Method for accurately forecasting five-axis processing milling force of spiral cutter

Abstract

The invention discloses a method for accurately forecasting the five-axis processing milling force of a spiral cutter. The method comprises the following steps: 1) acquiring coordinates of a cutter blade line of the cutter in a cutter rotating coordinate system XrYrZr according to the eccentric state of the cutter; 2) acquiring an instant blade line locus equation containing a cutter eccentric parameter according to an instant cutter tip position and the angular position of a pendulum shaft; 3) building a parameter equation of a straight line l which passes any given cutting point S<*>(i<*>, zc<*> and t<*>) and is perpendicular to the axis of the cutter; 4) acquiring the positions of intersections T of the straight line l and first mi adjacent blade loca according to the instant blade line locus equation containing the cutter eccentric parameter and the parameter equation, and acquiring the cutting layer thickness h(i<*>, zc<*> and t<*>) of the cutting point S<*>(i<*>, zc<*> and t<*>) according to distance h(i<*>, zc<*>, t<*> and mi) between the cutting point S<*>(i<*>, zc<*> and t<*>) and the corresponding intersection T; 5) calibrating the cutter eccentric parameter and a specific cutting force coefficient according to a thin plate milling experiment scheme; 6) acquiring the total cutting force exerted on a workpiece with a basic cutting force mechanical model according to the cutting layer thickness h(i<*>, zc<*> and t<*>)of the cutting point S<*>(i<*>, zc<*> and t<*>), the cutter eccentric parameter and the specific cutting force coefficient. The method can be used for accurately forecasting the total cutting force exerted on the workpiece.

Description

technical field [0001] The invention belongs to the field of mechanical manufacturing, and relates to a method for accurately predicting the milling force of a helical milling cutter in five-axis machining. Background technique [0002] The five-axis milling of end mills is very suitable for side milling of complex curved surface parts due to the excellent characteristics of adjustable tool attitude. The milling force in the milling process acts as an excitation on the tool system and the workpiece system, which will cause complex and unexpected displacement responses between the tool and the part at the cutting point, directly affecting the processing quality of the part. For this reason, accurate prediction and analysis of the milling force in the five-axis machining process of end mills is of great significance for understanding the machining process, optimizing the tool path and cutting parameters. [0003] In the past few decades, many scholars at home and abroad have ...

AI Technical Summary

Problems solved by technology

In the analysis of tool / workpiece meshing state, the calculation of instantaneous cutting layer thickness under fixed tool attitude is mostly obtained by empirical formulas, while in the process of five-axis machining, the formation process of the cutting edge trajectory is actually a three-dimensional cycloidal motion. The calculation method of instantaneous cutting layer thickness needs numerical calculation, and the solution process requires nonlinear iteration, which takes a huge calculation time and is not conducive to the rapid prediction of milling force

In terms of calibrating the specific shear force coefficient and tool eccentricity parameters, many scholars regard the specific shear force coefficient as a constant and use the method of combining the cutting force theory model with milling experiments to identify and obtain it. related size effect

In addition, tool eccentricity, including offset and yaw, is a very common phenomenon in the machining process. The existence of tool eccentricity will make the instantaneous cutting layer thickness more complicated and difficult. At present, most scholars only consider tool offset. Under the condition of

In addition, there is a nonlinear coupling relationship between the tool eccentricity and the specific force coefficient, which also leads to no good method to solve the accurate specific shear force coefficient and eccentricity parameters

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