Drill Cutting Insert Curved Edge for Chip Clingage
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Solution Overview
Problem
Drills used for cutting ductile workpieces often experience chip climb and clingage issues due to uncurled chips not being properly discharged, leading to reduced surface accuracy and increased tool holder contamination.
Innovation Solution
A drill design featuring a columnar drill holder with first and second insert pockets, where the first insert has a straight cutting edge and the second insert has a concave, curved cutting edge, facilitating chip curling and discharge through spirally formed flutes, thereby improving chip directionality and reducing clingage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear cutting edge is used, then the structure is simple and easy to manufacture, but chips do not curl properly and cling to the drill holder
Solution Approach 1:
The cutting edge is designed with a curved profile instead of a straight line. The curvature radius varies along the cutting edge, creating different cutting angles that force chips to curl properly. This curved geometry transforms the chip flow path, preventing clingage while maintaining manufacturability through standard forming processes.
2Productivity
If chips are not curled, then the cutting process is simpler, but chip discharge performance deteriorates and surface accuracy decreases
Solution Approach 1:
The curved cutting edge with variable curvature radius creates controlled chip curling. This curling action properly forms chips for discharge through the drill flutes, improving chip evacuation. Simultaneously, the controlled curling prevents chip buildup on the workpiece surface, maintaining surface accuracy.
Solution Approach 2:
The curvature radius of the cutting edge is varied along its length, creating different effective cutting angles at different positions. This parameter variation optimizes chip formation and curling behavior, enabling both good chip discharge and surface finish quality.
3Object-generated harmful factors
If a curved cutting edge is used, then chip curling and discharge performance improve, but the device complexity increases
Solution Approach 1:
The curved cutting edge geometry, while more complex than a straight line, can be manufactured using standard forming processes. The curvature provides the necessary chip control functionality, reducing clingage and improving discharge, with the complexity being justified by the performance benefits.
Data Source
AI summary
A drill, including: a substantially columnar drill holder including, at a front end portion thereof, a first insert pocket and a second insert pocket formed closer to the outer periphery of the drill holder than the first insert pocket; a first insert which is attached to the first insert pocket and includes a first cutting edge at an intersection of an upper face and a side face; and a second insert which is attached to the second insert pocket and includes a second cutting edge at an intersection of a upper face and a side face. The first insert pocket is located passing through a central axis of rotation of the drill holder. The second cutting edge has a concave shape when viewed from the front end side of the drill holder, and has a curved line at least a part thereof.