砂型(芯)在烘干后,有时需要检查其烘干程度是否符合要求。根据湿砂型与干砂型电阻率相差较大的特点,我们采用兆欧表(俗称摇表)测出砂型的电阻以反映其干燥程度,效果良好,且操作方便、简单。具体做法是,在兆欧表(一般选用500V,0～500 MΩ的兆欧表)两测量端的连线上分别栓上钉子,将钉子钉入被测砂型,间距以100mm为宜,钉子钉入深度即为所要求的干燥层深度。当测得的电阻值大于20MΩ时表明砂 Sand (core) after drying, and sometimes need to check whether the degree of drying meets the requirements. According to the large difference between the wet sand and dry sand resistivity, we use the megger (commonly known as shake table) to measure the resistance of the sand to reflect the degree of drying, the effect is good, and the operation is convenient and simple. Specifically, the megohmmeter (usually 500V, 0 ~ 500 MΩ megohmmeter) the two measuring ends of the connection were tied on the nail, the nail into the measured sand type, spacing of 100mm is appropriate, the nail into the nail Depth is the required depth of drying layer. When the measured resistance is greater than 20MΩ shows sand