Welding robots set new pace

At the end of 2008 Årdal Stålindustri merged with the company Impec and took that company’s name. Impec offers products and services to the aluminium industry and also manufactures light metal scaffoldings.

Impec has some 60 employees and is located in Sogn og Fjordane, a Norwegian county that has long been a centre for the Norwegian aluminium industry.

“Aluminium scaffolding is relatively new,” explains Ståle´Øvstetun, Impec manager. “It was developed because there was a need for it in the oil industry. It is important to limit weight as much as possible on platforms.

” Aluminium scaffolding weighs half as much as scaffolding made from galvanised steel but equals steel scaffolding in strength.

“You also avoid corrosion, which can be a big problem with traditional scaffolding when it is used offshore,” says Øvstetun. “And while scaffolding of galvanised steel counts as problem waste, the scrap-metal value for aluminium is high.”

Impec began production of scaffolding in 2006. Today capacity is for 300 tonnes per year, set to increase rapidly.

“It would be no problem to increase capacity to 1,000 tons per year,” says Øvstetun. “In Norway aluminium scaffolding holds not quite a third of the market. Internationally the market share is still very small.”

Even though welding is automatised and carried out by two robots, there are a couple of hundred welding points on every scaffolding part. It is important that production is as efficient as possible, because competition from low-cost countries is tough. So Impec contacted AGA, as Årdal Stålindustri had worked with AGA since 1994, when Årdal introduced Rapid Processing – the second company in Norway to do so. Before that, all welding was with MAG wire.

Helge Bergfjord, technical expert at AGA Norge, was involved in the change.

“Back then we could show how big the profit was for the customer to switch to compact wire,” says Bergfjord. “It meant there was less spray, and at the same time the amount of steel welding smoke was halved.”

He also had the job of introducing Rapid Processing when the company began working with aluminium a couple of years ago. By changing the parameters and the angle of the welding robot, the speed could be doubled.

“Unfortunately this meant that productivity increased by not more than 5 percent, because there is a human operator who is not so easy to speed up,” he says.

But when the welding robot goes twice as fast, it uses half as much gas.

“If a welding robot is used 1,850 hours per year, and productivity is [increased] by 5 percent, the job is done 92.5 hours faster,” says Bergfjord. “Every welding hour costs 93 euro. The saving is therefore 8,575 euro a year.”

Impec has two welding robots, but when the adjustments have been made on one, the company will adjust the other on its own.

It took Impec two days to carry out the change. That included training of operators.