CNC Lathe Turning with Adjustable Rake Angle for Tool Wear
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Solution Overview
Problem
Existing metal cutting tools, particularly those using cubic boron nitride (CBN) or ceramic cutting elements, experience wear on the rake and flank faces, leading to reduced tool life and compromised machining quality, necessitating frequent replacements and inefficient machining processes.
Innovation Solution
A method for CNC lathe turning that involves rearranging the cutting element's nominal rake angle to maintain effective clearance and rake angles, compensating for wear, thereby extending tool life and ensuring high-quality machined surfaces, even when the tool is considered worn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a CBN or ceramic cutting element is used for machining hard materials, then wear resistance is improved, but tool life is still limited due to wear on the rake face and flank face
Solution Approach 1:
The cutting element is designed with the capability to be repositioned or re-oriented on the tool holder, allowing dynamic adjustment of the cutting edge orientation. This enables the use of different effective rake angles and clearance angles as the tool wears, extending the functional life of the cutting element by adapting to wear conditions rather than requiring replacement
Solution Approach 2:
The invention changes the geometric parameters (rake angle and clearance angle) by repositioning the cutting element on the tool holder. As the tool wears, the effective angles change, and by re-orienting the cutting element, new effective angles are achieved, allowing continued machining with acceptable surface quality and process stability
2Productivity
If the cutting element is used for as long as possible to improve efficiency, then productivity increases, but machining quality deteriorates due to wear
Solution Approach 1:
The cutting element's orientation is made dynamic and adjustable. When wear begins to affect surface quality, the cutting element can be repositioned to present a different effective rake angle and clearance angle, restoring acceptable machining quality without replacing the tool, thus maintaining productivity throughout the extended tool life
Solution Approach 2:
The cutting element undergoes periodic repositioning or re-orientation during its usage life. This periodic adjustment of orientation allows the tool to maintain machining quality through multiple cycles of use, each cycle potentially utilizing different effective angles as the tool progresses through its wear lifecycle
3Manufacturing precision
If the cutting element orientation is fixed to maintain optimal effective angles, then machining quality is maintained, but tool life is reduced due to frequent replacement
Solution Approach 1:
Rather than fixing the orientation, the invention makes the orientation dynamic and adaptable. The cutting element can be repositioned to different orientations as needed, allowing the effective angles to be optimized at different stages of tool life, thereby extending tool life while maintaining quality when needed
Data Source
AI summary
A turning method for a CNC lathe involves at least two machining steps, wherein a cutting element is re-arranged between the machining steps such that a nominal rake angle (γn) is changed. Thereby, the effective tool life may be increased and a high quality of the machined surfaces, and a stable cutting process, may be achieved even with a worn tool. A system and a computer program for performing the method is also provided.