Step Drill Chip Deflection Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drills face issues with long chip formation and chip balls when machining long-chipping materials, leading to tool breakage and increased machining times due to interference between chip removals from different cutting areas in step drills.
Innovation Solution
A drill design featuring a second cutting area with a geometrically defined cutting edge on the end face, arranged at an axial distance from the first cutting area, with a smaller machining diameter, and a chip-forming stage that includes a shoulder surface at an inclined angle to deflect chips, preventing long chip formation and tool damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drill is used as a step drill with first and second cutting areas, then the drill can perform multiple functions (drilling and countersinking), but chips from both cutting areas interfere and form balls leading to tool breakage
Solution Approach 1:
The invention extracts the harmful factor (chip ball formation) by providing separate chip discharge paths for the first and second cutting areas. The first chip discharge path is arranged separately from the second chip discharge path, preventing chips from both cutting areas from interfering and forming balls that would cause tool breakage.
Solution Approach 2:
The invention segments the chip discharge system into separate paths for different cutting areas. The first chip discharge path and second chip discharge path are spatially separated, allowing independent chip evacuation from each cutting area, thus preventing chip ball formation while maintaining multi-functionality.
2Object-generated harmful factors
If the feed is interrupted or reversed to avoid long chips, then chip formation is controlled, but machining time increases and wear increases due to changing stress
Solution Approach 1:
The invention extracts the harmful long chips from the machining process by providing a dedicated first chip discharge path that efficiently removes chips from the first cutting area. This allows continuous feeding without interruption or reversal, maintaining productivity while preventing long chip formation.
Solution Approach 2:
The invention creates dynamic chip control through the angled shoulder surface (5° to 15°) that actively deflects chips during the cutting process. This dynamic chip deflection mechanism continuously breaks up chips without requiring feed interruption, allowing uninterrupted machining while controlling chip length.
3Object-generated harmful factors
If the shoulder surface angle is increased to deflect chips, then long chips are avoided, but the cutting geometry becomes more complex
Solution Approach 1:
The invention controls chip length by optimizing the shoulder surface angle within a specific range (5° to 15°). This parameter optimization achieves effective chip deflection and length control while minimizing geometric complexity. The angled shoulder surface creates a chip forming step that actively manages chip flow without excessive complexity.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
What is proposed is a drill (1) having a tool shank (3), a central axis (5) and a first cutting region (7) with at least one geometrically defined first lip (9; 9'), which has a rake face (23) and is arranged at a radial distance from the central axis (5) of the drill (1), wherein the first lip includes a countersink angle (a) with the central axis. The drill (1) is distinguished by the fact that the first lip (9; 9') is assigned a chip breaker, which is formed by the rake face (23) of the first lip (9; 9') and by a shoulder face (31) which adjoins the rake face (23) and includes a shoulder angle (delta) therewith, wherein the shoulder angle (delta) is greater than 90°, preferably greater than 100°, that the rake face (23) runs at a radial rake angle (epsilon) with respect to an imaginary radial line (L) which intersects the first lip (9') assigned to the rake face (23), and that the radial rake angle (epsilon) is positive.