7.3 Forming Techniques for Complex Shapes
Key Concepts
1. Press Braking
Press braking is a forming technique that uses a press brake machine to bend sheet metal into complex shapes. The machine applies controlled pressure to create precise bends and angles. Press braking is versatile and can handle a wide range of materials and thicknesses.
Example: In automotive manufacturing, press braking is used to form the body panels of cars. The precise bends and curves created by the press brake ensure that the panels fit together perfectly.
2. Roll Forming
Roll forming involves passing a continuous strip of sheet metal through a series of rotating rolls to gradually shape it into a complex profile. This technique is ideal for creating long, uniform shapes with intricate details. Roll forming is commonly used in the production of roofing materials, structural beams, and automotive components.
Example: Roll forming is used to create the continuous ridges on a corrugated metal roof. The metal strip is gradually shaped by the rolls, resulting in a uniform and durable final product.
3. Stretch Forming
Stretch forming is a technique that involves stretching a sheet of metal over a mold while applying pressure to conform it to the desired shape. This method is particularly effective for creating large, complex shapes with smooth surfaces. Stretch forming is often used in aerospace and automotive industries for parts like aircraft fuselages and car hoods.
Example: In aerospace manufacturing, stretch forming is used to create the curved surfaces of aircraft wings. The metal is stretched over a mold, ensuring a smooth and aerodynamic shape.
4. Hydroforming
Hydroforming uses hydraulic pressure to shape sheet metal over a die. High-pressure water or oil is used to force the metal into the contours of the die, creating complex shapes with high precision. Hydroforming is suitable for both small and large parts and is often used in automotive and aerospace industries.
Example: Hydroforming is used to create the complex shapes of automotive fuel tanks. The high-pressure fluid ensures that the metal conforms perfectly to the die, resulting in a seamless and strong final product.
5. Deep Drawing
Deep drawing is a forming technique that involves pressing a sheet of metal into a die to create deep, hollow shapes. This method is commonly used for manufacturing items like automotive body panels, kitchen sinks, and beverage cans. Deep drawing requires precise control of pressure and temperature to prevent material failure.
Example: Deep drawing is used to create the body of a beverage can. The metal sheet is pressed into a die, forming the cylindrical shape with a smooth interior surface.
6. Spin Forming
Spin forming involves rotating a sheet of metal while applying pressure to shape it into a symmetrical form. This technique is ideal for creating circular or conical shapes with uniform thickness. Spin forming is often used in the production of light fixtures, decorative items, and industrial components.
Example: Spin forming is used to create the reflective surfaces of parabolic antennas. The metal sheet is rotated at high speed while pressure is applied, resulting in a perfectly symmetrical and smooth surface.
7. Incremental Forming
Incremental forming is a flexible technique that uses a CNC-controlled tool to gradually shape the metal by applying localized pressure. This method allows for the creation of complex geometries with minimal tooling. Incremental forming is suitable for prototyping and small-batch production.
Example: Incremental forming is used to create custom automotive parts. The CNC-controlled tool applies precise pressure to the metal, shaping it into the desired complex geometry without the need for extensive tooling.