Die Casting vs Sand Casting: A Comparative Analysis

Die Casting Housing
Die Casting vs Sand Casting

Metal casting is a fundamental manufacturing process used to create a wide range of metal components and products.
Among the various casting methods available, die casting and sand casting are two popular techniques with distinct advantages and applications.

This blog aims to provide a comprehensive comparison between die casting and sand casting, highlighting their differences, benefits, and considerations. Let’s explore the following topics:

Chapter 1: Overview of Die Casting

1.1, Definition and Explanation of Die Casting

Die Casting involves the injection of molten alloys into die-casting molds to produce a whole new set of products through different methods that use high pressure.

It is a process of steel fabrication where the most common materials used are nonferrous alloys like Zinc, Magnesium, and Aluminum.

Additionally, this procedure can manufacture molded products with precision, high accuracy, and durability. Most industries are deeply invested in the development of die casting as they have high resistance and tolerance.

Die Casting

1.2, Process Steps Involved in Die Casting

There are two types of die-casting processes, the Hot and Cold Chambers. But the standard method these two follow involves the injection of molten alloys into a structured die mold and going through high pressure. Check out the intricate die-casting process steps we highlighted below.

Step 1: Clamping Process

The first step in die casting starts with cleaning the die mold and eliminating impurities before the injection begins. Remove the unnecessary dirt and start lubricating the mold with its specific design; then, you can clamp and close the die with the most pressure.

Step 2: Injection Process

The melting process should happen before the injection begins. When the molten alloys are ready, start pouring them into the shot chamber, but there are other factors, whether the process you’re using is the hot or cold chamber. After that, start the injection procedure with very high pressure from a hydraulic system.

Step 3: Cooling Process

While the die mold is clamped, please wait for a few minutes and allow the alloys to cool down and let it go through solidification. The material will soon have a shape similar to your prepared mold design.

Step 4: Ejection Procedure

You now unclamp the die mold and go through the ejection procedure. Push the solidified casting out of the die by following a mechanism. Check if it was adequately hardened before ejecting the mold’s final product.

Step 5: Trimming Process

The final step in die casting is trimming, or the removal of the excess metals in the solidified product. Check for the unnecessary details in the runner or sprue of the finished product, and use a trim die to clean them all. You can also use a saw and other trimming procedures to achieve a smooth surface and finish.

1.3, Advantages of Die Casting

Most industries invest in die casting because it requires less machining and operations. Manufacturers are after the benefits of die casting, producing metals with the highest quality and best performances in every application. Here’s a list of the advantages of die casting and how it became globally competitive in the market:

  • Repeatability in Usage
  • High Precision
  • High Dimensional Accuracy
  • Mass Production
  • Suitable for Complex Shapes
  • Better Tolerance and Resistance
  • Great Production Efficiency

1.4, Limitations of Die Casting

Die casting is very beneficial, but everything has its limitations too. Die casting has some disadvantages since the process requires complex mold designs and advanced equipment. Here is the list of constraints in die casting:

  • Limited to Non-Ferrous Alloys Only
  • Time-Consuming Procedures
  • Potential Defects on Products
  • Complex Casting Methods
  • High Upfront Cost
  • Alloys Can Generate Porosity

Chapter 2: Understanding Sand Casting

_Sand Casting

2.1, Introduction to sand casting

Sand casting is a process where liquid metals go through a solidification procedure inside a sand mold with the desired shape to produce.

The process involves preparing the liquid materials and finalizing the form of the sand mold before the injection and solidification.

2.2, The role of sand molds in the process

Sand casting mold plays an essential role, as it is used in pouring metal fluid collected for the casting method.

It has a shape and features that can hold the liquid metals to prepare the following post-machining process and achieve the desired outcome in sand casting.

