DUNKES – Experience on which
I can rely

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

Hydraulic powder press

Custom-configured hydraulic press forms disc brakes from ceramic composites 

High-performance motor vehicle in the premium segment are subject to elevated vehicle safety requirements. This is particularly true for the brake system. Specifically the disc brakes need to demonstrate specifications with respect to service life and thermal resistance that cannot be met by conventional metal disc brakes.

 

A southern German automobile manufacturer known throughout the world equips its high-performance motor vehicles with fibre-reinforced ceramic disc brakes. The company was looking for a manufacturer for the production of these components who could demonstrate the necessary press building expertise, and who could also provide this in combination with the associated process technology, therefore ensuring that the required quality standards could be manufactured with the necessary cost-efficiency.

 

Of the many submitted proposals, the overall concept provided by Dunkes met the requirements of the automobile manufacturer, and complied with the specifications identified in the specification document. The machinery builder from Kircheim/Teck was not only able to advance a compelling manufacturing concept, but  also provided its references for a host of successful projects, demonstrating its powder pressing technology expertise.

 

The centrepiece of the plant is the hydraulic four column press of type HS4-P-250 with a press force of 2500 kN. Its ram guide and servo controlled stroke motions position the ram with a reproducible accuracy of ± 0.02 mm at minimum working speed. For very time-consuming press processes, the ram can be held at the lower tolerance limit for two 2 hours with the preselected force.

Two-piece guide bushings are used on column presses, rendering the units extremely user-friendly for service purposes.

 

The tool is moved from a roller track into the press workspace with a pusher chain. This type of drive facilitates linear pulling as well as pushing, therefore providing ideal conditions for a space-saving, cost-effective tool changing solution. Retracting, hydraulically driven rollers in the interior space of the press simplify accurate positioning of the up to 1000 kg weighing tools. After the tool is positioned and secured on the press bed, safety doors close the fully enclosed press space. The ram is triggered with a two-hand control and travels into the preselected pre-pressing position selected by the operator. The vacuum collection system triggers at the same time and removes the generated smoke from the workspace. The pre-pressing operation analyses the force-distance function to identify potentially occurring volume variations of the inserted granulate, which is taken into account during the subsequent press forming cycle. This lasts approximately 2 minutes, after which the operator can open the safety doors. The ram then travels into the home position with the upper die, the pusher chain pushes the tool from the press space and onto the roller track, the ceramic disc is removed, and the tool is refilled with granulate.

 

All process or quality influencing data is programmed and optimised with the CNC control. Using the touchscreen monitor control, the functions of the respectively active  modules can be retrieved, and the current machine status displayed. Text and graphics software is available for quality assurance, which facilitate gap-free production logs in combination with the production data stored in the machine A particularly user-friendly feature is the ability to store technology and geometry data of up to 500 different tools in the hardware memory. This allows the user to conveniently identify and retrieve tools stored in a shelf, or to refer to optimised technology data associated with the tool for repeat components, therefore saving production time while maintaining consistent quality. The user is provided with additional safety margins with the programmable force- distance function with a specified envelope, whose upper and lower threshold values immediately provide visual references for irregularities in the process sequence.

 

Dunkes powder presses are supplied as column and also as frame presses for prepressing diamond powder to produce cutting inserts for pyrotechnical and ceramic products. 
Press forces range from 160 kN to 10 000 kN.

 

The extensive product line includes all automation options for automatic filling, weighing of granulate, palletising, and automatic loading and unloading. 
Every plant is adjusted to the specific needs of the customer.

Dunkes HS4-P-250 hydraulic powder press during assembly