PROJECTS

TECHSPRING PROJECT

For more information regarding this project contact the project coordinator, Mark Hayes, m.hayes@ist.org.uk or visit the TechSpring Website at www.spring-tech.eu.

BACKGROUND

Improving the technical performance of springs through scientific understanding of dynamic stress profiles using advances in software design and measurement technologies.

This European Commission funded project will support the community of over 600 European SME spring manufacturers with a toolkit for innovation, in spring design. The consortium of partners brought together by Mark Hayes, Senior Metallurgist at IST, who is the project co-ordinator, comprise ANCCEM, DSA, Turton Springs Ltd, Mevis Spa, Metalpol, Lake Image Systems Ltd., Peen Services Srl, Joh. Pengg AG and Innotech GmbH, believes that this programme will improve the spring design process and answer many of those unanswered questions about spring performance. This will be by providing the large community with the knowledge and know-how necessary to individualise their strategy and approach with products giving increased performance and durability.

MAIN GOALS

The technologies to be studied by this project include:

· Enhanced scientific knowledge of residual and applied stresses
· “Next generation” software design tools, integral to CAD/FEA and MKS
· New innovative software packages and prediction models for improving spring designs and ensuring optimum material selection.
· A prototype system making use of advanced camera and stroboscopic technologies to quantify dynamic deflections.
· A prototype adapted X-ray machine for residual stress analysis

The above will result in a standard, comprehensive, innovative and affordable “toolkit” which will be made available to SMEs involved in spring manufacture across Europe.

TECHNICAL APPROACH

The following specific case studies will be created as a result of the project:

End Coil Failures.
Vibratory Screen Springs.
Sub-Surface Fatigue Cracks without Inclusions.
Extension Spring Hooks.
Prestressing Benefits.
The Stress Profile in Larger Wires.
Speed of Production.
Speed of Loading.

The provision of the individual case studies will be followed by two full project consortium events and one-off individual (SME) company knowledge transfer event and secondments from R&D performers to each SME partner for a period sufficient to ensure they fully understand the needs of the spring manufacturers.

EXPECTED ACHIEVEMENTS

· The development of new innovative spring software design, material selection and modelling technology will create an additional 960 jobs over 5 years. Clearly, in the short term the project will safeguard existing employment.
· We estimate that the project will lead to European manufacture and substitution of high technology springs for the high technology sectors within Partner Countries. This will be targeted at aerospace, automotive, railway/rapid light transit, electrical, electronic and medical and healthcare (for the elderly).
· We estimate that we will optimise spring designs and thereby reduce materials use by up to 20%, saving up to 12,000 tonnes of steel.
· We estimate that the cost savings in the manufacturing of springs (all types) using our new technology will reduce manufacturing costs and a market price by about 7%.
· The reduced material costs and improved manufacturing efficiency will reduce energy consumption, and greenhouse gases by 7%.

For further information regarding this project contact Mark Hayes, Senior Metallurgist at IST on Tel +44 (0)114 252 7984 or Email m.hayes@ist.org.uk.

PUBLISHABLE EXECUTIVE SUMMARY

The main aim of the Tech-Spring project is to develop a toolkit to enable European Spring Manufacturers to help their customers design novel lightweight springs. The toolkit will be comprehensive in supplying advice about the design of compression, extension, torsion springs made from wire and also springs made from strip. It will be integrated with an existing computer aided design package providing accurate quantification of maximum stresses to utilise without compromising performance or reliability.

The Tech-Spring project has just completed the first of three years. During this first year a number of case studies have been initiated to explore the limits of performance of a range of different types of springs.

These case studies are:

a) Compression spring end coil failures.
b) Springs operating in the extension and compression mode.
c) Sub-surface fatigue failures without inclusions.
d) Factors affecting end hook failures in extension springs.
e) Effect of prestressing on compression spring fatigue performance.
f) Stress profile in compression springs made from wire larger than 6mm.
g) Effect of speed of production on spring dimensions and load.
h) Effect of speed of testing on fatigue performance.
i) Effect of stress relief time on fatigue performance.
j) Factors affecting the fatigue performance of torsion springs.
k) Effect of coiling method on spring properties.
l) Stress analysis in springs made from strip.
m) Appearance due to shot peening.

A considerable program of testing is in progress addressing each of the above case study topics. A few of the case studies have been completed - for example case study e) the results of which will be presented at the only international conference on springs to be held in 2007. The way in which prestressing benefits are illustrated in a Goodman Diagram will be modified as a result of this work. This result will appear in the toolkit and will be presented in training programs given first to DSA and ANCCEM and then more widely in Europe. Each of the case studies will yield results and training opportunities during the second year of the Tech-Spring project. The toolkit will be completed in the third year.

Another aspect of the Tech-Spring project is the evaluation of advanced stress analysis methods.

These will include:

i) Finite Element Analysis and MKS to calculate stresses in springs too difficult to calculate by other means.
ii) Use of a high speed camera to capture the true deflection of springs made and operated at high speed.
iii) X-ray residual stress analysis methods to quantify residual stress after heat treatment, shot peening and prestressing.
iv) Strain gauging to correlate with FEA and CAD outputs.
v) Non-axial force testing to identify how to minimise non-axial forces and to evaluate whether these undesirable forces affect fatigue life.

The toolkit will identify the circumstances in which these analysis methods would be a cost effective investment for spring manufacturers.

The team actively engaged on Tech-Spring comprises:
Two spring trade associations - DSA and ANCCEM, from The Netherlands and Italy.

Six SME companies involved in the spring supply chain or supply of stress analysis methods, these are:
Metalpol, Poland, spring manufacturer and FEA
Mollificio Mevis, Italy, cold formed spring manufacturer
Turton Springs, UK, hot formed spring manufacturer
Joh Pengg, Austria, supplier of oil tempered and drawn carbon steel spring wire
Lake Image Systems, UK, high speed cameras
Peen Services, Italy, X-ray residual stress analysis
and two research providers IST and Innotech from UK and Germany.

The technical tasks of the project should be complete by the end of the second year of the project with dissemination of results, development of the toolkit and training being the focus of the third year.