2.3, Process Steps in Sand Casting

Sand casting is one of the most commonly used and popular metal casting methods where manufacturers use sand molds. If you want to know the process, here are the primary steps of sand casting:

Step 1: Placement of Mold Pattern

The first step in sand casting is placing the pattern in the sand with the exact shape and size for the desired outcome. Depending on companies ‘ requests, custom designs for different metal products are also possible.

Step 2: Preparation of Gating System

Sand casting uses a gating system or simply pouring the tunnels or cups into the mold. A funnel transmits the molten mold into the cavity, and the gating system connects the ladle and the mold.

Step 3: Removable of Mold Pattern

After putting the pattern, it must be removed from the sand since it already took the shape. The mold pattern will no longer be used in the following steps after its removable from the sand.

Step 4: Pouring of Molten Metal & Cooling Down

Heating the metals to 3,000 degrees Fahrenheit begins, and when they’re in the liquid state, it’s time to pour the molten alloys into the mold cavity. Then, wait for the metal to cool down and solidify.

Step 5: Remove the Metal Casting

The final step is breaking the sand casting open to remove the new metal casting. Solidified metal is now ready to get manufactured and used for applications.

2.4, Advantages of Sand Casting

Sand casting is another way to produce new metal products, which is beneficial to most industries and companies. Here’s a list of the advantages of sand casting:

  • Versatile
  • Low Equipment Costs
  • Simple Production Procedure
  • Suitable for Complex Shapes
  • Short Lead Time

2.5, Limitations of Sand Casting

Sand casting is also limited to some factors despite its many advantages to companies and industries. Here are the limitations when dealing with sand casting:

  • Handmade Procedure
  • Lower Strength and Dimensional Accuracy
  • Rough Surface
  • Prone to Casting Defects

Chapter 3: Comparison of Key Differences

_Sand Casting vs Gravity Die Casting

3.1, Material Sustainability

Die casting and sand casting have been weighed on with their advantages and limitations for years, as the two processes differ.

The highly adaptive process in sand casting is perfect for alloys with high melting temperatures, such as Nickel, Titanium, and Steel. But the most commonly used are Cast Steel, Cast Iron, and Brass.

On the other hand, the applicable metals for die casting process are non-ferrous such as Aluminum, Magnesium, and Zinc.

3.2, Complexity and Design Considerations

In sand casting, design considerations are needed to achieve the desired outcome of new metal products. There are three most important details, and the first is the Detailed Prints & Drawings, where the process depends since mold designs should be on top of the list.

Next is the Alloy Selection, and it’s also critical in the procedure since it includes the properties and qualities of the alloys you will use. Lastly, the Rounds & Fillets are essential for improving the appearance of the metal casting.
On the other hand, in die casting, there are also several considerations in terms of quality control. First, the Wall Thickness & Uniformity covers the all-around aspects of the casting method.

Next is the Draft & Pockets, which help open the die, and pockets are considered metal savers. Fillets and Corners are the curved parts of the surfaces and help eliminate the hard edges. Lastly, the Ribs & Bosses work on providing support as mounting points and eliminate the sharp corners of the metal casting.

_Sand Casting vs Gravity Die Casting (1)

3.3, Surface Finish and Detail

Die casting vs. sand casting has been compared for a long time, especially the pros and cons of the two casting methods.

But one of the best characteristics of die casting is having good surface finishes, the best dimensional capacity, and being thinner-walled for their metal casting. It is possible through the material selection, especially using Aluminum alloy.

Sand casting produces parts with rough surfaces with 250-500 Root Mean Square. Smoothening the finishes might take a while, and only fine sand can make the process have smoother parts compared to the usual sand.

3.4, Production Volume and Speed

Die casting and sand casting have become one of the leading manufacturing processes in the market, and the production rate has increased in the past few years.

As of now, die casting can make 20-200 pieces per hour, depending on the complexity of the design and the custom sizes requested by clients. Also, sand casting became popular despite the intricate process.

