Engineering Integrity Society

Structural Performance of Rapid-Prototyped Materials and Components
Tuesday 9 March 2010, Wolverhampton University, Telford Campus

Abstracts:

Graham Tromans, Manager, Additive Manufacturing Knowledge Hub, Loughborough University
Where Are We Going With Additive Manufacturing

Additive Manufacturing, sometimes referred to as Rapid Manufacturing is quickly being accepted as a feasible manufacturing process in some sectors of industry.  Some industrial sectors are benefitting tremendously by adopting the technologies. Getting the technologies accepted  in other industries is proving to be difficult owing to the reluctance of managers, engineers and designers to accept them because of the material differences and design capabilities and the uncertainty of trying the unknown.  There are a wide range of industries that have embraced the technologies. This presentation will be focussing on where the technologies have been accepted as feasible manufacturing technologies.

Roger Fairclough, TWI Technology Centre, Yorkshire
Assessment of material properties produced using Additive Layer Manufacture

Additive Layer Manufacturing (ALM) processes are automated systems that take 2-dimensional layers of computer data and rebuild them into 3-dimensional solid objects. As such, very complex geometries can be produced direct from CAD information without the need for dies, form tools or moulds. It is an evolution of rapid prototyping technologies but provides components that are final production solutions unlike those from RP which are only ever produced for evaluation and visualisation purposes. As such, ALM is an exciting concept that is becoming increasingly accepted as a commercially-viable alternative to conventional manufacturing processes. Due to the high potential of ALM, it is the subject of extensive research internationally, and the UK has a thriving community developing knowledge and capability in this technology.

TWI Ltd., at their Technology Centre on the Advanced Manufacturing Park in South Yorkshire, are developing ALM technologies using laser deposition. This uses a laser beam and metal powders both to manufacture and to repair components. Currently the technology is directed towards aerospace and medical components which are normally small, intricate and high cost parts. However, the benefits of near net shape manufacture, no tooling costs, low material waste and high functionality suggest that the technology could be targeted at applications within other engineering industry sectors. In fact the availability of this technology turns product design on its head, as some of the restrictions of current conventional manufacturing processes are removed and designs can now be produced that were previously impossible.

This presentation gives an overview of laser deposition processes, both powder bed and blown powder as well as providing material properties derived from test coupons of various material grades (both titanium alloys and steels) which have been produced using the technology. Results of both static and fatigue testing are presented.

The results are compared with manufacturers’ published material property information, with the emphasis being placed on the production of consistent and reliable data. To produce a good spread of data, approximately 100 full size test coupons were produced using laser deposition. The results of these tests give a good indication of the future acceptability of the process for the manufacture of critical engineering components.  

Dr Iain Todd, University of Sheffield
The dynamic mechanical properties of metallic materials manufactured by Additive Layer Manufacturing

The properties of metallic materials are determined by a number of factors including, surface quality, the presence of defects and the material microstructure with the first two of these factors having an enormous effect on fatigue life in particular. In this contribution the influence of build direction, defect type and density and surface finish will be reviewed and assessed and conclusions drawn about both the suitability of certain metallic materials for the process and process improvements required for the manufacture of structurally sound metallic components directly using ALM.

Jonathan Meyer, EADS Innovation Works UK, Filton
A revolution in Hybrid Component manufacture

The recent increases in CFRP usage in primary aerospace structures, together with the relentless drive for cost saving and improved structural efficiency have introduced new challenges for managing areas of high-load input, particularly when joining between composite and metallic parts.

The Hybrid Penetrative Reinforcement (HYPER) concept is under development within EADS as a potential solution to this problem. It works upon the basis of securing a mechanical joint between the metallic and composite parts by use of embedded metallic features. The key innovation with the HYPER concept is the utilization of Additive Layer Manufacturing (ALM) as an enabling technology, which gives much greater flexibility in terms of feature definition, and enables excellent control of the feature geometry.

While static testing has demonstrated significant benefits for this joining method, there is still the question of fatigue performance, particularly of the metallic features produced using the ALM process, and the fusion of these features into the parent part. The small scale of these features, and the large size of the feature arrays may require a very different approach to prediction of fatigue behaviour, and novel NDT methods may need to be developed to enable flaw detection in a manufacturing environment.

The behaviour of the Hyper joint is inherently ductile, and so non-linear analysis methods will need to be used to develop models for fatigue behaviour, with many permutations of behaviour depending upon the initial number of cracks/flaws and their locations. In addition there is the highly complex matter of predicting fatigue performance in the composite laminate, which will be influenced by the presence of the Hypin features.

This type of novel structural joint presents a whole range of exciting new challenges for fatigue specialists, as well as the potential for revolutionizing the manufacture of composite hybrid structures. The potential performance and cost benefits are there to be taken, but much hard work is required in order to provide the required confidence and expertise to make it happen.

Dr Neil Hopkinson, Loughborough University
Additive manufacturing and its potential for high volume production.

Rapid Prototyping emerged in the late 1980's as a commercially attractive solution to the problem of going "from art to part" during the product development phase across many sectors of manufacturing. For twenty years as the process became more widespread there had been little thought or prospect of the underlying technology (now referred to as "Additive Manufacturing") being used for series manufacture. Around the turn of the millennium it was apparent that advances in the technology were such that manufacturing using this approach was a viable solution and high volume non-series manufacture emerged in niche medical markets. However attention has turned to developing Additive Manufacturing technologies for high volume production to challenge some of today's manufacturing processes. This talk will discuss the evolution of Additive Manufacturing from prototyping to production.