The Study On Tthe Influence Of Cutting Environment Of Minimum Quantity Lubrication On Tool Wear And Wear Mechanism In The High Speed Milling Of Mold Steel

• Main Authors: Chang, ChiaHao, 張家豪
• Other Authors: Lin, HsienMou
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/34417833101744755644

碩士 === 南開科技大學 === 車輛與機電產業研究所 === 100 === The high cutting temperature generated in the high-speed milling of mold steel would lead to the rapid wear of cutting tool and poor surface roughness. The technique of minimum quantity lubrication (MQL) is regarded as an alternative to solve the above-mentioned problems. The objective of this work is to study the influence of cutting environments of MQL on the tool wear and wear mechanism in the high-speed milling of mold steel used with coated carbide tool. Cutting force, tool wear and machined surface roughness under various cutting environments such as direction of fluid application, type of lubricant supplication will be evaluated. SEM micrograph and EDAX analysis will be used to investigate the wear mechanism and the formation of oxide layer in cutting tools as well. Consequently, the appropriate cutting environment will be proposed to get the best tool performance. Firstly, the influences of direction of lubricant application on tool wear is investigated. Secondly, various types of lubricant, such as oil-based MQL, water-based MQL, high-pressure air, cooling air and dry cutting, were taken into account to find the optimal type of lubricant. It is shown that the smallest tool wear, in comparison with other directions of lubricant application, was induced by the external lubricant which was supplied to the cutting area as cutting tool was engaged in cutting. As regards the influences of various types of lubricant, the oil-based MQL would lead to the lowest tool wear under lower cutting speed as 300 m/min. While the water-based MQL performed the best when the cutting speed increased to 400 m/min and 500 m/min. It was attributed to the appropriate cooling effect of water mist and the formation of oxidation layer on the cutting tool. While the excessive cooling effect of cooling air would reduce the strength of cutting edge; hence in tern to cause a deteriorated tool wear such as breakage. It is concluded that the tool wear can be significantly reduced when the appropriate direction of lubricant application and type of lubricant were supplied.