Green Lasers: The Copper Welding Powerhouse

Interplex uses automated green lasers to weld copper with less energy, spatter and pollution

An automated green laser in the process of welding two copper pieces. Source: Interplex

An automated green laser in the process of welding two copper pieces. Source: Interplex

Interplex, a Singapore-headquartered manufacturer and design partner for a variety of other manufacturers, is spearheading the use of green lasers to weld copper,  increasing efficiency, lowering costs and promoting sustainability. 

Green lasers operate at 515 nanometers wavelength rather than the 1030-1070 nanometers wavelength of typical red lasers. The green laser beam significantly lowers the amount of laser reflection from copper surfaces, allowing up to seven times the energy absorption of typical red lasers. Interplex’s recent work also shows green lasers result in a cleaner, better weld than typical fiber lasers.  

In addition, green lasers decrease the amount of weld spatter—the drops of molten metal and non-metallic materials produced during welding. They generate a lower CO2 footprint and power-usage-per-weld joint.  

“The green laser provides a very nice-looking weld while decreasing the amount of energy required to weld 2mm of copper from 6 kW to 2 kW. Green lasers are also more cost competitive and produce results more quickly than typical welding lasers. The technology enables Interplex to speed up manufacturing cycle times and improve production yields,” says Charle Ng Han Kee, global welding specialist for Interplex. 

Green lasers could change EV, telecommunications manufacturing  

Interplex is currently focused on serving Electric Vehicle (EV) manufacturers, who request a variety of welding tasks. An EV’s charging system, converter, sensor systems, and battery pack can all contain copper. In addition, copper is used in electric drives. These can be located anywhere from the motorbox to current collector assemblies.   

“We have to ensure that a copper element is welded well so that it will hold. That makes the EV more marketable. The automotive industry also wants to create quick prototypes. Copper is an important material to deploy for that purpose,” says Ng Han Kee.  

Melting copper is difficult because the metal is reactive during the weld process. As the temperature of the copper increases, the metal tries to dissipate heat. Copper balls up rapidly after it reaches its melting point of 1084.62°C. Leaving a laser on a spot for too long can result in parts covered in soot and black scales. Welding at too high a temperature lessens the quality of the weld. Yet if the temperature is too low, the weld is ineffective. 

A clean weld in a copper part, produced with the help of a green laser. Source: Interplex

A clean weld in a copper part, produced with the help of a green laser. Source: Interplex

Interplex uses the green laser to weld numerous plastic molded parts in vehicles as well. This requires a delicate touch because the heat needs to make the weld without melting the plastic. 

“You have a window of less than three seconds to accomplish the task. That’s why more engineers need to train with this tool. You cannot exceed a certain temperature. You also need to be at a very close distance to accomplish the work,” says Ng Han Kee.  

Interplex’s next set of clients may be telecommunications firms. Copper is a preferred material for cables because it is easy to shape. It is a good conductor of electrical current and less expensive than gold or silver.  

“Give it five years. We should have a lot more green lasers in our Interplex facility. We’ll be able to serve a higher number of clients in both industries by then,” says Ng Han Kee.  

Green Laser Economics 

One of the obstacles for companies offering welding services is purchasing their first green laser. The price for optical components such as a 10kW laser can be up to $100,000.  

Buying such expensive, automated equipment requires having enough business for the niche to thrive. New clients should understand that a green laser is an option, the company offering welding knows how to use it, and its engineers outperform those in other businesses.  

“The green laser is the most powerful laser we have for copper processing and requires three levels of safety clearance to fire it. We’ve done simulations of how to use it before actually using it. We’re learning from every simulation and deployment. There are few standards, models, and articles relating to green lasers,” says Ng Han Kee. 

Even with the challenges, green lasers save money from the get-go. Before green lasers were in use, welders attempted to generate the high power needed to weld copper with Nd:YAG lasers and a longer laser flashlamp pumping. Such methods caused the lens of the primary laser to resonate at a high frequency. Sometimes this led to breakage. Most lenses cost a minimum of $2,000 USD to replace. Green lasers also operate more quickly than typical red lasers. Interplex is learning to turn concerns like the global chip shortage into an advantage by showing it can overcome problems with ease.  

“The chip shortage meant that the laser’s chip had to be installed one month after the laser arrived. Yet the laser worked immediately and perfectly after the chip came. Retaining clients involves boosting their confidence despite hiccups,” says Ng Han Kee.  

He adds using the green laser for the first time was a transformative experience.  

“The moment it fired, suddenly everything in the room was encapsulated in green. The whole room glowed. It was amazing because before, no one could see the beam from the traditional lasers. Everyone can see the illumination generated by green lasers with their eyes,” says Ng Han Kee. 

Green lasers are Class 4 lasers, meaning they are hazardous to view at all times. Being in the same room as an active green laser requires wearing ultrasafe protective goggles.  

Interplex’s key to success was having a close group work together in testing and deployment. That allowed the company to adhere to an efficient timeline. Satisfying clients requires timely installations and tight deliveries on services.  

Team members included senior engineer Naigil Sebastian, who worked on space allocation of the various equipment, the layout of the manufacturing floor space and the process flow to ensure machining and installation tools were well positioned and well spaced; automation engineer Vaishnav Chali Puthiyapurayil, who made sure the integrity of wires were upheld as per schematics; senior automation engineer Samson Anthony, who made certain machine automation ran smoothly and there was an accurate exchange of data between various pieces of equipment and software programs; and Ng Han Kee, who made sure all planned activities and contingencies met the Production Part Approval Process (PPAP) plan. Senior project manager Nathan Govindasam played a significant role by communicating the efficacy and safety of the green laser to Interplex’s clients.  

As Interplex comes to understand green lasers better, it may allow more remote deployments of the tool. This involves an engineer in another location welding with the green laser to confirm the safety before firing it from the manufacturing facility. Interplex is also looking into acquiring and testing blue lasers, which operate at between 360 and 480 nanometers wavelength. Blue lasers are not yet commercially available. Interplex is now researching potential uses for the technology.