Michelin’s Stoke Site Aims to be Cutting Edge Facility

If and when the plans come to fruition, the headline news is that the Campbell Road facility will be able to retread the French manufacturer’s latest generation of truck and bus products – Michelin Durable Technologies. Stoke Site Manager, Peter Marsh, makes a point of highlighting the complex process casings go through at Campbell Road. He believes the term re-engineered tyre (rather than retread) better describes the high-tech processes Remix and Encore tyres go through.

The proposed modernisation would also reduce solvent emissions during the manufacturing process and greatly improve its employees’ working environment. With the study phase due to be completed this year, subject to obtaining the necessary funding, the plan will go into action in 2009 and continue over approximately five years. While the evolution programme means Michelin decided to close the metallic fabric production line it has been running on-site as a feeder for its Ballymena, Northern Ireland truck tyre factory from the end of March 2008, Peter Marsh told T&A that the space this operation currently occupies could become the site of a new retread production line. According to Marsh, this does not mean site capacity (currently around 400,000 retreads a year) would suddenly double, but rather that the production process would be significantly upgraded. The resultant new plant is expected to be equipped with a “similar” sized annual capacity in mind. However, as you would expect with an industrial venture like this, the option to increase capacity over and above what it is today will also be built into the site upgrade proposals.

In the meantime, retread production managers have been implementing a series of improvement measures based on an internal benchmarking programme. Called Michelin Manufacturing Way (MMW), the programmes compares the Campbell Road site with the other Remix facilities in Europe (in Spain, France, Germany and Italy) and around the world. The idea is for each Remix site to share efficiency and process ideas with the others, so all sites are operating at the highest level. The Remix and Encore plants in Stoke are now in the third year of implementing MMW and as a result the facility has seen investments in every area of the factory.

One the most notable upgrades was the installation of Michelin’s Savfi (Systeme Automatique de verification des cuissions) computer controlled curing technology last year. Casing control However, as the saying goes, any retreader is only as good as their casings. That’s why Michelin has also taken steps to upgrade the process at the Campbell Road site’s Casing Acceptance Warehouse (CAW). This part of the operation employs 70 inspectors, who sort through 2,400 casings, or as the French say – carcasses, each day. Casings are brought to Stoke by a number of firms including Vellco and Global Remould Services. Vellco, for its part, is contracted to do some very preliminary sorting of casings by tyre size so as not to bombard Michelin with sizes it isn’t retreading at that time. However, company representatives made it clear that the French manufacturer would never outsource the actual casing acceptance procedure.

Campbell Road’s CAW houses 16 visual inspection bays, the first port of call for any would-be Remix or Encore tyre. Here casings are thoroughly checked for any defects and cross-checked against Michelin’s Retread Traceability System in Clermont-Ferrand as a safeguard against the very few tyres that come in with altered sidewall markings. This, for example, avoids accepting a 10 year old casing that has had its DOT age changed – Michelin only accepts casings up to a maximum of five years old. This skill-based process is supplemented by three more technology-based checking procedures – x-ray, shearography and the Hawkinson testing. Michelin only just installed a new Shearography machine last year and has already planned to invest a further £250,000 on another one soon. Then there is the Hawkinson electrical testing machine, used to highlight small faults by passing an electrical current through the casing. Currently around 70 per cent of casings are checked using Hawkinson technology; however, the substantial investment put aside for a new machine demonstrates the company’s intentions to increase this to 100 per cent as soon as possible. After all this, roughly 1 per cent of casings are x-rayed.