Papers by Keyword: Uncut Chip Thickness

Abstract: A simplified model for micro milling process is presented, as well as results on temperature on tool and work piece. The purpose is to investigate on finite element modelling of two flute micro end milling process of titanium alloy, Ti6Al4V with prediction of temperature distribution. ABAQUS/Explicit has been chosen as solver for the analysis. A thermo-mechanical analysis was performed. First model was created by selecting medium carbon steel, AISI1045, as workpiece material for model validation purpose. Second model was created by modifying the workpiece material from AISI1045 to Ti6Al4V. The model consists of two parts which are tungsten carbide micro tool and workpiece. Johnson-Cook law model has been applied as material constitutive properties for both materials due to its severe plastic deformation occur during machining. Prediction on forces was obtained during the analysis. Model validation was done by comparing results published by Woon et al. in 2008. The results showed a good agreement in cutting force. Once this was proved, the same model was then modified to simulate finite element analysis in micro milling of Ti6Al4V. Prediction of temperature distribution of micro end mill of Ti6Al4V was done in relation of different undeformed chip thickness. The findings showed that temperature increases as undeformed chip thickness increases. Temperature distribution of Ti6Al4V and AISI1045 under same machining conditions was compared. Results showed that the highest temperature was concentrated at tool edge for Ti6Al4V.

Abstract: Surface roughness plays a critical role in evaluating and measuring the surface quality of a machined product. Two workpiece materials have been investigated by experimental approach in order to gain a better understanding of their influence on the obtained surface roughness in the micro-milling processes. The experimental results show that: surface topography is completely different for different materials at the same cutting speed and feed rate; surface roughness increases with an increase of material grain size. Surface roughness decreases to a lowest value, and then increases with an increase of the feed rate. A new surface model to illustrate the influence of material and uncut chip thickness was developed. The model has been experimentally validated and shows more promising results than Weule’s model.

Abstract: The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Abstract: The application of an ultrasonic vibration is one of promising means in machining micro-holes. In this study, the differences of in the geometric machining mechanism between the ultrasonic and the conventional drilling were investigated. Specifically, the uncut chip thickness before machining and the tool trajectories of the cutting edges were formulated and compared with machining results. Through the machining experiments, it was found that those these parameters well matched with the appearance of both the disposed chips and the machined surface. Furthermore, the results indicated that the change of uncut chip thickness resulted in decreased machining resistance as well as improvement of the machined surface