Pioneering a completely new machine conceptTo stay competitive, electrical engineering and automotive manufacturers need highly productive stamping and bending machines. Their equipment must not only produce a wide range of parts quickly and precisely, but also allow easy retooling for various batch sizes.
The French company Pressmac had already developed a completely new slide machine concept in 2000 that replaced mechanical cams with numerically controlled axes. This allowed strip material to be processed while applying tremendous bending force and helped Pressmac break into the electrical engineering and later the automotive sector.
Marcel Becker, managing director of Pressmac, confirms: “We have been supplying the electrical engineering market for some time now, including companies that make circuit breakers. Our machines can stamp many different types of metal – copper, brass, steel and so on. Fifteen years ago, we tapped into the automotive sector, where our machines are deployed for the production of electric motors.”
Compared to the mechanical cam, one advantage of the NC slide machine technology concept is its higher rate of 150 to 180 cycles per minute – an improvement of up to 50%. Pressmac developed its own program for improving cycle times: The Optimization Cam Program (OCP) automatically allocates cam profiles using a reference point to optimize machine operation. Another benefit is the flexibility: “Every slide follows the cam we have programmed,” explains Becker. “The motions can be executed in series with the feed moving forward and backward. This gives the user tremendous flexibility during processing.”
Since the early years, Pressmac has continuously developed the NC slide technology. The new CMP 400 model is another big step forward.
With the SIMOTION motion controller, manufacturers can retool in an hour or less. Before, it took almost four times as long.Marcel Becker, Managing Director at Pressmac
For the CMP 400, Pressmac chose a complete Siemens solution. As many as 16 axes have to be controlled – this is carried out by the SIMOTION D455-2 motion controller. Operation of the slide machine follows a 360° cycle until parts are finished, meaning all actuators are calculated in relation to this cycle. For the individual axes, SIMOTION specifies electronic cam disks to synchronize all process steps – for a highly precise production. Marcel Becker emphasizes another advantage: “Today, manufacturers have to retool quickly because their order book includes small, medium and large batches. This can now be done in an hour or less, whereas before it took almost four times as long.”
The motor system, however, turns the linear slide machine into a true “tiger.” The machine includes a mobile double-grip infeed guide, mobile eccentric press for radial and linear operation as well as CLxxx linear slides with planetary roller screws. Pressmac required a water-cooled motor for each of these linear axes. Siemens was able to supply a high-torque solution with the SIMOTICS S-1FT7. “For the linear slides, we have a setting range of 120 mm – before, it was 60 mm,” says Marcel Becker. “That gives us more options during processing. We also reach a high speed of 300 stroke per minute when feeding in strip material, and tremendous forces of 40 tons on the press module.”
Safety is also taken into account in the sensitive press area and its rapid machine motions: The fail-safe SIMATIC S7-1512F reliably controls the entire unit and, thanks to the LDrvSafe library, facilitates implementation of many safety-related applications such as emergency stops, protective enclosures and much more.
Marcel Becker praises the support from Siemens: “Switching to a completely different system was not easy, especially in the narrow timeframe for implementation. It was important to us to launch not only a unique machine but a machine using standard elements without any “teething problems.” The Siemens teams provided us with excellent support to help us achieve our goal.”
Pressmac appreciates having a solution from one source, as all components work smoothly together. This means the company can offer higher manufacturing speeds, faster product changeover and greater design flexibility. But choosing Siemens was the right thing to do not only from a technical standpoint: The NC slide machine specialist can now also offer its customers in Germany controls they are familiar with.
And the company also has plans for the future: Over the next two years Pressmac wants to work with Siemens on phasing out the flywheel from its mechanical presses and integrating the servo drive directly within the press.