A Complete Gravity Casting Overview


At Leiseng Machinery, we can provide Gravity Casting Services for many industry. However we found that many of our customers that don’t know Gravity Casting very well. So we write this article focus on the detailed introduction of Gravity Casting, which can help you to get to know it and make the very right decision.

Table of Contents

What is Gravity Casting

Gravity casting is a metal or metal alloy fabrication process in which liquefied metal is streamed from the crucible into the mold to produce parts with the desired shapes. The process is usually used to create premium metal components with low melting temperatures, for instance, aluminum, zinc, and copper metals and alloys. The melted metal jetted out of the crucible and put inside the die cavity, flows freely, and fills the mold cavity under the gravitational force, without the use of vacuums, compressed gases, or centrifugal force, it solidifies quickly to create metal components. As a result of rapid solidification, the final parts produced have better mechanical and physical properties as compared to sand casting.

Gravity casting also referred to as gravity die casting is a preferred method of producing parts in the manufacturing industry due to its diverse benefits as compared to other casting methods. When the final parts have solidified and have been removed from the mold cavity, the mold can be reused to make other parts. This method allows a single set of dies to be used indefinitely to produce the same part. Because the process of creating metal dies can be costly, the ability to reuse one makes the process more cost-effective, time efficient, and desirable in the manufacturing industry.

Where the production of parts with complex designs is required, gravity casting can combine both metal and sand cores. The method works best for applications that call for a compromise between the sand casting process and high-pressure casting. Gravity die casting uses a steel mold to produce parts that are more durable than sand casting while using a lower cost mold than high-pressure die casting in that parts made by this method are thinner than those made by sand casting, but heavier and thicker than those made by high-pressure die casting.

If you have projects that require Gravity Casting, Leisheng Machinery should be good choice for you

The Process Of Gravity Casting

Gravity die casting technique can be done manually or automatically. Automated crucibles pouring molten metal into the mold are used in automatic processes, pour molten metal into the mold are used in automatic processes, which are typically used in high-volume volume production. On the other hand, a manual process makes use of labor, holding molten metal and manually pouring molten metal into a mold.

Although many gravity die casters prefer to do it by hand, both procedures follow the same steps. The cost of production varies depending on the tools used, the amount of energy used, and other factors, with automatic processes typically having higher costs than manual processes. There are four steps to the process of gravity die casting

  1. Heating the Metal
  2. Pouring the Metal
  3. Releasing of the Part
  4. Final Processing

Step 1: Heating the Metal

The process usually starts with heating the metal to a liquid state. To facilitate the removal of final parts after fabrication, molten metal is poured into the mold along with a die release agent. The die release agent aids in the cooling of the fabricated parts’ surfaces and acts as a primer in preparing the die for subsequent production processes.

Step 2: Pouring the Metal

The molten metal alloy is manually or automatically fed into runners, which carry the liquid material into the mold cavity and continue to flow until the void is filled. A designated runner ensures that the liquid fills the cavity from the bottom up to prevent turbulence in the hardened part as well as pores. Bottom-up filling aids in avoiding the production of defective final parts with a poor finish.

Step 3: Release of the Part

The cooling process begins immediately after the liquified metal is streamed into the mold cavity. The process has accelerated by the die’s ability to absorb heat as well as the releasing agent that was sprayed on it initially. Once the metal has cooled sufficiently, the machine operator opens the die and removes the final piece, along with the runners that feed the melted metal alloy into the die cavity.

Step 4: Final processing

The final step involves fine-tuning the finish of the fabricated part. Cutting and filing are used to remove any excess materials, rough or sharp edges from the casting. Depending on the client’s specifications, the piece can be brushed, polished, or shined, as well as final touches such as assembly and packaging for delivery.

The Machines for Gravity Casting

Gravity die machines are classified into three types based on how they operate and their distinguishing features. The three categories are tilted gravity casting machine, non-tilted gravity machine, and hydraulic gravity die machine, which is identified by the degree of tilting angle and machine operation.

