To further strengthen the cluster effect of the laser industry, the 2021 High-Power Fiber Laser Technology and Its Advanced Industrial Applications Forum was held in Chengdu on April 21. During the forum, renowned academicians, experts in the high-power fiber laser field, industry representatives, and heads from relevant government departments delivered keynote speeches.

As an advanced technology in laser manufacturing, laser cleaning plays a crucial role in enhancing the competitiveness of China's high-end manufacturing equipment industry. Standardization and regularization within the laser cleaning sector will accelerate industry growth, helping to establish laser cleaning as a standout feature in the blueprint for advancing modern manufacturing.

In laser welding, the shielding gas significantly influences weld bead formation, weld quality, penetration depth, and weld width. In most cases, introducing a shielding gas has a positive effect on the weld, but it can also lead to unintended drawbacks.

In urban areas, fine particulate pollution consistently reaches levels severe enough to pose health risks. Notably, 25% of these fine particle emissions come from brake pad wear.

Laser welding technology—boasting significant advantages in joining metal materials such as aluminum alloys, magnesium alloys, copper alloys, nickel alloys, and titanium alloys—is gradually replacing traditional welding methods. This advancement is accelerating the adoption of laser welding across various industries, including batteries, bathroom fixtures, new-energy vehicles and their components, hardware, jewelry, and 3C products.

