Leifeld PNC 350-19/2 Spinning Machine Retrofitted with Siemens SINUMERIK 840D CNC Control

CNC Design recently decided to endeavour into another technology by retrofitting a Leifeld PNC350-19/2 Spinning Machine at Murdock Metal Spinning in Melbourne, Australia. This model of Leifeld’s Spinning Machines was designed to be self programming, hence, having the ability of learning from the operator and accurately playing it back. This machine was originally built in Germany in 1985. After 20 years in operation, the machine had aged, electronic components had become unreliable and extremely expensive to replace, support had become very remote and the operator interface had been outdated.

The retrofit involved the installation of the Siemens SINUMERIK 840D CNC Control and SIMODRIVE HLA card. The hydraulic axes controlled by Moog servo valves where retained and interfaced to the CNC system. The critical teach panel controls where connected to fast analog I/O via the digital bus to ensure the system is responsive during the teaching process. A new operator panel was installed with a 10 inch colour screen and machine control panel. A dedicated operational system was integrated into the standard Sinumerik HMI Advanced software.

A unique feature of the machine is its ability of learning from the operator manually spinning the part and then generating a program. Hence, no CAD/CAM or programming skills is required. Before manual spinning, the roller is taught the working area for collision prevention with the tool and other devices. Special software was developed to ensure that the roller will maintain minimum pressure requested by the operator when teaching the tool contour. During teaching not only is the position of the X axis controlled but so is the applied pressure as this parameter is critical to the spinning process. During commissioning, together with the operator, the manual spinning was finely tuned, hence, the operator can ‘feel’ the spinning of the part.

Strong engineering at CNC Design was needed to develop the software for real time data acquisition and program generation during teaching. Customised screens where developed to save programs, change system variables and view and edit programs. After program generation, programs can be viewed graphically with the ability to navigate through passes and delete unnecessary movements, hence, optimising the cycle time.

All development and design of the system was completed offline while the machine was in production. The commissioning phase involved cabinet and machine wiring, servo valve servicing, tunning of axes, testing all software, fine tunning of machine and trials. The machine performance is now as the existing with the addition of many enhancements such as graphical representation for editing, more sophisticated data management and many other customer requests.

And a new technology was added to CNC Design’s vast know-how library!