A Numerical Study to Investigate Machining Aspects of Convex Surface Drilling

Abstract

Abstract Metallic alloys with convex curved surfaces have large scale applications in several industries such as in the automotive, marine and aerospace industries. These curved surfaces are used in the applications where surface integrity is extremely important. A large amount of research has been conducted related to the finishing processes, such as surface milling, that improve the finish quality of the manufactured part. However, there is a lack of knowledge of on how the curvature of the parts affect machining performance. Drilling of non-flat surfaces are not easier to conduct due to slippage and less accuracy. The cutting mechanism on the conventional drilling process is well studied in the conventional metal cutting literature, but on curved non-flat surfaces it is not studied. The thrust force signature in convex curved surface drilling is different from the conventional drilling because of the difference in engagement of chisel edge and cutting lips. It is also observed in the conventional drilling process that cutting parameters such as feed rate and cutting speed have controlling influence on the drilling performance. There is a need to investigate the influence of these cutting parameters on convex curved surfaces as well. Similarly chip clogging and evacuation are very important and decisive factors in the conventional drilling. It would be interesting to visualize and discuss these factors in convex surface drilling. In the case of convex surface drilling, curvature of surface being drilled is also an important factor that can limit the drilling process. The curvature of surface also defines the tool – workpiece engagement and cutting action of chisel edge and cutting lips. Due to convex curved surface, variation in chip load is expected due to variation in the cutting area. Titanium alloy Ti6Al4Vis a commonly used alloy used in the aerospace industry. The aim of this study was to investigate the effects of curvature of a titanium alloy, Ti6Al4V, on the cutting forces experienced during the drilling process. The effects of the curvature of the surface were compared to the effects of the cutting speed and feed rate, in order to establish the significance of the effect of the curvature compared to other factors that affect the drill machining process. The effects of these parameters on the power and temperature during the drilling process were also analyzed and compared. The study is beneficial for the metal cutting academia and industry as it can provide the basic understanding and open up new areas of application.