Die casting is a typical manufacturing method that can efficiently produce various delicate metal parts. Die casting is also a standard manufacturing method. Casting intricate aluminum components can be accomplished with either high pressure die casting or low pressure die casting, which are standard techniques utilized in high pressure aluminum die casting. Because of this, it is essential to have a solid understanding of the fundamental distinctions between the two processes if you are starting in the die casting sector.

The term "low pressure die casting" refers to what exactly?

Using low-pressure die casting equipment, the molten metal is transferred to a crucible or furnace that is hermetically enclosed, insulated, and subjected to pressure. The pipe is covered with a furnace cover at the top flange, sealed off, and submerged at the bottom, where it travels up and down inside the furnace. After that, the open end of the pipe is sealed, and the die is attached to the die casting machine. While the stove is being pressurized with air, the bottom end of the pipe is submerged in the molten metal, and the furnace discharges the molten metal, which causes the molten metal to be propelled up the pipe and into the mold cavity. This takes place during the pressurization process. A decrease in air pressure is utilized to remove undesirable metals from the casting. 

Because of the smooth filling throughout the die casting process, die castings produced using a low-pressure die have superior mechanical qualities, fewer flaws, and a smoother surface than those made using a high pressure die casting parts. Because of this, the essential aluminum alloy dies castings will transition to low-pressure die castings because of liquid and airflow constancy during the casting process.

The Advantages of Low-Pressure Die Casting and Their Features

  • Outstanding quantitative measures of strength
  • Sand cores allow the creation of geometries with the most intricate details imaginable.
  • Greater material efficiency; there is no requirement for feeders
  • A level of dimensional accuracy that is of the most excellent order.
  • Every process may be simply automated.
  • The technology behind machines and dies is not quite as advanced.

There are a few disadvantages associated with low-pressure die casting:

  • Casting cycles that require a more significant amount of time to finish
  • Minimum wall thickness of approximately 3 millimeters (in die)
  • Inadequate production

What is meant by the term "high pressure die casting"?

During the die casting process, the molten metal is forced into the steel mold at a high rate of speed to guarantee that the molten metal is injected into the hollow space between the two halves of the die. Shrinkage is brought about by forcible chilling and injection. When molten metal is poured into a mold, the heat is transferred from the metal to the mold, resulting in the metal becoming cooler than before. When the casting has reached room temperature, it is time to remove it from the mold where it was made. Within the "Cold Chamber" mechanism, the metal will melt at an extremely high temperature. Iron is attractive to aluminum, brass, and magnesium, all capable of spontaneous combustion when reduced to a liquid condition. Within the cold chamber process framework, there are two distinct ejecting mechanisms: horizontal and vertical. It is common practice for the agency known as the "hot chamber" to be composed of zinc and lead metal. The metals lose their attraction to iron when subjected to low melting temperatures.

High-pressure die casting uses molten metal to be pushed into a sealed hole under high pressure. After the molds have been opened, the casting will be expelled, and the final item will be removed. When the casting is removed from the mold, the mold is lubricated, closed, and sealed to be ready for the next cycle.

The following characteristics and advantages are associated with high-pressure die casting:

  • Casting processes with relatively quick cycle durations
  • Compatible with components with thin walls
  • surfaces that are clear of smudges
  • Independent in all aspects

There are a few disadvantages associated with high-pressure die casting:

  • A death that is both costly and difficult
  • Outrageous initial investment as well as continuous operational costs
  • Only for die-cast items that do not require undercutting should sand cores be used.
  • A decline in the object's robustness
  • The locking force of the machine places limitations on the weight of the die-casting.

A Comparison of Low and High Pressures casting in dies

When making shell casings, high pressure aluminum die casting is the method that is utilized the vast majority of the time. Casting at high pressure and using dies allows for the incorporation of metal, but the process cannot be heat treated. Castings made under low pressure can be heat treated if necessary. The structure of the equipment and the pressurization systems are different.

The low-pressure die casting process has a limited capacity for productivity while having a compact structure and excellent mechanical properties. Castings made with high-pressure die casting have a higher surface quality, but because the casting process leaves some air holes, it is more appropriate for castings with thinner walls. Select low-pressure die casting when there is a necessity for a high level of air tightness, and select high-pressure die casting when there is a requirement for large-batch manufacturing but no densification is required.

When choosing a production method to meet your component requirements, you must consider the high-pressure and low-pressure die-casting processes, each of which has unique capabilities and limitations. Low-pressure casting accounts for around 20 percent of the total production of light metal castings. In contrast, high-pressure casting accounts for approximately 50 percent of the total output of light metal castings.

In low-pressure die casting, which may manufacture pieces weighing up to 150 kilograms, it is usual to employ alloys with low melting points. Both having high strength and the ability to design intricate geometries are advantages, and both help to maximize the amount of material used.

When the wall thickness sought is less than 3 millimeters, the process becomes less suitable. When opposed to high-pressure die-castings, low-pressure die-castings require a more significant amount of time to produce. The dimensions of a machine can influence the proportions of the casting it makes.

Aluminum and zinc alloys are the most commonly cast using high-pressure die-casting. Because the metal alloy is driven into the mold at high pressure and speed, the casting process can be made to go more quickly. High-pressure casting can produce components with thinner cross-sections than any other casting technology, with wall thicknesses as low as 0.40 millimeters (mm), depending on the element's size and the specifications you specify.

High pressure aluminum die casting results in smoother surfaces and can be sanded more easily, expanding the range of possible finishes. The final surface polish is significantly influenced by the quality of the dies used in the process. Because of its superior quality, this finish enables subsequent coatings to be applied directly on top.

When working with high-pressure die-castings, porosity can be an issue; however, by collaborating with your supplier, you can find solutions to this problem. It is essential to remember that the lowest possible production costs can only be attained through placing large orders.

It is in your best interest to have a conversation with your casting supplier about the various casting procedures, determine the approach that will be most beneficial to your final product, and get you the results you are looking for.

To reveal the final product after the sand-casting process has been completed, it is required to break the sand mold used to produce the mold in the first place.

When making minimal cast parts using investment casting as an alternative, molds and models are discarded after the casting process is complete.

Gravity Die casting is used to make molds; this method does not require significant pressure to compress the molten material into the mold. Instead, creating a casting or filling a mold is done by allowing gravity to do the work.

When it comes to aluminum die casting manufacturer, many different approaches can be taken to meet the requirements of a particular project. At Arbomex, we will work with you to meet your needs and provide the most acceptable counsel to support your goods and components in achieving the most outstanding results possible. We will do this by collaborating with you to satisfy your needs.