Double-Margin Small-Diameter Drill Bit for Vibration Suppression
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Solution Overview
Problem
Elongated small-diameter drill bits with cutting blades of 2 mm or less and a margin-to-diameter ratio of 3 or more experience significant shaking during drilling, leading to decreased hole accuracy and increased risk of cutting blade breakage due to reduced rigidity.
Innovation Solution
A double-margin drill bit design with symmetrically formed chip discharge grooves, intersecting ridgeline cutting blades, and carefully angled tip flank faces to distribute cutting resistance evenly, supported by four margin parts and a thinning part to enhance rigidity and prevent shaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drill bit is designed with small cutting blade diameter (2 mm or less) and large margin-to-diameter ratio (3 or more), then the drill bit can achieve precise hole formation capability, but the rigidity of the cutting blade part decreases causing shaking during drilling
Solution Approach 1:
The cutting blade part is segmented into multiple cutting blades (typically two) with margin parts, allowing the structure to be optimized for both precision and rigidity. The segmentation enables distributed support while maintaining cutting effectiveness
Solution Approach 2:
The margin parts are nested on the land portions between cutting blades, creating a compact structure where support elements are integrated into the cutting structure itself, maximizing rigidity within the constrained diameter
2Manufacturing precision
If the drill bit is designed with small cutting blade diameter (2 mm or less) and large margin-to-diameter ratio (3 or more), then the drill bit can achieve precise hole formation capability, but the cutting blade part is likely to break during drilling
Solution Approach 1:
Margin parts are provided in advance on the land portions to serve as cushioning elements that absorb shocks and distribute stresses before they can cause cutting blade breakage, preventing failure through proactive structural design
Solution Approach 2:
The drill bit structure combines cutting blades with margin parts made of appropriate materials to create a composite structure that balances cutting performance with breakage resistance
3Stability of the object's composition
If four margin parts are used to support the cutting blade part, then shaking can be suppressed to some extent, but the complexity of the drill bit structure increases
Solution Approach 1:
The margin parts are merged with the land portions of the drill bit structure, combining the support function with the existing geometric structure rather than adding separate components, thereby reducing overall complexity
Data Source
Figure 1
Figure 2
AI summary
In this small-diameter drill bit, two cutting blades (7) having main cutting blades (7a), of which a difference between lengths (W) are 0.04 mm or less, are formed on a tip of a double-margin drill bit body (1) having a diameter of 2 mm or less and a margin length/diameter ratio of 3 or more. Two tip flank faces (5) are formed such that a first extension line (N1) extending from a linear first intersecting ridgeline (M1) between a first tip flank face (5a) and a second tip flank face (5b) of one of the flank faces to the linear first intersecting ridgeline (M1) of the other flank face is located on a side in the drill bit rotation direction (T) with respect to the other linear first intersecting ridgeline (M1). A distance (d1) between the first extension line and the linear first intersecting ridgeline is in a range of 0.04 mm-0.08 mm. A second extension line (N2) extending from a linear second intersecting ridgeline (M2) between the second tip flank face (5b) and a thinning face (8a) of the one flank face to the linear second intersecting ridgeline (M2) of the other flank face is located in a straight line with the other linear second intersecting ridgeline (M2) or located on the side in the drill bit rotation direction (T) with respect to the other linear second intersecting ridgeline (M2). A distance (d2) between the second extension line and the linear second intersecting ridgeline is in a range of 0.08 mm or less.