A Decade of Transformation
Just ten years ago, fiber laser cutting machines were viewed as specialists for thin sheet applications. Today, these machines have undergone a remarkable evolution, compelling fabricators to invest in them not just for thin sheets but also to compete in cutting thicker gauge materials. The landscape of laser cutting, especially for sheet metal fabricators, has experienced a significant shift.
Elevating Cut Quality
The journey toward high-quality plate cutting with fiber lasers was initially hindered by the limitations in cutting thicker stock. However, with advancements in assist gas technology, specifically through gas mixing, the scenario has dramatically changed. Modern fiber lasers, boasting powers ranging from 20 to 50 kW, are now achieving swift and clean cuts through thick plates.
The operative word here is “cleanly.” The economic viability of laser cutting sheet metal is now intricately linked to the cost per part. High-powered lasers have found their niche in precision plate cutting, replacing traditional methods like plasma cutting and milling. Assist gas mixing, particularly with a nitrogen-oxygen blend, has played a pivotal role in making this transition possible.
Evolution of Gas Mixing Strategies
Gas mixing applications had their roots in the dross-free cutting of aluminum more than a decade ago. However, as fiber lasers took center stage, gas mixing strategies evolved.
Engineers began experimenting with different nitrogen and oxygen ratios, ultimately paving the way for precise mixes that optimized cut quality and speed.
The early 2010s saw the emergence of gas mixing for a 4-kW CO2 system cutting 0.125-inch-thick aluminum. The unique features of aluminum demanded a careful balance, and gas mixing proved to be a crucial ally. With the rise of fiber laser powers, the industry witnessed a shift towards precise nitrogen-oxygen mixes, particularly in the 1.5% to 5% range, depending on the application and machine.
Challenges and Solutions
Despite the strides made in gas mixing technology, challenges surfaced, especially with higher-powered fiber lasers cutting thick stock at high speeds. Gas consumption became a critical factor, and achieving a laminar flow of assist gas around the powerful laser beam became imperative. Nozzle designs were optimized, and innovative technologies like air “curtains” were introduced to ensure the best-cut quality at the lowest cost per part.
Future Trends in Gas Mixing Technology
As we look ahead, the future of gas mixing technology demands digital control interfaces for enhanced consistency. Programmable mixing systems are becoming standard, adapting to variations in materials and ensuring a consistent gas mix under variable conditions. The industry’s focus is now on refining plumbing and gas supply systems to accommodate the increasing powers of metal laser cutting machines.