Multiple Edge Drill for Tough Cast Iron
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Solution Overview
Problem
Machining highly tough and difficult-to-machine materials like cast steel, tempered steel, and metallic cast materials poses challenges due to high abrasive wear and the need for precise geometry and tool design to maintain service life and accuracy, while existing drilling tools face limitations in production complexity and regrinding ease.
Innovation Solution
A multi-cutting drilling tool with a redesigned main cutting edge featuring two distinct tip angles, allowing for simplified grinding and reduced load on the cutting edge, enabling longer service life and improved machining accuracy, and incorporating features like internal coolant channels and specific tip angles for enhanced wear resistance and chip formation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a continuously convex main cutting edge is used to lengthen the cutting edge and reduce pressure, then the service life is improved, but the grinding complexity and device complexity increase
Solution Approach 1:
The main cutting edge is divided into multiple straight sections (first, second, third, and fourth main cutting sections) instead of a continuous convex curve. Each section can be independently ground, simplifying the grinding process while maintaining the load-distributing function of a lengthened cutting edge.
Solution Approach 2:
Different sections of the main cutting edge have different orientations and functions. The first and second sections form acute angles with the axis for primary cutting, while the third and fourth sections form obtuse angles for support and chip evacuation, optimizing local performance throughout the cutting edge.
2Reliability
If the main cutting edge is lengthened to reduce pressure on the cutting edge, then the wear resistance is improved, but the machining accuracy may deteriorate due to vibrations
Solution Approach 1:
The drilling tool incorporates local reinforcement elements such as a strengthened core and specific support section geometries that provide vibration damping exactly where needed, without requiring overall lengthening of the cutting edge that would compromise accuracy.
Solution Approach 2:
The drilling tool uses composite construction with different materials or structures in different regions - for example, a hardened cutting tip region combined with a more vibration-resistant core structure - to simultaneously achieve wear resistance and vibration control.
3Reliability
If solid carbide class K30 to K40 is used to achieve high hardness and wear resistance, then the wear resistance is improved, but the toughness and fatigue strength are reduced
Solution Approach 1:
The drilling tool employs composite material construction, combining solid carbide cutting edges for wear resistance with a tougher core material or coating system that provides the necessary toughness and fatigue strength. This allows each component to be optimized for its specific function.
Solution Approach 2:
Different regions of the drilling tool use different material properties - the cutting edges use hard, wear-resistant solid carbide, while the core and support structures use materials with higher toughness and ductility to absorb impacts and prevent catastrophic failure.
4Productivity
If fine or ultra-fine-grain hard metals with WC crystal grain sizes smaller than 0.8 μm are used to increase cutting performance, then the cutting speed and feed are improved, but the manufacturing cost and complexity increase
Solution Approach 1:
Instead of relying solely on ultra-fine grain sizes to achieve high cutting performance, the invention optimizes geometric parameters such as the angles of the main cutting sections, the configuration of chip grooves, and the distribution of cutting edges to enable effective machining at moderate cutting speeds and feeds.
Solution Approach 2:
The cutting tool is segmented into multiple functional sections with different geometries, allowing each section to be optimized for specific cutting conditions. This modular approach enables better performance than uniform fine-grain materials alone while using more manufacturable material grades.
Data Source
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AI summary
The invention relates to a multiple edge drill such as is especially used for machining difficult-to-machine, e.g. high-toughness materials, such as e.g. cast steel, steel for hardening and tempering or other difficult-to-machine steel materials including metallic cast materials, such as e.g. gray cast iron, and especially GGV or ADI cast iron. The facet is designed in such a manner that the main cutting edge has at least two main cutting edge sections (22, 24) that define point angles of different size, the radially outer point angle (WSPA) being smaller than the radially inner one (WSPI), thereby obtaining a good cutting behavior and long service life of the tool.