Composite Drilling Tool Chamfer Geometry for Heat and Guidance
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Solution Overview
Problem
Conventional drilling tools generate excessive heat and struggle with guidance when processing carbon fiber-reinforced plastics and other materials, leading to inefficiencies and potential damage during machining.
Innovation Solution
A drilling tool with a cutting part featuring round-grind chamfers and lifting bevels that vary in width along their length, providing initial heat avoidance and weak guidance at the cutting tip, transitioning to stable guidance and reduced heat dissipation further back, ensuring effective chip removal and machining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional drilling tools are used to machine composite materials, then the cutting tip can penetrate the material, but excessive heat is generated at the borehole tip
Solution Approach 1:
The drilling tool is segmented into multiple functional zones along the axial direction: a first chamfer zone with a first clearance angle for initial heat reduction, a second chamfer zone with a second clearance angle for stable guidance, and intermediate transition zones. This segmentation allows different sections to address different problems (heat vs. guidance) simultaneously, resolving the contradiction between heat management and machining reliability.
Solution Approach 2:
Different clearance angles are applied to different axial zones of the drilling tool. The first chamfer zone has a larger clearance angle optimized for heat reduction at the cutting tip, while the second chamfer zone has a smaller clearance angle optimized for stable guidance. This local differentiation allows each zone to perform its specific function optimally, resolving the contradiction between heat management and guidance stability.
2Temperature
If the cutting tip is designed to reduce heat generation, then heat avoidance is improved, but guidance stability in the borehole deteriorates
Solution Approach 1:
The chamfer structure is divided into multiple zones with different clearance angles arranged axially. The first chamfer zone with larger clearance angle addresses heat avoidance, while the second chamfer zone with smaller clearance angle addresses guidance stability. This segmentation allows both conflicting requirements to be satisfied in different spatial zones simultaneously.
Solution Approach 2:
The solution moves from a single clearance angle design to a multi-zone clearance angle design along the axial dimension. By distributing different clearance angles along the axial direction, the patent resolves the contradiction in the spatial domain, allowing heat avoidance and guidance stability to be optimized at different axial positions.
3Temperature
If a pilot drill bit with reduced diameter is used, then heat generation is reduced and initial guidance is improved, but the ability to create the final borehole radius is compromised
Solution Approach 1:
The drilling tool is designed with multi-functionality: it can perform initial penetration with heat reduction capabilities while simultaneously creating the final borehole radius with required precision. The multi-zone chamfer structure enables the single tool to achieve both heat management and precise borehole formation, eliminating the need for separate pilot drilling operations.
Data Source
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AI summary
Drilling tool 50 for machining composite and other materials, comprising a shank 59 and a cutting part 55 with: - a cutting tip 51 with front main cutting edges 2, - radially external secondary cutting edges 12, - circular chamfers 25 and - reamed chamfers 15; 15a, 15b formed at least near the cutting tip 51 with a clearance angle relative to an outer radius R of the drilling tool 50, - wherein the circular chamfers 25 adjoin the secondary cutting edges 12 and follow them in the direction of rotation and wherein the reamed chamfers 15; 15a, 15b adjoin the circular chamfers 25 and follow them in the direction of rotation, - wherein the circular chamfers 25 have a chamfer width b which varies over at least part of their length L, and - wherein the front end 26 of the respective circular chamfer 25 begins with a non-constant chamfer width bm which increases with increasing distance e from the cutting tip 51.