IT WAS once said that "it is the framework which changes with each new technology and not just the picture within the frame." This quote captures the essence of what is occurring in the field of industrial plastics.
The development of Finite Element Analysis (FEA) design techniques specifically tailored by Dotmar EPP for application to plastic materials has not simply improved the application of plastics, but strikingly broadened the scope of engineered applications.
FEA consists of a computer model of a component or structure that is analyzed to determine the stress and deflections of a structure whilst exposed to different types of loading. It is used in new product design, and existing product refinement. Using sophisticated solid and shell mesh FEA techniques, we are able to verify that a proposed design, manufactured from any number of plastic materials, will be able to perform to the client's specifications prior to manufacturing or construction.
The technology can also be applied to the modification of an existing product or structure to qualify the product or structure for a new service condition. Utilising our own experience, and reference to particular data, FEA can also account for visco-elastic behaviour of plastic materials over time.
Finite Element Analysis (FEA) itself has been around since the 1940s, but, until a generation or so ago, was limited to expensive mainframe computers generally owned by the aeronautics, automotive, defense, and nuclear industries. But as the cost of computers has come down, while their power has increased phenomenally, FEA has been developed to an incredible precision. Present day processors installed in high-end desktop computers are now able to calculate accurate results that allow us to take into account all the extra parameters inherent in analysing plastic structures.
At Dotmar, we have embraced this new technology-based paradigm to unlock the engineering potential of superplastics. Proprietary FEA techniques enable us very quickly, to quantify, test and refine the optimum material and design combinations required for specific applications - electronically traversing and ideally combining the extraordinary range of variables that can be designed into thermoplastics.
Using FEA, today's families of super plastics can be engineered such that long-term stresses, deflections and residual forces are known with a high degree of accuracy. This allows us to optimise design for low weight, high strength and very high impact resistance (attributes invaluable in applications as diverse as chemical vessels -both above and below ground, chemical scrubbers, flotation cells, anode/cathode filter frames, gears, sheaves, conveyors, impellers, wear resistant hoppers)
Building on the solid foundation of over 40 years of material data, as published in the standard DVS 2205, our own "plastics tailored" FEA techniques are now considered to be state of the art. As a result of this capability we have significantly reframed our view on what can be achieved with industrial thermoplastics.
What was previously considered not possible, has become possible. For example, we have successfully designed:
* 10m high flotation circuit sumps, manufactured completely out of high density thermo-plastic and able to withstand cyclonic wind loads.
* Steel reinforced PP-H pickling lines manufactured up to 26m long by 3.2m high.
* 8m high chemical scrubbers capable of supporting 10 tonnes of activated carbon.
* High temperature anode/cathode filter frames.
* 4m high by 3m diameter agitators with wear-resistant Matrox lining and baffles.
* 12m long self supporting, 'non-stick' launders shaped to provide constant surface velocity.
* Boat-lifting structures of completely thin walled sheet construction capable of lifting and balancing 6 tonne vessels.
* Horisontal circular or oval truck tanks of up to 4m diameter and 10 meters length.
These examples represent just a small cross-section of what has been proven to be possible, both by state-of-the-art analysis, construction and/or testing.
However, whilst design technology may prove what is achievable, it is of course only worth applying if the resulting product is competitive.
It is true that if the thermoplastic industry was limited to utilising traditional welding and fabrication techniques the cost can limit the commercialisation of many technically feasible projects. However, in fabrication too, new technology has changed the landscape for the industry.
Over the last two years Australian fabricators, encouraged by the significantly increased investment in plastics engineering, have purchased state-of-the-art, PLC-controlled, butt-welding machines. These machines, capable of automatically welding and bending 4m lengths of sheet, substantially decrease the labour required in the fabrication process, whilst increasing the weld strength and assuring its quality. Expanding access to such machinery across Australia is allowing nationwide access to efficient plastic fabrication.
The technological picture of the plastics industry has indeed changed, but the exciting part is the broadening of the applications for plastics this has made possible.
* Michael Shea is National Development Manager for Dotmar EPP.