Accommodating aluminium

Supplier of metals to the aerospace industry in the UK, Wilsons, has invested in three high speed, automatic bandsawing machines from Kasto in the past five years. However, the latest acquisition is setting new standards in reliability and speed when it comes to cutting aluminium.

Founded in 1947, Wilsons currently stocks over 10,000 tons of plate, sheet, bar, tube, pipe, fittings and flanges totalling over 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.

The latest saw to be installed is a dedicated aluminium cutting machine – the KastoTec AM4. According to Wilsons' director and general Manager, James Digby, it is 10 times faster at cutting aluminium alloys than two early Kasto bandsaws installed in the 1980s, which are still in daily use.

Demand is not only for aluminium – which accounts for the majority of turnover – but also for other aerospace metals including nickel and titanium alloys, and more recently a range of ferrous materials. Additional high technology companies that take advantage of the stockist's service include most of the UK-based Formula 1 teams.

Branching out

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%. 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 purchase a 430mm capacity KastoTec AC4 bandsaw.

Mr Digby comments: "We asked several different sawing machine suppliers to cut a 203mm diameter bar of 2014 aluminium. The Kasto machine proved to be by far the quickest. Thankfully the machine was in stock, as our requirement was urgent at the time, and the saw was operating in our warehouse within three days.”

Grant Clay, operations manager, adds: "Since that moment we have never looked back – the reliability of the machine has been second to none and it 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.

“Even Kasto's engineers are surprised at how hard we are able to work the machine, which is easily three times faster at cutting all materials than the older bandsaws in our warehouse,” he continues.

Clean cut

With the advent of steel supply at Huntingdon, the rigid, powerful AC4 was naturally deployed onto that work, which curtailed its availability to cut aluminium. So the decision was taken to buy a second, slightly larger capacity (530mm bar diameter) KastoTec bandsaw – an AC5.

This is similarly run at maximum speeds and feeds, predominantly on steel. Even when cutting case hardened varieties, high productivity rates are achieved.

Mr Digby elaborates: "Our main reason for choosing the Kasto's apart from the speed aspect, 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."

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. Additionally, the company had always been impressed with the aftersales service, both over the telephone and when engineers visit.

The KastoTec AM4 aluminium machine was installed in Huntingdon at the end of 2009 in response to increased order levels for aluminium alloys, the result of a growing aerospace market in the UK, despite the recession, and Wilsons having increased its market share.

Mr Clay explains: “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 per minute, 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."

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. 

Programming perfection

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

"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," he says. “In fact, it takes longer to complete the paperwork for a job than it does to program it.

“The beauty of having automatic bandsaws as reliable as the Kastos is that they can run without operator attendance from the end of the day shift,” Mr Digby adds. “This is particularly useful for us because we often run a ghost shift that extends right through the night.”

Mr 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 180 mm diameter steel – are in the basket before the next morning shift starts.

It is interesting that 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.

Maintaining efficient customer service in terms of quality and delivery is essential in stockholding, especially in the aerospace and F1 sectors. With its substantial investment in sawing machines over the past five years and the confidence to buy the latest bandsaw in a difficult business climate, Wilsons believes that it is well positioned to take advantage of the upturn when it comes.

Kasto
www.kasto.uk.com