Self-Clinching Rivet Extrusion Forming for Waste-Free Strength
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Solution Overview
Problem
Conventional machining processes for manufacturing self-clinching I-rivets are inefficient, result in material waste, and can damage the fibers, leading to reduced strength and inconsistent dimensions.
Innovation Solution
An extrusion forming method and apparatus that upset-extrudes a wire blank to form a self-clinching rivet with a material pushing portion, shank portion, and slot shaft portion, using multiple extrusion mechanisms to create a complete and continuous metal streamline without waste, ensuring consistent dimensions and improved strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If machining process is used to manufacture self-clinching rivets, then complex shapes with recessed grooves and slots can be achieved, but material waste increases and processing efficiency decreases
Solution Approach 1:
The patent changes the manufacturing process parameter from machining (subtractive) to extrusion forming (additive/formative). The wire blank is extruded directly into the final rivet shape with grooves and slots formed during the forming process, eliminating material removal and achieving near 100% material utilization while maintaining dimensional precision through controlled extrusion parameters
Solution Approach 2:
The patent applies local quality by creating specific geometric features (grooves, slots, tapered portions) only where needed in the rivet structure during the extrusion process. The wire blank is selectively deformed in specific regions to form the material pushing portion, shank portion with groove, and slot portion, achieving complex local geometries without global material removal
2Manufacturing precision
If machining process is used to manufacture self-clinching rivets, then complex shapes with recessed structures can be achieved, but processing time increases and efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-forming the wire blank into a head billet with predetermined dimensions before the final extrusion process. This preliminary shaping prepares the material in advance, allowing the subsequent extrusion to quickly form the final complex geometry without requiring multiple machining operations, thereby significantly reducing total processing time while maintaining geometric accuracy
Solution Approach 2:
The patent merges multiple manufacturing operations into a single extrusion forming process. The formation of the head billet, material pushing portion, shank portion with groove, and slot portion is achieved through integrated extrusion steps rather than separate machining operations, consolidating multiple process stages into one efficient workflow that improves productivity while maintaining precision
3Manufacturing precision
If machining process is used to manufacture self-clinching rivets, then material can be removed to form shapes, but fiber continuity is disrupted and strength decreases
Solution Approach 1:
The patent changes the material processing parameter from cutting/removal to plastic deformation through extrusion. The wire blank is plastically deformed under controlled pressure and temperature to form the complex rivet geometry, which preserves the continuous metal fiber structure and maintains material strength, unlike machining that severs fibers and creates weak points
Solution Approach 2:
The patent applies local quality by selectively deforming specific regions of the wire blank during extrusion to create the grooves and slots. The material flows locally into the die cavity spaces to form these features while the rest of the material maintains its continuous fiber structure, ensuring strength is preserved in critical load-bearing areas while achieving the required geometric complexity
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 extrusion forming method significantly reduces material waste and energy consumption, ensures consistent dimensions, and enhances the strength of self-clinching rivets by forming a complete metal streamline, while avoiding hydrogen embrittlement risks in surface treatments.
Implementation Method 1
upset-extruding a first end of a wire blank to shape the first end into a material pushing portion and an annular shank portion billet
Implementation Method 2
upset-extruding the shank portion billet, such that the tapered portion flows in a direction away from the wire blank
Data Source
AI summary
The present invention discloses a extrusion forming method and a forming apparatus for manufacturing a self-clinching rivet, wherein the forming method comprises: upset-extruding a first end of a wire blank to shape it into a material pushing portion and a shank portion billet, upset-extruding the shank portion billet to shape it into a shank portion and a groove portion, and upset-extruding a second end of the wire blank to create a slot portion and a slot shaft portion. The invention for manufacturing the self-clinching rivet by one-time extrusion forming does not generate waste during processing, which greatly improves a utilization rate of raw materials compared with the traditional machining method. Meanwhile, a formed piece manufactured by the present invention has complete metal streamlines, which can greatly improve its strength compared with the one manufactured by machining and avoid a risk of hydrogen embrittlement in a subsequent surface treatment.