Lubricants are critical to the die casting process. Without proper lubrication, you can quickly run into issues with your dies and parts, thereby slowing productivity and decreasing part quality. Henkel’s full portfolio of BONDERITE® die casting lubricants provides solutions for a wide range of casting applications.
Why Are lubricants Used in Die Casting?
Die lubricants provide a lubricating film on the mold surface during the die casting process to aid in die release. Proper die lubrication results in clean, bright castings and a lower likelihood of corrosion or pitting on the mold surface. Below are several reasons die lubricants are used.
RELEASE
Die lubricants prevent welding of molten metal to the die and release the cavity easily without distortion.
LUBRICATION
Die lubricants aid in die fill and lubricate the moving parts, such as ejector pins and cores.
COOLING
Water-based die lubricants help lower the temperature of the die.
PROTECTION
Die lubricants protect the die surface against attack by the molten metal.
INSULATION
Die lubricants can control directional flow, solidification, and die fill.
What Problems Can Lubricants Help Solve?
The right die lubricants can solve the following common problems during die casting.
Porosity: During die casting, gas bubbles can become trapped in the metal, leaving behind holes in the part. There are several causes of porosity, one of which is excess die lubricant on the mold surface. If too much lubricant is on the mold, gases cannot evaporate fast enough when the molten metal is injected. Choosing a lubricant that minimizes overspray can combat this issue.
In-Cavity Buildup: Scale can build up on the die cavity, typically from the oxide of the metal being cast and the parting material. A soft-water-based lubricant reduces the chances of in-cavity buildup, particularly products that can be sprayed and are formulated with finely sized solid lubricant particles that form a thin, even coating on the die surface.
Fish Eye: Fish eyes are small holes that appear on the surface of the part when painting. Proper lubrication helps keep the part surface clean prior to painting to improve paint adhesion.
Cold Shut: Cold shut is when the casting begins solidifying before the mold completely fills, creating dark lines on the casting surface. It is more prevalent in magnesium alloys. Proper lubrication helps transfer heat to prevent cold shut from occurring.
Stuck Castings: Stuck castings occur when improper die lubrication results in metal adhesion to the die surface, effectively trapping the casting within the mold. This interrupts the production cycle and necessitates additional labor and time to remove the stuck parts without causing damage to either the casting or the die. Stuck castings often lead to surface imperfections, rendering the parts unsuitable for final usage unless reworked, which further escalates costs. Effective die lubricants are pivotal in preventing stuck castings by ensuring adequate die release, facilitating the smooth ejection of cast parts.
What Lubricants Are Used in Die Casting?
There are many different types of mold release lubricants for die casting, depending on the application and the metal being cast. Water-based lubricants are the most popular and typically preferred because they both lubricate and cool the die. Oil-based lubricants are sometimes used when increased temperature is required for high-quality finishes, but they do not have the same cooling efficiency as water-based lubricants. Some mold release lubricants act more as release agents, while others provide insulation to the die. Henkel has a wide selection of lubricants to improve your die casting performance.
BONDERITE® Casting Lubricants
Ladle Coating
Ladle coatings play an important role in die casting to protect ladles and extend their lifespan. BONDERITE® L-CA 696 is a soft grease that protects ladles from molten metal attack. Learn More
High-Pressure Die Casting
High-pressure die casting (HPDC) is becoming increasingly popular, especially in automotive applications, as large-scale manufacturers are casting larger aluminum parts at higher speeds. High-pressure die casting machines rely on best-in-class lubricants to improve productivity and reduce costs. Henkel's cutting-edge BONDERITE® HPDC lubricants are engineered with superior release, cleanliness, and wetting performance to ensure the casting process runs as efficiently as possible. Learn More
Low-Pressure, Permanent Mold Casting
Low-pressure, permanent mold casting is still an important process within metal manufacturing. It can often rely on several different types of lubricants to achieve optimal performance. BONDERITE® low-pressure die casting lubricants provide exceptional insulation and release for enhanced part finish on non-ferrous metal alloys, such as aluminum, magnesium, and zinc. It also forms a barrier on the mold surface to protect the mold from thermal fatigue, a common issue in repeated casting cycles. Learn More
