The three-section boom flexible production line of Zoomlion's Concrete Machinery Company is currently the most advanced flexible structural component production line in China's construction machinery industry. It not only features numerous highlights but also lays the foundation for improving the production efficiency and product quality of the Concrete Machinery Company.

 

    Highlight 1: Widespread Use of Tooling

 

    Zoomlion has a great many pump truck models and a great many types of pump truck booms. Among all booms, the curved boom is the most difficult to control in terms of quality due to its structural particularity. In the "three-section boom flexible production line," tooling is used for the panel splicing and rivet welding of the upper and lower cover plates, the panel splicing and rivet welding of the left and right webs, the rivet welding of the shaft sleeves, and the assembly and rivet welding of the box body. At present, the use of tooling has basically become widespread across all composite brands. These general-purpose fixtures can achieve accurate positioning of plate parts, and under their assurance, the manufacturing precision and production efficiency of products have been greatly improved, and the manufacturing cycle has been shortened.

 

    Compared with straight booms, curved booms are not only more difficult to control in quality but also present difficulties in flanging. In the past, the flanging of boom bodies and plates was carried out by traditional crane-bound flanging, which was complicated to operate and had a low safety factor. Stability during the flanging process was poor, and a slight lapse could cause the boom body or plates to fall off, posing serious safety hazards. Now the "three-section boom flexible production line" uses a dedicated plate splicing and welding flanging machine and a dedicated fixed chain flanging machine for boom bodies. In the future, a more advanced electric hoist chain flanging machine will also be introduced, and both the efficiency and safety of flanging will be greatly improved.

 

    Highlight 2: Robotic Welding

 

    Welding quality control has always been a major challenge in structural component manufacturing. Welding operations are the main factor affecting quality and depend to a large extent on the skill level and quality awareness of the welder. The welding environment is usually very harsh. During welding in summer, the local temperature can even reach as high as 50°C, the labor intensity for welders is very high, and operational stability is difficult to control. In the past, when output was high, quality was often difficult to guarantee, and the failure rate of weld quality remained high. In addition to the operator's own reasons, factors such as airflow, temperature, and humidity during the welding process can also lead to weld quality problems. At present, the "three-section boom flexible production line" has introduced advanced foreign welding robots for welding, mainly used for double-sided welding of webs, internal welding during box assembly, and external welding of boom bodies. After workpieces are mounted on tooling and fixtures, automatic welding can be achieved by calling up programs, greatly reducing workers' labor intensity. At the same time, the robots also have functions such as contact seam finding, arc tracking and laser tracking, and automatic preheating of shaft sleeves, further ensuring welding quality.

 

    Highlight 3: Flow-Line Operation

 

    The box assembly process of the "three-section boom flexible production line" adopts precise lifting and automatic transfer. Through precise lifting, the upper and lower cover plates and the left and right webs are lifted onto the box assembly tooling and fixed, after which automatic transfer begins to the next workstation for riveting. After riveting is completed, the workpiece continues to flow to the next workstation to complete the corresponding work content. Each workstation has a clear division of labor, and the flow is orderly. After the last workstation of box assembly is completed, it can also return automatically, greatly improving the efficiency of box assembly. The currently planned and under-construction "three-section boom flexible production line" will adopt automatic rail traction transfer for the repair welding and inspection process. This "repair welding and inspection assembly line" can achieve functions such as automatic disengagement from traction, rapid re-establishment of traction, and automatic return. At the same time, advanced lean concepts will be used to design the working rail and the empty return rail differently, maximizing the use of site space. In the design of rails and other supporting tooling, full consideration has been given to cost, replicability, and the convenience and safety of personnel operations, which will greatly improve production efficiency and production safety.

 

    Highlight 4: Standardized Management

 

    The "three-section boom flexible production line" has also specially designed relevant processes for handling abnormal conditions and introduced corresponding fault-reporting equipment, which can greatly improve the response speed for handling abnormalities, reduce abnormality handling time, and improve production efficiency. In addition, for key work content in the production process, dedicated personnel assignments and corresponding process specifications have been implemented, greatly improving product quality. In the future, the "three-section boom flexible production line" will also adopt an electronic pull delivery system. Through the combination of the electronic pull delivery system and a visual system, logistics delivery efficiency will be further improved and the accumulation of line-side inventory will be reduced. Relevant responsible personnel can see the status of the entire production line at a glance through electronic kanban boards.

 

    "First-class enterprises manufacture first-class products, and first-class products originate from first-class manufacturing technology." As a representative of Zoomlion's advanced production lines, the "three-section boom flexible production line" has greatly improved the production efficiency and quality of Zoomlion curved booms and reduced the product production cycle and workers' labor intensity. In future production, it will certainly add strong momentum to Zoomlion's development.