PTG Heavy Industries has designed and manufactured two Binns and Berry lathes for producing the critical components for the world's largest mining shovels, each capable of loading a 500-ton dump truck in just three minutes. The order was secured against stiff competition from German and Italian manufacturers and the machines have now been installed in the United States and China.
The challenges presented to PTG were many and complex, involving multi-axes, heavy duty milling and drilling, a massive thread and $50,000 forging. Total precision and a high quality surface finish were also very high on the customer's agenda. The machines in question, two special Binns and Berry VT7 twin saddle lathes, will be used to manufacture major components such as the main shipper shaft, centre gudgeon and crawler drive shafts, the machines' unique specification having been developed by PTG in close collaboration with the customer.
The key benefit that the machines will give the customer is that of being able to manufacture the components on a single machine where previously no less than three different machines, a lathe, horizontal boring machine and a milling machine, needed to be deployed for the manufacturing of the shafts, the largest of which weighs in at 11 tons.
The unique specification means that the machines can execute the turning, keyway milling, threading, drilling, tapping and thread milling of one and a half UNC holes x 5.5 inches deep in single set ups, allowing the component to be machined complete on just one machine, eliminating multiple handling operations and so significantly reducing manufacturing time. In fact, with the elimination of multiple handling and the necessity of transport to a second location, cycle time was more than halved from 65 to 32 hours. The specification of the new machines also enabled inspection online, eliminating the need for a separate validation process. While intelligent motor and drive power utilization were incorporated along with tool monitoring.