How to Control Porosity in Pressure Die Casting

  • Pressure die casting is the most efficient and cost-effective method of producing large quantities of aluminum, zinc, or magnesium parts.

    Parts made from die aluminum die castings have excellent surface finishes, maintain consistent features and tolerances, and waste little raw material during the die casting mould process.

    Engine blocks and motor housings, appliance parts, heat sinks, fittings, brackets, and a slew of other common industrial and commercial products are manufactured using pressure die zinc alloy die casting.

    Any product development team considering pressure die zinc castings for a project should be aware that all cast parts must deal with the issue of porosity, which is a characteristic of all porous materials. It is unavoidable, but it can be managed. Let's take a look at what causes porosity in your parts and how to use best design practices to manage porosity for superior results in order to mitigate its effects.

     

     

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    What is the definition of porosity?
    A hole or void in an otherwise solid cast metal part is referred to as porosity. Larger voids (measured in cubic millimeters or greater) can exist alongside microscopic pores. Porous structures are not always circular in cross-section, and may instead appear as irregular linear cracks.

    Porosity has two primary causes: solidification shrinkage and gas porosity. Solidification shrinkage is the result of solidification shrinkage. Let's take a closer look at the root causes of these two types of problems, and then we'll discuss possible solutions.

    the amount of gas that can be held in a given amount of space


    Gas pockets can form in a variety of ways. It is possible that hydrogen will come out of suspension and fill voids with hydrogen gas in the case of aluminum.

    It is also possible that air was trapped within the mold tool because it was not completely evacuated or vented as the cavity was filling. Entrained air is the term used to describe the trapped air.

    Finally, during the injection process, other liquids may be introduced into the molten metal. Mold release agents, hydraulic fluid leaks, and even high levels of humidity are all possibilities. Any of these substances has the potential to vaporize quickly and form gas bubbles. During the drying process, any liquids or oils that do not evaporate become contaminants that may form inclusions in the final product.