Gravity die casting machines are ideal for producing complex aluminum castings such as turbo engines, braking systems, knuckles, engine compartment heads, engine parts, and hydraulic systems. It is also appropriate for a wide range of industries, from lighting components to kitchen tools. Gravity die casting machines are commonly used for:

  • Ability to produce complicated designs
  • High-volume production capabilities
  • Cost saving properties
  • Excellent final product finish

There are three different types of gravity casting machines as listed below:

  1. Tiltable Gravity Die Casting Machine
  2. Non-tiltable gravity machine
  3. Hydraulic gravity machine

Tiltable Gravity Die Casting Machine

The tiltable gravity die casting machine is powered entirely by a hydraulic system, and the tilting angle is adjustable from 0° to 90°. Tilting towards the pouring side reduces the feed rate, lowering the possibility of oxide and bubble formation and resulting in the formation of excellent high-finish parts. Due to its superior finish quality compared to other machines, the tiltable gravity machine is employed to give metals like copper, zinc, and aluminum better finishes. The machine is valued for its accurate surface finish, ease of maintenance, and stress-proof design and is used in a variety of industries, including automotive, machine tool, and telecommunications.

Non-tiltable Gravity Casting Machines

These are stationary machines that do not tilt, and the casting process takes place from the same manufacturer’s location.

These are applicable to non-ferrous metallic materials such as like aluminum, copper base, and zinc alloys. Both manual and digital control mechanisms are available on a tilting die casting machine. A die casting machine frequently includes a compression cylinder, heating system, and transmitting tube. Metal coating, fabrication, and repair operations frequently use die casting machines.

Hydraulic Gravity Casting Machine

These are utilized for copper alloys and aluminum alloys. Usually, they exist in both tilting and non-tilting versions across the board. These are used for alloys of copper and aluminum. They are present throughout the entire selection in both tilting and non-tilting versions. Both manual and PLC systems can operate the tilting gravity die casting machines. Hydraulic machines come with mounting core pulls that can be moved into various positions depending on the die design.

Materials Used for Gravity Casting

Die casting makes use of a variety of alloys, each with its own rigidity, weight, strength, wear resistance, and other properties. Gravity die casting has a wide range of alloys that it can use. Manufacturers will select specific metals in order to achieve certain qualities.

Gravity Die Casting uses cast iron or steel molds to produce aluminum and zinc castings more accurately and cheaply than sand casting, with better surface finish and mechanical properties. Gravity casting tooling costs a fraction of what pressure die casting does

The following are the various alloys used and their basic strengths including:
Aluminum/ Copper/ Zinc/ Magnesium/ Cast Iron


This alloy is the best material for gravity die casting. Mostly preferred due to its extreme stability and strength, enabling manufacturers to achieve greater complexity in their shapes and designs. Furthermore, aluminum is light in weight and corrosion-resistant. It has excellent mechanical qualities, mechanical or electrical conductivity, as well as stability retention at extreme temperatures


Copper alloys are desirable because they have the greatest level of hardness, oxidation resistance, and exceptional mechanical properties of any alloy used. Copper is also extremely durable, dimensionally solid, and nearly as powerful as steel.


Because of their impact strength, outstanding ductility, competitive prices, ease of plating, and minimal impact on the die itself, these alloys are simple to die cast.


Magnesium is ideal for machining because it has a high power-to-weight percentage and is straightforward to fabricate. It is also the least dense casting alloy available

Cast iron

This is a widely used material for pipes, manufacturing equipment, and automotive components such as gearbox cases and cylinder components. It has a low boiling point, has always been wear-resistant, is predominantly castable, and can be fabricated as and is predominantly castable and can be fabricated as sand casting

The Application for Gravity Casting

Because of today’s advanced technology, it is possible to create complex parts using gravity casting. Many industries, including automotive, kitchen components, lighting, and so on, use this process to produce various parts and appliances.

