Die Casting vs Sand Casting: What’s the Difference?
Die casting involves using high pressure to inject molten metal into a metal mold, and sand casting involves pouring molten metal into a sand mold. Die casting and sand casting are both reliable processes, but each has its pros and cons. When choosing which technique to use in your manufacturing process, it is important to consider the type of object you are producing, your budget, and production volume. Keep reading to learn more about the differences between die casting vs sand casting, and which casting method is right for you.
What is Die Casting?
Die casting is a process that forces molten metal into a die mold with extreme pressure. The die mold is made of steel, and as the hot molten metal is injected, it fills the negative space of the steel mold to produce the desired shape. The metal cools down until it is solid, and the mold is then removed. The die is immediately ready to be used again. The average production cycle of die casting takes 30 seconds to 1 minute.
Pros of Die Casting:
- High-speed production capabilities
- Minimal downtime between rounds of production
- Uniform design
- Cost-effective, especially when produced in high numbers
- Smooth surface finish
Cons of Die Casting:
- The process is not suited for ferrous metals due to high melting temperatures
- High tooling costs
What is Sand Casting?
The name sand casting comes from the mold the metal is being poured into as it is made of sand. The sand casting process includes molten metal being poured into the mold via a metal ladle. This process does not require high-pressure metal injections done in die casting. The sand mold is created by a pattern.The pattern is made of plastic or wood and then put into an enclosure. The sand is poured around the pattern within the enclosure and densely packed. After the sand is packed, the pattern is removed and the molten metal fills the space.
Once solid, the mold is opened and the sand is brushed off the metal product. Sand casting requires some preparation time between cycles, whereas die casting has little to no downtime between casting rounds.
Pros of Sand Casting:
- Flexibility in the shape of design
- Larger mold capability
- Cost-efficient when producing low quantities
Cons of Sand Casting:
- Coarser surface finish
- Longer mold preparation time between casting
- Lacks dimensional accuracy compared to die casting
Die Casting vs Sand Casting: What’s the Difference?
There are a few key differences when it comes to die casting vs sand casting. These differences include the materials used, the precision and intricacy ability of each design, the wall thickness, the production volume capabilities, costs, and more.
1. Materials Used
The main difference in die casting vs sand casting is in the materials used and therefore the differences in each process. Die casting molds are made of metal and sand casting molds are made of sand. Molds made of sand allow for a more intricate design, while molds made of metal typically have a more durable result as the high-pressured injection of molten metal fills any little gaps within the product.
When deciding if die casting vs sand casting is better for you, consider if you need the final product to be more detailed and intricate, or if you need it to be as durable as possible.
2. Complexity of the Results
As mentioned above, the intricacy of the final product depends on the process used. Sand casting allows for more flexibility in object shape and larger end results, but lacks the dimensional accuracy of die casting as the sand can be packed around a plastic or wooden object as well as carved to create the mold. While die casting does not have the flexibility in design complexity, the process of high-pressure metal injection offers more dimensional accuracy.
3. Thickness of Walls
Wall thickness refers to the thickness of one surface of a 3D object to the other side of its surface. Sand casting typically requires thicker walls, but allows a more forgiving post-casting process where one can correct the inaccuracies. Die casting has thinner walls, but offers more dimensional accuracy and precision. Sand casting is not recommended for small objects as it is difficult to maintain the proper dimensional accuracy.
4. Production Capabilities
Die casting has a far quicker production cycle, but preparing the die casting process usually takes longer. On the contrary, sand casting is faster and less complex to set up, but the production cycle takes longer than die casting. For this reason, die casting is better for high-production volume projects, and sand casting is better for low-volume projects.
Creating a metal mold for the die casting process takes more money and expertise. If you plan to produce a high volume of a particular object, investing in a metal mold will help save production time and thus cut costs in the long run. If you do not need a high volume of products, sand casting may be more cost-effective.
6. Surface Finish
The surface finish between the processes may be an important factor in determining which process to use. Die casting produces a wonderful, smooth finish. Sand casting produces a rough, coarse finish depending on the sand used, which may require additional finishing treatments.
Die Casting vs Sand Casting: Which Process Should I Use?
When it comes to deciding which casting method to use, the deciding factors are usually the end use of the product and production volume. If you want to make medical instruments, die casting is a better fit as it is optimal for small, durable, and precise objects. If you want to produce large objects such as truck drums or motor housings , sand casting is great as the molds used can handle large sizes.
If you are planning to produce a high number of small to medium-sized objects, die casting will suit you best. If you are planning to produce around fewer medium to large objects, sand casting is the method for you.
General Kinematics Has you Covered
If you don’t know where to start with your foundry project, you’ve come to the right place– General Kinematics has your back. General Kinematics has a team of engineers ready to answer any of the questions you may have about metalcasting systems, equipment and processes. GK is an industry leader with more than 60 years of experience serving metalcasting customers and helping them exceed their manufacturing expectations. Speak with a General Kinematics engineer today!