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Evaluation of FRACMAT test for specifications


The Objectives

To improve upon their competitive position in the world market, it is essential that European spring manufacturers make products that are dimensionally consistent and accurate. One of the major sources of variability in spring manufacture arises from the wire used as the raw material, but none of the national or international specifications for spring wire contain an effective test method for evaluation of wire variability. Joint work by SRAMA and the University of Warwick Mathematics Institute has produced the FRACMAT test machine, which quantifies the sequential elastic/frictional wire variability by computerised Statistical and Chaos Theoretic analysis techniques. This project is designed to confirm that the FRACMAT test is a fast, inexpensive, robust and reliable method for evaluating wire variability over a wide range of spring wire sizes and qualities, and to generate a high level of confidence in the test among leading European spring wire producers and SME spring manufacturers.


Incorporating the FRACMAT test into wire specifications will provide the following important benefits:

For wire producers

* An increased level of confidence that wires of high consistent quality can be reliably supplied to customers.
* Identification of wire process routes for the most consistent product. thereby producing wires 'right first time' at lowest cost.
* Ability to distinguish between wire induced coiling problems and those created by user.

For Springmakers

* Shorter set-up times and reduced scrap by elimination of inconsistent wire. * A genuine Just-In-Time production capability reducing inventory levels and enhancing customer service.
* Improved ability to specify consistent wire for critical orders.
The Projcet

The intended research will generate/analyse FRACMAT wire data and spring tolerance data for a full range of wires, in the size range 0.2 -3.0mm diameter, used to manufacture springs by normal automatic springmaking processes. More than 20 wires in each of at least three different grades of spring steel will be used in the project. From each wire two spring designs will be manufactured, and the springmaking tolerances will be correlated with FRACMAT data from each wire. Once the applicable scope of the FRACMAT test has been fully defined, it will be included in the next revision of all the applicable European spring wire and spring manufacturing specifications. This project will enable wire producers and springmakers to make significant financial savings and give greater certainty that the wire supplied will be satisfactory. The savings made would be expected to exceed 50m ECU/annum for an industry that turns over approximately 1000m ECU/annum in the production of engineering. bedding and seating springs from wire. The project will have sigificant spin-off benefits for other wire products that have to be formed accurately, e.g. from mild steel. Hence this research project's overall costs of 1005K ECU over 30 months would be a good investment both for the EU and participating companies. The partnership that will undertake this project will comprise three European wire producers, two European spring manufacturers and SRAMA.

Funding Scheme

CSC - Cost-sharing contracts


Henry Street
S3 7EQ Sheffield
United Kingdom

Participants (6)

Bekaert SA/NV
8550 Zwevegem
Fabriressort S.A.
35,Avenue Lavaisier
1300 Wavre
Hengelose Verenfabriek Bakker B.V.
7550 AB Hengelo
Joh. Pengg Aktiengesellschaft

8621 Thörl
Ressorts Vanel S.A.
576,Rue Des Mercières
69165 Rillieux
Sprint Métal

58160 Imphy