Curved Pipe Burring with Slanted Seating Face to Reduce Cracks
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Solution Overview
Problem
The burring process on curved metal pipes often results in cracks at the ends due to varying height and high curvature, leading to stress concentration and potential failure.
Innovation Solution
Form a seating face with a slanted design and two crests on the seating face to reduce stress concentration, using inner and outer dies to press and form a circular second hole, minimizing high curvature and reducing crack occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the seating face is made flat and the pilot hole is formed with a circular shape, then the manufacturing process is simple, but stress concentrates at the small-R portions causing cracks
Solution Approach 1:
The seating face is designed with different local geometries: a slanted portion with larger radius of curvature at the ends in the circumferential direction, and a flat portion with smaller radius of curvature at the center. This local differentiation reduces stress concentration at critical areas while maintaining manufacturing feasibility.
Solution Approach 2:
The seating face transitions from a symmetric flat shape to an asymmetric slanted shape with varying radius of curvature. The slanted portion extends more prominently at the ends in the circumferential direction, creating an asymmetric geometry that redistributes stress away from high-curvature small-R portions.
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 method effectively reduces cracks during the burring process on curved members by forming a slanted seating face with crests, ensuring a circular second hole and minimizing stress concentration.
Implementation Method 1
forming a side wall and a seating face by pressing an inner-circumferential surface of a curved portion in a first direction
Implementation Method 2
the seating face may be pressed in a second direction, which is opposite to the first direction, thereby forming the second hole
Data Source
AI summary
In a method for manufacturing a burring processed member, an inner-circumferential surface of a plate-like curved portion is pressed in a first direction, thereby forming a side wall and a seating face, the side wall protruding from a rim of a first hole, the seating face extending from a tip of the side wall. In the method, a circular second hole is formed on the seating face, and the burring processed portion protruding in the first direction from the rim of the first hole is formed. The seating face includes two crests, each situated on a periphery of each end of the curved portion in a circumferential direction, and is slanted such that a seating face height becomes smaller from each of the crests to a substantial center in the circumferential direction.