Pressure riveting (press riveting) is a cold-forming bonding technique that uses external pressure to plastically deform riveting parts (such as compression nuts, nuts, screws, etc.) and base materials (such as sheet metal) to create permanent mechanical interlocks. Its core principles, process characteristics and application scenarios are as follows:
I. Process Principle: Plastic Deformation and Mechanical Interlocking. A pressurised component (such as a nut with embossed teeth) is pressed into a pressurised hole slightly smaller in diameter than its embossed teeth. Pressure forces the embossed teeth into the metal plate, causing the material to plastic deformation around the hole and then press into the guide groove, creating a mechanical locking effect. For example, after the compaction teeth of the compaction nut are embedded in sheet metal, the deformation material is pressed into the guide groove to prevent the nut from loosening or falling off.
Cold Forming Characteristics: Pressure riveting is a heat-free deformation process. It directly changes the shape of the material through pressure, avoids the heat impact zone problem caused by welding, and reduces the heat induced material properties change (e.g., decreased hardness, increased brittleness). ii. Process Characteristic
One-sided operation, high efficiency: pressure riveting allows connection from one side only, not from the back of sheet metal. This makes it suitable for enclosed structures or spatially restricted environments (such as squares). Compared with rotary riveting or welding, its installation cycle is short, greatly improves efficiency and is especially suitable for mass production.
High strength and reliability: Compression riveting has strong tensile, shearing and torque resistance compared to traditional threaded connections connections, which are more uniform. Stamping rivet nuts, for example, have a tensile strength of 330-480 N/mm2 and meet the high intensity requirements of aerospace, automotive and other industries.
Material Compatibility and Surface Preservation: Applicable for common low carbon steel, aluminum alloys, copper plates, even high carbon steel and stainless steel (special rivet nuts required). New techniques such as non-marking press riveting use servo motors to control pressure and avoid the "hard impact" damage caused by traditional riveting on the surface coating of workpiece.
Automation and intelligent potential: combined with pressure displacement monitoring systems, end-to-end quality traceability can be achieved, increasing productivity and reducing costs. For example, low-damage servo press riveting technology has been applied in aerospace to meet the needs of composite bonding.
III. Typical Application Scenarios
Aerospace: lightweight structural connection for aircraft skins, launch vehicle sections, etc., to replace welding, avoid thermal deformation, and meet requirements of fatigue resistance, vibration resistance and easy maintenance.
Automotive industry: Installation of nuts or bolts in body panels, interiors, instrument panel brackets, etc., to solve the problem of thin plate (0.5mm-6mm) connection and improve assembly efficiency.
Electronics and communication: provides high precision threaded connectors for server racks, audio equipment panels, etc., to ensure equipment stability.
Home Appliances and Building Decoration: Enables rapid and reliable connection of sheet metal to the housing of home appliances such as refrigerators and washing machines, as well as the installation of metal partitions and signage.
IV. INTRODUCTION Advantages and limitations of the process
Strengths: Simple installation, no pre-tapping or welding required, reducing the number of parts and processes.
The connection strength is high, the thread distribution is even, the anti-loosening performance is good.
Minimize personnel and equipment to meet production safety requirements.
Limitations: There are strict requirements for malleability of materials; hard materials,such as high-carbon steel, require special treatment.
Traditional processes can lead to scratches, indentations or paint chippings the workpiece surface, so improvements need to be made through techniques such as seamless riveting.
Due to physical size limitations, riveters are only suitable for open side structures.