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Stretch Stretch forming is a metal forming process used to shape sheet metal into curved or contoured parts by stretching the material over a form or die.
Forming This process involves applying controlled tensile forces to the sheet metal to achieve the desired shape while maintaining its uniform thickness.
Stretch forming is commonly used in industries such as aerospace, automotive, and architectural applications to create complex and aesthetically
pleasing components.
The key steps in the stretch forming process are as follows:
• Preparation: A flat sheet of metal is placed over a die or form that has the desired contour or curvature.
• Clamping: The edges of the sheet are clamped securely to prevent movement during the forming process.
• Stretching: Tensile forces are applied to the sheet, typically by hydraulic or mechanical means. This stretching causes the material to gradually
conform to the shape of the die.
• Forming: As the stretching continues, the sheet metal gradually takes on the contour of the form or die, resulting in a smoothly curved or (Source of image:
shaped part. https://www.thermalengineering.co.uk/our-
• Release and Trimming: Once the desired shape is achieved, the clamps are released, and the formed part is removed from the die. Excess capabilities/stretch-forming/)
material may be trimmed off if necessary.
Stretch forming offers several advantages:
• It allows for the creation of complex, contoured shapes that are difficult to achieve using other forming methods.
• Uniform thickness of the material is maintained, leading to consistent mechanical properties.
• Minimal material distortion and spring-back compared to other forming processes.
• Smooth and high-quality surface finish.
However, stretch forming also has limitations:
• It may require specialized equipment and tooling, which can be costly.
• Certain shapes may be challenging to achieve using stretch forming, especially those with tight radii or complex curves.
• Setup and tooling changes can take time, making it more suitable for larger production runs.
Stretch forming is used to produce a wide range of components, including aircraft fuselage sections, architectural panels, automobile body parts,
and curved structural elements. It is particularly valued in applications where both aesthetics and structural integrity are important.
Spinning The spinning process, also known as spin forming or metal spinning, is a metalworking technique used to shape a flat metal disc or blank into a
desired hollow, cylindrical, or conical shape. It involves rotating the blank while applying force to it, causing the metal to flow and take on the shape
of a rotating form or mandrel. Spinning is commonly used to produce symmetrical parts with smooth surfaces, such as cylindrical or conical objects.
The spinning process is widely utilized in industries like aerospace, automotive, lighting, and household items to create a variety of products,
including lampshades, cooking utensils, automotive components, and more.
Here's an overview of the spinning process:
• Blank Preparation: A flat metal blank, often in the shape of a circular disc, is cut to the appropriate size and placed on a spinning lathe.
• Setup: The blank is clamped between the spinning lathe's chuck and tailstock. A mandrel or form, shaped to match the desired final shape, is
placed against the blank.
• Rotation and Compression: The spinning lathe is activated, causing the blank to rotate rapidly. The operator applies pressure using specialized
tools, causing the blank to deform and flow over the form. This compression process shapes the metal around the form. (Source of image:
• Shape Adjustment: The operator may adjust the pressure and positioning to achieve the desired shape and dimensions. The spinning process https://www.youtube.com/watch?v=
can involve multiple passes or steps to achieve more complex shapes. 43N44ICyuEU)
• Finishing: Once the desired shape is achieved, the formed part is removed from the lathe. Additional finishing steps, such as trimming,
smoothing, and polishing, may be performed to achieve the final desired appearance.
Key characteristics of the spinning process include:

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