Crownless servo presses do more with less, reducing deflection by 30 percent
Above: Twin Servo Technology favorably leverages force flow
July, 2023- Guest Editorial: Crownless servo presses do more with less, reducing deflection by 30 percent
For over a decade, presses with Schuler’s TwinServo technology (TST) have been steadily increasing in market share in the production of B-pillars and other high-demand automotive parts, such as ones formed from advanced high-strength steel. Although this trend is more apparent in Europe, experts predict it will follow a similar trajectory in North America as more customers recognize the advantages of servo bottom-driven presses.
There tends to be more of a purchasing focus on press tonnage when considering third-generation steel requirements, but greater eccentric load capacities of a press system are just as, if not more, important. TST can achieve more with less—less de flection, less footprint and less energy consumption.
LEVERAGING FORCE
Schuler created TST to favorably leverage force flow for manufacturers of parts and components. The slide of a traditional press is pushed downward—resulting in a reaction force that has to be absorbed by the press frame and pretensioned tie rods. The TST slide, in comparison, is pulled downward—resulting in a much more direct force flow that reduces de ection by 30 percent.
The force application toward the outer edges enables geometrically enhanced conditions and off-center loads that improves tilting resistance by up to 400 percent in comparison to conventional press systems. Another benefit of force application toward the outer edges of the slide includes using the entire clamping service, making larger eccentric loads with the same press force possible. This benefit is particularly important for metalformers using multi-station presses. Maximum force is achieved in the center, as with traditional presses. The difference is in the form of additional permissible eccentric forces, and this indicates the unprecedented flexibility made possible with TST technology.
SPOT ON
Another key difference between traditional press systems and Schuler’s TST involves the positioning of the slide. The gradual forming of parts typically results in the tilting of the slide for transfer presses. There is an active parallel positioning of the TST slide and widely spaced pressure points that are ideal for off-center loads. The under floor drives are not mechanically coupled, so an asymmetrical control can be used to actively counteract any tilting of the slide.
The neutralization of possible skewing increases the precision of formed parts and extends the life span of dies. Dies that normally run on other equipment can also be used quickly and easily on the TST press system.
Eliminating the crown of a press provides metalformers with a much smaller footprint. Facilities with lower ceilings would be a suitable fit for TST presses. The foundation dimensions and underfloor space requirements have not increased, despite the drive being integrated into the press bed, and there is still great accessibility for service and maintenance.
TST enhances the flexibility and possibilities already offered by modern servo drive technology, and significant output gains are a direct result, including higher part quality, shorter tryout times, less die wear, and greater availability and process reliability. Additional benefits specific to the TST’s bottom-driven mechanics include noise emissions reduced by 6 decibels and a largely oil-free work environment. -FFJ
