Goodyear Takes Retreading to the Max

Goodyear has long run its retreading operation in the UK from Wolverhampton but retreading was never really promoted as a core activity in the past. The concept of four lives for a tyre may have been practised by the truck tyre sales team but when compared to its competitor just along the M6 at Stoke, there was never really any focus on the retread element in promotional material or arguably even in practice.

A previous visit to Wolverhampton some six years ago showed a rather typical well controlled operation but spread out and perhaps not always equipped with the latest technology. However, that has changed with the recently reorganised retread plant at Wolverhampton. The closure of the tyre plant, the sell off of property for redevelopment, and a restructure of operations have all combined to make the Goodyear retread operation much more compact, more easily managed with a better end product, and ultimately, a greater contribution to the group's earnings.

Essentially, the £1.579 million redesign of the retread operation has been done on as clean a sheet as was feasible with the existing buildings at Wolverhampton. There is at the start of the process the inevitable stock yard for incoming tyres. The tyres are selected from stock for retreading and brought indoors to a holding area, where they are allowed to dry and warm up. Goodyear believe that an ambient temperature tyre is more conducive to a quality retread than a cold wet casing dragged in out of the yard.

The casings used have already been inspected by the casing partners, TRS and Statham, and all but the top grade casings have been rejected. At the outset, every casing is entered in the Goodyear Tracking Retread Automated Casings System (GTRACS)and given a barcode to identify it ( work is ongoing with RFID chips to test effectiveness and durability).

GTRACS records every detail of the casing; manufacturer, quality, number of injuries, machines used, operators involved and product into stock.

A first visual inspection is followed by a nailhole test, before the casing is presented to the latest item of high tech inspection equipment - the PTS machine.

The Pressure Test System (PTS) has been designed and built by SDS in partnership with Goodyear. The concept inflates the casing at a low pressure of about 3bar. This is just sufficient to allow any imperfections in the sidewalls to show symptoms. These are identified as variations by laser reading the surface of the sidewall. So accurate is the laser reading that it can identify chalk marks on the tyre as a potential fault.

The PTS at Wolverhampton is believed to be the only operational unit in the world and it is still undergoing development, but will be available to the wider market through SDS once proving has been completed.

A pair of SDS shearography machines are the next stage in the line and if a casing has passed thus far without being rejected it moves on for further preparation. The buffing process has been enhanced by the addition of a Marangoni Giotto 3000 fully automated buffing machine. This complements a pair of older generation buffers. The normal preparation of skiving and filling remains an individual personal task, as does spraying before the tyres are built on either a Marangoni Omega or Alpha tyre builder (The Omega can also be used to laminate sidewalls but manual veneering of the sidewalls still plays a large part in the operation).

Curing is by way of a range of 37 moulds, either steam and nitrogen or water cured, The older SIO presses gradually being replaced by more modern TRM steam and nitrogen presses.

It is worth noting that the moulds for the latest generation retreads are all Teflon coated to aid release and improve appearance.

Finally the tyres are trimmed, given a visual inspection and then pressure tested on Matteuzzi pressure testing equipment.

Previously retreads made at Wolverhampton were then shipped to the Tyrefort where they were distributed to 1200 centres around the UK. Now they are stored on site and the retread operation has full control of its own stock and distribution to 105 centres - this as part of a total reorganisation of the way Goodyear distributes to and services the truck tyre market. Notices around the retread operation suggested that the daily target for retreading was 303 tyres per day. With the plant operating three shifts five days per week this figure is about 80% of the capacity of the plant in its current format. With a stored capacity of up to 3,800 tyres the store has the capacity for up to 10 day's worth of production.

Future developments should improve performance through the introduction of a monorail system and a series of AEP tyre handling equipment.

The Wolverhampton model is being mirrored at Riom in France. The Wolverhampton plant can now boast an 89.9% availability on all orders and has an adjustment level of 0.008%. This compares favourably to the new tyre adjustment rate of any mainstream manufacturer.

Ken Wilson, QTECH Manager, offered the figure of 1.26% for internal cured waste for the last quarter of 2008, whilst the YTD level had been reduced further to 0.87%

Issue 2009/2