Polished Office Chair

The polishing of office chair legs requires adherence to standardized procedures to ensure precise grinding and surface quality. Polishing is a crucial process for enhancing the appearance and durability of office chair legs, with its core being the removal of surface imperfections and the formation of a smooth coating through mechanical friction. The specific process can be divided into the following steps:

1. Workpiece Positioning and Alignment
Before polishing, the office chair legs should be disassembled from the assembly or fixed individually to ensure they are in a horizontal and stable state. Use specialized fixtures or positioning devices to secure the workpiece, preventing surface scratches or sanding belt misalignment due to vibration during the polishing process. During alignment, check the alignment of the workpiece axis with the polishing equipment axis, such as confirming that the center of the chair leg aligns with the rotation axis of the sanding belt using a laser positioning device or mechanical scale, with an error tolerance of ±0.1mm to ensure uniform subsequent grinding.

2. Moving to the Polishing Work Area
Transport the positioned chair legs to the polishing machine workbench using a robotic arm or manually, taking care to avoid collisions between the workpiece and equipment edges. The work area should be kept clean, free of metal debris or oil stains, to prevent impurities from embedding in the sanding belt or scratching the surface of the chair legs. If an automated polishing line is used, transfer the workpiece via a conveyor belt or robot and trigger safety light curtains to ensure operator isolation from the equipment.

3. Initial Outer Surface Grinding
After starting the polishing machine, prioritize treating the outer curved surface of the chair legs. Select an aluminum oxide sanding belt with a grit size of 120-180 mesh, applying moderate pressure (approximately 0.5-1 MPa) to the workpiece surface, with the sanding belt linear speed controlled at 15-20 m/s. During grinding, maintain dynamic contact between the sanding belt and the curved surface of the chair legs, such as using an elastic floating device to automatically adjust the pressure of the sanding belt with the surface undulations, avoiding local over-grinding or under-grinding. For curved transition areas, reduce the feed speed (approximately 50-100 mm/s) and increase the number of grinding passes (3-5 times) to eliminate seams.

4. Rotating the Workpiece and Precise Contact
After completing the outer surface grinding, adjust the angle of the chair legs using a rotating workbench or robotic arm to expose the inner curved surface or edges to the polishing area. During rotation, maintain parallelism between the workpiece axis and the sanding belt rotation axis, with an error tolerance of ≤0.5°. For complex structures (such as chair legs with reinforcing ribs), use a multi-axis联动 (simultaneous) polishing machine to control the sanding belt trajectory through programming, ensuring that the sanding belt always maintains normal contact with the machined surface, such as using a small-radius sanding belt (diameter ≤50 mm) for local polishing at the root of the ribs.

5. Surface Quality Inspection
After polishing, conduct surface roughness testing using a stylus-type roughness meter to measure the Ra value, with a standard requirement typically of Ra ≤ 0.8 μm. For high-gloss finish requirements, further manual treatment with polishing paste is necessary, selecting a silicon dioxide polishing paste with a grit size of ≤3 μm and using a low-speed (500-1000 rpm) wool wheel for fine polishing, with the final surface glossiness needing to reach 60-90 GU (measured at a 60° angle).