Closed-Die System Redesigned for Precision, Automation

April 1, 2019
5,000-mt SMS eccentric forging machine will produce light-truck crankshafts for Dongfeng Forging

Forging press technologies subtly parallel broader industrial trends: demand for gears and turbines will drive demand for ring-rolling machinery, and demand for discs, hubs, or shafts will prompt demand for open-die forging. The sustained demand for automotive and commercial vehicle components over recent years has guided increased demand for new closed-die forging machinery.

Forging technology developers respond to these variations in demand with updated designs for well-established forming concepts. The current demand for closed-die forging systems has developers reemphasizing their designs’ performance in terms of precision forming, process reliability, and availability for automation.

The latest example of all this is a contract for SMS group to design and build a 5,000-metric ton closed-die machine for Dongfeng Forging Co. Ltd., a subsidiary of commercial-vehicle manufacturer Dongfeng Motor Group, operating at Shiyan, Hubei Province, China. That plant already has a total of 26 forging lines in operation, including a 12,000-mt wedge press supplied by SMS.

The new MP 5000 eccentric forging press will be designed to deliver a forging force of 5,000 metric tons (50 MN), for manufacturing light-truck crankshafts with a maximum finished weight of 21.5 kg.

Eccentric forging presses deliver force that is derived from a circular motor device, with a mechanism that converts the motor’s circular motion into a linear stroke. Some of the advantages of the process are longitudinal rigidity and minimal ram tilting, contributing to high forging precision, and fast stroke rates that correlate to high productivity.

SMS designs eccentric presses for 6.3 to 160 MN of press force, offering “the rigidity in both longitudinal and transverse directions ideal for producing precision forgings.” The presses are designed with integral automation and rapid-die-change functions, capable for hot or warm forging, as well as flash-free forging.

The FEM-optimized design of the MP 5000 includes very large housing “windows,” which improves the availability or press automation and simplifies die and die-holder changes.

According to SMS, the MP series has been extensively redesigned to reduce the labor and costs involved in press maintenance and inspection. This includes "an almost maintenance-free, low-noise electrohydraulic coupling and brake. The hydraulic single ejectors in the table and ram can be individually operated for each forming station. In addition, the ram adjustment device that, in automatic mode, enables a ram adjustment of 0.1 millimeters between two strokes was improved on the drive side."

For the Dongfeng Forging project SMS also is supplying process development services; sequence-controlled loading and unloading belt conveyors; an electrically operated, automatic walking-beam table for part handling; and an integrated die-spraying system. It’s also supplying a line control system to connect other equipment, such as the heating system.

Dongfeng Forging chose the eccentric press design to forge parts with precision and efficiency — and fully automatically. In addition to the press, the scope of supply includes process development services.

Commissioning for the new machine is scheduled for Q2 2020, according to the developer.