Abstract
The control of water content for green molding sand is very important in the quality control of castings. However, with the present electrical measuring apparatus, it can be controlled with the precision of only up to ±0.2%. This is because the measured date of the local points of sand do not always represent the real average value of water contents and this is particularly true with the return sand before conditioning. Therefore, we have made a study to find out a more appropriate measuring process for green sand with different levels of water content and developed a sensor and a system in which the average figure of water content of a certain amount of sand can be calculated by a micro-computer. Applicability of the system to the foundry was confirmed.
