Impeller Corner Machining With Variable-Radius Cutting Paths
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Solution Overview
Problem
Existing methods for manufacturing processed articles, such as impellers, do not effectively address the machining of corners between adjacent machined surfaces, leading to increased machining time and surface roughness.
Innovation Solution
A method using a tool with a cutting blade featuring arcs of different curvature radii, where the machining pitch is adjusted based on the curvature radius to optimize tool usage and maintain surface roughness, allowing for efficient machining of adjacent surfaces and complex three-dimensional curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a straight portion of the tool or a portion with large radius of curvature is used as a cutting blade to increase the width that is cut at the same time, then the machining time is reduced, but the surface roughness increases at corners between adjacent machined surfaces
Solution Approach 1:
The patent applies dynamics by making the tool's effective cutting radius variable rather than fixed. The tool is designed with a curved side surface where the radius of curvature changes along the tool's path, allowing the effective cutting radius to be dynamically adjusted based on the machining location. This enables using a larger effective radius for faster machining in open areas while automatically using a smaller effective radius at corners to maintain surface quality, thus resolving the contradiction between machining speed and surface roughness.
Solution Approach 2:
The patent changes the geometric parameter of the tool's side surface from a constant radius to a variable radius profile. By designing the side surface with a specific curvature function where the radius of curvature varies along the tool path, the effective cutting radius becomes a controllable parameter that can be optimized for different machining conditions. This parameter change allows the tool to adapt its cutting characteristics dynamically, achieving both high productivity and good surface finish.
2Ease of manufacture
If a tool with constant radius is used for machining, then the tool design is simple, but the machining efficiency at corners between adjacent surfaces is low
Solution Approach 1:
The patent transitions from a static, constant-radius tool design to a dynamic, variable-radius tool design. The curved side surface with varying radius of curvature allows the tool to automatically adapt its effective cutting radius based on the local geometry being machined. At corners between adjacent surfaces, the tool's geometry naturally provides a smaller effective radius, improving corner machining efficiency without requiring complex active control mechanisms, thus maintaining relative design simplicity while enhancing productivity.
3Productivity
If the machining pitch is increased to reduce machining time, then the productivity improves, but the surface roughness exceeds the set value
Solution Approach 1:
The patent applies local quality by making the tool's cutting characteristics location-dependent. The variable radius of curvature along the tool's side surface creates different effective cutting radii at different locations during machining. At corners between adjacent surfaces, the tool geometry provides a smaller effective radius that naturally produces finer surface finish, while in open areas, the larger effective radius enables faster machining with acceptable surface quality. This local adaptation of cutting quality resolves the contradiction between machining speed and surface roughness.
Solution Approach 2:
The patent changes the geometric parameters of the tool to achieve location-dependent cutting performance. By designing the side surface with a specific curvature function, the effective cutting radius becomes a variable parameter that changes with the tool's position and orientation. This parameter variation allows the machining pitch to be effectively adjusted without physically changing the pitch, enabling faster machining while maintaining surface roughness within specifications through the tool's inherent geometric adaptation.
Data Source
AI summary
A processed article is manufactured with a tool including a cutting blade. The cutting blade is arranged to be in contact with two machined segment surfaces so that two contact points are defined between the two machined segment surfaces and the cutting blade in a corner. A machining pitch is set in a pick feed direction of the tool at the corner to a first machining pitch for when a part of the cutting blade corresponding to a projected shape of a side surface of the cutting blade having a first curvature radius is a cutting point. A cut is performed along a feed direction in the two adjacent machined segment surfaces successively at the corner so that the tool proceeds toward the corner in one of the machined segment surfaces and away from the corner in the other one of the machined segment surfaces.