Single-Edge Deep-Hole Drill With External Coolant and Chip Discharge
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Solution Overview
Problem
Conventional deep hole-forming drills face challenges in efficiently supplying coolant liquid and effectively discharging chips when using an external oil supply method, leading to reduced machining performance and potential damage to the workpiece, especially when forming deep holes in metals.
Innovation Solution
A single-edge drill design featuring a large-diameter portion with coolant delivery grooves and a small-diameter portion that creates a supply path for coolant liquid, allowing efficient external oil supply and effective chip discharge without the need for step feed or internal coolant systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an external oil supply method is used with conventional drills, then coolant liquid can be supplied to the cutting part, but coolant liquid cannot be efficiently delivered to the cutting part and chip discharge is impaired
Solution Approach 1:
The drill body is segmented into a large-diameter portion and a small-diameter portion, creating distinct functional zones. The large-diameter portion houses coolant delivery grooves for efficient coolant supply, while the small-diameter portion provides a clear path for chip discharge, preventing interference between coolant flow and chip ejection
Solution Approach 2:
The small-diameter portion acts as an intermediary structure that mediates between the coolant supply system and chip discharge path. It creates a dedicated channel that allows chips to be ejected without being obstructed by the coolant delivery grooves, while still allowing coolant to reach the cutting edge
2Temperature
If coolant delivery grooves are added to improve coolant supply, then coolant delivery efficiency improves, but device complexity increases
Solution Approach 1:
The coolant delivery grooves are merged with the outer peripheral surface of the large-diameter portion, integrating the coolant supply function into the existing drill structure rather than adding separate components. The grooves utilize the natural geometry of the drill body, reducing overall structural complexity while achieving effective coolant delivery
Solution Approach 2:
Coolant delivery grooves are localized to specific regions of the large-diameter portion where they are most needed for effective coolant supply to the cutting edge. This localized approach avoids unnecessary complexity in other areas of the drill structure
3Device complexity
If a single-edge drill design is used to simplify structure, then device complexity reduces, but coolant supply and chip discharge efficiency are compromised
Solution Approach 1:
The drill design utilizes dimensional variation by creating a small-diameter portion that extends axially behind the large-diameter portion. This axial dimensionality change creates a three-dimensional chip discharge path that is separate from the coolant delivery grooves, enabling both functions to operate efficiently in a single-edge drill configuration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The drill achieves stable deep hole formation exceeding 20D without step feed, ensuring efficient coolant delivery and chip discharge, preventing workpiece damage and maintaining machining tool rigidity.
Implementation Method 1
The margin includes a sub-groove twisted around the rotational axis of the drill in the direction opposite the direction in which the chip discharge groove is twisted, to extend from the shank toward the distal end of the cutting part, such that the sub-groove generates pumping action to supply coolant liquid to the cutting part
Implementation Method 2
a single chip discharge groove having a concave curved groove surface, and extending from the cutting tip of the drill toward the shank in the center axis direction
Data Source
AI summary
A single-edge drill for forming a deep hole is provided which includes a body and a shank. The body has a single chip discharge groove in the outer periphery thereof, and includes a small-diameter portion, and a large-diameter portion having coolant delivery grooves in the outer periphery thereof. The body has a core thickness at the distal end portion of the large-diameter portion. At the other portion of the body, the groove bottom of the chip discharge groove is located beyond the rotation center of the drill such that the body has no core thickness, and when taken perpendicularly to the axial direction of the drill, the cross section of the body has a crescent shape. When a hole is formed with the drill, a supply path for coolant liquid is defined between the outer peripheral surface of the small-diameter portion and the radially inner surface of the hole.