Line III consit of a feeding metal frame, leveler grooving roller, hydraulic notch and punch saquare machine, hydraulic shearer and fodler. The electrical control system uses a computer with closed-loop servo-system to increase the precision and realiability of the line.

The maximum working speed is 10m/min. The length Tolerance us +0.5mm. The diagonal line tolereance is +0.8mm .

The capacity if the manufacturing process will produce 1000m² of square duct.