Offset-Axis Drill Bit for Single-Pass Multi-Material Stacks
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Solution Overview
Problem
Drilling through stacks of materials with different characteristics poses challenges due to incompatible drilling requirements, leading to suboptimal hole quality and tool damage, especially when using conventional methods that require multiple tool changes and compromise on drilling conditions.
Innovation Solution
A drilling device with a drill bit featuring multiple cutting edges, each optimized for specific materials, and a tool holder that allows lateral axis offsetting to alternate between cutting edges during drilling, enabling independent operation of different cutting edges to accommodate varying material characteristics in a single drilling operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drill bit is used to drill through a stack of different materials, then the device complexity is reduced, but the manufacturing precision deteriorates because the drill cannot be optimized for each specific material
Solution Approach 1:
The drill bit is segmented into multiple cutting edges, each optimized for specific materials. The drill bit includes a first cutting edge for drilling metal parts and a second cutting edge for drilling composite material parts, allowing each segment to be specialized while remaining part of a single tool
Solution Approach 2:
Multiple cutting edges with different optimizations are merged into a single drill bit. The drill bit combines cutting edges for different materials (metal and composite) into one tool, eliminating the need for multiple separate drill bits while maintaining material-specific optimization
2Ease of operation
If drilling parameters are compromised to work with both materials, then the ease of operation is improved, but the manufacturing precision deteriorates due to suboptimal drilling conditions
Solution Approach 1:
The drilling system dynamically switches between different cutting edges based on the material being drilled. The control system detects material transitions and automatically changes the active cutting edge, allowing optimal drilling conditions for each material without manual intervention
Solution Approach 2:
The system changes drilling parameters (rotation speed, feed rate, active cutting edge) based on the material being drilled. Each cutting edge has optimized parameters for its target material, and the system adjusts these parameters dynamically to maintain manufacturing precision
3Manufacturing precision
If multiple tool changes are made to drill different materials, then the manufacturing precision is improved, but the productivity deteriorates due to increased implementation time
Solution Approach 1:
Multiple cutting edges for different materials are merged into a single drill bit, eliminating the need for tool changes. The drill bit includes cutting edges for metal, composite, and other materials, allowing continuous drilling through stacked parts of different materials without stopping for tool changes
Solution Approach 2:
The drilling operation continues without interruption by switching between cutting edges on the same drill bit. The control system maintains continuous drilling action by automatically selecting the appropriate cutting edge for each material, preventing alignment defects that occur during tool changes
4Ease of operation
If a compromise drill is used for incompatible materials, then the ease of operation is improved, but the reliability deteriorates due to rapid tool damage
Solution Approach 1:
The drill bit is segmented into specialized cutting edges, each designed for specific materials. This segmentation allows each cutting edge to be optimized for its target material, preventing the rapid damage that occurs when using a compromise drill for incompatible materials
Solution Approach 2:
The system changes operational parameters including which cutting edge is active based on the material being drilled. Each cutting edge has optimized parameters for its target material, maximizing tool lifespan by avoiding the use of inappropriate cutting edges for incompatible materials
Data Source
Figure 1~2(b)
Figure 3a~3b
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AI summary
The drilling method for an assembly forming a stack of at least two different materials employs a drill bit (30) having at least a first cutting edge (31) and a second cutting edge (32) inclined in an axial plane of the drill bit (30) so as to give the drill bit a protruding conical end shape, and: - the first cutting edge (31) is formed for drilling a first material; - the second cutting edge (32) is formed, differently from the first cutting edge (31), for drilling a second material; - a first axis (21) for rotating the drill bit (30) during drilling is offset laterally by an offset distance D relative to the axis (33) of the drill bit; - in a direction opposite to the first cutting edge (31) when the drill bit drills the first material and alternately; - in a direction opposite to the second cutting edge (32) when the drill bit pierces the second material.A drill bit for implementing the process has at least two cutting edges adapted to drill through different materials in the stack. A drilling device for implementing the process includes a tool holder to which the drill bit is attached, and whose arrangement allows for an offset of the tool holder's axis of rotation relative to the drill bit's axis. This offset can be modified to change the cutting edge that performs the drilling as the material being drilled changes during the drill bit's progression.