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Kasto has revealed how its high-speed, automatic bandsaws are enabling Wilsons to increase productivity in aluminium-sawing applications.

Wilsons has invested in three of the machines in the past five years, with the latest saw to be installed a dedicated aluminium-cutting machine designated Kastotec AM4.

According to James Digby, director and general manager at Wilsons, the Kastotec AM4 is 10 times faster at cutting aluminium alloys than two early Kasto bandsaws installed in the 1980s, which are still in daily use.

Wilsons stocks more than 10,000 tons of plate, sheet, bar, tube, pipe, fittings and flanges, totalling more than 3,000 line items for JIT, Kanban, direct line feed and other forms of supply to customers.

In addition to dealing directly with primes such as Airbus and Bombardier, the stockist also services the first-, second- and third-tier supply chain.

Demand is not only for aluminium, which accounts for a majority of turnover, but also for other aerospace metals including nickel and titanium alloys, and more recently a range of ferrous materials.

By 2005, Wilsons had increased its supply of aluminium bar to the UK aerospace industry to the point where its market share had reached nearly 40 per cent.

The same year, it decided to branch out into stocking aerospace steels.

Additional sawing capacity was clearly needed and after a brief foray into circular sawing, the company opted to buy a 430mm capacity Kastotec AC4 bandsaw.

Grant Clay, operations manager at Wilsons, said: ‘The reliability of the machine has been second to none.

‘The AC4 has been running flat out, eight and a half hours a day, five days a week, ever since it was installed.

‘To maximise productivity, we program maximum band speed and infeed for every material it cuts, yet I struggle to think of a single breakdown in five years,’ he added.

With the advent of steel supply at Wilsons, the AC4 was deployed onto that work, which curtailed its availability to cut aluminium.

The decision was taken in 2006 to buy a second, slightly larger capacity (530mm bar diameter) Kastotec bandsaw – the AC5.

This is similarly run at maximum speeds and feeds, predominantly on steel.

Even when cutting case-hardened varieties, high productivity rates are achieved, Kasto said.

Digby said: ‘Our main reason for choosing the Kastos, apart from their speed, was the clean cut that they achieve.

‘On other machines we looked at, fine swarf was produced, which, when mixed with coolant, resulted in a dirty cutting environment.

‘The cut on the Kasto saws is cleaner as it uses minimum-volume coolant and the chips are much thicker, more like those produced when milling,’ he added.

Other features of Kasto saws that Wilsons’ engineers appreciate are the integral control panel instead of a bolt-on type, and the ease of programming.

The Kastotec AM4 aluminium machine was installed at the end of 2009 in response to increased order levels for aluminium alloys.

Clay said: ‘This machine is finely tuned to cutting aluminium and nothing else, and achieves extraordinarily fast cutting rates, three to four times higher than even the AC4.

‘Downfeed on the AM4 is up to 1.5m/min, which is progressively slowed automatically by the control the closer the blade gets to the centre of round material so that the chip load on the teeth remains constant.

‘When cutting single pieces of flat bar or rafts, the blade goes straight through at a high constant speed, finishing in less than an hour what would take a day to cut on one of our older saws,’ he added.

A typical order placed on Wilsons is 10- to 20-off, but may be as high as 500-off, while ones and twos are regularly processed on most days.

With the machines being so fast and batch sizes often low, speedy changeover is paramount to avoid loss of production.

Digby said that on all of the Kasto machines, a new job can be programmed in a matter of minutes, even if new data has to be entered at the control.

If the program is already in memory, changeover is faster still.

He said: ‘Even when a new material type, size and cross-section plus cut-piece length and quantity have to be keyed in, the program is always ready before another operator can load the material onto the input conveyor.

‘In fact, it takes longer to complete the paperwork for a job than it does to program it,’ he added.

The advantage of having automatic bandsaws as reliable as the Kasto machines is that they can run without operator attendance from the end of the day shift.

A ghost shift often extends right through the night.

This is because Clay adopts the policy of backing off feeds and speeds by 30 to 50 per cent to guard against blade breakage.

A calculation is made as to how fast each machine needs to run so that the requisite number of parts, for example 200-off pieces of 180mm diameter steel, is in the basket before the next morning shift starts.

The Kastotec machines at Wilsons are of robust specification to allow the option of using carbide blades, yet the stockholder chooses to use bimetal blades for all its cutting requirements, except on titanium.

The reason is that bimetal is nearly as fast as carbide when cutting all other materials and results in lower cost per cut, due to the higher consumable cost of bands with tungsten carbide teeth.

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