EXHIBITION PREVIEW

EXHIBITS AND INNOVATIONS:

OTTO JUNKER and its subsidiary, INDUGA, will be showcasing the following key exhibits and innovations from their extensive range of application-oriented induction melting and pouring furnaces:


HIGH-POWER MEDIUM-FREQUENCY CORELESS INDUCTION FURNACE WITH A CAPACITY OF 10 TONNES AND A POWER RATING OF 8,000 KW:

Designed for use in a DUOMELT plant, this unit will be shipped to a renowned Chinese foundry. It delivers an output of 15 tonnes gray iron/h at a melting temperature of 1,550°C.
The furnace on exhibit supports a multi-frequency operating regime – switching the frequency from 250 to 125 Hz to promote intense stirring down of alloying elements and carburizing agents.
In order to facilitate slag skimming while also reducing operator fatigue, the furnace can be steplessly tilted backwards by up to 20°.
The system features an extraction hood of innovative design, successfully optimized on the basis of practical experience gained with prior technology. The new hood is characterized by its lower height and improved, reliable protection of the hydraulic components.


LOW-PRESSURE DIE CASTING LINE FOR BRASS:

The entire system consists of a 90 kW induction melting and pouring furnace, die manipulator unit, blackwash bath, electronic control system and operator control desk.
Intended for a Chinese customer, the installation is designed for a cycle time of 45 seconds and permits an automatic production of approx. 500 brass castings in one shift. The complex system covers all operating steps, from fitting the die to removal of the casting with subsequent die cleaning and re-coating. The die is advanced to the individual stations by a manipulator fitted on a linear motion gantry.
This low-pressure casting process ensures a smooth, low-turbulence die filling operation as the melt is forced into the die from below with a controlled pressure increase.


PRESENTATION OF AN INNOVATIVE MAGNESIUM MELTING PROCESS:

State-of-the-art magnesium melting and pouring technology typically relies on protecting the melt from undesirable chemical reactions by means of climate-relevant and/or corrosive gases.
To reduce the use of such gases in magnesium melting and pouring applications, a new process principle has been developed and tested successfully on a laboratory scale. Especially in a quasi-continuous operating mode, the new process has been found to yield advantages.
In cooperation with the Foundry Institute of the Technical University of Aachen (RWTH) and the Kahn engineering firm based in Ehringshausen/Germany, the new process was then researched and analysed on a scaled-up prototype installation in a series of systematic basic technology validation and screening trials. The aim now is to progress this innovative melting furnace design from its laboratory scale to volume production viability.
At the present project state, an operational-scale system is being designed and built for use in a leading German automotive manufacturer's magnesium die casting plant.


DEVELOPMENTS AIMED AT REDUCING COIL LOSSES AND PROVIDING IMPROVED CRUCIBLE MONITORING:

Reducing ohmic coil losses is the decisive step towards achieving further energy efficiency improvements in inductive melting.
The solution approach is aimed at reducing the current density and hence, ohmic losses, by enlarging the current-carrying surface area. Ideally, the current density should be distributed as homogeneously as possible throughout the coil. Simple though this may sound, implementation of this principle is difficult to achieve since the current will not distribute evenly over the entire cross-section.
A special coil design has now been developed which results in a wider current distribution.
Industrial applications of this new coil design have clearly confirmed the savings computed in theory. Based on these results, work is now ongoing to further refine and optimize this innovative coil design.
Another example of a successful development for widespread industrial use is the OCP crucible monitoring technology.
The OCP (Optical Coil Protection) system constitutes a latest-generation temperature measuring and monitoring system which relies on the use of fibre-optical sensors. Such sensors are particularly well suited for interference-free monitoring of induction melting furnaces as they provide direct and independent temperature field data.
A sensor cable embedded in the permanent lining of the furnace provides full-area measurement of the temperature field across the inside of the coil. Unlike earth leakage monitoring devices, this technology allows a very accurate selective localization of potential crucible defects.


POWERFUL OTTO JUNKER CORELESS INDUCTION FURNACE AT GIFA SPECIAL SHOW FOCUSSING ON ENERGY EFFICIENCY:

The special show of the Institut für Gießereitechnik (Institute of Foundry Engineering) in hall 13 takes the example of a high-power melting furnace with advanced process control by OTTO JUNKER GmbH to highlight the potentials of energy savings in induction melting.
The furnace on show has a capacity of 10 tonnes and a nominal power rating of 8,000 kW. The system features a multi-frequency operating regime – switching the frequency from 250 to 125 Hz to promote intense stirring down of alloying elements and carburizing agents.
Since the early days of industrial use of induction furnaces for melting metals in the 1950s, the energy consumption could be reduced and melting rates increased substantially thanks to technical progress and innovation.
For the melting of grey cast iron the energy consumption dropped by about 25 % and melting rate increased to as much as 485 %.
And this development is going on: Optimized induction coils set the overall efficiency target at approx. 85 %.


   
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