Date Published: April 4, 2019
Publisher: Public Library of Science
Author(s): Weiguang Li, Zhankuan Zhang, Antonio Riveiro Rodríguez.
A reasonable micro-pits texture has been initially proved that it can improve friction characteristics between wood and cemented carbide surface and reduce surface friction coefficient. In order to study the cutting performance of the micro-texture when it is applied to the cutting tool for cutting wood more effectively, this paper selected micro-pit texture for studying influence of surface micro-texture cutting tool on wood cutting performance and cutting temperature, finding that when micro-pit cemented carbide cutting tool is adopted for turning the northeast China ash (Fraxinus spp.), it can reduce cutting force of turning and surface friction coefficient between rake face and cuttings. Moreover, for type A and type B cutting tools, when the texture parameters are that the diameter of the micro-pit is 80μm, the depth of the micro pit is: 10μm, area occupancy is 20% and the diameter of the micro-pit is 120μm, the depth of the micro-pit is 10μm and the area occupancy is 20%, the effect generated is the best. When a texture cutting tool is used for cutting, the decrease of the highest temperature in the cutting area is not very great, but the average temperature in the cutting area changes a lot, which is mainly caused by that micro-texture is processed at a position of the rake face close to the main cutting edge and that the highest temperature of cutting is mainly generated on the contact point between tool tip and wood. A reasonable micro-texture parameter can form a layer of liquid lubricating film on the up and down contact surfaces such that the direct contact between cemented carbide and northeast China ash is changed into indirect contact between lubricating films formed by the liquid so as to reduce the surface friction coefficient.
Friction plays an important role in the wood cutting process. A large part of the energy consumed in wood cutting is used to overcome the friction generated by wood workpiece and tool surface . Especially, when considering the direct effect of the tool rake face and the chips formed, it is quite necessary to correctly understand the friction phenomenon. The friction force acting on the tool rake surface not only directly affects the tool wear, but also affects the surface quality of the machined workpiece[2–4], so reducing the coefficient of friction between the cutting tool and the wood in the wood cutting process has always been a core issue in the field of wood cutting.
Fig 8 shows the changes of cutting force using Kistler measuring for analyzing signal fitting of software DynoWare. As shown in Fig 8, the main cutting force (Fz) > the normal force (Fy)> the axial force (Fx) using a cutting tool with zero rake angle. Fig 9 shows the curve about changes of the highest temperature and average temperature in cutting area(AR01) when the non-texture cutting tool analyzed by using Thermal CAM Researcher Pro 2.7 analysis software of infrared thermal imager is used for turning ash. As shown in Fig 9, the highest temperature of cutting in the cutting area is 63.8°C and the average temperature reaches a highness of 33.2°C. Fig 10 shows the thermal infrared diagram of a temperature field in cutting area at a different moment using non textured tools.
It can reduce the cutting force and the friction coefficient between the rake face and chips when using micro-pit cemented carbide cutting tool for turning the northeast China ash. Moreover, for type A and type B cutting tools, when the texture parameters are: the diameter of the micro-pit is 80μm, the depth of the micro pit is: 10μm, area occupancy is 20% and the diameter of the micro-pit is 120μm, the depth of the micro-pit is 10μm and the area occupancy is 20%, respectively, the effect generated is the best.