"Fit-and-forget" chains keep sawmill running

Tsubaki UK has supplied BSW Timber, the UK's largest specialist sawmill business, with a complete solution to its conveyor system maintenance problems.

Tsubaki UK has supplied BSW Timber, the UK's largest specialist sawmill business, with a complete solution to its conveyor system maintenance problems.

Shaping the wood from rough-cut logs requires a five stage conveying process, involving loads of up to 10 tonnes of timber and exposure to considerable amounts of airborne debris.

From the initial drive ramp conveyor to final chipper edging machines, the non-lube low-elongation properties of Tsubaki's third generation Lambda chain has significantly cut maintenance costs and downtime.

The operating conditions in any sawmill are tough for moving machinery due to the large amounts of airborne dust from the cutting and shaping processes.

At the BSW Sawmill in Caerphilly, the problem is exacerbated by the Mill exclusively cutting Spruce Sitka, a highly resinous variety of tree.

Richard Barnet, the maintenance engineer on the site explains, "BSW had problems with dust sticking to the greased chain and sprockets, which often caused clogging and derailment.

Machines were constantly having to be adjusted, dismantled and cleaned, taking up valuable production time as well as resources".

Two years ago, a Tsubaki third generation Lambda chain was fitted to a chipper edging machine, which profiles the sides of 120 metres of board per minute.

Previous conveyor chains used on feeding ramp of the machine had an average service life of six months due to the amount of debris produced by the chipping process.

Barnet states that: "we chose Tsubaki's Lambda III because the oil impregnated bushings allow the chain to effectively run dry, avoiding the problem of sawdust building up and clogging the links.

We now only need to give the system a monthly visual check and have had to adjust the chain just once in two years".

BSW Timber produces 500,000m3 of cut wood a year and have recently invested over GBP 3 million to improve the efficiency of its mills.

The use of Tsubaki chains has now significantly contributed towards BSW's programme of continuous improvement at the large South Wales site.

Due to the success of the first application, Tsubaki's lube-free Lambda chain has been fitted on machines throughout the plant.

These further applications highlight the second major benefit of its use, namely virtually zero elongation.

The aside transfer system, which handles wood cut by the band saw, requires chains to be automatically tensioned as they operate in forward and reverse motion.

Barnet explains that: "a standard chain would last three to six months during which time the automatic tensioners would often fail or have to be padded out until the chain stretched enough to insert an extra link.

The thick pin, narrow side plate design of the Lambda chain enabled us to avoid rubbing against components such as gearboxes and its very low-elongation properties have allowed us to fit smaller automatic tensioners and resulted in twelve months of trouble free operation to date".

Specialist Tsubaki sprockets have also provided additional benefits on the largest chipping machine at BSW.

Used for squaring the edges of the rough-cut logs, it produces so much dust that the conveyor chains and sprockets often have to work through the build ups, making normal lubrication impossible.

BSW used a combination of 1in Lambda chain and Tsubaki duplex sprockets with extruder grooves to successfully prevent sawdust getting trapped in the teeth and causing derailment.

According to Mr Barnet "the self lubricating properties of the Lambda chain increased the effectiveness of the 'sparge line', used for blowing chips away from the conveyor and similarly has enabled the whole system to run problem free for over twelve months".

Tsubaki's third generation Lambda chain offers the user extremely low elongation and at low speeds, has a wear life more than 30 times greater than that of standard roller chains.

This has been demonstrated by its use on the return drive ramp conveyor in the mill, which delivers 22 x 22 x 3.6m logs to the main band saw.

Even with an average load weighing over 10 tonnes, the chains have only needed one minor adjustment in the last year in comparison to a 3 to 6 month life expectancy of the previous type.

Tsubaki UK offers a wide range of lubrication-free drive and conveyor type chain suitable for all types of demanding industrial environments.

In addition, Tsubaki also offer highly specialised products such as water protected, antibacterial and low-noise chains for specialised industries such as the food, printing and chemical processing.

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