Among the most common gravity die-cast applications are:

  • Engine components, gearbox cases, cylinder componentry, electronic equipment, and structural equipment are examples of automotive parts.
  • Electronic lighting components, control panels, fixtures, housing, and components
  • Military sectors require reproducible parts for weaponry, surveillance, and other applications.
  • Electronics include hi-fi equipment, consumer electronics, housing, tools, and other items.
  • Surgical instruments, gearboxes, and hospital equipment
  • Spoons, pots, and other kitchenware

Benefits of Gravity Casting

Gravity die casting has the advantage of producing premium castings with complicated shapes while preserving superior mechanical qualities like strength. This makes it excellent for producing aluminum parts that pressure die casting cannot produce.

The following are some of the benefits of gravity die casting:

Alternatives to Gravity Die Casting

In addition to gravity die casting, other casting techniques include sand casting as well as high-pressure casting. As illustrated below, each approach has distinct characteristics and use cases.

The Sand Casting Process

In the process of sand casting, liquified metal is steamed straight from the melting bowl into a die cavity. A mold is constructed when a wooden template is placed within an enclosure. Sand is then deposited into the matchplate and the enclosure. After the sand has now been introduced and densely compacted, the matchplate is eliminated, and the remaining die cavity is packed with liquid metal. The metal alloy solidifies after the spilling, the mold cavity is opened, and the sand is mixed thoroughly off the hot workpiece, resulting in the manufacturing of a final product. The gating and runner material is now detached, and the die casting process is done.

Gravity die casting and sand casting processes are comparable in that the melted metal alloys are both pumped under gravitational forces rather than added pressure or forces. The following are the key distinctions:

  • Gravity die casting uses metal as the mold material, whereas sand casting uses wood.
  • Sand casting is preferable when the aluminum parts are quite large.
  • Gravity die casting has a better surface finish and dimensional accuracy than sand casting.
  • Gravity die casting has a slightly higher cost.

For Details Of Sand Casting, Please read article of <A Complete Guidance for Sand Casting>

High-Pressure Die Casting

A steel mold is usually first created to form a die cavity with the right dimensions of the requisite casting throughout the high-pressure die casting, and then liquified steel is pressed into a sealed die at high pressure. The solid final metal component is removed from the furnace after the metal instantly solidifies in the die following injection. As the metal cools, the filler metal is removed, and a perfect-shaped part is formed. This process is repeated in order to produce the ordered quantity of parts.

There are several distinctions to be made when comparing gravity die casting process to the pressure die casting:

  • The mold price for high-pressure die casting is much significantly greater than for gravity die casting because the mold is made of steel material. As a result, for small-quantity production requirements, the gravity die casting process is preferred.
  • High-pressure die casting is preferable for parts with thin walls, as gravity die casting is prone to casting defects.
  • Gravity die casting employs gravity to flow melted metals, whereas high-pressure die casting is achieved under high pressure, resulting in gravity die casting having significantly reduced strength compared to high-pressure die casting.

Valuable Suggestions for Choosing Gravity Die Casting Procedure

Selecting the ideal casting method for your design is essential. Before making that choice, one should take into account a number of things, including production limitations, operational efficiencies, capital, material properties, dimensional accuracy, and delivery schedules, among others. Purchasing companies generally choose to purchase castings from businesses with a long and rich history of production and yield to their refined production process and relatively low production costs.

Both pressure die casting and gravity die casting processes may be suitable for a designed aluminum casting part. When there are few orders, gravity die casting is recommended because the mold is less expensive. Keep in mind that only materials with low melting temperatures can be cast using this method; other materials cannot. Gravity die casting is susceptible to defects, so pressure die casting is recommended for thinner parts.

About Us

Leisheng Machinery is a professional manufacturer in China since 1991, founded by Li, which is a famous china enginner. At the very beginner and we only focus on CNC Machining. And in 2006, our capabilities extend to casting, including investment casting, aluminum die casting & sand casting. In 2008, we build our another fatory, and our capabilities expend to metal forging.

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