Davison-machinery developed a new multiple roll bonding and HF Welding Companies cutting machine (SM-450-SA series) for the production of underground ventilation pipes in heavy PVC. The machine creates pipes with variable diameter up to 3,0 m and infinite length used to transport fresh air into mountain tunnels.
The PVC jumbo rolls with weight up to 1.200 kg are unwound by 3 motorized unwinding stations with edge control (automatic correction of the roll position) and digital dancers for total fabric tension control. The unwinding stations are perfectly synchronized with the feeding speed of the fabric into the machine to guarantee a very high quality of the seams even on great lengths. Fabric that is not used is led back towards a motorized rewinding station and rewound to be reused.
Three A-fame folders pre-fold the fabric into pipe shapes.
The fabric is then led underneath a tool bridge with 3 hot air welding heads that weld the fabric into a single pipe of variable diameter. Simultaneously a double row of U-strips with eyelets are welded on top of the pipe by another 4 welding heads.
Four bridges secure easy access to all welding and cutting tools during the production cycle and allow real-time small adjustments without interrupting the production.
At the end of the cycle a last A-frame folds the pipe in two. Finally, a custom made fan-folder places the finished product in a box ready to be stocked or shipped to the customer.
The machine, with a footprint of 16 x 27 m, was designed to be operated by 2 operators and is able to manufacture up to 2.100 m of RF Welder duct pipe in a single 8 hour shift.