Face-milling insert with intermediate edge for CGI burr prevention
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Solution Overview
Problem
Face-milling inserts with round or arched secondary edges fail to effectively machine Compacted Graphite Iron (CGI) due to burr formation and inefficient chip removal, which is not addressed by previous modifications designed for grey cast iron.
Innovation Solution
A face-milling insert with a triangular basic shape, featuring a 45° setting angle between the main cutting edge and secondary edge, an intermediate cutting edge with a specific angle and arched part edges, and a short intermediate cutting edge that redistributes component forces to minimize burr formation and enhance chip removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If round or arched secondary edges are used to solve edge breakout problems in grey cast iron, then edge breakout is prevented, but burr formation occurs in CGI machining
Solution Approach 1:
The cutting edge is segmented into three distinct parts: main cutting edge, intermediate cutting edge, and secondary edge. The intermediate cutting edge acts as a transition zone that prevents burr formation while the secondary edge maintains its edge breakout prevention function. This segmentation allows each part to perform its specific function without interfering with others.
Solution Approach 2:
Different sections of the cutting edge have different geometric properties optimized for their specific functions. The main cutting edge has a specific angle for efficient cutting, the intermediate cutting edge has a transition geometry for burr prevention, and the secondary edge has a round or arched shape for edge breakout prevention. Each local section has the quality needed for its particular task.
2Stress or pressure
If arched secondary edges are used to redistribute forces, then lateral stresses are reduced, but heat generation increases due to longer edge length
Solution Approach 1:
The force redistribution function is partially performed by the intermediate cutting edge rather than requiring the entire secondary edge to be arched. The intermediate cutting edge handles the transition and force redistribution, allowing the secondary edge to be shorter and generate less heat while still achieving the stress redistribution goal.
Solution Approach 2:
The intermediate cutting edge acts as an intermediary between the main cutting edge and the secondary edge. It mediates the transition of forces and materials, redistributing lateral stresses before they reach the secondary edge, thereby reducing the need for a long arched secondary edge and consequently reducing heat generation.
3Object-generated harmful factors
If the intermediate cutting edge is kept short, then burr formation is prevented, but chip removal efficiency may be compromised
Solution Approach 1:
The chip removal function is segmented between the main cutting edge and the intermediate cutting edge. The main cutting edge performs the primary cutting and chip separation, while the intermediate cutting edge, though short, contributes to chip formation and prevents burr formation. This segmentation allows the intermediate edge to be short without compromising overall chip removal efficiency.
Solution Approach 2:
The geometry parameters of the intermediate cutting edge are optimized to achieve the right balance. By adjusting the angle and length parameters of the intermediate cutting edge, the system achieves effective burr prevention while maintaining sufficient chip removal capability through the coordinated action of all cutting edge segments.
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The invention relates to a face-milling insert, which comprises a chip-removing main cutting edge (3) adjacent to a first clearance surface (6), and a surface-wiping secondary edge (4) adjacent to a second clearance surface (7), the main cutting edge forming an angle of 45° with an imaginary straight line in the extension of the secondary edge. Adjacent to a third clearance surface (12), an intermediate cutting edge (11) is formed between the main cutting edge (3) and the secondary edge (4), which intermediate cutting edge is shorter than the main cutting edge (3) and forms an angle within the range of 20-40° with said extension line. The intermediate cutting edge (11) transforms into the adjacent edges (3,4) via arched part edges (13,14) adjacent to convex clearance surfaces (15,16).