Sheet Metal Tube Clinching on a Mandrel for Precise Diameter Control
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Solution Overview
Problem
Current sheet metal tube manufacturing processes are inefficient and costly, particularly in achieving precise diameters and connections, with methods like laser welding being expensive and manual clinching or riveting prone to inaccuracies and labor-intensive.
Innovation Solution
An integrated system for forming and clinching sheet metal tubes that uses a mandrel with clinching die bars and a sealing mechanism for simultaneous clinching along the tube length, reducing labor and capital costs by automating the process and allowing for precise control over tube diameter and connection patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is used to connect longitudinal edges, then connection strength is improved, but manufacturing cost and factory floor space requirements increase substantially
Solution Approach 1:
The patent replaces the thermal laser welding process with a mechanical clinching system that uses a clinching tool with a punch and die to mechanically interlock the overlapping sheet metal edges. This mechanical approach eliminates the need for expensive laser welding equipment while achieving comparable connection strength through formed clinch structures that interlock the metal edges.
Solution Approach 2:
The patent changes the connection method from thermal welding to mechanical forming by controlling the punch force and die geometry parameters. The clinching process uses controlled mechanical pressure to deform and interlock the edges, providing a cost-effective alternative that maintains connection integrity without requiring high-cost laser welding parameters.
2Ease of manufacture
If manual clinching is used to connect edges, then manufacturing cost is reduced, but manufacturing precision and time consumption increase
Solution Approach 1:
The patent incorporates preliminary positioning features including a positioning finger that engages with a positioning slot on the mandrel, and pre-aligned clinching tooling that automatically positions the clinching operation. This preliminary positioning ensures precise and consistent clinch locations without requiring manual measurement or adjustment, achieving both low cost and high precision.
Solution Approach 2:
The clinching tooling is designed to self-position and self-align during the forming process. The punch and die automatically locate themselves relative to the sheet metal edges through fixed geometries and guiding features, eliminating the need for operator intervention while maintaining consistent precision across all clinching operations.
3Productivity
If simultaneous clinching along the entire length is performed, then productivity is improved, but tube diameter accuracy deteriorates due to overlap inaccuracies
Solution Approach 1:
The patent applies local quality control by providing continuous support and positioning along the entire tube length during simultaneous clinching. The mandrel with its positioning features and the distributed clinching tooling ensure that each local section is accurately positioned and formed, maintaining overall tube diameter accuracy even during high-speed simultaneous operation across the entire length.
Solution Approach 2:
The mandrel serves as an intermediary element that mediates between the sheet metal blank and the clinching tooling. It provides a rigid reference surface and positioning features that ensure accurate tube diameter formation while allowing the simultaneous clinching operation to proceed at high speed without compromising precision.
4Adaptability or versatility
If rolled tube formation followed by separate connection operation is used, then process flexibility is maintained, but manufacturing time and cost increase
Solution Approach 1:
The patent merges the tube formation and edge connection operations into a single integrated process. The sheet metal blank is formed into a tube shape on the mandrel and the longitudinal edges are clinched to secure the tube in one continuous operation, eliminating the need for separate handling and transportation between operations, thereby reducing manufacturing time while maintaining flexibility.
Solution Approach 2:
The integrated system performs multiple functions simultaneously: it forms the tube shape, positions the edges, and executes the clinching operation all within one setup. This multi-functional approach maintains adaptability to different tube configurations while significantly reducing the total manufacturing time compared to sequential operations.
Data Source
AI summary
A system for automatically forming sheet metal tubes from blanks cut to size. The system having a mechanism for positioning a blank for processing. A lifting arrangement having a wrap strap and pressure pad to raise the blank to a forming station having a mandrel is positioned so that the wrap strap extends on either side of said mandrel and underneath the blank before a side wiper on each side of said mandrel forces the overlap of opposite edges of the blank along a length of the mandrel. The mandrel includes a clinching die bar along its length. A sealing mechanism with a vertically movable row of clinching prongs is lowered to attach the overlapping edges of the blank by clinching at multiple positions to form a tube around the mandrel before being removed by a gag bar and a stripper plate.