Today’s metal service centers are expected to offer more than just raw material. Their customers are often looking for metal fabrication services, first-step or custom processing, and even finished parts. Fab shops will turn to their metal supplier to expedite their own manufacturing and assembly operations. As service centers look to add more value, fiber laser cutting is becoming easier to justify as a way to process a wide range of material types and thicknesses.
Taking that a step further is the extra-large, or XXL, format fiber laser cutting system. With table sizes starting at 40 ft. (12 m), such a system takes a service center’s cutting capabilities and business opportunities to a new level.
Fiber laser advances
Many service centers rely on a number of methods to process the materials their customers order, including flat sheet and tube cutting, sawing and shearing. Plasma cutters have long been a staple of the service center operation, known for their high productivity, wide cutting range and low cost of ownership. They offer a cut quality that is often adequate for many applications.
Historically, laser cutting had limited appeal for service centers. While laser cutting was more precise than plasma, the cutting range was limited and a higher price tag meant a longer payback time. Exponential advances in fiber laser cutting technology – the rise of high-power sources 10 kW and above, auto-adjusting cutting head designs, and integrated automated features like the 30-position automatic nozzle changer – as well as new XXL format systems are changing the story.
The gantry-style design of the XXL format laser cutting machine is similar in construction to a plasma cutter. The gantry provides accurate motion for the machine and rugged construction to support the size and weight of the system.
The advantage of this design is that the limitation in the machine’s length comes down to the available floor space and not the machine construction. The system in Figure 1 is a modular format starting at a 40-ft. bed length and expandable in increments of 6.5 ft. (2 m) up to a bed length of 130 ft. (40 m). It allows the use of extra-large sheets, which means more efficient nesting and less material handling throughout the process.
Power and performance
Power and performance are additional reasons XXL format laser cutting systems are a great fit for service centers. High-kilowatt power sources provide higher cutting speeds, a broader cutting range, faster piercing times and the ability to cut thick materials faster and more efficiently with no secondary finishing required. This all adds up to more throughput at a lower cost per part.
A 20-kW laser is able to process ferrous and non-ferrous materials up to 40 mm thick, cutting up to 2.5 times faster than a 10-kW laser. The 20-kW laser pierces and cuts thick materials at rates faster than most plasma cutting systems with straighter kerfs and the ability to cut holes half the thickness of the sheet. Advanced cutting technologies offer a rapid piercing time in thick plate of less than 3 sec. For the service center, the high-power laser translates to increased capacity to take on more work, a greater diversity of jobs and a higher potential profit margin.
Using an assist gas mixture of nitrogen and oxygen is also becoming more commonplace. Introducing a small percentage (3 percent) of oxygen into the nitrogen assist gas provides a number of advantages, including better edge quality (no dross or burr) in mild steel and a significant gain in cutting speed, particularly in thick mild steel. Cutting with oxygen in 3/4-in. mild steel provides a cutting speed around 40 ipm. By employing a mixture of 97 percent nitrogen and 3 percent oxygen with a 20-kW laser, cutting speeds are improved to 180 ipm.
A gas mixing device is required to mix assist gases. This device is integrated into the laser cutting machine, which controls the pressure of the mixed assist gas. The gas mixing device is an additional investment but can generate impactful savings in assist gas as well as increases in cutting speed and productivity.
Stable and consistent
With an XXL format laser cutting system, a service center can accommodate large and complex jobs to enhance its competitive edge. The laser can process large parts without repositioning and smaller parts can be positioned on the cutting table and processed in continuous fashion, without interrupting the laser cutting process.
Advanced software supports smart nesting to optimize part programming and cutting. Parts can be cut on one section of the table, while offloaded on another, keeping downtime to an absolute minimum. Continuous cutting eliminates steps in the process and saves time and money.
Large-format fiber lasers can cut thicker materials and can cut over longer periods of time, unlike plasma. The end result is a high level of productivity.
Fiber laser cutting technology is stable and consistent. Even when cutting in a large format, the laser system can operate without supervision and in a lights-out manner. To address health and safety risks of XXL format laser cutting, manufacturers have incorporated greater protections for system operation and maintenance. This includes multiple control panels situated at strategic points along the machine, collision-prevention 2-D scanners, an integrated fume exhaust system, and scrap bins with fork pockets for easy removal by forklift. These safeguards enhance process reliability.
More than just the basics of providing plates, tubing, bars and sheet, the metal service center looking to bring more to the table needs to consider technologies that allow for increased efficiency and precision. More than any other thermal cutting process, fiber laser cutting technology in an XXL format system can deliver dynamic advantages that translate to a more agile business model and increased sales revenues and profits.