Common Problems and Solutions of Aluminum Extrusion

Aluminum extrusion is a process that involves forcing heated aluminum alloy through a die to create objects with a specific cross-sectional profile. While this process is widely used due to its efficiency and versatility, there are common issues that can arise during extrusion. Here’s a detailed look at these problems, their causes, and how to address them:

The production of aluminum extrusion is not simple. During the process it often has problems making the product substandard. Therefore we summarize the following common problems and solutions.

 

 

 

1.Extrusion deformation

Extrusion deformation refers to the aluminum extrusion process, the extruded aluminum profiles appear irregular shape, and even cracks and other problems. The main reason is that the mechanical properties of the aluminum itself is insufficient or the extruder’s operating condition is poor

 

The usual solutions include:

1. Improve the temperature and pressure of the extruder to increase the extrusion force, so that the aluminum is easier to extrude.
2. Optimize the design of the extrusion die to improve the precision and stability of extrusion.
3. Adopting higher strength aluminum.

 

Belows are the process of aluminum extrusion from Hugh Aluminum

2. Thermal cracking

In the aluminum extrusion process, due to the excessive heat generated, the internal aluminum profile is subjected to temperature differences, thermal cracking may occur.

 

This problem is mainly related to the following factors:

1. The temperature of the extruder is too high .
2. The thermal conductivity of aluminum is too low.
3. Uneven temperature of the mold.

To solve this problem, we can consider:

1. Reduce the temperature of the extruder to reduce the heat generated.
2. Optimize the selection of aluminum material, choose more suitable aluminum alloy.
3. Improve the temperature uniformity of the mold, control the uniformity of the mold temperature in the extrusion process.

 

 

3. Air bubbles on aluminum extrusions surface

In the aluminum extrusion process, air bubbles are usually due to the aluminum gas is not completely discharged, or extrusion process to produce air bubbles.

This problem is mainly related to the following factors:

1. Air bubbles remain inside the aluminum .
2. Poor oxidation of the extruder.
3. Poor exhaust piping.

Methods to solve the air bubble problem include:

1. Optimize the ratio of aluminum alloy to improve the antioxidant performance of aluminum.
2. Check the extruder and mold to ensure that the exhaust system is smooth.
3. Appropriately increase the extrusion speed and head vibration to help discharge air bubbles.

 

 

 

 

4. Insufficient hardness of aluminum extrusions

The lack of hardness or strength of extruded aluminum is also a common problem. It is mainly reflected in its inability to support relative weight as a building material and its tendency to break under impact. This problem can even affect the safety of the building, so it is important to pay attention to this one issue:

 

This problem is mainly related to the following factors:

1. The aging and holding time of aluminum extrusions do not strictly comply with the requirements.
2. Problems with aluminum alloy composition (there are other elements in the composition of aluminum alloy).
3. the temperature when extruding aluminum is too high or too low.
4. Problems with the design of the extrusion mold.

 

Methods to solve this problem include:

1. Carry out aging heat preservation in strict accordance with the requirements of the process to ensure that the heat preservation time is sufficient.
2. Control the aluminum alloy composition, for example, the silicon component in 6063 aluminum alloy must reach 1.2%.
3. control the machine temperature and extrusion speed in the process of extruding aluminum.
4. design better molds, test the molds and make adjustments and updates.

 

 

 

5.Dimensional Inaccuracies

Accurate dimensions are critical for many applications, but issues can arise that lead to deviations in the final profile.

1. Warping and Twisting

• Causes:
  • Uneven cooling of the extruded profile.
  • Internal stresses due to improper handling.
• Solutions:
  • Use controlled and gradual cooling techniques.
  • Implement straightening processes if necessary.
  • Ensure consistent handling during and after extrusion.

2. Size Variations

• Causes:
  • Die wear leading to inconsistencies in profile dimensions.
  • Variations in extrusion speed or temperature.
• Solutions:
  • Maintain consistent extrusion conditions (speed, temperature).
  • Regularly monitor die condition and replace when necessary.

 

 

 

6.Inconsistent Material Properties

Inconsistent properties, such as hardness or strength, can occur due to process variations.

1. Grain Structure Issues

• Causes:
  • Improper temperature control during billet heating.
  • Inconsistent cooling leading to varied grain sizes.
• Solutions:
  • Use precise temperature control systems.
  • Implement consistent quenching and aging processes to standardize material properties.

2. Anisotropy (Directional Strength Variation)

• Causes:
  • Uneven metal flow during extrusion.
  • Improper die design.
• Solutions:
  • Optimize die design to promote uniform metal flow.
  • Adjust extrusion conditions to minimize anisotropic effects.

 

 

 

 

Conclusion

By understanding these common problems and their solutions, manufacturers can improve the quality and efficiency of their aluminium extrusion processes. Regular maintenance, process optimisation and proper material handling are key to reducing defects and producing high quality extrusions.

Hugh Aluminum is an aluminum profile manufacturer based in China. We have been in the aluminum extrusion industry for 15 years. We currently have five extrusion lines with production capacity of anodizing, powder coating, CNC, welding and polishing.