When selecting a machine, the most critical factor is the processing capacity (gauge thickness). Ensure the machine can handle the specific range of galvanized sheet metal you use, typically ranging from 0.5mm to 1.2mm (26 to 18 gauge). Additionally, verify the forming speed, which usually averages 6-9 meters per minute, and the motor power (typically 1.5kW to 3kW) to ensure it meets your production volume requirements. High-quality machines should feature rollers made of GCr15 bearing steel, vacuum quenched to a hardness of HRC58-62 for maximum wear resistance.