There are two main forming methods for automotive body parts: separate forming and integral forming. The separate forming method involves using different presses to shape individual components individually, which are then welded together to create the final part. While this approach enhances flexibility in material selection, it also leads to higher costs associated with stamping, machining, and assembly, as well as challenges in achieving precise shape alignment. Additionally, the overlapping of materials during spot welding can inadvertently increase the overall weight of the vehicle body. In contrast, the integral forming method uses a single press to simultaneously shape multiple components from a single sheet of metal. From the perspective of body structure design, each component has unique requirements for thickness and corrosion resistance. However, if a single sheet is used for all parts, it necessitates employing the same grade, coating type, and material thickness across all components. This often results in excessive material selection for certain parts, leading to unnecessary weight increases, higher production costs, and greater complexity in the forming process. To reduce vehicle weight, improve assembly precision, enhance body rigidity, and lower both stamping and assembly costs during automotive manufacturing—while simultaneously minimizing the number of body parts—it’s essential to move toward integrating these components into a cohesive whole. As a result, a new production technique has emerged that addresses the limitations of both traditional separate forming and integral forming methods: laser-welded blank (LWB) stamping. Advantages of Laser-Welded Blanks Technology Produced using advanced laser welding technology, LWBs offer remarkable benefits. According to research by international experts, these blanks boast up to 37 distinct advantages. For instance, the ULSAB (Ultra-Light Steel Auto Body) project, launched in 1998, showcased a prototype vehicle featuring 16 LWB components, accounting for approximately 45% of the vehicle’s total body weight. By leveraging LWB technology, the project achieved a 25% reduction in the number of body parts, while simultaneously boosting torsional rigidity by 65% and improving vibration characteristics by 35%. Moreover, the technology enhanced bending stiffness, further reinforcing the vehicle’s structural integrity. The key advantages of laser-welded blanks can be summarized as follows: a. **Reduced Part Count**: By combining multiple components into a single, integrated unit, the number of individual parts required is significantly cut down. This simplifies both production equipment and manufacturing processes, leading to substantial improvements in efficiency and a notable reduction in overall vehicle manufacturing and assembly costs. b. **Enhanced Precision**: Since the various components are laser-welded together before forming, the resulting product exhibits superior accuracy. This minimizes manufacturing and assembly tolerances, ensuring tighter fitment and improved quality control. c. **Weight Reduction**: Optimizing the use of materials—particularly through selective application of high-strength, lightweight steel—leads to a lighter overall vehicle. In an era increasingly focused on environmental sustainability, this weight-saving feature is crucial for improving fuel efficiency. d. **Improved Corrosion Resistance**: With no need for additional reinforcing plates or overlapping seams, the corrosion resistance of the assembled components is dramatically enhanced. The elimination of lap joints not only boosts durability but also reduces the reliance on sealing measures, further lowering maintenance needs. e. **Optimized Material Performance**: Rigorous selection of material thickness and quality enables a significant leap in the strength and impact resistance of individual components. At the same time, the optimized design ensures that more energy is absorbed during collisions, thereby enhancing the vehicle’s passive safety features and protecting occupants in the event of an accident. f. **Material Efficiency and Flexibility**: The ability to vary material thickness while maintaining consistent quality allows for targeted reinforcement in critical areas without compromising overall structural integrity. This approach maximizes material utilization, enabling designers to achieve the most efficient combination of properties tailored to specific applications. g. **Maximized Material Utilization**: By selectively applying high-strength, thick materials in strategically chosen areas, the overall efficiency of material use is greatly improved. Additionally, advanced nesting techniques employed during the blanking process ensure that diverse steel sheets are optimally combined, drastically reducing material waste. h. **Enhanced Structural Rigidity and Vibration Control**: The strategic integration of high-strength materials through laser welding significantly improves the overall rigidity of the structure, optimizing the vehicle’s vibration characteristics. This, in turn, contributes to reduced noise and vibration levels, enhancing passenger comfort and overall driving experience. i. **Support for Wider Vehicle Designs**: Due to limitations imposed by the width of steel mill rolling machines, the availability of wide steel sheets is inherently restricted. However, as the automotive industry continues to demand wider panels, laser welding emerges as an effective and cost-efficient solution to meet these growing needs. Applications of Laser-Welded Blanks Technology Laser-welded blank technology begins with cold-rolled steel sheets of varying thicknesses, strengths, or compositions—whether identical or dissimilar. These sheets are precisely cut into the desired shapes and sizes before being joined together via laser welding, creating a seamless, unified component known as a laser-welded blank. Laser welding offers numerous advantages, including high efficiency, precise energy transfer, minimal post-weld distortion, reduced deformation, and exceptionally smooth surface finishes. As a result, this technology is increasingly being adopted in automotive manufacturing—for components such as those shown in Figure 1. Figure 1: Application of Laser-Welded Blanks in Automotive Components 01 Laser-Welded Inner Door Panels In conventional door panel designs, an additional reinforcing plate is typically added at the front section where the door hinge is mounted, ensuring sufficient structural support for the entire door assembly. This reinforcing plate undergoes separate processes—cutting, stamping, and sub-assembly welding—before being integrated into the final door panel. The newly designed laser-welded door inner panel leverages structural analysis to directly join steel sheets of varying thicknesses or strengths. By capitalizing on the distinct material properties of each component, this approach optimizes the part’s strength and weight compared to using a single sheet. This innovative design strategy involves employing thicker, high-strength materials precisely where the door hinges are installed, eliminating the need for conventional reinforcement processes. As a result, production steps are reduced, streamlining the manufacturing workflow while significantly enhancing side-impact resistance. The rigidity of the structure is improved by approximately 40%, leading to further reductions in interior vehicle noise during driving. Since the entire component is stamped from a single piece, edge trimming is optimized, resulting in a notable increase in material utilization. This translates into impressive overall efficiency gains. For instance, as shown in Figure 2, traditional manufacturing generates 0.886 kg of scrap per part, whereas laser-welded panels produce only 0.138 kg of waste. If we consider that each part saves 0.726 kg of material, the entire vehicle could see a weight reduction of up to 1.45 kg. In terms of reinforcement, traditionally, parts require a combination of 2 mm and 0.8 mm thick