Drill Web Thickness for Composite Delamination
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Solution Overview
Problem
Conventional drills face challenges in drilling composite materials like GFRP and CFRP, experiencing delamination and burr formation due to high cutting resistance, and existing drills for metals also struggle with precision and burr suppression.
Innovation Solution
A drill with a web thickness between 5% and 25% of the diameter, featuring a two-stage step design with tapered web and nicks on the lands to reduce cutting resistance and prevent delamination and burr formation, made from materials like cemented carbide or high-speed tool steel for enhanced toughness and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If web thickness is increased to maintain drill strength, then drill strength is improved, but cutting resistance increases causing delamination and burrs
Solution Approach 1:
The patent applies local quality by creating a tapered web structure where the web thickness varies along the drill length. The web is thinnest (5-25% of diameter) at the cutting tip to minimize cutting resistance and prevent delamination, while being progressively thicker toward the shank to maintain overall drill strength and rigidity. This gradient structure allows each section to have the optimal thickness for its specific function.
2Object-affected harmful factors
If web thickness is decreased to reduce cutting resistance, then cutting resistance is reduced, but drill strength decreases
Solution Approach 1:
The patent applies segmentation by dividing the web into multiple sections with different thicknesses along its length. Rather than a uniform thickness, the web is segmented into a thin cutting section at the tip and progressively thicker sections toward the shank. This segmentation allows the cutting portion to have minimal thickness for reduced resistance while the supporting portions maintain sufficient thickness for strength.
3Adaptability or versatility
If conventional drill geometry is used for metal drilling, then metal drilling capability is maintained, but precision and burr suppression deteriorate in composite materials
Solution Approach 1:
The patent applies parameter changes by modifying the web thickness parameter from conventional values to a specific range (5-25% of drill diameter) at the cutting tip. This parameter change optimizes the drill for composite material drilling by reducing cutting resistance and preventing delamination, while the overall drill geometry maintains compatibility with metal drilling applications.
Data Source
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AI summary
A drill (1) is provided that is adapted to drill at least one of a composite material and a metal. A web thickness (W) at least at a tip of the drill (1) is not less than 5 % and less than 25 % of at least one diameter of the drill (1). Further a method of manufacturing a drilled product is provided. The drilled product is manufactured by drilling a workpiece using the above-mentioned drill (1). The workpiece is made of at least one of a composite material and a metal.