There are multiple key factors to crafting a top-quality casting. Die lubrication is a key component to ensure the success of die casting. While pressure, size, and temperature play a significant part in the process, the mold release agent is crucial to making the ejection of parts from the die effortless and flawless.
Functions of Release Solutions in Die Casting
Auxiliary materials as release solutions are called die spray, mold release, or die lubricant. It’s a prerequisite for modern, high-quality, precision die casting manufacturing. A well-defined amount of the solution gets sprayed inside the mold before every shot.
The solutions must cover the cavity or empty void filled with molten metals. It immediately gets evaporated in contact with the hot liquid metal. This evaporation should leave a lubricated coating, ensuring a smooth, even-surfaced, specified casting outline.
Any die casting mold release spray is expected to perform the following functions –
- Sufficient and workable lubricating properties at higher temperatures.
- Implementation of a cooling effect by adjusting various parts’ temps for relative stability.
- Improvement of the overall casting quality and production efficiency.
- Reduction of direct impacts of metal liquid on the mold by preventing surface stickiness.
- Even cooling across the castings produces a uniform, aesthetic, smooth surface finish.
- Minimization of friction between the forming part and the casting within the mold.
- Elimination of potential wear of the cavity and its core to extend the lifespan of the mold.
Sunrise Metal’s dedicated team of expert engineers ensures the best die-cast production process. They keep designing, sampling, and testing all the steps to maximize productivity and precision.
Types of Mold Release Options
Available die lubricants in the market have many different types, primarily based on casting materials and solvent/base liquid. Most agents are categorized based on die-casting metals such as aluminum, zinc, and magnesium. And they are either water-based or oil-based release agents.
Each lubricant can be further categorized by its overall functions and the complexity of the cast parts.
- Water-based liquids are the most desirable, popular, and effective sprays for standard casting. They have a releasing agent that also works as a cooling medium. These ready-to-use lubricants implement excellent creeping effects with or without wax.
- But painting or plating the component may use oil-based sprays. An oil-based lubricant delivers release agents with a lower to minimal level of cooling. They are either fully or partially synthetic without wax, silicone, or solvent.
This particular difference enables increased surface temperatures, leading to top-notch cosmetic finishes. Also, an oil-based liquid can yield superior productivity.
Still, water-based release coatings are the universal mold release agents. Its low cost, easy volatility features, and regulation of mold temperatures are more practical.
Excessive or Insufficient Die Lubricants
Too much lubricant in the cavity can’t evaporate fast enough during the molten metal injection. It leads to porosity, damaging the mechanical properties significantly. Also, buildups of the lubricant on the surface after too quick cooling can cause porosity.
A higher volatility point of the die sprayer often leads to excessively fast evaporation. And it increases the vapors or gases in the cavity, incorporating gas porosity. Even the decomposition of harmful gas can leave pores inside the die-cast parts.
However, porosity is inevitable in die casting, no matter what a manufacturer promises/says. It’s only a matter of how much is in part. Check our Porosity Reduction Strategies in Die Casting to develop an idea of minimizing porosity at multiple levels.
Any less than the necessary amount will lead to surface and close-to-surface defects. The solution from die lubricant spray guns may remain stuck to the castings, damaging the surfaces. So, it’s a must to specify the amount of lubricant right after designing the draft of molds.
Requirements of Die Casting Release Agents
The specifications vary depending on the part design, process, materials, and other factors. But a release solution should possess the following features in almost all cases –
- Lower volatility points of 100°C to 150°
- Good coating on exteriors without buildup.
- Easy to clean the formed layer after shot.
- No corrosive effects on casting or molds.
- No odor, precipitation, or decomposition.
- Stable performance, preservation period.
Thin and light coating in casts, preferably for magnesium, need cleaner and ready-to-use agents. The die lubricant should facilitate effortless die release, good metal flow, and superior solder protection without surface stain.
Highly engineered releasing solutions are now available to improve overall production efficiency. They can effectively ease the metal flow and maximize the wetting-spreading time while reducing the cooling time.
Die surfaces can maintain temps within a narrow range by using these well-engineered agents. All these effects eventually help prolong the die-cast part’s lifespan while allowing for faster cycles.
Health Concerns of Mold Release
A big question regarding die lubricants comes with castings for bio-compatible applications. A part for surgical or medical uses must require FDA approval. And there are several crucial and complex steps to get the green signal for medical castings.
Sunrise Metal collaborates with leading automotive, medical, and telecom companies on the latest trends and terms. We have several international certifications including the IATF 16949:2016, ISO 13485:2016, and ISO 9001:2015. We ensure strict quality control and utilize non-hazardous die lubricants for production. You can contact our experts for any other queries on die lubricants.