Skiving Tool Flank Contour for Positive Rake Angle Cutting
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Solution Overview
Problem
The existing methods for determining the flank contour and clearance angle of skiving tools result in high manufacturing inaccuracies and tool wear due to varying rake angles, especially negative rake angles of up to -50°, leading to increased cutting forces and reduced productivity.
Innovation Solution
A method to determine the free surface contour of the skiving tool by analyzing the spatial movement of the rake face, selecting a transmission ratio that produces positive effective rake angles during engagement, allowing for a tool-friendly cutting operation with controlled clearance angles between 2° and 10°, enabling the tool to plunge radially to full depth and reducing cutting forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods determine the flank contour with traditional clearance angles, then the tool structure is simple, but negative rake angles up to -50° occur during cutting, leading to high cutting forces and increased tool wear
Solution Approach 1:
The invention changes the geometric parameters of the tool by determining a new flank contour based on the actual path movement of the rake face during skiving. This results in varying clearance angles that adapt to the cutting conditions, preventing excessively negative rake angles and reducing cutting forces while extending tool life
Solution Approach 2:
The invention introduces dynamic adaptation by calculating the flank contour based on the actual motion trajectory of the rake face. The clearance angle becomes a dynamic parameter that varies along the cutting edge, optimizing the cutting conditions at different positions and reducing overall cutting forces
2Manufacturing precision
If conventional flank contours are used, then manufacturing is simple, but manufacturing inaccuracies increase due to high cutting forces and vibratory movements
Solution Approach 1:
The invention performs preliminary calculation of the optimal flank contour before tool manufacturing. By pre-determining the contour based on path movement analysis, the tool is designed to minimize cutting forces and vibrations from the outset, preventing manufacturing inaccuracies before they occur
Solution Approach 2:
The invention replaces traditional empirical tool design with a calculated approach based on kinematic analysis of the rake face path movement. This substitution of mechanical trial-and-error with computational design improves manufacturing precision while maintaining reasonable ease of manufacture
3Productivity
If the tool operates with high negative rake angles, then material removal is aggressive, but tool wear increases and productivity decreases due to frequent tool changes
Solution Approach 1:
By changing the clearance angle parameters along the flank face based on path movement analysis, the invention maintains optimal cutting conditions throughout the cutting process. This prevents excessive tool wear while sustaining high machining efficiency, eliminating the need for frequent tool changes
4Ease of operation
If traditional clearance angles are applied, then the tool design is straightforward, but chip removal becomes difficult and adhesion increases
Solution Approach 1:
The invention varies the clearance angle parameters along the flank contour to optimize chip flow characteristics. This dynamic parameter adjustment improves chip removal and reduces adhesion, while the computational complexity is managed through systematic path movement analysis
Data Source
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AI summary
The invention relates to a method for determining the flank face contour, more particularly the clearance angle, of a blade-like tool or tool tooth of a tool for hob peeling workpieces, according to which - in a first step, the rake face contour of the tool is defined and the progression of the path movement of the rake face of the tool during chip-breaking hob peeling is calculated, taking into account a predetermined or pre-determinable transmission ratio between the tool and the workpiece determined by the respective number of teeth, and the desired tooth cross-section contour of the tool, and - in a second step, the tangential speed for each point of the cutting edge of the tool during chip-breaking hob peeling is determined in the form of vectors and these vectors are displayed graphically as bundles for each point on the cutting-edge and a closed envelope surface is determined, inside of which there are no vectors, and finally - this envelope surface plus a desired clearance angle is selected as the shape for the flank face contour of the tool or of the flank face of the tool tooth. The invention further relates to a tool for hob peeling with a plurality of teeth each having rake faces with cutting edges and adjoining flank faces, the teeth being arranged on a cylindrical or conical jacket. The tool is rotationally drivable about a tool axis a radial distance away from the workpiece axis and can be brought into rolling engagement at an axis intersection angle between the rotational axis of a driven workpiece and the tool rotational axis. A closed annular envelope surface is formed by the bundle of tangential speed vectors for each cutting-edge point, inside of which envelope surface no tangential speed vectors are present and with respect to which envelope surface the flank face of each tooth is inclined by 2° to 10°, preferably 3° to 7°. The invention also relates to use of said tool.