Aluminum bending typically refers to the bending process of aluminum extrusion profiles, commonly used in various applications like pipes, rods, and structural shapes. It also includes the bending of aluminum sheets.
Aluminum profiles are widely used in construction and industrial fields due to their light weight, corrosion resistance, and ease of processing. During usage, aluminum profiles often need to be bent to meet specific design requirements. Well-designed and effectively bent profiles create seamless connections within structures.
The most common bending process for aluminum is cold bending. The cold bending aluminum profile process allows parts to achieve optimal shaping allowances, enhancing manufacturing precision while reducing production costs. The bending aluminum profile process finds extensive applications in manufacturing bent components for architecture, curtain walls, aviation, aerospace, automobiles, and high-speed rail.
Performance of Bending Aluminum Profiles
Two crucial factors determine the bending performance of aluminum profiles:
- Aluminum Alloy Elements
The bending performance of aluminum profiles mainly depends on their microstructure and the alloy elements’ content. Generally, adding alloy elements can significantly increase aluminum’s strength and hardness but also make it more brittle, which hinders bending. Therefore, it’s essential to select the appropriate strength and hardness based on the specific application needs.
Tip: You can refer to common aluminum alloy grades to understand their composition. Read more: - Heat Treatment State
The bending performance of aluminum profiles also relates to their heat treatment state and surface finish. Heat treatment alters the aluminum’s grain structure and stress state, improving its bending performance. Common heat treatments include annealing, solution treatment, and aging, which can significantly enhance bending capabilities. Surface treatments like spraying, anodizing, and electrophoretic coating typically improve corrosion resistance and surface hardness but have little effect on bending performance, which is generally negligible.
Tip: For parts with a challenging minimum bending radius, adjusting the heat treatment state can help. Read more:
Common Aluminum Alloys Used for Bending
Commonly used aluminium alloys include:
- Series 1xxx (Pure Aluminum): Known for excellent corrosion resistance and high ductility, these alloys are ideal for applications requiring minimal strength but maximum flexibility.
- Series 3xxx (Aluminum-Manganese): Offers good corrosion resistance and moderate strength, making it suitable for roofing, cladding, and other architectural uses.
- Series 5xxx (Aluminum-Magnesium): High strength and corrosion resistance make this alloy ideal for marine and automotive industries. It also demonstrates good bending properties, especially in annealed states.
- Series 6xxx (Aluminum-Magnesium-Silicon): Balancing strength, corrosion resistance, and excellent machinability, this versatile alloy is widely used in construction and transportation.
- Series 7xxx (Aluminum-Zinc): With superior strength and hardness, these alloys are suitable for aerospace applications but require careful handling during bending due to lower ductility.
The commonly used aluminum alloys are 6063, 6061, etc., which are heat-treated to T5 or T6 states to enhance the mechanical properties of the profiles. These alloys are widely applied in various industries, including:
- Construction Industry: Doors, windows, curtain walls, sunrooms, handrails, partitions, etc.
- Transportation: Car frames, train carriages, aerospace components, bicycle frames, etc.
- Electronics and Electrical: Heat sinks, cable trays, electronic device housings, etc.
- Mechanical Manufacturing: Industrial frames, assembly line equipment supports, tool supports, etc.
- Consumer Goods: Furniture, household appliances, sports equipment, lighting fixtures, etc.
Aluminum Bending Processes
There are various forms of aluminum bending processes, with two main classification methods:
Bending Temperature
The process of bending at room temperature is known as cold bending, which doesn’t require additional heating of the material.
Bending that occurs when the metal reaches a certain high temperature is called hot bending. It typically requires heating the metal above its plastic deformation temperature.
Due to the limited plasticity of aluminum profiles at room temperature, cold bending may be challenging for complex shapes with smaller radii. Hot bending, however, can accommodate a wider range of materials and easily achieve smaller radii bends.
Key Point: Cold bending is the preferred process for aluminum bending due to its wide application range and stable forming.
Read more:
Why Choose Cold Bending for Aluminum?
Aluminum Bending: Choosing and Calculating the Minimum Bending Radius.
Bending Methods
There are various mechanical principles for aluminum bending, with the most commonly used being roll bending and stretch bending. In fact, there are many other methods for forming aluminum parts, such as the following 8 bending processes:
- Ram/Push Bending
- Rotary Draw Bending
- Compression Bending
- Free-Form Bending
- Press Brake Bending
- Hydraulic Press Bending
- Fluid Cell Press Bending
- Hand Bending
Read more: How to Choose the Right Bending Process for Aluminum?
7 Steps for Bending Aluminum
- Incoming Material Inspection
Inspect profile cross-sectional dimensions, straightness, blank length, and surface quality. Pay special attention to any surface defects. - Milling
For reverse T-shaped frames, mill the profile cross-section before bending to ensure post-bending dimensions meet specifications. - Pre-Bending
Conduct pre-bending tests on CNC aluminum bending machines to achieve the desired pre-formed shape:- CNC Aluminum Roll Bending Machines: Set roll bending parameters or import drawings for pre-bending. Adjust based on spring-back to achieve optimal results. For the PBA series aluminium bending machines, the CNC system calculates compensation coefficients based on the actual radius, completing the process efficiently.
- CNC Stretch Bending Machines: Use stretch bending molds and clamps to pre-stretch blanks by controlling parameters such as stretching force and bending angles to meet pre-forming requirements.
- Trimming
Verify the flatness and angles of both surfaces, ensuring they meet the required specifications. In stretch bending processes, pre-bending can assist in fine-tuning the R-value to achieve the desired shape. - Inspection After Pre-Bending
Check the flatness, angles, and cross-sectional width of the profile to ensure compliance with specifications. - Mass Production
Proceed with mass production using pre-bending parameters established during testing. - Final Inspection
Use inspection molds along with calipers and feeler gauges to verify that the final products meet technical and drawing requirements specified by the customer.
Conclusion
Aluminum profiles possess excellent bending performance, but their specific bending capabilities depend on factors like alloy composition, microstructure, surface treatment, and heat treatment state. When bending aluminum profiles, it’s crucial to select the right material based on the specific application needs and process requirements. Understanding the proper aluminum bending techniques ensures high bending performance and quality.