Possibly, a total of 10-150 pieces per hour has had a faster turnaround recently. It might take up to 3-5 weeks for delivery, depending on the number of orders and the custom designs requested.

_Sand Casting vs Gravity Die Casting (2)

3.5, Cost Considerations

The cost of die casting and sand casting depends on the complexity of designs and the customized details demanded by the clients. In die casting, a rate of $5,000 to $75,000 will cost you considering the tool life, high pressure, and the exclusive die-casting parts used in the process.

On the other hand, sand casting costs $500 to $7,500, depending on the features and fabrications requested by the client.

Chapter 4: Applications and Industries

Industries Utilizing Die Casting
  • Industries Utilizing Die Casting

Various industries invest in the metal parts produced from this casting method in die casting. Consumer and Industrial Products, Automotive Products, and Aerospace Parts are most companies that purchase from a die-casting manufacturer.

  • Industries Utilizing Sand Casting

Sand casting has been producing small parts belonging to industries like Automotive and Aerospace. The metal parts made with steel, nickel, and titanium are excellent for applications in the mentioned industries.

  • Specific Product Examples

Die casting and sand-casting produce metal parts that are now part of the production of various pieces of equipment in both commercial and industrial settings. Here is some the example of the products made by die casting and sand casting:

Die Casting Products:

  • Medical Devices        
  • Parts for Industrial Equipment      
  • Outdoor Lightning       
  • Parts of Firearms      
  • Appliance Components    
  • Automotive Housings

Sand Casting Products:

  • Pistons and Valves       
  • Blowers     
  • Bushings and Bearings     
  • Electronic Equipment      
  • Parts of Automobile       
  • Engine Blocks

Chapter 5: Factors Influencing Process Selection:

Factors Influencing Process Die Casting

Several factors influence the die-casting and sand-casting process before the production process begins to prevent defects and other issues from arising while the machine is running and the workforce are exerting efforts.

  • Complexity and size of the component

In sand casting, the average size distribution starts from 0.01mm to 0.08mm, and the mean size is between 0.2mm and 0.45mm. It is the standard parameter in sand casting. While in die casting, the intricate and complex shapes can be around 25g up to 25 kg, and the thinnest walls can be 0.38mm.

  • Volume and production requirements

The usual quantity of die-casting products can range from 5,000 pieces of metal parts per year, but some manufacturers can offer a higher production volume. Also, sand casting can produce 1,000 to 5,000 pieces within a year or more.

  • Material properties and alloy selection

Sand casting’s extremely adaptable method is ideal for alloys with high melting points, such as steel, titanium, and nickel, mainly Cast Iron, Cast Steel, and Brass.

Compared to this, non-ferrous metals, including aluminum, magnesium, and zinc, are suitable for die casting.

oSurface finish and tolerance requirements

In die casting, the surface finish goes through a process designed to reshape, remove, and alter the newly created metal parts. The final stage is where the Quality Control and Application Techniques are highly observed.

While in sand casting, the top-notch finishes follow a standard that must meet the design requirements. Both casting methods must go through quality management and detail-oriented surface finishing for a better product result.

  • Cost considerations and budget constraints

You are not only paying for the products in die casting and sand-casting costs. The custom mold designs and alloys to use impact the price, especially if you request different fabrications and quality control.

Also, the required amount differs from the machine type that the manufacturer uses, plus the workforce’s labor behind the successful casting procedures.

Conclusion

Die casting and sand casting are both valuable metal casting techniques, each with its unique strengths and applications.

Die casting offers high precision, intricate details, and efficient production for large volumes, while sand casting provides versatility, lower costs, and suitability for larger and more complex components.

Manufacturers must carefully evaluate their specific requirements and consider factors like complexity, volume, material, and cost to determine the most suitable casting method for their production needs.

By making informed decisions, companies can achieve high-quality metal components that meet their design specifications and production goals.

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Willie

Willie is a professional metal processing and manufacturing writer with more than eight years of industry experience.

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