Papers by Keyword: Tool Deflection

Abstract: Friction Stir Welding (FSW) is an innovative welding process increasingly used by industry for the welding of aluminum alloys. In order to reduce the high investment costs of a dedicated FSW’s machine and in order to offer more flexibility to weld complex geometry, high payload robots may be used. A serial kinematics robot meets these specifications but under the stresses generated during welding, its structure readily deforms. The consequences are deviations of the tool nominal position with respect to the seam. The work presented here proposes to study the process tolerances with tool positioning defect. An experimental study enables to evaluate the influence of the tool position disorientation on weld quality, the travel force and torque generated. The objective is to estimate the impact of the disorientation on the tool mechanical interactions when welding using a serial kinematics robot.

Abstract: This report describes a two-dimensional monitoring system for milling machines using small-diameter tools. Small-diameter tools are used for high-speed milling, and they are indispensable for high-quality and high-productivity manufacturing. However, tool breakage occasionally occurs, and this becomes a serious problem in automated production. This study aims to develop a system for monitoring the cutting state that can prevent tool breakage. The proposed system consists of two charge-coupled device (CCD) cameras, an image processing device, a man-machine controller (MMC), and a machining center with an open computer numeric (CNC). This monitoring system is connected to the machining center by Ethernet. It enables the precise measurement of tool deflection during high-speed milling. In an experiment, we applied this system to the end milling of a steel plate under different cutting conditions, and we examined the relationship between tool deflection and the cutting conditions. In addition, we applied this monitoring system to measure tool wear, and we examined the relationship between tool deflection and tool wear. It was found that the proposed system enabled in-process monitoring of the cutting state and tool wear.

Abstract: The error due to tool deflection is detrimental to machining precision. In order to predict tool deflection more accurately, this paper presents a special three segments cantilever beam model for ball-end tool deflection in sculptured surface milling. Different from the traditional two segments cantilever beam method, the ball-end tool is divided into the shank, the flute and the ball-end parts in this new model. Then the ball-end tool deflection is simulated also by utilizing the finite element software ANSYS 12.0 Workbench to calibrate the accuracy of the tool deflection models. The three segments cantilever beam model for ball-end tool deflection matches better the finite element method (FEM). In the last part of the paper, the sculptured surface machining experimental results show that, the surface precision after tool deflection compensation based on the new three segments cantilever beam model is higer than that based on the two segments cantilever beam model.

Abstract: This paper presents the results of a series of experiments performed to examine the validity of a theoretical analysis for evaluation of machining error in ball end milling of spherical surface. In the analysis, the trochoidal paths of cutting edges are considered in the evaluation of chip geometry. The cutting forces are evaluated based on the theory of oblique cutting. The machining errors resulting from cutting force induced tool deflections are calculated at various parts of the machined surface. The experiments are carried out at various cutting conditions for convex spherical surface, and the influences of cutting mode and milling position angle on machining error are examined.

Abstract: NC geometric cutting simulators are a widely used software. However, it is difficult to represent the cutting load, tool deflection and tool wear caused by physical phenomena. The purpose of this research is to develop a NC geometric cutting simulation that will be able to easily calculate these phenomena during simulated machining. This paper describes the calculation algorithms of cutting loads, deflections, and wear of tools based on a removal volume, and the implementation of the NC geometrical cutting simulator. The removal volume is an interference area calculated between a workpiece and a swept volume of the tool movement, and the removal volume at each height is calculated at the same time. As a result, it is confirmed that the proposed algorithm is able to estimate the cutting load and the tool wear.

Abstract: The present work puts forward a generalized simulation model to evaluate the topography of ball-end milled surfaces by considering both the tool deflection and the tool runout. Firstly, a solid ball-end mill with S-shaped cutting edges is modeled as the basis. Then the tool tip trajectory is derived from the tool runout as well as the cutting forces induced tool deflection. And consequently the topography and scallop height of the machined surface are estimated by the numerical calculations of the matrix equations. With good expandibility, the proposed model can incorporate more machining information such as the movements of rotatory axes and tool wear, and hence, can be used to optimize the cutting conditions and parameters in 5-axis ball-end milling process.

Abstract: Recently, ultra-precision micro patterns and shapes have been widely used in optical field. Various methods which are based on semi-conductor fabrication methods are nowadays used in fabrication of micro shapes and patterns, but micro endmilling technology has lately attracted considerable attention because of various available materials, flexibility of process and high-productivity. For the precision micro endmilling process, analysis of micro cutting error is mandatory. In general, tool deflection is a major factor which causes cutting error and limits realization of the high-precision cutting process. Specially, in micro endmilling process, micro tool deflection generates very serious problems compared to macro tool deflection. In this paper, it is performed to observe the real tool deflection shapes in micro endmilling process, so the trend of micro tool deflection was analyzed using real captured images in this study. To get the real images of micro tool deflection, micro slot cutting processes were executed under various cutting conditions using micro endmill and the real images of tool deflection were obtained during cutting process by high-speed camera. Finally, the extent of tool deflection was calculated by the deflection angle according to cutting conditions and two trends (the point of first tool contact and the cutting stage) of micro tool deflection were analyzed.