Roll forming, as an advanced forming technology, is a significant forming method in sheet metal forming. For the specific process of roll forming, evaluating the formability of automotive roll-formed parts is a prerequisite for reasonable material selection, forming process design, and optimization. It is an important factor in predicting the forming process of automotive roll-formed parts, improving forming precision, and controlling the forming quality of the parts.
Roll forming is a sheet metal deep processing technique that continuously bends metal sheets such as coils and strips transversely using sequentially arranged multi-pass forming roll molds to produce specific cross-sectional profiles.
Roll forming is an energy-saving, material-saving, efficient, and advanced sheet metal forming technology. Compared to other sheet metal forming processes, roll forming not only has high production efficiency and low investment but also produces roll-formed parts with high precision, good consistency, and optimal cross-sectional mechanical properties.
Roll forming is suitable for a wide range of materials, including various mechanical properties and different organizational structures of steel, aluminum alloys, magnesium alloys, especially ultra-high strength steel.
Roll forming uses multi-pass gradual bending forming, which can achieve smaller bending radii compared to stamping forming. It can form various open or closed complex cross-sectional parts, and the formed part has good stiffness. Through multiple passes of deformation, springback compensation is performed, making it easier to control springback and achieve good forming accuracy with high dimensional precision and good surface quality of the parts.
Roll-formed parts have excellent performance. When manufacturing automotive structural components with the same material and sheet thickness, roll forming absorbs 25% more energy during impact deformation compared to cold pressing. Thus, it can reduce the sheet thickness and weight by approximately 15% (according to estimates by Kobe Steel).
Compared to stamping forming, roll forming uses continuous feeding, with a forming speed that can exceed 10 m/min in production, enhancing efficiency over 10 times compared to stamping and bending processes, significantly improving production efficiency. Moreover, roll forming does not require high-tonnage presses, greatly reducing manufacturing costs.
Roll forming has a high material utilization rate. The blank for roll-formed parts is a sheet of a certain width, and except for punching, there is almost no excess waste such as trimming as in stamping processes. Therefore, compared to stamping, it can save 15%~30% material, with significant material cost advantages.
Other processing technologies can be integrated into roll forming production lines, such as punching, welding embossing, bending, etc., leading to a high degree of automation in the production process.
Roll forming has a significant cost advantage. According to Kobe Steel, it can reduce costs by about 15~20% compared to cold pressing and about 30% compared to hot pressing.
The production noise is low, and there is no environmental pollution.
Roll forming can produce various parts, mainly including: front and rear bumper beams, door sills, seat beams, exterior panels of automotive door frames, outer water-cut bright strips, door tops, window regulator guides, glass guides, seat rails, door guides, anti-trim strips, etc. With the control of costs and the requirements for lightweight design by the main engine plant, as well as automotive engineers' understanding of roll forming, more parts in automobiles will be applied to roll-formed parts.
