Excerpt from the Spotlight Metal December 2019 article by Nicole Kareta.
The use of die casting release agents represents an essential process step in the production of cast parts, as the so-called mold release agent prevents components from sticking to the mold or the metal from being soldered to the mold. What else is worth knowing about die casting release agents?
As a rule, release agents are sprayed onto the wall of the die casting mold. This separates the metal from the mold and also simplifies the de-molding of the casting. In addition, die casting release agents offer numerous other functions and advantages which have a positive influence on the entire production process:
- Improved flow of molten metal
- Easy removal thanks to homogeneous coating
- Good lubrication of moving parts
- Improvement of economic efficiency due to lower material requirements
- Shortened cycle time due to cooling properties
- Continuously high product quality
- Reduced scrap rates
- Increased mold life
Composition of Die Casting Release Agents
Basically the agents can be used for various metals such as aluminum, zinc, magnesium and their alloys, whereby the correct composition depends on the respective variant. It is therefore particularly important that the metal to be de-molded is neither physically nor chemically compatible, otherwise the release agent could be absorbed. In addition, the release agent ingredients have an influence on the cycle times of the casting process and on the quality of the cast components.
The main components of die casting release agents can be divided as follows:
- Mineral oils
- Ester oils
- Silicone oils
While the content of paraffins and aromatics in mineral oils is still high, ester oils make a positive contribution to the environment as they leave a low CO2 footprint and are a renewable resource. Silicone oils have excellent lubricating properties and high thermal resistance, making them well suited for use in die casting. The use of waxes is limited due to the high temperatures in die casting. Surfactants are used to emulsify the materials and form a bond between water and oils or waxes.