With its sleek good looks and aura of cutting edge technology, Stenner‘s PK quad bandsaw wouldn’t have looked out of place in 2001: A Space Odyssey. But although its appearance at Ligna 2001 represented a similar quantum leap to that of the black obelisk in the film, the PK is no space-age dream.

Designed for cutting hardwood flooring strips to an accuracy of +/-0.1mm and with a superfine surface finish, the PK created a new market for wide bandsaws by offering greater productivity, higher yield and lower maintenance costs than the circular and frame saws traditionally used.

Four have been sold since the worldwide launch last May at Ligna, and the initial caution which greets new technology is being rapidly overcome as these installations prove the benefits of the machine. Stenner expects to sell at least a dozen over the next 12 months – and that is a conservative estimate, with more than 60 enquiries received from the Far East alone since Ligna.

‘Wide bandsaw technology has undergone a revolution over the last decade or so,’ said managing director Doug Shopland.

‘There have been major advances in the design of blades and the equipment used to manufacture and maintain them – and these have allowed us to develop new generations of machines offering much improved performance. Bandsaws can now be viewed as precision machine tools, with increasing applications in secondary processing sectors.’

Wealth of experience

With a history spanning 132 years and installations around the world, Stenner draws on a wealth of expertise in the sawmilling sector. The company continues to supply its traditional primary processing markets with a wide range of equipment for processing both hardwood and softwood logs, but there has been a definite expansion into machinery for ‘dry’ mills processing dried timber into added-value products.

In part, this has been driven by the strength of sterling. In order to succeed against European competitors who enjoy weaker currencies and larger domestic markets (the sawn softwood industry in the UK is about one-sixth the size of that in France, for example), Stenner has concentrated on developing wide bandsaw technology, successfully competing on the basis of higher performance, quality and state-of-the-art technology rather than just price alone.

Operating from extensive premises in Tiverton, Devon and with 40 employees supported by a worldwide network of distributors, Stenner’s sales are split roughly equally between the UK and overseas. The fact that export business includes a large Scandinavian market underlines the company’s leading position in sawing technology.

Stenner’s ‘core’ range of wide band resaws comprises four categories of machine: the ST range of stand-alone vertical resaws; single, twin and triple vertical resaws with handling systems for dry mills (some installations are running at more than 100m/min); the MH series horizontal multi-head machines (applications include resawing timber in green mills, cutting fencing and pallet timber, and specialist added-value production); and the PK range for hardwood flooring.

‘The PK was developed as a result of enquiries from customers who wanted to use our MH9 horizontal resaw to cut hardwood flooring strips,’ said Stenner’s marketing manager Syd Mather.

‘Considerable investment was made in R&D in order to achieve better accuracy and a fine surface finish – so that the strips did not need to be further processed for thicknessing or levelling purposes but merely given a light sanding for appearance.’

While the PK range is designed specifi-cally for hardwood flooring, the MH series continues to provide effective solutions for a wide range of applications. For example, in its ‘wide mouth’ configuration the machine is being used to produce thin, laminated boards for wall panelling, drawer bottoms and wardrobe backs. The panels cannot be laminated directly in the thickness required because not only would throughput be uneconomic but the press would crush the board! Instead, the customer presses beams measuring 100mmx1mx6m and then cuts them to the required 3mm thickness on the precision MH resaw.

As well as improving the cutting performance, Stenner developed a sophisticated HMI controller for the PK. Designed for ease of use, the system replaces many manually operated knobs, levers and handles with a single screen. In fact, the only mechanical control on the body of the machine is the emergency stop.

Tailored screens

HMI technology is now to be used on all other machines, with the screen tailored to suit the application. Larger machines include a colour display showing real-time graphics of machine settings and functions, touch-screen controls, integrated diagnostics, and a modem option for remote troubleshooting.

For all resaws the HMI can include an integrated PLC controlled digital setting system. On multi-head applications, required cutting patterns are easily programmed into the HMI and the options are then presented to the operator as a pictorial simulation on the touch-screen. For the ST range of stand-alone resaws there’s a smaller LCD and membrane ‘soft-touch’ buttons in place of the touch-screen.

The ST has been a highly successful product, with customers ranging from timber merchants and DIY stores that need occasional cutting capability, to larger volume mills that want additional off-line flexibility. One of the first ST models to benefit from the HMI system is a new machine. Due to be formally launched in the UK at an open house at AL Dalton Ltd on April 25-27, the ST130 is a significant addition to the range.

‘There has been a fundamental change in stand-alone resaws,’ said Mr Shopland. ‘A machine with 36in pulleys will now outperform a 48in of 10 years ago.’

As a general rule, in order to cut larger boards in high volume and at high speed a wider blade is needed because it has a bigger gullet (more efficient removal of sawdust) and better stability. Historically, to run such a wider blade, larger diameter pulleys were needed, which meant the stand-alone resaw had to be installed over a pit to ensure the cutting area was at the right height for the operator. That made the overall installation more complex and costly and, in some cases, not feasible.

The new ST130 draws together developments in blade technology, straining and guiding systems to solve that problem. It sits between the existing ST9 (36in/900mm diameter pulleys) and ST105 (42in/1050mm) resaws, and carries a blade 130mm wide – 30mm wider than the ST9 – but with pulleys of just 950mm diameter.

‘The ST130 fills an important gap in the market,’ said Syd Mather. ‘It’s for customers who want to cut larger, heavier sections up to 400mm thickness and who would previously have bought a 42in machine – but unlike the ST105, the ST130 does not require a pit.’

While Stenner’s technical developments have allowed it to move into new areas, the company has not neglected its traditional markets. By combining its own expertise in sawmilling equipment with those of other companies with which it has formed partnerships, Stenner is successfully supplying a wide range of equipment – from complete turnkey chipper-canter based sawmills to upgrades of existing installations both to improve performance and to meet the latest safety standards.

In the dry mill market Stenner enjoys a successful relationship with System TM, the Danish handling systems specialist. Together they have installed automated high-speed resaw systems at numerous customers in the UK and mainland Europe.

‘Stenner is a turnkey provider of solutions centred on wide bandsaws – offering the latest in technology and support to customers worldwide,’ said Doug Shopland.

‘Our range represents a new generation in wide bandsaw technology – and is really just an indication of the developments which we will bring to the market as we continue to develop solutions for both existing and new applications.’