How to Reduce Porosity in Die Casting and Improve Quality

Porosity—which refers to the formation of air pockets, holes, or indentations within or on the surface of die-casting parts—is more than just a cosmetic issue. It can adversely affect the structural integrity of die-cast parts, potentially leading to leakage and corrosion, especially in products requiring high strength for demanding applications.

Understanding types of porosity in die-cast parts

Recognizing and addressing porosity is crucial as it can lead to the failure of die-casting parts, rendering them unsuitable for high-strength applications. There are three primary types of porosity encountered in die-casting parts:

  • Blind porosity – This type starts at the surface and extends into the body of the die-cast part. Although it may not always affect mechanical strength, it can lead to corrosion and water pooling. A solution is to seal these pores immediately after casting to maintain pressure integrity.
  • Through porosity – Pores that extend from one side of the casting to the other can significantly impact the part’s structural integrity and its ability to retain fluids or gases. Sealing these pores from both sides can mitigate their effects.
  • Fully enclosed porosity – These pores are completely enclosed within the die-cast part. They typically don’t cause issues until post-processing, where they might develop into through or blind pores. Detecting them may require X-rays, CT scans, or physically opening the part.

Identifying causes and solutions

Porosity in die-casting parts mainly arises from trapped gas, leading to surface blistering during solidification. Shrinkage porosity is another concern, occurring due to uneven solidification rates influenced by the metal’s properties and the thickness of the die walls.

At HLH Proto, we prioritize minimizing porosity in die-casting parts. Our approach includes using high-quality materials, precise tolerances, controlled cooling times and temperatures, and improved mold designs to mitigate these issues. For flawless die-casting parts, reach out to us for a quote and benefit from our expertise in managing porosity effectively.


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