The process of die casting has advanced much in the last fifty years. It was used to make small parts from metals and alloys with lower melting points like Zinc, but today, the die casting process is used to manufacture very large parts like engine blocks from relatively high melting alloys of metals like Magnesium and Aluminum. These alloys are cast at very high pressures to offer complete cavity fill and minimum porosity to the parts.
As the die casting conditions like pressure, temperature, and parts size become increasingly severe, lubricants need to be used to enhance the process. However, the lubricants used should not adversely affect the product or its characteristics. Die casters use many techniques to improve their operational efficiency and to decrease production costs. A high-pressure die casting machine has a number of moving parts that need proper lubrication.
A die casting system needs lubrication because of the thermal stress that is experienced by the system as a result of the exposure to molten metal at very high temperatures. The different types of lubricants used in die casting systems are die lubricants and plunger lubricants.
Die Lubricants
The demand for reduced processing times and more complex castings has led to much stress to casting systems. Die lubes are used to offer increased wetting and film forming at very high temperatures, thereby decreasing the stress on the system. Die casters across the globe understand that it is very difficult to manufacture parts without using die lubricants. Die casting lubricants for aluminum die casters will offer:
- Hotter die surface adhesion;
- Decreased time to get optimum lubricant application;
- Improved solder protection;
- Effective release and, bright, and clean castings; and
- Decreased gas generation, improved protection of the die against corrosion and pitting.
Lightweight thin walled castings like magnesium die castings need die lubricants to offer cleaner, installation ready parts. The die lubricant used should not cast any stains on the parts and should facilitate easy die release, good flow of metal, and improved solder protection throughout the production.
Highly engineered die lubricants are available to improve the overall efficiency of the process. These lubricants can optimize wetting and spreading time, help in easy metal flow, and reduce the cooling time of die surfaces to maintain the die temperature within a narrow range. All of these will help increase the die life and allow for fast cycle.