Segmented Drill Groove Structure for Chip Removal and Strength
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Solution Overview
Problem
Conventional drills face issues with breaking and poor cutting ability due to shallow chip-discharging grooves and reduced strength, especially when drilling at inclines, leading to potential osteonecrosis during medical procedures and inefficiencies in industrial drilling.
Innovation Solution
A drill design featuring symmetrically formed cutting edges with chip-discharging grooves and arc-shaped grooves that enhance cutting ability and strength, preventing breakage and allowing effective chip removal without thinning, which also reduces frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chip-discharging grooves are formed deeply to improve chip removal, then cutting ability is improved, but drill strength is reduced leading to breakage
Solution Approach 1:
The invention divides the chip-discharging groove into multiple segments: a first chip-discharging groove extending from the forward end along the cutting edge, and a second chip-discharging groove extending from the outer peripheral side toward the center. This segmentation allows chips to be evacuated through multiple pathways without requiring excessively deep single grooves, thereby maintaining drill strength while improving chip removal capability.
Solution Approach 2:
The invention applies different groove depths and configurations at different locations: the first groove is deeper near the cutting edge where chip generation occurs, while the second groove provides additional evacuation capacity near the outer periphery. This localized optimization ensures effective chip removal where needed without uniformly reducing strength throughout the drill body.
2Ease of operation
If the forward end is thinned to reduce cutting resistance, then ease of operation is improved, but rotational torque resistance deteriorates
Solution Approach 1:
The invention optimizes the web thickness distribution and groove dimensions as variables: the web is thinned at the forward end to reduce cutting resistance, but the thinning is controlled within specific parameters (web thickness 0.05-0.3mm, thinning angle 1°-4°) to maintain sufficient rotational torque resistance. The dual groove configuration compensates for the strength reduction from thinning.
3Productivity
If two symmetric chip-discharging grooves are provided to improve chip discharging, then productivity is improved, but drill strength is reduced
Solution Approach 1:
Instead of providing two complete symmetric grooves that would significantly weaken the drill, the invention segments the groove function: the first groove handles chip removal from the cutting edge, while the second groove provides additional evacuation capacity. This segmented approach achieves effective chip discharging without the strength penalty of two full symmetric grooves.
Data Source
AI summary
The problem to be solved is to provide a drill that is difficult to break and has a good cutting ability. The drill according to the present invention comprises: a first and a second cutting edge formed symmetrically with respect to a rotation axis; a first and a second relief surface formed symmetrically with respect to the rotation axis on back surfaces of the first and the second cutting edge, respectively; one chip-discharging groove formed from one of the first and the second cutting edge toward an outer peripheral side; and one or more arc-shaped grooves formed from another of the first and the second cutting edge toward the outer peripheral side.