Spin-Welded Assembly with Interlocking Feature
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Solution Overview
Problem
Conventional spin-welding processes often result in weld joints with less than optimal bonding strength and durability, particularly when used for welding components of different shapes or materials, limiting their application to small cylindrical parts.
Innovation Solution
Incorporating an interlocking feature formed by the movement of molten flash during the spin-welding process, specifically a circumferential undercut or groove in the disc and optional inwardly-projecting splines, to enhance the retention and stability of the welded components, both axially and torsionally, independent of the weld joint's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional spin-welding process is used, then welding efficiency and cycle time are improved, but bonding strength and durability of weld joint deteriorate
Solution Approach 1:
The retention mechanism is segmented into two independent components: the weld joint itself and the interlocking feature formed by molten flash. This segmentation allows the weld joint to provide primary bonding while the interlocking feature provides additional mechanical retention, ensuring that if one fails, the other maintains the connection.
Solution Approach 2:
The weld joint combines two different retention mechanisms: the metallurgical or molecular bond from the weld zone and the mechanical interlock from the molten flash trapped in the undercut. This composite approach creates a dual-mode retention system that significantly enhances overall bonding strength and durability.
2Device complexity
If conventional spin-welding process is used, then process simplicity is improved, but applicability to different shapes and materials deteriorates
Solution Approach 1:
The disc component is given a specific local feature (circumferential undercut or groove) at the weld interface that is tailored to capture and retain molten flash. This localized structural modification enables the spin-welding process to be adapted to various component geometries and materials without changing the overall welding mechanism.
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 interlocking feature significantly improves the overall strength and durability of the welded assembly by ensuring axial retention and preventing relative rotation, even if the weld joint fails, thereby expanding the applicability of spin-welding to various shapes and materials.
Implementation Method 1
The frictional heating generated at or along a boundary or interface between the components melts a portion of the material
Implementation Method 2
the frictional heating generated at or along a boundary or interface between the components melts a portion of the material
Implementation Method 3
When the molten flash cools, a homogenous weld joint is formed at or along the weld zone from the now intermixed materials of the welded components
Data Source
AI summary
A welded assembly includes a weld joint formed via a spin-welding process. A disc receives a cylinder prior to spin-welding, with the disc having a circumferential groove undercutting or defining an annular shelf. An interlocking feature retaining the cylinder and disc is formed between a flow pattern of the cylinder and the annular shelf upon cooling of molten flash in the groove underneath the annular shelf. Teeth can be formed integrally with the disc to provide a torsional interlocking feature between the disc and cylinder. A method for forming a weld joint between a plastic cylinder and disc includes providing the disc with a circumferential groove forming an annular shelf, and rotating the cylinder with respect to the disc under an axial force to thereby form an outflow of molten flash. The flash forms an interlocking feature when cooled after flowing into the groove underneath the shelf.