Oct 16 2007
PowdermatriX's flagship EPSRC-funded project, Engineering the Green State, came to a resounding conclusion with a lively and informative Open Workshop at CERAM Research, Stoke-on-Trent, on 27 September 2007.
This project has delivered fundamental understanding for improved process control of each step involved in the production of green (unsintered) compacts by die pressing.
The project was considered to be sufficiently important to devote almost half of the £1 million funding provided by EPSRC for university research when PowdermatriX was established in 2003. Die pressing is the dominant powder forming route in most sectors within its membership constituency and the project work was supported by over 20 companies.
The project's broad appeal was further reflected by the 40 workshop delegates including representatives from 21 companies in the powder metals, ceramics, hard metals and magnetic materials sectors.
During the workshop the researchers took the delegates through the full process from starting powders to the formed compact. Among the many important new insights, highlights included:
- Process maps produced by University of Birmingham, to relate "degree of mixedness" to blending conditions in a double cone blender.
- Guidelines proposed by University of Greenwich for equipment design for powder handling and delivery to the press shoe to minimise chemical segregation effects.
- Quantification by University of Leicester, of the beneficial effects of suction filling and fluidisation in the fill-shoe on powder flow into the die.
- Novel X-ray Tomography techniques, developed by University of Manchester, to identify the formation defects during pre-compaction powder transfer and to follow particle re-arrangement during early stage (low pressure) compaction. These latter studies have fed into numerical modelling by University of Aberdeen.
- A viable feedstock for die pressing zirconia nanopowders by spray freeze drying to form soft agglomerates, developed by Loughborough University that can be crushed in compaction and subsequently sintered to a nanoscale structure.
Gavin Buckles, Materials Engineer, Morgan Electroceramics, commented, "It's not just about getting a better understanding of the science of powder handling. I can take the results and immediately start to improve the efficiency of our factory processes."
The final discussion period produced ideas for follow-up projects, so expect to see new proposals emerging from the academic groups in the near future.
Contact David Whittaker ([email protected]) if you have further questions about die pressing.