Comprehensive Analysis Of Working Principle Of Press Rivet Nuts: From Structure To Installation Process

Stamping rivet nuts have become indispensable fasteners in industry because of their high efficiency and reliability. This paper will analyze the technical core of compacted rivet nut from four aspects: structural characteristics, working principle, installation process and industry application.
I. Structural Characteristics: Mechanical Aesthetics of Precision Design
The typical structure of a compactedbolt nut consists of three parts:
Circle size: As the basic frame, its diameter ranges from M2 to M12 and is suitable for plate requirements of different thickness. For example, the S-Series compacted rivet nuts have an external diameter of between 6.3mm and 17.35mm and can meet connection requirements for plates above 0.8mm.
Pressing tooth array: one end of the nut is designed to be a circular arrangement of pressing teeth. Accurate calculation of tooth angle and pitch to ensure that the plate surface is evenly cut during stamping. As an example, CLS series stainless steel piezoplatinum nut was used for laser cutting, and the height of the piezoplatinum was precisely controlled within ±0.05 mmWave.
Guide groove system: The inside of the pressing tooth is surrounded by multiple guide grooves, the depth and width of which are dynamically matched with the plastic deformation of the plate. When the nut is pressed in, the plate metal will fill the guide grooves accurately, forming a mechanical interlock structure.
ii. How it works: plastic deformation synergizes with mechanical interlocking
The stamping riveting process follows the following mechanical principles:
Pre-set hole match: Before installation, a circular hole with a diameter slightly lower than the outer diameter of the nut embossed tooth should be drilled into the plate (diameter deviation usually controlled within -0.075mm). For example, when installing an M4-sized nut, the preset hole diameter should be designed to be 3.925mm.
Pressure application: Perpendicular pressure is applied to nuts through hydraulic presses or pneumatic riveting equipment (typical pressure range 5-20kN). At this time, the embossed teeth cut into the surface of the plate, producing a concentration of local stress.
deformation process: When the pressure reaches the yield strength the plate, the plastic flow of the material around the hole begins. For example, the its elongation rate of low carbon steel plate (hardness ≤ 70HRB) can be more than 25%, which meets the deformation requirements.
Interlock structure formation: Extrusion of the deformed material into a guide groove to form a three-dimensional mechanical interlock. Experimental data show that the structure has an torque resistance of up to 15 Nm, far higher than the 3-5 Nm of ordinary nuts.
III. Installation process: Precise control standardized operations.
Professional installation should follow the following steps:
Plate pretreatment:
Clean paper surfaces to remove oil stains and oxide layer
Confirmation of plate hardness (carbon steel ≤ 70HRB, stainless steel ≤ 80HRB)
Check the edges of the preset holes for burrs (beveling treatment at C0.2 is recommended)
Equipment calibration:
Select a special pressure riveter the PEM series) and adjust pressure parameters (e.g. M5 nuts, recommended pressure is 12kN)
Install the lower die of the appropriate specification (e.g. D10.5mm a D10.5mm lower die for the S-M5-2)
Validation the coaxiality of upper and lower die (error ≤ 0.05mm)
Dynamic crush riveting:
Place the nuts in a lower die and make sure the embossed teeth face the plate
Start the equipment and complete installation at a pressure rate of 0.5-2mm/s.
Monitor the pressure-displacement curve in real time to ensure that the deformation range is within 1.2-1.5mm.
Quality inspection:
Appearance inspection: Nuts level with sheet surface (deviation ≤ 0.1mm)
Torque test: Validate torque the torsional performance with a torque wrench (e.g. M6 nuts need to be up to 8Nm)
Salt spray test: Plates must pass a 72-hour neutral salt spray test
Four. Industrial applications: from precision electronics to heavy equipment
The unique advantages of stamping rivet nuts make them widely used in multiple fields:
Electronic equipment manufacturing: Lightweight and conductive balance is achieved with the CLA series copper aluminum rivet nuts on 5G base station heat dissipation plates (thickness 1.2mm).
Automotive industry: New Energy Motor battery tray (3mm thickness) with SP series stainless steel nuts, IP67-level waterproof seal under pressure of 10kN.
Aerospace: The luggage rack of the C919 passenger aircraft (2.5mm thick), using the CLS-M6 stainless steel nuts, is stabilized at 20g vibration acceleration, as verified by vibration tests.
Rail: High-speed rail seat installation plate (4mm thick) with S-M8 carbon steel nuts meets 10-year fatigue life requirement at a 20kN pressure.
Technological developments and future trends
Current research and development priorities are:
Material Innovation: titanium alloy compaction nut developed with 40% weight loss and unchanged strength
Intelligent Installation: Integrated pressure sensors and Internet of Things technology to achieve real-time monitoring of the installation process.
Eco-friendly process: Promotion of chrome-free Dacromet coating to comply with RoHS 2.0 environmental standards
The technological development of pressurized nuts is a typical example of the ``big impact of small parts' 'in the field of mechanical connectivity. Through precise structural design, strict mechanical principle and standard installation flow, an indispensable connection solution in modern industry is established.