The conveyor from the casting plant is about 50 m long. At the end the ingots are automatically tilted out of the moulds. A gripping arm picks up each individual ingot and transfers it to a chain conveyor. During transport the ingots are put in rows of five (each ingot is about 10 or 11 cm in height), stacked by means of a lifting device which turns each row 90° to be cross stacked in five layers. This load weighs about 1.200 kg.
The number of straps depend on the customer’s requirements, these differ from a single strap to double cross strapping. The stack is moved into the strapping machine and remains stationary while the mobile strapper unitises the load. If cross strapping is necessary the lifting device turns the load through 90°.
Since steel strap has been replaced by polyester strap the ingots are being cast with a groove as protection for the strap, against tearing.
Lead ingots cool down fast but by the time they are to be strapped the temperature is still about 60° C – this is no problem for polyester strapping.