Why are heavy equipment frames commonly constructed using welded frames rather than castings?
Publish Time: 2025-08-25
In heavy machinery and equipment, such as construction machinery, presses, large machine tools, wind turbines, and automated production lines, the frame serves as the core structure that bears the weight of the entire machine, transmits loads, and supports moving parts. Its design and manufacturing are directly related to the stability, safety, and service life of the equipment. Despite the long history and strong molding capabilities of casting, modern heavy equipment frames have generally shifted to welded frames, becoming the mainstream choice. This shift is not accidental; it is based on the comprehensive advantages of welded structures in terms of design flexibility, manufacturing efficiency, cost control, material performance, and maintainability.1. Flexible Design, Adaptable to Complex and Non-standard StructuresHeavy equipment often has unique functional requirements and spatial layouts. Their frame structures are complex and often include non-standard features such as multi-level supports, special-shaped sections, and integrated mounting platforms. Welded frames are constructed from raw materials such as steel plates and steel sections (such as H-beams, square tubes, and angle steel). These frames are cut, bent, assembled, and then welded together, allowing for easy realization of a wide range of geometric shapes and spatial configurations, offering a high degree of design freedom. In contrast, castings rely on molds. Design changes require re-manufacturing, resulting in high costs and long lead times, making them difficult to adapt to the high-variety, small-batch manufacturing demands of modern manufacturing.2. Short Manufacturing Cycle Time and High Delivery EfficiencyThe casting process is complex, and production cycles often take weeks or even months. Welded frames, on the other hand, utilize modern processes such as CNC cutting (such as laser and plasma), bending, and robotic welding. With standardized raw materials and a high degree of automation, the process can go from drawing to finished product within a few days, making them particularly suitable for urgent projects or equipment development requiring rapid iterations. For engineering equipment requiring rapid delivery, welded frames significantly shorten the overall manufacturing cycle.3. Controllable Material Properties and Higher Structural StrengthAlthough cast parts are integrally formed, they are prone to internal defects such as porosity, shrinkage, and slag inclusions, which affect the uniformity of mechanical properties. They are particularly prone to cracking at these defects when subjected to dynamic loads, shock, or vibration. Welded frames, on the other hand, utilize high-quality structural steel (such as Q345B, 45# steel, and stainless steel) with stable material properties. Through the appropriate design of stiffeners, ribs, and load paths, equal or superior strength designs can be achieved. Critical welds undergo flaw detection (such as ultrasonic and X-ray) to ensure high structural reliability. Furthermore, after welding, an overall annealing treatment can be performed to eliminate residual stress and prevent deformation during long-term use.4. Lightweight Design Improves Equipment Energy EfficiencyWelded structures facilitate "on-demand material placement," where reinforcement is applied in high-stress areas and thinning is applied in low-stress areas, avoiding material waste. Optimized cross-sectional design (such as box beams and trusses) can significantly reduce weight while maintaining rigidity. In contrast, castings often require thicker walls to ensure fluidity, resulting in "bulky" structures that are heavy and consume more energy. Lightweight welded frames not only reduce equipment weight but also reduce transportation and installation costs, improving overall energy efficiency.5. Significant Cost Advantages, Especially Suitable for Small and Medium-Sized Production BatchCasting requires high mold investment and is only suitable for large-scale production to spread out costs. Welded frames, on the other hand, require no molds. Raw materials are standard profiles or steel plates, making procurement easier and the processing equipment more versatile. The production cost of single pieces or small batches is significantly lower than that of castings. For customized heavy equipment, welded frames are more economical.6. Easy Modification and Maintenance, Extending Equipment LifeEquipment may require upgrades, modifications, or repairs during use. Welded frames offer excellent disassembly and weldability. Partial damage can be cut and replaced, and new components can be directly welded and installed, making maintenance easy. Cracked or damaged castings, on the other hand, are difficult to repair and often require costly replacement.7. High Level of Integration, Facilitating Functional ExpansionWelded frames allow for pre-defined mounting holes, positioning datums, cable channels, hydraulic connections, and lifting points during the structural design phase, achieving "functional integration" and reducing subsequent processing and assembly steps. Robotic welding also ensures hole placement accuracy and consistency, improving overall assembly efficiency.Welded frames have become the mainstream choice for heavy equipment frames, replacing castings, because they better meet the modern manufacturing industry's comprehensive requirements for efficiency, flexibility, reliability, and cost-effectiveness. They are more than just structural support; they are system solutions that integrate design, process, materials, and functionality.
