X-ray detection of internal defects in die castings

aluminum castings are widely used in industries such as automotive parts, mechanical manufacturing, computers, electronics, medical equipment, watch instruments, hardware products, aerospace, etc. Mainly because Aluminum castings have a smooth surface, high practicality, and precise dimensions. The general casting production process mainly includes: material selection - melting - low-pressure casting - X-ray inspection - cleaning, Sandblasting, deburring - heat treatment - mechanical processing - surface treatment. However, the finished castings often have too many defects. Casting is one of the basic processes in modern mechanical manufacturing industry, which has the advantages of low cost, one-time forming, and the ability to manufacture complex structural large parts. It is widely used in automotive parts, mechanical manufacturing, electronics Numerous fields of industrial production such as medical equipment, clock instruments, hardware products, aerospace, etc.

Casting, as an important fundamental industry in the mechanical industry, with the rapid development of information technology, improving the production efficiency and quality of casting will be a necessary task for many casting workers. The high scrap rate of castings has always been a common problem in various casting methods in the industry. It is particularly important to better control the quality of castings and improve casting processes.

Due to the complexity of the casting process, there are many factors that affect the quality of castings. Poor control of raw materials, unreasonable process plans, unreasonable design of mold structures, and improper production operations can all lead to various defects in castings. Common defects include inclusions, bubbles/pores, porosity, and cracks.

Common defect factors:

1. Cracks

Mainly caused by unreasonable structural design and substandard manufacturing processes, the cracks mainly come in two forms: casting cracks and heat treatment cracks. The cracks appear as light colored lines in the X-ray inspection image.

2. Bubbles/pores

This is mainly caused by poor ventilation during the casting process, as well as the doping of air or impurities. The bubbles/pores on the surface of the workpiece can be detected by sandblasting, and the bubbles/pores inside the workpiece can be detected by X-ray fluoroscopy.

3. Looseness

Mainly caused by unreasonable design structure, casting porosity generally occurs at the thick and thin junction of the wall near the inner runner, the thicker part of the flying riser root, and the thin-walled part with a large plane. X-ray fluoroscopy can reveal this defect, which is severely filamentous in X-ray images and generally appears as a light colored cloud.

4. Inclusions

Mainly caused by unclean furnace materials or improper operation of slag inclusion, mainly distributed on the upper surface of aluminum castings and at the corners of the mold where there is no ventilation. X-ray fluoroscopy can reveal this defect, which appears deep in the X-ray image