Rounded Nose End Mill Cutting Edge Geometry Optimization
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Solution Overview
Problem
In multi-axis CNC machining with fast horizontal feed rates, traditional rounded nose end mills with constant rake and relief angles experience elevated cutting forces, heat, and rough surface quality due to low cutting speed and geometrically reduced angles near the tool tip.
Innovation Solution
The optimization of rake and relief angles along the cutting edge of rounded nose end mills, where these angles gradually increase from the full diameter to the tip, expressed through various mathematical expressions such as linear, cubic, exponential, or logarithmic functions, to enhance tool performance and adaptability to different workpiece materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If constant rake and relief angles are used along the cutting edge, then manufacturing simplicity is maintained, but cutting forces and heat increase near the tool tip
Solution Approach 1:
The patent applies local quality by varying the rake and relief angles along the cutting edge according to the local cutting speed conditions. Near the tool tip where cutting speed is low, the angles are increased to reduce cutting forces and heat. At the periphery where cutting speed is high, the angles are optimized for material removal efficiency. This localized optimization resolves the contradiction between manufacturing simplicity and cutting force reduction.
Solution Approach 2:
The patent changes the geometric parameters (rake angle and relief angle) along the cutting edge based on the position-dependent cutting speed. The angles are not constant but vary continuously or in steps from the tool tip to the periphery. This parameter change allows the tool to adapt to varying cutting conditions, reducing cutting forces and heat at low-speed regions while maintaining performance at high-speed regions.
2Device complexity
If constant rake and relief angles are used along the cutting edge, then tool structure simplicity is maintained, but surface quality deteriorates near the tool tip
Solution Approach 1:
The patent applies local quality by optimizing rake and relief angles specifically in the low-cutting-speed region near the tool tip to improve surface quality. The varied angles reduce cutting forces and heat in this critical zone, preventing tool marking and improving surface finish. The rest of the cutting edge maintains simpler geometry for efficient material removal, balancing surface quality improvement with overall tool structure.
Solution Approach 2:
The patent changes the rake and relief angle parameters along the cutting edge to improve surface quality at the tool tip where cutting speed is low. By increasing these angles in the low-speed region, the tool produces cleaner cuts and better surface finish without requiring complete redesign of the entire tool structure.
3Device complexity
If constant rake and relief angles are used along the cutting edge, then tool design simplicity is maintained, but tool life decreases due to elevated heat
Solution Approach 1:
The patent applies local quality by optimizing rake and relief angles in the low-cutting-speed region near the tool tip where heat generation is most problematic. The increased angles in this region reduce cutting forces and heat generation, extending tool life. The rest of the tool maintains simpler design for manufacturing ease and cost effectiveness.
Solution Approach 2:
The patent changes the rake and relief angle parameters along the cutting edge to manage heat generation and extend tool life. By varying these parameters to be larger at the tool tip where cutting speed is low, the tool experiences reduced thermal stress and wear in the most vulnerable region, thereby extending overall tool life without requiring complete redesign.
Data Source
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AI summary
A rounded nose end-mill (10) modified by optimization of geometrical parameters of both the rake angle (30) and relief angle (34) along the cutting edge (29) of the rounded portion (16), wherein the rake angle and the relief angle gradually increase along the cutting edge from the full diameter of the rounded portion to the tip.