CNC Design recently added another technology to their vast knowledge base by retrofitting a Leifeld PNC350-19/2 spinning machine at Murdock Metal Spinning in Melbourne.
This particular Leifeld spinning machine model was designed to be self programming in that it had the ability to learn from the operator and accurately play it back. Originally built in Germany in 1985 and with over two decades of operation under its belt, the spinning machine had aged, it's electronic components had become unreliable and were expensive to replace, the operator interface had been outdated, and service support had become very remote.
The retrofit of this Leifeld spinning machine involved the installation of the Siemens Sinumerik 840D CNC Controller and Simodrive HLA card. The hydraulic axes, controlled by Moog servo valves, were retained and interfaced to the new CNC system.
The critical teach panel controls where connected to fast analog I/O via the digital bus to ensure the system was responsive during the teaching process, and a new operator panel was installed with a 10" colour screen and machine control panel. A dedicated operational system was also integrated into the standard Sinumerik HMI Advanced software.
A unique feature of this spinning machine is its ability of learning from the operator manually spinning the part and then generating a program. This mean that no CAD/CAM or programming skills are required. Before manual spinning, the roller is taught the working area for collision prevention with the tool and other devices. For the retrofit, special software was developed to ensure that the roller would maintain the 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; a parameter critical to the spinning process. During commissioning, together with the operator, the manual spinning was finely tuned allowing the operator to ‘feel’ the spinning of the part. Strong engineering at CNC Design was required to develop the software for real time data acquisition and program generation during teaching.
The Leifeld spinning machine retrofit project also included the development of customised screens 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, which optimises the cycle time.
All development and design of the new spinning machine 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 Leifeld spinning machine's performance is now enhanced with features such as graphical representation for editing, more sophisticated data management and many other customer requests.