Materials Science Forum Vols. 800-801

Abstract: Dynamic cutting force will induce vibrations in hardened steel precision turning process. The dynamic cutting force in the process of turning was studied, and the dynamic cutting force model of hardened steel precision turning system was set; Based on DEFORM-3D software, a three-dimensional model of hardened steel turning was established by pre-set some fluctuations workpiece geometry; the turning test of hardened steel GCr15 in CAK6150DI lathe by using PCBN cutting tools, simulation and experimental results show that the high-speed precision turning will produce strip and sawtooth chip morphology; the maximum cutting force of hardened steel precision turning is the radial cutting force, which is greater than the main cutting force; cutting forces have a larger amount of fluctuation, which can reach 30% -55%. This research will provide a theoretical basis for related study on the vibration of the hardened steel turning process

Abstract: Hard cutting process is easy to produce serrated chip. Hardened steel GCr15 as the object for the study, chip morphology was studied on hard cutting test and chip cross-sectional microscopic analysis methods. The boundaries of ribbon cuttings to serrated chips cutting was determined, under certain conditions of PCBN cutting tool cutting precision hardened steel GCr15, and form a quantitative description of the chip. With the increase in the amount of cutting, serrated chips have the degree of improved trend, in which the most significant impact of cutting speed, while the hardness increases, the degree of sawtooth also increases. Hard cutting research will enrich the theory provides a theoretical basis for the choice of cutting parameters.

Abstract: Consider to the properties of Super Alloy GH4169, planning the milling experiment with ceramic cutting tool, which is aimed at studying the milling force of different parameters in each direction based on the software of Labview and KISTLER three-component dynamometer. Then the milling force experience formula was established by MatLab, which offered the theoretic reference to the studies of high speed milling super alloy GH4169 through the analysis and studies of the milling parameters based on the experimental data.

Abstract: In this paper, the cutting experiment was used to study the influence of various cutting parameters on cutting force when rough turning titanium alloy (TC4) with the whole CBN tool. The results indicate that among the cutting speed, feed rate and cutting depth, the influence of the cutting depth is the most significant on cutting force; the next is the feed rate and the cutting speed is at least.

Abstract: When machining the complex parts of aircraft engines, the milling force for the circular contour must be accurately predicted to reduce machining vibration. In this paper, the prediction model of the mean milling force per tooth during machining circular contour is developed. Firstly, the formulas of the entry angle, the exit angle and the equivalent feed per tooth are established through the analysis of circular contour milling process. Then, the equation of the mean milling force per tooth is deduced based on mechanistic force model during the circular contour machining process. Finally, the prediction model of mean milling force per tooth during machining circular contour is developed using MATLAB programming. The relationship between the milling force per tooth and surface curvature radius of the machined workpiece is also analyzed in this paper.

Abstract: The mathematic model of rake face was set up for precise description on the rake face of end mill in grinding process, with its basis on the fillet of grinding wheel with six axes linkage movement and two attitude angles. The sectional drawing of rake face and three-dimensional entity were drawn based on the mathematic model in SolidWorks. At the same time, the discrete entity of rake face also set up based on the Boolean calculation. The sectional drawing of mathematic model and the discrete entity tallies with each other perfectly, which indicates the correctness about the mathematic model of rake face.

Abstract: Five-axis ball-end milling technology is widely used in many industries such as aerospace, automotive and die-mold for complex surface machining. Despite recent advances in machining technology, productivity in five-axis ball-end milling is still limited due to the high cutting forces and stability. Moreover, cutting forces in machining is determined by extracting the cutter workpiece engagement (CWE) from the in-process workpiece. A discrete boundary representation method is developed. Cutter is firstly divided into disk elements along the tool axis. And in each disk element, boundary representation based exact Boolean method is introduced for extracting complex cutter-workpiece engagements at every cutter location due to its efficiency and speed over other discrete methods. Developed engagement model is proved to calculate complex engagement regions between tool and workpiece efficiently and accurately.

Abstract: In order to better study hardened steel cutting process, we should model and simulate the process of cutting hardened steel by DEFORM-3D on the basis of applying finite element method to analyze the influence of cutting speed and feed to main cutting force, cutting heat and stress. Study shows that the cutting speed and feed is an important factor to determine the main cutting force. Cutting heat affects the physical properties of metal materials as a product of the energy conversion. The distribution of equivalent stress decided to point the strength of the cutting performance in different region. Reasonable utilization of cutting speed, feed processing has important significance for practical production on the premise of to ensure good cutting tool performance.

Abstract: In order to study the phenomenon of micro-milling process influenced by the minimumcutting thickness, the milling thickness calculation model was established considering the minimumcutting thickness. For the sake of studying the effect of the failure of micro-milling cutter andsurface qualification of workpiece influenced by the minimum cutting thickness phenomenon,establish the milling model to simulate stress distribution and temperature distribution on thecondition of minimum cutting thickness in the process of micro-milling.

Abstract: In this paper, based on finite element software DEFORM, the model of a large cutting depth and quasi-high speeds milling of titanium alloys is built to study the cutting temperature and cutting force variation along with the change of cutting parameters. The simulation results show that: the location of the maximum cutting temperature appears in the cutting edges of the tool nose circular profile. Meanwhile, due to workpiece material rebound in the cutting process, the interface between workpiece and tool flank face occurs serious extrusion, which results in relatively high cutting temperature on the workpiece machined surface. In addition, cutting speed and feed rate per tooth play a key role in influencing the cutting temperature. However, the influence of cutting depth on the cutting temperature is less clear. With the increase in the feed rate and depth of cut, cutting force increased significantly. In particular, within the scope of the cutting speeds under the given conditions, the cutting force has a tendency to decrease with the cutting speed increasing over 120m/min.