Thin Drill Coolant Hole Layout for Chip Removal Without Flutes
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Solution Overview
Problem
Conventional drills with helical discharge flutes are ineffective for drilling small-diameter holes in hard brittle materials like glass, ceramics, or silicon, as they suffer from reduced strength and chip accumulation, leading to prolonged drilling times and potential drill breakage.
Innovation Solution
A thin drill design with a coolant hole extending along the axis of the drill shaft, branching into a discharge hole at the rear of the cutting edge, eliminating the need for helical discharge flutes and preventing coolant fluid from pressurizing the discharge direction, thus enhancing strength and manufacturing ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If helical discharge flutes are formed on the drill shaft, then chip discharge function is improved, but drill shaft strength is significantly lowered
Solution Approach 1:
The drill shaft is divided into two functional sections: the leading end part with discharge flutes for chip removal, and the main body without flutes to maintain strength. This segmentation allows each part to perform its specific function optimally without compromising the overall structure.
Solution Approach 2:
Discharge flutes are applied locally only to the leading end part of the drill shaft where chip discharge is most critical, rather than along the entire length. This localized application maintains drill shaft strength in the main body while providing effective chip discharge where needed.
2Object-generated harmful factors
If a coolant hole is formed in the thin drill shaft, then chip flushing capability is improved, but drill strength is further reduced
Solution Approach 1:
The coolant hole is positioned and dimensioned to serve the leading end part effectively without compromising the main body strength. The coolant delivery is segmented to target the cutting zone precisely, avoiding the need for a large-diameter hole through the entire shaft length.
3Productivity
If the drill is used for deep hole drilling, then productivity is improved, but chip discharge becomes insufficient and drill breakage risk increases
Solution Approach 1:
A coolant delivery system is implemented to flush chips from the drilling zone, particularly effective for deep holes where mechanical discharge flutes alone are insufficient. The coolant flow removes chips from the bottom of deep holes, preventing accumulation and drill breakage while enabling continuous high-speed drilling.
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 design ensures effective chip removal and prevents drill breakage by maintaining strength at the cutting edge and simplifying production, reducing drilling time and improving operational efficiency for small-diameter hole drilling in hard brittle materials.
Implementation Method 1
a coolant hole which extends from a rear part of the shaft body toward the leading end along an axis of the drill shaft
Implementation Method 2
a discharge hole which is branched from the coolant hole at a position rearward of the cutting edge and opens at an outer periphery of the drill shaft
Data Source
AI summary
[Problem] To protect a leading end part of a drill having a coolant hole which is adapted for drilling a thin diameter or very thin diameter hole in a workpiece.[Solution] A coolant hole 33 is formed in a shank 3 and a shaft body 7 so as to extend through from a rear end surface 31 of the shank 3 to a leading end surface 15 of the shaft body 7 along an axis thereof. A leading end part of the coolant hole 33 is branched into a pair of discharge holes 35, at a position slightly toward a base end relative to the leading end surface 15 of the shaft body 13. The discharge holes 35 extend in the opposite directions, perpendicular to the coolant hole 33, respectively, and open at opposite side surfaces 37, 37 to define discharge ports 39, 39. A leading end opening 41 of the coolant hole 33 is closed by a bottom face 17 of the drill part 9.