The two new technologies – a dynamic gating system and the ‘ATM runner system’ – produce high-integrity castings with fine-grained microstructure and low porosity by improving the feed of molten metal into the casting. Both systems are suitable for use with aluminium and magnesium alloys.
“This is accomplished by influencing the flow behaviour of the molten metal, the fill pattern of the die, and subsequent solidification,” says the leader of CSIRO’s research team of metallurgists and casting engineers, Dr Rob O’Donnell.
“Our researchers realised that by changing the way in which molten metal is delivered to the die we could take advantage of the high pressure inherent in the process to make castings with finer microstructure and lower porosity,” Dr O’Donnell says.
The researchers achieved higher quality castings by changing the architecture of the runners (the passages along which molten metal flows into the die) and the gate (the narrow opening to the die cavity).
“Our improved melt delivery systems are cost-effective, can be used with existing casting machines, and can significantly reduce the mass of the metal runner, wasting less metal.
“They represent new ‘green’ die casting technologies, which are low-energy and highly effective.”
Gases captured during the passage of the molten metal into the die cavity cause porosity, which together with voids created during solidification, reduces the quality of the casting.
Die castings with low porosity are stronger and can be successfully heat treated post-casting to improve their mechanical properties.
The dynamic gating system (DGS) incorporates a gate capable of changing its size in response to the pressure of the melt during filling.“Our improved melt delivery systems are cost-effective, can be used with existing casting machines, and can significantly reduce the mass of the metal runner, wasting less metal”
Dr Rob O'Donnell, CSIROX-ray analysis of test castings showed a significant improvement in density in both thicker and thinner areas of the casting, when the dynamic gate was used.
A paper describing the dynamic gating system received the best paper award at the North American Die Casting Association (NADCA) CastExpo10 congress, held in March in Orlando, Florida.
A reviewer of the paper commended the CSIRO researchers for producing a technology with “real-world” relevance to high pressure die casting, saying “This is a technology that has significant promise in the future of our industry”.
ATM technology uses a revolutionary melt delivery system for the high pressure die casting (HPDC) process, which is cheaper to operate than conventional HPDC.
The ATM casting technology has been proven by a number of companies in commercial production, and its effectiveness in reducing both shot weight and reject rates has been demonstrated.
“ATM conditions the melt prior to filling the cavity so that the melt enters the die in a less viscous, ‘runnier’ state,” Dr O’Donnell said.
“As a result, melt flow is improved and separate melt fronts fuse together better when they meet within the casting.”
The outcome is a casting with a more uniform distribution of nucleation sites, a refined, homogenous microstructure, and exceptionally low porosity.
CSIRO seeks commercial partners interested in licensing either the dynamic gating system or the ATM melt delivery system.
National Research Flagships
CSIRO initiated the National Research Flagships to provide science-based solutions in response to Australia’s major research challenges and opportunities. The nine Flagships form multidisciplinary teams with industry and the research community to deliver impact and benefits for Australia.
Nola Wilkinson | EurekAlert!
Jelly with memory – predicting the leveling of com-mercial paints
15.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Fraunhofer researchers develop measuring system for ZF factory in Saarbrücken
21.11.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences