Orbital Drill with Mixed Spiral Flutes for CFRP Drilling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drilling through stacks of multiple materials, such as carbon fiber reinforced plastic (CFRP) and metals, often results in fiber delamination and requires a separate reaming operation due to differences in machining properties, increasing manufacturing costs and complexity.
Innovation Solution
An orbital drill with right-handed spiral flutes having a positive axial rake angle for cutting into materials and left-handed spiral flutes located rearward for cutting out, allowing for continuous hole formation and removal of residual material without the need for reaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional push drilling is used on CFRP materials, then side to side deflection is reduced, but fiber delamination and other damage occur
Solution Approach 1:
The patent employs orbital drilling where the drill bit executes a circular orbital motion in addition to rotational spinning, creating a vibrating cutting action that reduces fiber delamination while maintaining hole stability through the combined motion pattern
2Object-affected harmful factors
If orbital drilling is used to machine through stacks of multiple materials, then fiber delamination is reduced, but hole tolerance cannot be maintained through entire hole depth
Solution Approach 1:
The drill bit is segmented into distinct functional zones: right-handed spiral flutes at the leading end for entry cutting, left-handed spiral flutes in the middle section for material removal, and right-handed spiral flutes at the trailing end for exit cutting and hole finishing, with each zone optimized for its specific function to maintain hole tolerance throughout the entire depth
Solution Approach 2:
Different sections of the drill bit have different flute configurations and cutting edge orientations tailored to their specific functions - the leading section has right-handed flutes for efficient material engagement, the middle section has left-handed flutes for optimal chip evacuation, and the trailing section has right-handed flutes for hole finishing, creating local optimization along the tool length
3Object-affected harmful factors
If orbital drilling is used on multiple materials with different machining properties, then fiber delamination is reduced, but a separate reaming operation is required
Solution Approach 1:
The patent combines drilling and reaming functions into a single orbital drilling operation by incorporating multiple flute configurations in one tool - the right-handed flutes perform the primary drilling function while the left-handed flutes simultaneously perform the reaming function by removing residual material, eliminating the need for a separate reaming operation
Data Source
AI summary
An orbital drill includes a drilling portion, a shank portion, and a neck portion between the drilling portion and the shank portion. The drilling portion includes one or more right-handed spiral flutes with cutting edges having a positive axial rake angle for positive cutting action while orbiting into a material. The right-handed spiral flutes have a positive radial and axial rake angle. The drilling portion also includes one or more left-handed spiral flutes located rearward of the one or more right-handed spiral flutes with cutting edges having a positive axial and radial rake angle for positive cutting action while orbiting back out of the material and removing any material left in the hole, thereby eliminating a separate reaming operation. A method of machining a workpiece using the orbital drill is also disclosed.