What lubricant is used in die casting mold?

In the daily production of die casting molds, lubricants act like oiling the bottom of a pan, both to prevent the "food" from sticking and to make the pan more durable.

Common lubricants are mainly divided into two categories, each with different uses:

1. Mold Release Agents (the oil applied to the "bottom of the pan")

This is the most commonly used type, sprayed onto the mold cavity before each die casting. Its main function is to prevent the hot molten metal from sticking to the mold.
Water-based release agents: This is currently the mainstream. It mixes lubricating components (such as silicone oil, wax, etc.) with water. After being sprayed onto the mold, the water evaporates when heated, which both removes excess heat from the mold (providing a cooling effect) and leaves a thin lubricating film.
Oil-based release agents: This type does not contain water and is mainly composed of synthetic or mineral oils. It has excellent lubricating properties and is usually used for parts with particularly complex shapes that are prone to jamming, or for products requiring extremely high surface brightness.
Powder release agents: This is a more advanced dry lubrication method, applied to the mold surface like powder spraying. It produces no oil fumes and is more environmentally friendly.

2. Plunger Lubricants (the oil applied to the "piston")

The die casting machine has a piston-like part called a "plunger," which is responsible for pushing the molten metal into the mold. The friction in this area is extremely high.
Granular lubricants: These are solid particles, like small plastic beads, that melt between the plunger and the injection chamber when heated, providing long-lasting lubrication.
Plunger oil: This oil is very high-temperature resistant and highly viscous, ensuring that the plunger does not wear out or seize during repeated pushing and pulling.

3. Why use lubricants?

In die casting mold production, not using lubricants can have serious consequences:
Preventing mold sticking: Without lubrication, the molten metal will stick to the steel mold like it's welded on, making it impossible to remove the parts.
Protecting the mold surface: The film formed by the lubricant can mitigate the direct erosion of the mold steel by the high-temperature molten metal, extending the service life of the mold. Improved surface finish: Using the right release agent results in smoother, brighter parts with no imperfections.
Assists in heat dissipation: Water-based lubricants, in particular, cool the mold during the spraying process, preventing overheating and deformation.

4. Important details during use:

Even spraying is crucial: Too much spray can leave air bubbles on the part's surface, while too little can cause the part to stick to the mold.  Experienced workers or automatic spraying systems precisely control the amount of lubricant.
Select based on the metal: The lubricant formulas for die-casting aluminum alloys and zinc alloys are different because of their differing melting points and chemical properties.