Structure and Principle: Design Logic Combining Flatness and Anti-Loosening Performance
The structural design of the flat-head vertical groove press rivet nut revolves around two core goals: "efficient assembly" and "reliable connection." Its head features a pure flat structure without taper transition, with a thickness usually controlled between 1-2mm. After installation, it can fit perfectly with the surface of the connected component, with a flatness error ≤ 0.03mm. This makes it particularly suitable for scenarios where no countersink hole is needed on the surface and only flat assembly is possible, such as sheet metal chassis enclosures and equipment panels. Compared with countersunk nuts, it eliminates the need for pre-processing conical countersink holes, reducing 1-2 manufacturing steps and improving processing efficiency by over 30%.
The vertical grooves on the cylindrical surface are its core functional design: the grooves are distributed in parallel, with a depth of 0.2-0.4mm and a spacing of 0.5-0.8mm, and their direction is consistent with the cylinder axis. This structure plays a dual role during the press-riveting process: on one hand, the vertical grooves embed into the inner wall of the mounting hole of the connected component during press-riveting, forming a "mechanical interlock" that effectively resists loosening risks in vibrating environments—in vibration tests at 10-500Hz, its loosening probability is 60% lower than that of smooth-surface press rivet nuts; on the other hand, the vertical grooves disperse the stress during press-riveting, avoiding excessive extrusion deformation of soft materials such as aluminum plates and galvanized plates. This expands the applicable range of plate thickness to 0.8-5mm, covering the assembly needs of most sheet metal parts.
From the perspective of working principle, the flat-head vertical groove press rivet nut achieves fastening through "cold press forming": no pre-tapping is required. Simply place the nut into the prefabricated hole of the connected component, and use a press riveter to apply an axial pressure of 5-15kN. This causes the knurled teeth and vertical grooves of the nut to work together, squeezing the material of the hole wall and causing plastic deformation, ultimately forming a non-detachable rigid connection with the connected component. The entire process requires no heating, additional welding, or bonding, and a single press-riveting operation takes only 3-5 seconds, making it suitable for mass production lines.
Application Fields: Multi-Scenario Adaptation from Electronics to Sheet Metal
1. Electronics and Communication Equipment: Efficient Fastening in Compact Spaces
In communication equipment such as server chassis and router enclosures, the flat-head vertical groove press rivet nut is a core component for connecting internal brackets and panels. Taking server chassis as an example, it needs to connect a 2mm-thick cold-rolled steel plate panel with a 1.5mm-thick galvanized steel bracket. Traditional screw connections require pre-tapping, which easily causes plate deformation. In contrast, the flat-head vertical groove press rivet nut can realize press-riveting through a φ4mm prefabricated hole. Its flat head fits perfectly with the panel, without occupying internal wiring space, and the vertical grooves can resist fan vibrations during server operation, ensuring long-term connection stability.
In the bottom case assembly of laptops, this nut also plays an important role. Its flat-head design prevents the bottom case from protruding (which would affect hand feel), and the press-riveting installation eliminates the need for screw holes, reducing the risk of bottom case cracking. After adopting this nut, a laptop brand increased its bottom case assembly efficiency by 40% and reduced after-sales repair rates caused by loose screws by 50%.
2. Sheet Metal and Furniture Manufacturing: Mass Assembly with Flat Surfaces
The sheet metal manufacturing industry has extremely high requirements for "flatness" and "efficiency" of fasteners, and the flat-head vertical groove press rivet nut perfectly meets these needs. In the production of sheet metal products such as file cabinets and distribution boxes, it can be used to connect cabinet doors and cabinet frames: the flat head is flush with the sheet metal surface, without affecting door opening/closing or appearance; press-riveting installation eliminates manual screw tightening, making it suitable for automated production lines. One production line can assemble over 5,000 sheet metal parts per day, far exceeding the 1,500 parts per day of traditional screw connections.
In the metal furniture field, such as the bracket connection of office desks and chairs, this nut also demonstrates advantages. For example, when connecting the aluminum alloy bracket of an office desk with a steel plate tabletop, the flat-head design prevents the bracket from protruding and scratching clothes, while the vertical grooves can resist collisions and shaking during daily use. Its load-bearing capacity can reach over 50kg, meeting the strength requirements for office furniture use.
3. Automotive and Rail Transit: Balancing Lightweight and Vibration Resistance
In the assembly of automotive body accessories, such as door interior panels and instrument panel brackets, the flat-head vertical groove press rivet nut can adapt to 1.2-2mm-thick aluminum alloy plates: the press-riveting process does not damage the plate coating, and the flat head ensures a smooth interior surface; the vertical grooves can resist bumpy vibrations during vehicle driving, preventing interior parts from loosening and generating abnormal noise. In the assembly of new energy vehicle charging pile enclosures, this nut can also achieve rust prevention through galvanization treatment, meeting the corrosion resistance requirements for outdoor use.
In the rail transit field, such as the connection of interior panels of subway cars, it is also applicable. Subway car interiors require frequent cleaning—the flat-head design has no depressions for dust accumulation, and the vertical grooves can resist high-frequency vibrations during train operation, ensuring long-term stability of the panels and complying with the high reliability standards of rail transit equipment.
Selection and Usage: Key Points for Ensuring Fastening Effect
Three parameters should be focused on during selection: head size, material, and press-riveting hole diameter. The head size should be selected based on the plate thickness—for example, plates with a thickness of 1-2mm are suitable for models with a head diameter of 6-8mm to ensure sufficient fitting area. For materials: galvanized steel (low cost, rust-proof) is suitable for ordinary scenarios; 304 stainless steel (corrosion-resistant) is used for humid environments; aluminum alloy (lightweight) is preferred for lightweight requirements. The press-riveting hole diameter must strictly match the nut specification—for example, an M3 nut is suitable for a φ3.2mm prefabricated hole. An excessively large hole diameter may lead to unstable press-riveting, while an excessively small one may damage the plate.
During installation, attention should be paid to adjusting the pressure of the press riveter: pressure should be set differently for plates of different materials—5-8kN for aluminum plates and 10-15kN for steel plates. Insufficient pressure will cause loose connections, while excessive pressure may crush the plate. Two checks are required after installation: first, head flatness—the gap measured with a feeler gauge should be ≤ 0.05mm; second, pull-out force—the pull-out force of an M4 galvanized steel nut should be ≥ 1500N to ensure it meets the required use strength.
For maintenance: avoid severe impacts on the press-riveted parts in daily use to prevent nut loosening; for outdoor scenarios, it is recommended to inspect the anti-rust coating every 1-2 years and touch up with anti-rust paint promptly if the coating is damaged; if disassembly is needed, a dedicated punch should be used to push the nut out from the back of the plate to avoid damaging the plate through violent disassembly.
With its efficient installation method, flat surface effect, and reliable anti-loosening performance, the flat-head vertical groove press rivet nut has become a practical choice in the industrial fastening field. As automated manufacturing and lightweight design become more widespread, its application scenarios will further expand, providing strong support for efficient production and product quality improvement in various industries.
