Step Drill Flute Convergence for Stable Deep Chip Evacuation
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Solution Overview
Problem
Step drills face challenges in chip control and removal due to varying rake angles and cutting speeds between the drill bit and boring stage, leading to difficulties in selecting optimal cutting conditions, especially when drilling ductile materials, which can result in chip collision and reduced stability.
Innovation Solution
A step drill design where the chip flutes of the drill bit and boring stage converge to form a single common flute at a greater distance from the distal end, allowing separate chip removal and flow before combining, reducing the risk of collision and enhancing stability by merging chip flutes and increasing the core diameter of the chip flutes associated with the drill tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate flutes are provided for drill tip and reaming section, then chip collision is prevented, but drill stability is significantly weakened
Solution Approach 1:
The chip flutes are segmented into separate regions: main flutes for the drill tip and auxiliary flutes for the reaming section. This segmentation allows chips from different stages to be evacuated separately, preventing collisions while maintaining drill stability through the integrated structure.
Solution Approach 2:
The main flutes and auxiliary flutes are merged into a unified flute structure that converges at a greater distance from the distal end. This merging provides structural support and stability to the drill while still allowing separate chip evacuation paths through the segmented flute regions.
2Reliability
If additional auxiliary flutes are added for reaming sections, then chip collision is prevented, but drill structure is weakened considerably
Solution Approach 1:
The auxiliary flutes are designed with local quality variations: they have smaller dimensions in the reaming section area and converge with main flutes at a distance. This localized flute design provides sufficient chip evacuation capability while minimizing the weakening effect on the overall drill structure.
Solution Approach 2:
The flute structure extends in multiple dimensions along the drill length. The auxiliary flutes start at the reaming section face and converge with main flutes at a greater distance, creating a three-dimensional chip evacuation pathway that efficiently removes chips without requiring large material removal from the drill body.
3Reliability
If small additional flutes are used for reaming sections, then chip collision is avoided, but chip removal at great depths becomes difficult
Solution Approach 1:
The auxiliary flutes are positioned to act preliminarily by evacuating chips from the reaming section before they can collide with chips from the drill tip. This preliminary chip removal action prevents blockages and ensures smooth chip flow throughout the drilling process, especially at great depths.
Solution Approach 2:
The main flutes and auxiliary flutes are designed to converge continuously at a greater distance from the distal end, creating a continuous chip evacuation pathway. This continuous action ensures that chips from both drill tip and reaming section are consistently removed without interruption, maintaining high productivity during deep drilling operations.
Data Source
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AI summary
The invention relates to a step drill (1) comprising the following: - a distal end (3) and an opposite proximal end (5), - a drill tip (7) that has a tip (9) at the distal end (3) of the step drill (1) and comprises a number of geometrically defined cutters (17, 19), each of which is paired with a flute (21, 22) and lies on an imaginary first circular line about a longitudinal axis (15) of the step drill (1), said circular line having a first radius, - at least one drill step (11) that is arranged at a distance from the distal end (3) and has an end face (13) with a number of geometrically defined cutters (23, 25), each of which is paired with a flute (27, 29) and lies on an imaginary second circular line that runs about the longitudinal axis (15) of the step drill (1) and has a second radius, wherein - the first radius is smaller than the second radius. The step drill (1) is characterized in that - the flutes (21, 22) of the drill tip (7) and the flutes (27, 29) of the drill step (11) run together in a region which is arranged at a greater distance from the distal end (3) than the end face (13) of the drill step (11) and form a single flute.