Office Chair Leg Construction Methods

The construction methods for office chair legs can be divided into three main types based on the material: nylon chair legs, steel chair legs, and aluminum alloy chair legs. The specific processes are as follows:

Nylon chair legs are made using the injection molding process. The core step involves heating nylon pellets to a molten state and injecting the molten material under high pressure from an injection molding machine into a pre-designed metal mold. The internal structure of the mold determines the final shape of the chair legs, including details such as the five-claw or three-claw support structure and the central connecting shaft hole. After the molten material cools and solidifies in the mold, the molded part will have residual material at the injection port, which needs to be precisely removed using fully automated cutting equipment to ensure a smooth surface. The advantage of this process is that it can form complex structures in one go, with high production efficiency, making it suitable for large-scale mass production. Some high-end products incorporate glass fiber reinforcement materials during the injection molding process to enhance the impact resistance and durability of the chair legs.

The production of steel chair legs is divided into two paths: steel tube bending and welding and steel plate stamping and welding. In the steel tube bending and welding process, steel tubes with a diameter of 25-32mm are processed into preset arcs using a CNC tube bending machine to form a five-claw support structure. The components are then connected using argon arc welding or carbon dioxide gas shielded welding, and the welding points need to be ground and polished. Steel plate stamping and welding uses 3-5mm thick steel plates, which are stamped into claw-shaped outlines using a stamping machine and then shaped into three-dimensional structures using a bending machine. Finally, the components are fixed using spot welding. To enhance strength, some designs adopt a hollow leg structure, which is formed by enclosing 1.2-1.5mm thin iron plates and changing the cross-sectional shape (such as from circular to octagonal) and adding convex reinforcing ribs to ensure load-bearing capacity while reducing weight. In terms of surface treatment, the spray-coating process can form a 0.1-0.3mm thick protective layer, which offers better corrosion resistance than electroplating, while electroplating provides a brighter metallic finish.

Aluminum alloy chair legs are made using the die-casting process. Aluminum alloy ingots such as A356 or ADC12 are heated to a molten state at 680-720°C and injected into a mold in a high-pressure die-casting machine (with a pressure typically reaching 150-200MPa), where they rapidly solidify within 0.01-0.03 seconds. This process can achieve thin-walled structures of 0.5mm and a dimensional accuracy of ±0.1mm. After molding, the chair legs undergo three surface treatments: first, mechanical polishing is used to eliminate mold marks; second, wire drawing is performed to create a matte finish; and finally, anodizing or spray-coating processes are used to form a protective film. Anodizing can generate a 5-20μm oxide film, significantly improving wear resistance; spray-coating, through electrostatic powder spraying technology, forms a 0.08-0.15mm thick coating on the surface of the chair legs, offering a wider range of color options.