Paint it black!

Energy-efficient laser welding

Tests on black-treated metals show that laser-welding speeds can be more than doubled compared to bare metals. By spraying surfaces black, we can reduce energy costs, or use the same energy to increase production speeds and boost profits.

Reducing reflection

 Long cable sheaths of aluminium or copper are welded longitudinally. These materials reflect up to 90% of laser light. To reduce reflection, we painted them black, a cheap and easy solution. The paint is burned off during the welding process.

Trial and success

Customers using Tungsten Inert Gas (TIG) welding were interested in laser welding because of its reliability for long lengths. However, production speeds were insufficient. Combining green and infrared lasers seemed promising, but increased production speeds by only 30%. So, we began testing surface treatments like roughening or multiple coatings, and concluded that a black coating gave the highest laser absorption. Our UNIWEMA welding machine achieved production speeds of 60 m/min for a 0.22 mm copper tube wall, using 3 kW laser power: over 200% of what can be achieved without the coating.

Time for a change

The welding of thin metal sheets is one of Nexans key areas of expertise since we design forming/welding machines for the cable and tube industry. With laser investment costs falling, lasers are becoming an attractive alternative to traditional welding methods, like TIG. Moreover, state-of-the-art technology and the opportunity to reduce energy costs is a positive inducement to change. Our innovation makes it possible for tube and cable manufacturers (who produce metallically-sheathed cables or fiber in metal tubes) to significantly lower investment costs or achieve higher production speeds.