Single-Lip Gun Drill Grooves for Shorter Chip Breaking
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Solution Overview
Problem
Conventional deep hole drills face challenges in efficiently machining tough and long-grained materials, with high energy requirements leading to tool wear and increased costs, and existing chip formers do not effectively produce short, compact chips for easy removal.
Innovation Solution
A deep hole drill design featuring parallel longitudinal grooves on the chip surface, which are wider than conventional designs, allowing for the production of two chips that break easily, reducing feed force and improving chip removal efficiency, and allowing for easier manufacturing and retrofitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional chip breakers (raised sections) are used on the rake face, then chip breaking is achieved, but manufacturing complexity increases and tool life decreases
Solution Approach 1:
The rake face is segmented into multiple functional zones: two longitudinal grooves (first and second) that act as chip breakers, a central land portion, and side portions. This segmentation allows each zone to perform its specific function independently, achieving effective chip breaking without the complexity of raised sections while maintaining tool life.
Solution Approach 2:
Instead of adding raised sections (protruding features) to break chips, the invention uses recessed longitudinal grooves. This inverted approach achieves the same chip breaking function while simplifying manufacturing and reducing stress concentration points that would otherwise reduce tool life.
2Productivity
If high drive power is used to machine tough materials, then material removal is effective, but tool wear increases and energy consumption rises
Solution Approach 1:
The cutting process is segmented into two separate cutting actions performed by the inner and outer cutting edges. Each edge creates its own chip that is independently controlled by the longitudinal grooves. This segmentation distributes the cutting load and allows for more efficient chip evacuation, reducing the overall energy required for material removal.
Solution Approach 2:
The longitudinal grooves extract and separate the chips from the cutting zone immediately after formation. By removing the chips from the high-stress cutting environment, the grooves reduce the energy required to continue cutting and prevent re-cutting of chips, thereby reducing total energy consumption.
3Ease of manufacture
If narrow longitudinal grooves (15% of rake face width) are used, then manufacturing is simple, but chip breaking effectiveness is insufficient for tough materials
Solution Approach 1:
Instead of using a single wide groove or raised section, the invention segments the chip breaking function into two separate longitudinal grooves positioned at specific locations on the rake face. This segmentation provides multiple chip breaking zones that work together to effectively handle tough, long-chipping materials while maintaining manufacturing simplicity.
Solution Approach 2:
The longitudinal grooves are positioned at specific locations (first groove near the inner cutting edge, second groove near the outer cutting edge) to provide localized chip breaking where it is most needed. Each groove has optimal dimensions and positioning for its specific location, ensuring effective chip breaking throughout the entire cutting width.
Data Source
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AI summary
The invention relates to a single-lip drill the rake face (23) of which has two longitudinal grooves (33.1, 33.2). They are arranged in the longitudinal direction of the tool and favor chip-breaking.