Upper Blade

The upper blade is a critical component of a sheet metal guillotine shear, typically mounted in a fixed position on the machine's ram or beam. It functions as the primary cutting edge that descends to meet the lower blade, creating a shearing action that cleanly cuts through sheet metal materials. The blade's precise alignment and sharpness are essential for achieving accurate cuts with minimal burr formation. This component is manufactured from materials such as tool steel, high-speed steel, or carbide-tipped steel, selected for their wear resistance and toughness. Key parameters include blade length (1000–6000 mm) to match the shear bed width, blade height (60–200 mm) for rigidity and cutting capacity, and blade thickness (12–50 mm) to resist deflection. The cutting angle (1–3°) affects cutting force and burr formation, while hardness (HRC 58–62) balances wear resistance and toughness. Material grades such as Cr12MoV, H13, and 9CrSi are referenced under GB/T 1299, but selection must be based on the specific sheared material. Surface roughness (Ra 0.4–0.8 μm) improves cut quality, and flatness tolerance (±0.02 mm) ensures a uniform cutting gap. Parallelism tolerance (±0.03 mm) is critical for blade alignment. Operating temperature ranges from -20°C to 80°C to avoid thermal softening. Weight varies from 50 to 500 kg depending on dimensions and material. These values are directory reference ranges; verify model-specific specifications with the legal manufacturer or supplier before procurement.

The upper blade operates on the principle of shearing. When the guillotine shear is activated, the upper blade descends vertically toward the stationary lower blade. As the two blades meet with minimal clearance, they apply opposing forces to the sheet metal, causing plastic deformation and eventual fracture along the cutting line. The blade's angle (rake angle) helps reduce the required cutting force.