Helical Multi-Cutter Drilling Tool for Composite Materials
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Solution Overview
Problem
Current drilling techniques for composite materials like carbon fiber reinforced plastics (CFRP) and light alloys face issues such as surface delamination, fiber breaking, burning, and ovalized holes due to the limitations of traditional cutting tools, which require multiple passes and result in reduced tool life and increased production costs.
Innovation Solution
A cutting tool with a unique geometrical shape featuring primary and secondary cutters arranged in helical grooves and a conical profile, allowing for single-pass drilling with a finished diameter hole without delamination or burning, and capable of drilling through composite materials and light alloys with reduced operator effort and increased tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional drilling techniques are used on composite materials, then multiple passes are required to achieve the desired hole diameter, but this results in surface delamination, fiber breaking, and burning
Solution Approach 1:
The drilling operation is segmented into multiple cutters arranged in sequence along the helical groove, with each cutter performing a specific function (breaking, roughing, finishing) to achieve the final hole diameter in one pass, eliminating the need for multiple separate drilling operations
Solution Approach 2:
The continuous helical groove design allows all cutters to work simultaneously in a continuous cutting action through the composite material, maintaining constant chip removal and cooling, which prevents burning and delamination while achieving the complete hole in a single continuous pass
2Productivity
If traditional cutting tools are used, then multiple passes are necessary to reach finished diameter, but this increases production time and reduces tool life
Solution Approach 1:
The tool is segmented into multiple cutters (breaking cutter, roughing cutters, finishing cutters) that perform different functions in sequence, allowing the tool to complete the entire drilling operation from pilot hole to finished diameter in one pass, thereby increasing productivity and reducing the number of tool changes required
Solution Approach 2:
The breaking cutters perform preliminary action by fracturing the composite material structure before the roughing and finishing cutters engage, which facilitates easier material removal and reduces the load on subsequent cutters, extending overall tool life
3Manufacturing precision
If multiple drilling passes are performed, then the desired hole diameter is achieved, but operator effort increases and ergonomics deteriorate
Solution Approach 1:
Multiple drilling functions (breaking, roughing, finishing) that were previously performed by separate tools and operations are merged into a single multi-cutter tool, allowing the operator to complete the entire drilling sequence in one insertion and rotation, significantly reducing operator effort and improving ergonomics while maintaining aviation tolerance compliance
4Productivity
If traditional drilling methods are used on CFRP packets, then holes are drilled through multiple layers, but surface delamination and fiber breaking occur
Solution Approach 1:
The cutting action is segmented into distinct zones along the helical groove, with breaking cutters handling the initial penetration through multiple CFRP layers, roughing cutters removing bulk material, and finishing cutters producing the final precise diameter and smooth surface, preventing delamination and fiber breaking while maintaining high drilling efficiency
Solution Approach 2:
Different sections of the tool have locally optimized characteristics: breaking cutters with aggressive geometry for initial penetration, roughing cutters for material removal, and finishing cutters with precise geometry for surface quality, allowing each zone to perform its specific function optimally without compromising overall surface quality or productivity
Data Source
AI summary
A hand drilling tool of one or more elements coupled therebetween comprising:a chuck (2) tightened in the spindle of a tool machine allowing the tool rotation;an elongated point body (3) with tool diameter (2) having at least four helical grooves developing longitudinally on the point body and defining at least two primary cutters, and at least two secondary cutters; said two primary cutters forming a tip angle; said secondary cutters having a discharge surface S; said discharge surface S is shaped so as to create an interruption between the secondary cutters and the primary cutters by contributing to reduce the operator's effort, to reduce the temperature and to promote the discharge of the worked material. Said point body (3) is formed by a substantially cylindrical first portion and a substantially conical second portion with taper towards the end of the tool.