Repair

Feed rollers - SCA Timber

The grooves of the roller are rebuilt with laser cladding

“In the autumn of 2007, we inserted a feed roller with laser-welded grooves into the feed in saw line 2. It has now been in operation for almost four years, and I would think that it will run for the same amount of time,” says David Engberg, maintenance manager at SCA Timber in Munksund. “The feed rollers that are delivered with new saw lines today have thermally sprayed grooves. These are completely worn out after two years.”

The task of the feed roller is to propel the log along the saw line. It has a ribbed surface layer to get a good grip on the log. If the roller and grip do not work well, the log slips and gets stuck or there is a fault in the feed to the dividing saw blade with serious quality disturbances as a result.

The surface layer of the roller is rebuilt using a laser

The grooves of the roller are rebuilt with laser cladding. The welded material is a durable tool steel mixed with hard, wear resistant carbide particles. 

About SCA Munksund

SCA Munksund delivers sawn and planed pine. The annual capacity amounts to 440,000 m3 of sawn timber. Keeping production as trouble-free as possible is, of course, of great importance for both product quality and profitability.

Press hardening tool - Gestamp Hardtech

Press hardening tools increase their service life with laser impregnation

“The first tool that was laser impregnated has to date completed 380,000 strokes,” says Age Risberg at Gestamp HardTech in Luleå. A tool without impregnation normally does about 20,000 strokes before it must undergo reconditioning.

A growing trend in the industry is thermoforming technology, so called press hardening. The method means that high-strength steel is heated up to over 900 degrees Celsius and then shaped and cooled at the same time in press hardening tools.

The component manufacturer Gestamp HardTech is the pioneer behind press hardening technology. The company supplies safety details to the automotive industry. In 2005, Duroc began a collaboration with Gestamp for laser impregnation of wear-exposed parts in press hardening tools.

Thin high-strength steel places new demands on the manufacturing processes

The background to thermoforming technology is, among other things, the increased environmental requirements. Car details will be lighter and thus more energy-efficient at the same time as they will be harder and safer. The use of thin, high-strength steel is increasing, which places new demands on the manufacturing processes.

In Olofström, Volvo Cars is preparing for an upcoming technology change, even though no formal decisions have yet been made. The method has also become common in other industries, where parts with high strength, low weight, and advanced geometries must be formed.

Wheel spindles - Caterpillar

Wheel spindles that are renovated with lasers last longer than new ones

“Laser cladding of a wheel spindle costs maybe a fifth compared to buying a new one,” explains Lars Almqvist, who together with Kalle Thyni is responsible for the maintenance of the Caterpillar trucks at the Aitik mine. “But above all, it holds up so well. You do not have to worry about costly warehouse breakdowns. Traditional overlay welding is not an option.”

“There is no alternative method to laser cladding,” Almqvist explains. “The heat beam is small and accurate and provides high precision, which means that you can weld without affecting the surrounding base material. With traditional overlay welding, the heat impact becomes so deep that you risk a fracture indication further down or in the weld itself.”

The Aitik mine outside Gällivare is one of Europe’s largest copper mines. Every year 17-19 million metric tons of ore and 25 million metric tons of waste rock are mined here. Duroc does maintenance work using laser cladding, mainly for preventive purposes, but even more urgent issues sometimes occur.

Through a full-service agreement, PonCat handles the maintenance of the mining trucks for Boliden Mineral. Maintenance is mainly for preventive purposes. According to a rolling plan, the components are lifted out for renovation after a certain number of hours.

“We work exclusively for preventive purposes. If a component were to break down, the repair cost would be almost double,” Almqvist explains.

Laser cladding lasts twice as long as the original spindle

The fleet of Caterpillar trucks in the Aitik mine consists of six 789s and seventeen 793s. In 1995, Duroc laser renovated the first wheel spindles on the CAT 789. After eleven years, the spindles have not yet needed to be repaired or replaced. To compare with the original spindle that lasted for six years. In 2006, the newer 793 truck model was also renovated.