleanse the workpiece and the cutting edge. These are functions that support the actual cutting. There is accordingly a need to carry out the cutting process in order to evaluate the effect of the cutting oil. Purchasers and users of cutting oil would like to be able to evaluate the myriad types of cutting oil available on the market easily and efficiently. The purpose of this study was to quantitatively evaluate a cutting oil already in use and three cutting oils being considered for use and decide which would be best. The cutting oils were evaluated by measuring chip weight and variation in electric power as the intrinsic function of the cutting process. A cutting oil was selected by balancing its performance against its cost.
In the vending machine industry, it is essential to save energy out of concern for the environment and reduce costs in order to reduce equipment expenses. We are developing vending machines that meet these requirements by using quality engineering to develop the fans needed to heat and cool the products and the peripheral structure of the fans, specifically by performing a parameter design of the control panel that controls the air flow. The structure that controls the airflow was first evaluated by simulation. The ideal function of directing a rectified airflow to the exit of the air passage was considered, the necessary functions were studied from visualizatioll information of the simulation, and they were assigned to an L9 orthogonal array to narrow down the candidate structures. Next, to finalize the parts of the structure that could not be analyzed by simulation, a simplified test device was fabricated, improvement items were assigned to an L18 orthogonal array, and an evaluation was done on the basis of the two functions of airflow volume and temperature. From a factor effect diagram of the S/N ratio and sensitivity, optimal conditions were found from the levels that could satisfy both functions and levels related to volume manufacturability and cost, and these results were incorporated before volume production began.
Unevenness is an issue in high-resolution image sensors. The unevenness shows up as black and white bands extending horizontally on a white back-ground. The degree of unevenness is ranked by visual observation, but visual judgement is an ambiguous, time-consuming, and nerve-wracking Process. A new method was developed to solve these problems. The outputs from the pixels were expressed as two-dimensionally discrete orthogonal polynomials. The coefficients in the polynomials were converted to characteristic items deemed appropriate for visual judgment. The T method was used to relate the items to visual judgment. A new screening method called the two-item round-robin system was used to screen the characteristic items for better accuracy.