Understanding Low Pressure Die Casting vs. High Pressure Die Casting

Die casting is a unique metal casting that forces molten metal in between two steel dies that create a cast. Usually, die casting is used during high-volume production settings and is known for creating a higher-quality and consistent product.

Equipment used in the die casting process will usually have a higher cost upfront than the equipment that is actively using a sand mold. While this is true, the daily costs of manufacturing using die casting are lower, which produces a much lower cost per item.

Die Casting History 

Die casting is a process that was originally created in 1838. At the time, it was used for creating “movable type” machines. The initial patent for die-casting was acquired in 1849, which was around 20 years later.

Once this machinery was made available in North America, the uses for it grew, too. During the 1900s, a mix of lead and tin began to be used for die casting and went through multiple trends before aluminum was discovered to be the best option for this process.

Today, there are a few modern methods of die casting. These include low and high pressure die casting. Keep reading to learn more about each of these.

About Low-Pressure Die Casting 

This process is done using a vertical process. It will shoot the molten metal (mentioned above) up and against the force of gravity. The metal will move from a furnace under it by way of a piston using low pressure moving through the shot chamber that is present in the two molds.

These molds are made from aluminum alloys. One of these is fixed, and the other can be pulled back, which lets the casting loosen from the mold after it is completely cool.

While the metal cools inside the mold, the pressure is kept at a steady level. This helps ensure an accurate and even fill. As the metal continues to cool, additional molten metal is added to fill in any shrinking or missing cavities.

One of the only downsides of this method is the slower casting cycle. While this is true, this method is less complicated and more affordable than high-pressure die casting.

About High-Pressure Die Casting

In the world of die casting, this option is considered the latest, trendiest option available. Unlike low-pressure die casting, the high-pressure method has a much shorter casting cycle. It also uses horizontal casting rather than vertical (this means it isn’t working against gravity).

With high-pressure die casting, you use two machine plates, one on each side, that lock together. This creates mold in the center. You can imagine this like a die-casting sandwich. Then, the molten metal will be pushed through the chamber using a piston at a very high speed. It will also be under extreme pressure while the mold is being filled.

After the mold is cool and solid, the die will be opened, and the casting that was created is removed. Unfortunately, this machine and the dies are very costly. Because of this, it is a method that is often reserved for higher-volume production runs only.

Even though high-pressure die casting will speed up the entire process, there are still some drawbacks. Also, the process is only limited to making smaller parts. This is because the locking mechanism on the dies will only be able to handle a specific weight. This has encouraged manufacturers to create stronger castings with less weight by using an aluminum alloy. This change offers significant benefits for many other industries that want to reduce the weight of cast components and parts.

Choosing the Right Process for the Job

When it comes to die casting, you will have to determine which process is best suited for your needs and your industry. With the information above, you should be able to figure out which one will work best. Keep this in mind and make an educated decision to ensure you achieve the desired results.