Schleicher's CNC control is used in IPC systems, such as in pressing plants in the automotive industry. The calculation of CNC data and simulation of the motional sequences takes place in advance. Then, using Schleicher's NERTHUS procedure (data reduction for free-form contours), the intermediate points for the paths are reduced and an optimised NC program is generated. Through the graphic simulation of all the components involved (press, tool, workpiece and feeders), a safe press cycle is achieved using rapid and accurate motional sequences. The executable programs are passed via the network to the ProNumeric controls, which then interpolate the motional sequence. In the press cycle, the CNC control minimises the dwell time of the feeders in the press. The motions are tailored to each other, resulting in a lift time close to the machine's gross output. Schleicher's NERTHUS procedure reduces the number of intermediate points and thus NC blocks in any free-form contours under a freely-selectable contour tolerance. The motional sequence can be simulated on a standard PC. From these few NC blocks, the CNC control re-generates the free form using the Online Curve Interpolator (OCI). This achieves a continuous and smooth path with optimised axis velocity. The program links the three axes of the charging feeder, the three of the discharging feeders and the two of the loading feeder to the vertical shaft of the press. To this end, the command value encoder is read in the interpolation cycle through the CANopen fieldbus and the axes are synchronised to each other dependent on the position and velocity of the press. The five individual presses can also be grouped together as a press line. Here it is possible to couple the group in turn to a higher-level virtual master sensor in order to achieve an optimal total production velocity.
The linear axes of the feeder driven by servomotors achieve accelerations of up to 2.5 m/s², at velocities of 150 m/min
The motion of the already fast feeder is optimised through path control
The motion is controlled by an IPC-based CNC, which interpolates nine NC axes (eight servoaxes and the leading axis) for each feeder – a task for which CNC control is naturally much better suited than a PLC
The CNC runs free outside the press.
The press only has to stop in the case of particularly complicated charging procedures, if at all. The master sensor, feeder and I/O modules are networked with the control using CANopen