Blade Machining Tool Orientation Without Rotation Axis Reversal
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Solution Overview
Problem
In high-efficiency machining of blade components, particularly turbine blades, the existing machining programs face challenges with increased machining time and surface defects due to the need for reversing the rotation axis direction, which leads to decreased speed and increased reversal errors, especially when dealing with convex and concave surfaces and edge portions.
Innovation Solution
A machining program creation method that sets a virtual convex curve for the concave surface with curvature matching the convex surface, creating a tool posture defining drive surface that maintains consistent curvature directions for all tool axes, allowing the tool axis direction to be set based on the normal to this drive surface, thereby avoiding axis direction reversals during removal machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tool axis direction is set to the normal direction of the concave surface curves, then the machining program can be created for the blade component, but the curvature direction becomes inverted when the blade component rotates, causing the rotation axis operation direction to reverse
Solution Approach 1:
The patent applies inversion by setting the tool axis direction to the normal direction of a virtual convex surface instead of the actual concave surface. This virtual convex surface is constructed by inverting the curvature of the concave surface, allowing the tool axis to maintain consistent directional relationship with the workpiece during rotation, thereby preventing rotation axis direction reversal while still achieving proper machining of the concave surface
2Manufacturing precision
If the rotation axis operation direction is reversed to accommodate the inverted curvature, then the concave surface can be machined, but machining time increases and tooling marks appear on the machined surface
Solution Approach 1:
By inverting the concave surface to create a virtual convex surface and setting the tool axis direction based on this virtual surface, the patent eliminates the need for rotation axis direction reversal. This maintains continuous tool engagement with the workpiece, preventing tooling marks and reducing machining time while ensuring high surface quality
3Productivity
If the tool axis direction is set to a one-direction vector such as the longitudinal axis, then the rotation axis direction reversal is avoided, but the tool tip at zero circumferential speed causes vibration and insufficient chip discharging
Solution Approach 1:
The patent avoids the problem of tool tip vibration by not setting the tool axis parallel to the longitudinal axis. Instead, it uses the inverted virtual convex surface normal direction, which ensures the tool maintains proper engagement angle with the rotating workpiece, enabling effective chip discharge and preventing vibration-induced surface defects
Solution Approach 2:
The patent changes the parameter defining tool axis direction from a fixed one-direction vector (longitudinal axis) to a dynamically calculated direction based on the normal of the virtual convex surface. This parameter change allows the tool axis to maintain optimal orientation relative to the workpiece surface at all positions, preventing vibration while maintaining high machining speed
Data Source
AI summary
In the high-efficiency machining of blade parts according to the present invention, there is no reversal of the operating direction of a rotating shaft, and a high-quality machined surface can be obtained rapidly. A machining program is created for a workpiece such that: when a part having a convex curved surface and a concave curved surface, with a pair of edge portions as a boundary, is removal-machined, a virtual convex curve, the curvature of which is not inverted with respect to the convex curved surface, with the curves of the pair of edges as the tangent line, is set for the concave curved surface; a drive surface, for defining tool orientation without curvature inversion, is created by using the virtual convex curve, the convex curve set on the convex curved surface, and the convex curves set on the pair of edges; and a tool axis direction during removal machining is set on the basis of the normal direction of the drive surface for tool orientation definition.