steel. However, by switching to laser-welded panels—specifically using 1.8 mm plus 0.8 mm—we can achieve equivalent strength performance while cutting down on material usage. This substitution not only reduces weight but also lowers production costs: each part now weighs 2.15 kg less, translating to a total vehicle weight reduction of 4.3 kg. **02 Laser-Welded Car Pillars** To ensure functionality, car pillars must maintain both adequate rigidity and energy-absorbing capabilities, safeguarding occupant safety during lateral impacts. Traditionally, this would involve designing additional reinforcing ribs. In contrast, laser welding allows two steel sheets of different thicknesses to be joined into a single, unified panel before stamping, as illustrated in Figure 3(a). This method enhances side-impact performance, eliminates the need for reinforcing ribs, reduces vehicle weight, improves assembly tolerances, simplifies production processes, and ultimately cuts costs. During laser welding, the position of the weld seam can be precisely adjusted to meet forming requirements. The resulting joint offers exceptional strength and hardness, effectively resisting lateral impacts while providing superior control over bending. By minimizing intermediate steps, material consumption is reduced by up to 14%. **03 Laser-Welded Car Front Longitudinal Beams** For optimal performance, front longitudinal beams must combine robust rigidity with energy-absorbing capabilities. They need sufficient strength to ensure that, in a frontal collision, thinner steel sections first absorb some of the impact energy, cushioning the initial force. Meanwhile, thicker sections withstand the remaining impact forces without significant deformation, thereby protecting occupants. Figure 2 illustrates how laser-welded panels are applied in automotive door interiors. Figure 3 showcases the versatile applications of laser-welded panels across various vehicle components, including car pillars (a), front longitudinal beams (b), wheel arches (c), and floor panels (d). When using conventional stamping methods, separate reinforcing plates are typically required. However, with laser welding technology, three steel sheets of varying thicknesses can first be joined into a single, integrated panel before being stamped into shape, as depicted in Figure 3(b). This approach not only boosts shock absorption at joint areas but also minimizes the number of individual components, contributing to lighter vehicle weight, simplified manufacturing processes, and cost savings. **04 Laser-Welded Car Wheel Arch Panels** As demonstrated in Figure 3(c), laser-welded panels used in wheel arches incorporate built-in shock-absorbing structures, further reducing both weight and the number of components. This innovation eliminates the need for spot welding, associated materials, and the corresponding welding processes, leading to tangible cost reductions. Additionally, the removal of sealing materials streamlines production and cuts labor costs. **05 Laser-Welded Car Floor Panels** Figure 3(d) highlights how laser-welded panels are increasingly being adopted in car floor applications to enhance crashworthiness and component stability. Beyond these benefits, this technology also enables the elimination of overlapping joints, removes the necessity for sealing materials, reduces overall vehicle weight, and facilitates easier recycling processes. Moreover, laser-welded panels have already become widely utilized in various automotive body components, such as trunk reinforcement panels, trunk inner liners, shock absorber mounts, bumpers, roof structures, chassis frames, and dashboard crossmembers. **Technical Challenges in Laser-Welded Panel Applications** While laser-welded panels offer numerous advantages, they also introduce certain complexities into the stamping process. Differences in plate thickness or material composition can lead to uneven blank deformation, causing issues like non-uniform weld seam movement, distortion, or wrinkling. These factors can alter material flow conditions, resulting in uneven bending and increased thinning tendencies in critical areas. Consequently, the formability limits around the weld seams may decrease, accelerating die wear and necessitating modifications to the press brake and clamping mechanisms. Additionally, as the surface area of the welded panel expands significantly, the required mold dimensions—and consequently, the complexity of mold design and manufacturing—also escalate. This places higher demands on both mold-making expertise and the capabilities of the equipment involved. Only by addressing these challenges can laser-welded panels be successfully scaled up for broader industrial adoption. **01 Design Considerations for Stamping Processes** Because laser-welded panels are composed of pre-formed blanks made from steel sheets of varying thicknesses, strengths, and compositions, stamping processes must be carefully adapted to account for these differences. Particularly near the weld seams, the hardened regions created by laser welding often exhibit enhanced strength, presenting unique challenges during stamping operations. Given that most laser-welded panels are fabricated using deep-drawing steels and dual-phase steels, the high-strength components within these panels are prone to conventional bending-induced springback and distortion during forming. These phenomena pose significant hurdles in controlling the stamping process effectively. Studies have shown that using a fixed clamping gap approach is more effective than applying a constant clamping force for sheet metal stamping, as it helps improve formability, reduces weld seam movement, and optimizes die loading conditions. The fixed clamping gap method proves to be an efficient clamping technique in the stamping of tailor-welded blanks. During the stamping process of laser-welded blanks, wrinkling typically occurs more easily in the thinner material side. Tensile tests conducted on laser-welded blanks [7] reveal that the thinner side experiences significant deformation and severe thinning, often leading to cracking. If the clamping force is too low, the thinner side tends to wrinkle; conversely, if the clamping force is excessive, the thinner side may crack. Additionally, the weld seam at the bottom of the part shifts slightly toward the thicker base material, while the weld seams along the sidewalls and flanges move more prominently toward the thinner base material—and this displacement becomes even more pronounced closer to the edges. To address these challenges, optimized stamping processes can be implemented, such as adjusting the stamping direction or incorporating supplementary process steps, to mitigate issues like excessive thickening in the thinner material, minimize peak tensile stresses in the sheet, and reduce strain concentrations at critical areas. Only by adhering to the fundamental principles of stamping deformation can we accurately design the shapes and dimensions of both the initial坯料 (blank) and semi-finished products, as well as the structural parameters of the die itself, thereby enhancing the overall rationality of the stamping process. Moreover, developing a well-optimized stamping workflow ensures that the material’s inherent deformability is fully utilized, ultimately pushing the forming limits to their maximum potential. 02 Die Development During the stamping of laser-welded blanks, the flow of weld seams and the movement of material are common phenomena. This necessitates careful consideration of potential weld seam migration during die design, ensuring that the die structure is optimized to accommodate these movements effectively. Weld seam shifting, wrinkling in the thinner material, and excessive thinning can all be controlled through strategic modifications to tooling and dies. For instance, employing stepped dies, segmented retaining rings, or multi-cylinder systems for localized clamping, combined with the use of draw beads, can yield notable improvements in managing these issues.