Forgingmagazine 407 Meeting0100png00000046769 2

Meeting Market Demands for Forging Equipment

Dec. 17, 2004
Demand for flexible forging units has increased, and SMS Eumuco's various developments have been applied to new installations, overhauls, and modernizations.

Eccentric Forging Press MP 1600 for manufacturing special steel fittings.

Wedge Press KSP 12000 for manufacturing crankshafts.

Presses built in the mono block design, with a large pitman and cast-steel ram, continue to be the solid basis for precision forging. Today, however, these presses are equipped with motor-driven ram adjustment capable of increments of 0.1 mm (0.004 in.) between press strokes (without interrupting the cycle), and with adjustable guides and a clutch/brake systems that operate virtually wear-free and significantly quieter than older systems — even when operating at a clutch/brake engagement cycle rate of 30 strokes per minute.

Examples of technical innovations introduced by SMS Eumoco include the automatic walking-beam transfer systems, controlled single ejectors, and automatic die-spraying devices with programmable spraying intervals and spraying agent volumes.

The job at the press is simplified by quickchange devices for dies and bolsters; cycles can be optimized and the cost for manufacturing forgings can be reduced.

Also important are developments in electric control systems, with a multitude of possibilities in the field of press and line control.

New forging lines
Since 1995, SMS Eumuco has received orders for 52 machines of various types and sizes from our product range of forging rolls, crank presses, friction and clutch-type screw presses, twisters, billet shears, horizontal forging machines, eccentric forging presses, and wedge presses.

New installations were made in the U.S., Canada, Brazil, China, England, France, India, Japan, Austria, and Germany. These installations involve hot and warm forming of various forgings produced from steel and various aluminum alloys.

For forging turbine disks made of titanium and heat-resistant nickel-based alloys, a clutch-type screw press with a maximum force of 140 MN was supplied to an American customer. The press is equipped with an electrically heated bolster and a quick-die-change system. The work pieces are processed by robots.

Using an electrically heated bolster system, die surface temperatures of up to 400°C assist with the forming of aluminum alloys and titanium.

In the past, turbine disks, depending on their size, have been forged on a hammer in 20 to 25 blows requiring several heats over several days of production. Using today's clutch-type screw press, forming is achieved in one heat and just two press strokes. Even at slower forming speeds the press has sufficient force and energy to fill the forgings. A specially developed management system makes it possible to record and trace the process for each forging back to the starting material.

Heating temperature, forming force, forming speed, and the number of forming stages are recorded for each part produced and the records can be retrieved from memory at any time in the future. In the aircraft industry today, this capability is imperative.

Included in those 52 machines delivered to customers are 13 dieforging presses with automated walkingbeam transfer systems. Among these automatic die forging lines, eight orders are from Germany, four are from North America, and one is from Japan. If automatic forging lines that use robots for their automation are included, then there are even more installations delivered to American and German customers.

Together with an order recently received from Japan for a fully automatic AKP 2500 line, SMS Eumuco will have supplied 33 lines dedicated to the manufacture of connecting rods.

Modernizing existing equipment
During the past two years there has been growing interest in overhauling and modernizing equipment built as long as 30 years ago.

The overhauled and modernized installations — a total of five — are operating now in China, Mexico, the U.S., and Germany. The press sizes are in the range of 16 MN to 120 MN. The scope of modernization varies widely and consists of adding such equipment as electro-hydraulic clutch/brake systems, servo-electric automatic walking-beam transfer systems, and complete modern control and visualization systems.

The decision to purchase a new electro-hydraulic clutch/brake system is made and justified, for example, because operating costs are reduced as a result of:

  • Eliminating the requirement for adjustment; varying clutch temperatures often result in standstill positions. However, this situation does not exist with the new system;
  • There is no requirement to adjust the clutch and brake due to worn friction blocks, and neither is there a requirement to replace the linings or blocks once this system is installed;
  • There is no air consumption for clutch and brake engagement. This can amount to a 40% reduction of the press air consumption.

The clutch is hydraulically engaged via an annular piston and disengaged by means of spring pressure. The brake is engaged by spring pressure and for safety reasons, hydraulically disengaged.

The special features and possibilities of the servo-electric automatic walking-beam transfer type EHA make installation onto an existing press particularly attractive.

Individual housings and drives can be adapted to suit each press size. The axes (step, stroke, opening) can be changed independently of each other. The master/slave function can be divided, and thus it is possible to move the individual axes. Any center position desired can be pre-selected and set. In addition to that, different opening strokes and a different displacement in height of each of the walking beams can be set and achieved. The system can also be designed as a one-side only walking beam with grippers.

The front walking-beam has an additional vertical stroke of up to 300 mm to accomplish die changing without the need to remove the beam.

Operation and programming of the EHA, as well as displaying the actual values achieved (e.g. paths, times, situation of all starting positions, etc.) is executed — and displayed — via the control panel.

Another development makes it possible to replace the hydraulic linear amplifier axes of a servo-hydraulically controlled walkingbeamtransfer Model GHA installed on an older existing SMS Eumuco press with servo-electric motors.

Using a conversion kit (a gear unit and servo-electric drive) and modifying the electric control, an existing type GHA transfer can be converted into a servo-electrically controlled walking-beam transfer type GEA.

Electric control
New possibilities in electronics and electric controls (see sidebar) mean it's possible to rejuvenate a forging unit. Modern machine controls and evaluation systems are successfully applied for handling complex processes.

For forging units more than 10 years old, two sorts of problems may lead to a requirement to upgrade the electrics/electronics:

  • Suppliers of electric and electronic components discontinue components and equipment. It becomes more and more difficult to procure spare parts,
  • Tougher standards for safe and reliable controls are required.

Lorenz Wenzel is general manager, SMS Eumuco GmbH, Eumuco Hasenclever Die Forging Division, Leverkusen, Germany.

A Standard Control Process

To maintain the operability and safety of the die forging press, SMS Eumuco developed a standard control concept that has been installed on forging rolls, wedge presses, and eccentric forging presses. The standard control concept comprises:

Press safety control EPSS—The press control was developed in cooperation with the German Technical Supervisory Council and the BG-Institute for Occupational Safety and Health, and is based on safety hardware in conjunction with a PLC control. It provides:

  • Stroke release via a two-hand-key, pedal switch, or in the case of an automatic press, a superset automatic system.
  • Supervision of essential safety functions, such as press safety valve, motional supervision, key supervision, protective grid, cam gear.
  • Supervision of selector switches for the various operating modes.
  • Connection to a general control via simple hardware coupling.

General control—Systems in operation confirm the following functions are fulfilled:

  • Administration of drive control, temperature detection, and electronic cam gear for precise press switch-off;
  • Data processing for visualization;
  • Interface between peripheral equipment, such as heater, spraying and transfer units,
  • Optional supervision of lubrication;
  • Optional adjustment (via the control system) of ejectors, ram, and rolling gap.

Visualization—By providing an operator terminal with the following functions:

  • Processing actual value;
  • Processing set value;
  • Fault message indication;
  • Indication of switch-on conditions
  • Recipes/menus - part parameters.

Hardware concept—

  • Switchboard equipment in Rittal enclosures;
  • Switch panel with variable control elements and display;
  • Main drive as slip-ring rotor or squirrel cage motor (optional) for converter drive with frequency converter and cooling zone;
  • Main drive with temperature monitor;
  • Main switch as power switch;
  • Monitoring and supervision of wire breakage for safety-relevant functions.