Design of Automatic Seaming Machine for Fire Air Ducts with 3D Model and Its Experiment

The fire air duct is one of the important components of the ventilation system in large buildings, which is is a unit system for ventilation and smoke exhaust. The ventilation system is a customized system with a wide range of applications and a high demand, resulting in the use of multiple sizes and specifications of fire air ducts. At the same time, fire air ducts are generally made of thin galvanized iron sheets, which have poor rigidity and are prone to deformation. For the two above-mentioned reasons, the seaming process of the fire air duct is currently mainly completed by manual tapping, resulting in low processing efficiency, high labor intensity, and high cost. Therefore, it is necessary to design an automated equipment that can complete the fire air duct seaming process. Firstly, a 3D model for automatic seaming machine for fire air ducts to demonstrate the working principle and a double head positioning and clamping mechanism is proposed to improve the pipe rigidity; Secondly, to adapt to most specifications for rectangular fire air ducts, a system was designed that utilizes the two right angle ends of the stitching edge for positioning and clamping without many special toolings. Thirdly, a set of automatic seaming prototype has been manufactured based on the above design ideas. The experimental results on the prototype show that the fire air duct automatic stitching machine can seam a fire air duct within 1 minute. Compared with manual processing, the processing efficiency is improved by more than 80%.