Description

The usual situation in the spring industry globally is that the responsibility for spring designs lies with the end user, and the spring manufacturer’s role is that of subcontractor, interpreting the design requirements of their customers. The spring manufacturer will expect to purchase wire of high quality that enables him to produce precise springs that meet his customer’s tolerances without significant wastage, and that the springs will meet the performance criteria specified. To facilitate this process IST have developed spring design software suitable for all companies in the springs supply chain – software marketed under the banner “Spring Calculator Professional”. However, this approach is not always sufficient because the spring not only has to function accurately and reliably, it may also be essential that the design is optimised for that spring to be competitive in a world market.
IST, in collaboration with a major end user of springs, Schneider Electric of France, have developed additional modules within their suite of programs to enable spring designs to be optimised. That is to say optimised to be of the lowest mass possible, or the design might have to optimised with respect to the space envelope, or optimised for rate (maximum or minimum). Indeed within these modules there is scope to optimise many parameters of spring designs.
This paper is the third in a series (References 1 and 2). The first described the optimisation of compression springs and was given at the SNFR Congress one year ago and was repeated at the Interwire conference in Atlanta in May 2011. The second described the optimisation of conical and torsion springs and that was given at the ESF (European Spring Federation) Congress in Paris in September 2011. These papers are available on request from IST. This third and last in the series concerns the optimisation of extension spring designs.