DUNKES – Experience on which
I can rely

  • Press stability
  • High availability of presses
  • Core competencies press construction
  • Reliable and robust press technology

Straightening, highly accurate and economical

Straightening workpieces of different lengths and cross-sections with press forces up to 15,000 kN.

Machining and forming processes, as well as heat treating on round, flat and profile materials can cause workpieces to warp. In order to avoid expensive post-processing, the axis variances therefore need to be compensated by straightening. These corrections are a speciality of Dunkes,  and require extensive know-how for press and control design, as well as knowledge about the characteristics of materials.

Straightening presses in C- frame design, with servo orientation-controlled ram axis and optional powered rotating and traversing drive, are available at various automation levels for press forces up to 15,000 kN.

The experience in forming and joining technology developed over a period of 45 years specifically for hydraulic presses with press press forces up to 50,000 kN specifically benefits users for straightening operations. Standard and custom machinery with straightening forces from 10 kN to 15,000 kN for workpieces up to diameters of 400 mm, in C- frame designs, either as horizontal units or in gantry designs, are available for a variety of tasks.  Motorised traversing and rotating workpiece pallets are available for large and heavy components. The press frame can also be configured as a traversing unit for workpieces with lengths in excess of 10 m. The respective press design is based on the operational requirements - manual, semi, or fully automatic, the unit volumes, the nature of the components, as well as the loading and unloading handling methods.


Control analyses a variety of control parameters

Straightening involves a blend of plastic and elastic forming processes. In both modes, the material properties can only be approximated and analysed in terms of their impact. Moreover, the rigidity of the machine as well as the straightening and forming travels impact the accuracy and the reproducibility of the straightening results. For these reasons alone, the control of the straightening press is of material significance for the quality of the results. This is why only manually operated, highly sensitive hand levers are used; electronic hand levers (joystick) are used for straightening forces in excess of 1600 kN. A combination of orientation controlled ram axes and controlled feed motions therefore provides an optimum of reproducible and position accuracy, which in turn is reflected in the straightening results with run-out tolerances of 0.03 to 0.05 mm/m

Plant to straighten profiles with horizontally arranged straightening unit, torsion straightening unit an inspection workstation.

Know-how as customer benefit

Due to its broad product line and many years of experience from well over 1000 supplied straightening plants, the Kircheim-based company enjoys an outstanding reputation in this niche segment. In addition to the mechanical engineering quality, an increasing number of customers value the benefits of controls, hydraulics and electrical systems that are customised for the respective application. The in-house (Siemens hardware-based) learning capable software gives customers individualised solutions without interface problems, which also provides them with significant time and cost advantages during service work. Especially when straightening large components, such as extruder augers, tie rods, guide columns, axes and shafts, or drilling rods in offshore applications, the available experience of the Kircheim-based straightening specialist for metrology and control technology, as well as workpiece handling, are a basic condition for economic solutions.


Concepts for future-proof solutions

By continuously updating designs, the value of which are frequently protected by registered designs, and the knowledge gained from the large number of straightening processes, allowed the creation of a database that facilitates finding a fast and economical solution for straightening tasks. In addition to proven straightening machines, plants for automatic straightening of small and miniature parts round out the product line. In addition to straightening processes for round solids and tubes, straightening of flat and profile materials has been increasingly incorporated into the performance portfolio. Since these applications not only need to correct straightness but also "torsion", we are developing machinery and plants with new concepts. Whether this involves the use of combined or separate equipment depends on the respective requirement and operational circumstances. Independent of this, the user is offered an end-to-end concept, giving him the ability to straighten components with the greatest possible ease and effectiveness, and to reintegrate these back into the production process as quickly as possible, inclusive of quality control. In-house service staff supports supplied plants worldwide. The process sequences on automatic plants can be monitored via modem interfaces, facilitating immediate analysis in case of malfunctions.