Sand casting parts are produced in a sand mold. Therefore, this manufacturing process is also known as sand molded casting. Steel, iron, and most of the non-ferrous alloy casting parts can be created with sand casting.

Sand casting has been the most basic operation for a long time since the materials used are cheap and easy to obtain, the mold is easy to make, and the process is flexible enough to handle single-piece orders and production in small batches or large scales.

Sand Casting Advantages

• Can deal with complex shapes and cavities, such as boxes, beds, frames, etc
• Can create casting parts ranging from a few grams to hundreds of tons
• The shape and size of sand casting parts are close to the final parts with little post-processing required

This casting process can present the finest details of metalwork and therefore is widely used in the fields of sculpture, jewelry processing, dentistry, and industrial restoration. The products for lost-wax casting are often difficult to manufacture because of their intricate designs.

Lost-Wax Casting Advantages

• Can produce complex shapes and subtle patterns
  Jewelry can be molded at one time, saving time and labor costs
• Good surface finish with few defects, reducing the polishing workload and material waste
• Can produce various blanks in batches with a streamlined production process, convenient for production management and quality control

In the pressure casting process, molten or semi-molten metal materials are injected into a mold at high speed, which is crystallized afterward under pressure. This method is widely used in high-pressure die casting (HPDC) applications, a process known for its precision and efficiency.

Generally speaking, the injection pressure is 30 – 70 MPa, the filling speed is around 0.5 – 50 m/s, and the filling time is 0.01 – 0.2 s. Learn more about this advanced technique in our detailed guide on What is the HPDC.

Pressure Casting Advantages

• Highly efficient with a high level of mechanization and automation
• Can produce thin-wall casting parts with complex shapes
• The minimum wall thickness of zinc alloy can achieve 0.3 mm
• The minimum wall thickness of aluminum alloy can achieve 0.5mm
• The minimum casting hole diameter can achieve 0.7 mm
• Can achieve high dimensional accuracy and small surface roughness values
• The dimensional tolerance level can reach CT3 – CT6
• Surface roughness is within Ra 0.8 – 3.2 μm
• Parts can be embedded in casting molds, saving time and materials
• Can simplify the manufacturing process by removing the component assembly

Low-pressure die casting (LPDC) refers to the manufacturing process where the molten metal slowly fills the die and solidifies.

It relies on the low pressure (0.06-0.15MPa) on the metal surface which is produced by compressed air in the crucible placed above (as the diagram shows).

Low-Pressure Casting Advantages

• Good feeding and compact casting structure
• Can create casting parts with big sizes, thin walls, and complex shapes without a riser
• High metal yield rate (95%)
• No pollution and easy-to-implement automated production
• Can be used in various casting molds (such as metal & sand molds) and alloys due to its adjustable pressure and pouring speed
• The metal liquid is stable with no splashing since it is bottom injected, avoiding gas inside and scouring to affect the casting success rate
• Good for creating thin-wall casting parts since it produces dense structure, clear outline, and smooth surface with great mechanical properties
• No feeding riser with improved metal utilization rate (90% – 98%)

Centrifugal casting injects molten metal into a high-speed rotating mold where the molten metal spreads along the inside mold wall and solidifies after cooling to form the casting parts.

With the nature of centrifugal casting being centrifugal motion, it helps fill the mold wall in a radial direction and form the surface of the casting parts.

A cylindrical hole can be obtained naturally without a core.

This manufacturing process removes gas and other inclusions in molten metal with a positive effect on metal crystallization, improving the mechanical properties of the casting parts.

Centrifugal Casting Advantages

• Good mechanical properties. The slag, gas spot, and other inclusions are concentrated on the inner surface of the casting parts, leaving the inner parts of the components in good condition with no porosity, shrinkage, slag, or other defects.
• Doesn’t require a gating system
• No consumption of molten metal at risers

Permanent mold casting refers to the casting process where molten metal fills the mold by the force of gravity and forms the casting parts after cooling and solidification.

Permanent Mold Casting Advantages

• High thermal conductivity and heat capacity with fast cooling
• Compact mechanical structure with high stability (15% higher than sand-casting parts)
• Higher dimensional accuracy with lower surface roughness
• Less dust and harmful gas emissions during manufacturing

Vacuum Die Casting Advantages

• Greatly reduced porosity
• Good mechanical properties with high hardness* and improved elongation**

* The aluminum-magnesium casting parts produced by vacuum die casting can be processed by welding, heat treatment and other post-processing techniques. Their performance at room temperature has also been noticeably improved.

** The elongation of die-casting parts has been increased from 8% to more than 16%.

Vacuum Die Casting Examples

• AM60B magnesium alloy automobile wheel (produced by die casting on a cold chamber die casting machine)
• AM60B magnesium alloy automobile steering wheel (produced by die casting on a hot chamber die casting machine with a locking force of 2940kN)

Squeeze casting is a casting technique where molten metal is solidified under mechanical pressure in closed dies to create casting parts.

The manufacturing process is also called liquid die forging.
During the squeeze casting process, high pressure is applied to the material as it cools until it forms the desired casting shape after crystallization and solidification.

Squeeze Casting Advantages

• No gating system that produces material waste
• Squeeze casting parts can be heat-treated
• Good feeding effect with fine grains and dense structure
• Less cost, longer service life and higher material utilization rate

The cavityless casting process adopts an expendable pattern that gets burnt and evaporated after the molten metal is poured into the mold.

Cavityless casting is used to combine paraffin or foam models (in similar sizes and shapes) to cast parts into clusters, which are brushed with refractory paint, dried, and buried in dry quartz sand.

The molten materials are poured into the molds which evaporate after the casting parts are created.

This is a new casting technique that creates the part by forming the model itself after cooling.

Cavityless Casting Advantages

• High precision with no sand core, saving production time
• Flexible in design with no parting surface
• Clean manufacturing process with no pollution
• Less investment and costs

Continuous casting is an advanced casting method in which the molten metal is poured into a water-cooled mold and the solidified castings are continuously drawn from the other open end. With continuous casting, you can get casting parts at any specific length.

Continuous Casting Advantages

• Compact structure and good mechanical properties due to its rapid cooling
• No riser of the gating system on the casting, so no need to cut the head and tail of the casting during rolling, saving time and materials
• Simplified process without modeling process, saving labor costs
• Less production area is required
• Can achieve high mechanization and automation in production
• Improved production efficiency with continuous casting and rolling in ingot casting