| 摘要 |
PROBLEM TO BE SOLVED: To alleviate the burden of a worker and improve the reliability of measurement by enabling an automatic detection of the specific gravity of working liquid reserved in a container reserving a working liquid through a sensor detecting a load detector set under the container and the surface position of the liquid. SOLUTION: A wire saw is cut into a plurality of thin plate-shaped wafers by the lapping of slurry 54 stored in a tank 52 when a semiconductor ingot is pushed against wire trains running at high speed after a work feeding table is moved in a cut feed direction. A specific gravity detection device for the slurry 54 is composed of a ultrasonic sensor 64, stirring motor 66, stirring bane (impeller) 68, load cell (load detector) 70, computing unit 72, and a display. The unit 72 divides the slurry weight detected by the cell 70 by the slurry volume obtained from the data stored in the sensor 64 and a memory part to calculate the specific gravity of the slurry 54 and output the same to the display 74. |
