Detection Technique for Ferrous Debris Concentrationand Viscosity in EDM Fluid

• Main Authors: Hung-yi Lin, 林紘億
• Other Authors: Rong-Tsong Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/20108292081727163525

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 104 === The integrated apparatus for detecting ferrous debris concentration and viscosity in EDM fluid has been developed successfully. This apparatus contains a sampling unit, and measurement units of the ferrous debris concentration and viscosity with a displayer unit. Measurement unit of the ferrous debris concentration adopts Ferrography technology, where ferrous debris are captured at the gap between the poles of magnet to change the magnetic flux, and its concentration is measured by using the output signal of Hall effect sensor. Measurement unit of the viscosity uses a piston to squeeze the EDM fluid in a hydraulic cylinder, and a load cell is used to measure the squeeze load. The output signal of load cell is transformed into the viscosity of EDM fluid. The ferrous debris concentration is calibrated using the given concentrations, and the maximum error is less than 2.3 ppm under numerous tests. The viscosity is calibrated using the general purpose viscosity fluids, and the maximum error is less than 5% under numerous tests. The ferrous debris concentration and viscosity in EDM fluid are detected using this integrated apparatus, and the effect of ferrous debris concentration on material removal rate and surface roughness of the machined workpieces is investigated. Experimental results show that this apparatus is capable of detecting ferrous debris concentration in EDM fluid. On the other hands, ferrous debris concentration in EDM fluid has an appreciable impact on the material removal rate and surface roughness of the machined workpieces. To maintain the performance of EDM machine, it is necessary to change the EDM fluid when the ferrous debris concentration is larger than 270 ppm. This indicates that the general EDM machine equips with a detecting apparatus for ferrous debris concentration in EDM fluid is important.