Parabolic Bone Drill Flutes for Better Chip Evacuation
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Solution Overview
Problem
Existing drill bit designs for medical and dental applications often result in flute blockages due to insufficient space for bone chip removal, leading to increased friction, thermal effects, and higher risks of osteonecrosis and compromised osteo-integration during drilling.
Innovation Solution
The design features a parabolic cross-section with convex surfaces and a fast helix angle, increasing the empty space for bone chip removal, reducing friction, and minimizing thermal effects by allowing for efficient bone chip evacuation and improved cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional drill bit designs with standard flute geometry are used, then the structure is simple and easy to manufacture, but the flutes become blocked during drilling due to insufficient space for bone chip removal
Solution Approach 1:
The patent applies curvature by defining the working portion with a parabolic cross-section featuring opposing convexed surfaces. This curved geometry creates expanded flute channels that prevent bone chip blockage while maintaining structural integrity, directly resolving the contradiction between chip removal efficiency and geometric complexity.
Solution Approach 2:
The invention transitions from traditional cylindrical drill geometry to a parabolic cross-section with convexed surfaces extending along the longitudinal axis. This dimensional change creates additional spatial volume within the flutes, enabling effective bone chip evacuation without proportionally increasing external dimensions or manufacturing complexity.
2Reliability
If bone chips are not correctly removed during drilling, then the drilling process continues without interruption, but friction and thermal effects increase leading to osteonecrosis risk
Solution Approach 1:
The patent extracts the harmful factor (bone chips) from the drilling zone by designing flutes with enhanced capacity and geometry that actively evacuate chips away from the cutting interface. This prevention of chip accumulation directly reduces friction-generated heat and eliminates the thermal pathway to osteonecrosis, improving reliability while controlling temperature.
Solution Approach 2:
The convexed parabolic flute geometry is designed in advance to prevent bone chip blockage before it occurs. The expanded cross-sectional area and optimized flow channels create sufficient space and velocity for continuous chip removal throughout the drilling process, proactively preventing the conditions that lead to thermal damage and osteonecrosis.
3Strength
If the land margin width is increased to improve structural strength, then the core becomes more robust, but the empty space for bone chip removal is reduced
Solution Approach 1:
The patent applies local quality by varying the land margin width along the longitudinal axis of the drill. The convexed surfaces create zones with different geometric properties: wider land margins in regions requiring structural support and narrower land margins in regions where chip removal space is prioritized. This localized variation resolves the contradiction between strength and chip evacuation volume.
Solution Approach 2:
The invention changes the geometric parameters of the land margins by defining them through a parabolic cross-section with convexed surfaces. This parameter transformation creates an optimized distribution of material, where the land margin width varies continuously along the flute length, balancing structural strength requirements with bone chip removal capacity in different axial positions.
Data Source
AI summary
An instrument comprising a shank and a working portion, the working portion having a tip and a plurality of flutes being defined by at least two lands having a land margin; wherein the working portion has a parabolic cross-section defining opposing convexed surfaces extending between at least two opposing land margins.