The Cold Extrusion Forming Principle and Applications of Automatic Thread Rolling Machines
Automatic thread rolling machines utilize cold extrusion technology to form threads, offering advantages over traditional cutting methods. This process leverages the plastic deformation characteristics of metals at room temperature, where mechanical force creates the desired thread structure on the workpiece surface. By using cold extrusion, this method improves both processing efficiency and the performance of the workpiece, making it widely applicable in industrial manufacturing.
I. Cold Extrusion Forming Principles
The core principle of cold extrusion forming in thread rolling machines is the synergistic effect of ‘plastic deformation’ and ‘die shaping.’ In operation, two rotating threading wheels with specific thread profiles work in opposite directions, and the workpiece is fed between them. As the wheels rotate, their tooth surfaces apply uniform, continuous pressure to the workpiece, which exceeds the metal’s yield strength but stays below its fracture strength. This induces plastic flow in the surface layer of the workpiece.
Roller grooves constrain the flowing metal and progressively form a thread that matches their profile. The process removes no material; it creates the shape by rearranging the metal’s internal grains. As a result, the finished threads have a smooth surface and enhanced hardness, with increased wear resistance due to the work-hardening effect, improving the overall mechanical properties of the workpiece.
II. Applications of Cold Extrusion Thread Rolling Machines
In practice, the cold extrusion process is used across various industrial sectors, taking advantage of its unique benefits:
• Automotive Manufacturing: Automotive manufacturers commonly use cold-extruded threads for critical connecting components such as bolts, nuts, and half-shafts. These parts require high thread strength and precision. Cold-extruded threads can endure higher torque and impact forces, minimizing the risk of loosening during vehicle operation.
• Construction: Cold-extruded threads are applied in rebar couplers and scaffolding fittings, ensuring stable connection points that meet the structural load-bearing demands.
• Mechanical Equipment Manufacturing: Manufacturers use this process to create high-precision threaded interfaces in drive shafts and hydraulic components. This minimizes the risk of leakage or loosening during operation.
• Hardware Tools and Home Appliances: Cold extrusion forming offers high processing efficiency (typically seconds to tens of seconds per piece) and nearly 100% material utilization, which lowers production costs while meeting mass production demands.
III. Advantages Over Traditional Cutting Processes
Compared to traditional cutting methods, cold extrusion forming on automatic thread rolling machines not only streamlines production workflows but also eliminates material waste and stress concentration issues. The process significantly reduces machining time and improves thread strength, resulting in enhanced performance for threaded components.
As industrial demands for higher performance components continue to grow, cold extrusion forming will see increasing applications in high-precision, high-strength thread manufacturing scenarios. This process is rapidly becoming a key technological driver for improving both quality and efficiency in the manufacturing sector.