TiN-TiCN多層被覆銑刀之耐磨耗性研究

• Main Author: 魏正松
• Other Authors: 蘇演良
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/63299306604193797478

碩士 === 國立成功大學 === 機械工程學系 === 85 === In this report, the Taguchi method was employed to design the experimental procedures. The WC milling cutters (P30) were deposited with a series of TiN coatings by Multi-Cathodic Arc Plasma Deposition process. The single-layer TiN films and twin-layer TiN/TiCN films vary in thickness only, while the multi-layered TiN and TiCN films not only vary the thickness of each layer but also the depositing sequences of the layers. The influence of various factors, such as the cutting speed, feed rate, depth of cut, workpiece hardness and milling type, were considered simultaneously. Experiments were carried out under dry condition on a NC Machining center. The wear on tools was measured, and examined in an SEM for judging the wear mechanisms. Using the experimental confirmation and analyses recommended by Taguchi method to optimizing a condition combined the cutting parameters and coating layers. 　The experiment results are shown as follows: (1) The tool with the best wear resistance is under the condition of twin-layered film, lower cutting speed, higher feed rate, higher depth of cut, up milling and normalized workpiece. (2) The amount of the thermal cracks increases with increasing cutting speed, depth of cut, feed rate and workpiece hardness, and the cutting speed is the most significant factor. (3) The fatigue cracks increases with increasing cutting speed, depth of cut, feed rate and workpiece hardness; furthermore, the up milling was the major contributor to the fatigue cracks. (4) The degree and amount of thermal cracks and fatigue cracks are fewer for the twin-layer films than for the single-layer films; that is, the twin-layer films have higher resistance to the enlarging of the cracks due to the fatigue and thermal action. (5) There were differences in the wear processes between the coated and uncoated cutting tools. The crater and smooth flank wear processes do not occur on the coated cutter because the coating layers have high wear resistance. Therefore, the wear of the coated cutter occurs on the cutting edge first and then was enlarged. (6) The higher the cutting speed, the more significant the enhancement of the coatings is for the cutting performance. In addition, the improving degree of the twin-layer coatings is higher than that of the single-layer coatings.