Drilling Tool with Expanded Diameter for Composite Holes
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Solution Overview
Problem
Drilling tools struggle to produce drill holes in composite materials with precise diameters across different layers due to varying elasticities and machining properties, often resulting in deviations and the production of long chips that can clog tools or damage surfaces.
Innovation Solution
A drilling tool with a geometrically defined cutting edge and an expanded diameter area that produces chips consistent with those from a geometrically undefined cutting edge, allowing for grinding or honing-like machining, which reduces chip size and prevents clogging, and a method using this tool to create drill holes in composite materials with a single work step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional drilling tools with geometrically defined cutting edges are used, then drilling capability is provided, but long chips are produced that clog chip spaces and damage drill hole surfaces
Solution Approach 1:
The cutting edge is segmented into two distinct zones: a first zone with a geometrically defined cutting edge for initial material removal, and a second zone with a geometrically undefined cutting edge for finishing. This segmentation allows each zone to perform its specific function optimally, preventing long chip formation while maintaining drilling capability
Solution Approach 2:
Different portions of the cutting edge are given different geometric properties. The first portion has a precisely defined geometry for efficient cutting, while the second portion has an undefined geometry that produces grinding-like effects. This local differentiation resolves the contradiction by allowing each zone to address specific requirements
2Manufacturing precision
If reaming is performed to achieve precise drill hole dimensions, then diameter precision is improved, but additional work steps are required and chip spaces remain insufficient
Solution Approach 1:
The drilling and reaming functions are merged into a single tool and one work step. The multi-zoned cutting edge performs both rough cutting and precision finishing simultaneously, eliminating the need for separate reaming operations while maintaining diameter precision
Solution Approach 2:
The precision finishing function is built into the drilling tool itself, performing the reaming action preliminarily during the drilling process. This prevents the need for subsequent reaming operations and ensures precise dimensions from the start
3Manufacturing precision
If drill reamers with combined drilling and reaming functions are used, then precision is improved, but chip spaces are smaller than in dedicated reaming tools
Solution Approach 1:
The problematic long chip formation mechanism is extracted and eliminated by replacing the geometrically defined cutting edge with a geometrically undefined second zone. This extraction prevents chip clogging while maintaining the precision function, without requiring reduced chip spaces
4Ease of manufacture
If drilling is performed in composite materials with different elasticities, then material penetration is achieved, but drill hole diameter varies across different layers
Solution Approach 1:
The cutting edge is divided into zones with different geometric properties to handle different material layers. The first zone with defined geometry handles the initial penetration, while the second zone with undefined geometry provides a finishing action that compensates for elasticity variations, ensuring consistent diameter across layers
Solution Approach 2:
The cutting edge geometry parameter changes from precisely defined in the first zone to geometrically undefined in the second zone. This parameter transformation allows the tool to adapt to different material elasticities and produce consistent hole diameters across composite layers
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 tool achieves drill holes with consistent diameters across layers and extended tool life by minimizing chip size and eliminating the need for reaming, ensuring precise tolerances and preventing surface damage.
Implementation Method 1
machining in the aforesaid areas is consistent with machining with a geometrically undefined cutting edge... there is preferably grinding or honing-like machining in the aforesaid areas
Data Source
AI summary
A drilling tool for producing drill holes includes a tip and a shaft arranged opposite the tip in a direction of a longitudinal axis of the drilling tool. The drilling tool has at least one geometrically defined cutting edge in the tip area, and has an expanded diameter trailing the tip in a longitudinal direction from the tip. The drilling tool has a first area with a first diameter that precedes the expanded diameter, and a second area with a second diameter, larger than the first diameter, that trails the expanded diameter. The drilling tool is distinguished in that the expanded diameter and/or the second area is/are embodied such that chips are produced in the area of the expanded diameter and/or in the second area when a workpiece is machined, chips consistent with those produced when a workpiece is machined with a geometrically undefined cutting edge.