Part five: Air bubble, Aluminum extrusion defect analysis and quality control method

Part five: Air bubble, Aluminum extrusion defect analysis and quality control method 

Air bubble, Aluminum extrusion defect analysis and quality control method 

Air bubble

The local skin metal is continuously or discontinuously separated from the base metal and shows a defect of a round single or strip-shaped cavity bulge, which was called air bubble.

It is one kind of defect in aluminum extrusion.

The main causes of air bubbles:

1. When it is in the extrusion process, the extrusion container and the dummy block with moisture, oil and graphite;

2. Due to the wear of the extrusion container, the air between the worn parts and the ingot go into the metal surface in the extrusion;

3. There is moisture in the lubricant;

4. The billets structure itself has loose and porosity defects;

5. The heat treatment temperature is too high, the holding time is too long, the atmospheric humidity in the furnace is high;

6. The hydrogen content in the product is too high;

7. The temperature of the extrusion container and the temperature of the billet are too high;

8. The gap between the billets and the extrusion container is too large, and bubbles are easily formed between the container wall and the extrusion container;

9. The extrusion speed is too fast, and the air bubbles are caused by the increase of the air volume in the extrusion container.

Solutions for air bubble

1. The surface of the tool and billets remains clean, smooth and dry;

2. Reasonably design the matching size of the extrusion container and the dummy block, and clean the extrusion container. When the extrusion container has a problem, it should be repaired in time, and the dummy block should not be out of tolerance;

3. Ensure that the lubricant is clean and dry;

4. Strictly abide by the extrusion process operation process, timely exhaust, correct cutting, no oil, completely remove the residual material, keep the mill finish and tools and molds clean and not contaminated;

5. The air content inside the aluminum casting billets should be minimized；

6. Control aluminum billets temperature not too high；

7. Control the amount of lubricant applied to avoid excessive lubrication；

8. Control the extrusion speed and make it according to the extrusion process.

Brightstar Aluminum Machinery provides not only aluminum profile shape corrector, aluminum profile wrapping machine and aluminum profile polishing machine auxiliary equipment, but also wood grain effect sublimation machine, aluminum profile brushing cleaning machine and aluminum profile shot blasting machine etc for our customers.

Turnkey project and completed solution, package deal and one-stop service. 

Contact us now for your aluminum project solution!

Get A No-obligation Quote