Understanding the Ins and Outs of Sand Casting Vs. Die Casting
There are many casting techniques in the metal foundry industry. However, every type is unique and has its goal.
Sand casting and die casting are different, as the names suggest. In other words, there are significant differences between sand casting and die casting, as explained in this article. It is essential to look into the differences before choosing the right one for your project.
What is Die Casting?
Die casting is a metal-making process where molten metal is passed through a die under high pressure. A die is a mold made of steel and designed to resemble the shape of the desired product. When the molten metal cools and solidifies, you get the final product from the mold. The mold can be closed and reused to make another product. The cycle is always quick, making die casting one of the fastest casting processes.
What is Sand Casting?
In sand casting, molten metal is poured into a mold made of compacted sand. The process does not involve high pressure. When the metal cools and solidifies, the mold is opened and sand brushed to get the product. However, the process has more downtime since the sand must be replaced around the match plate after every session. Due to this, sand casting is often suitable for low-volume production.
Sand Casting Vs. Die Casting Differences
Die Casting Advantages
- High production speed
- Helps in assembling more products
Sand Casting Advantages
- Low costs associated with tooling
- The most flexible process when it comes to sizes, shapes, and weight
- It can be used with many metals and alloys
Sand Casting Disadvantages
- The final product often comes with less accuracy
- Low tolerance of final products
- The final product will have a rough surface finish
Die Casting Disadvantages
- Requires more investment in tooling
- Only cost-effective when the volume of production is high
Sand Casting Vs. Die Casting Differences Explained
The most significant difference between sand casting and die casting is the material used to make the mold. Additionally, sand casting and die casting differ in their application. For instance, die casting is most applicable in parts that need more precision and have complex shapes. In contrast, sand casting may be more applicable in making parts with thicker walls that require cost-effective methods.
Sand casted products also come with textural imprints. The imprints can come in handy if you want a better look with the granular effect or imperfections that give the final product a more antique appearance. In contrast, this finish is often seen as a disadvantage when casting smaller parts with more complex shapes and requires precision in their finish.
In die casting, dies can be reused to increase precision and lower production costs in the long run. This is primarily because all parts to be cast can be made in one production session, and the process can be repeated severally. Die casting is also effective when you want features that cannot be produced through sand casting. This would help reduce secondary costs.
Die casting makes it difficult for you to achieve higher out-of-mold precision in the final product. In die casting, pressure and precision are injected in the molten metal makes a component that is ready to use straight out of the mold. This may not be achievable with sand casting since the final product comes out with questionable tolerance.
When it comes to the lead time, die casting becomes a less desirable technique. This is because die casting requires more preparations, such as mold machining, testing, and additional setups associated with the casting process. On the other hand, sand casting does not require more preps as mold can be made in less than a day if you already have your desired patterns. Therefore, sand casting is most effective when time is considered.
As suggested earlier, die casting offers the most exceptional surface finish since the molds are made with a smooth inner surface and high pressure. The lack of pressure in sand casting can mean less desirable final products if surface finish is a priority. However, the porous and granular finish in sand casting can be desirable in some products though manufacturers often use post-casting methods to remove the imperfections.
Considering the amounts of investment and effort required to create metal parts, die casting is recommended for high volume production, such as making more than 1000 parts. This is because it does not make economic sense to invest highly in costly dies and equipment if you want to create only a few parts. Additionally, since the molds can be reused, the whole process is incentivized when repeated.
On the other hand, sand casting is more affordable and more straightforward. However, this process becomes burdensome when the production volume is raised. This is mainly because every part would require a new mold since the mold is often destroyed when removing the finished product. Therefore, sand casting is only recommended if you want to create less than 1000 parts.
Lastly, sand casting is the most desirable process if you want to consider the overall cost. The process is straightforward and way less costly since it does not require high initial investments. On the other hand, die casting is expensive and only best for applications that require high quality and low maintenance parts.
Sand Casting Vs. Die Casting Similarities
One of the most notable similarities between sand casting and die casting is that they have applications in commercial manufacturing processes. The two methods give companies sufficient lead time to reduce costs by making molds out of steel. For instance, die casting is more cost-effective in the long run, while sand casting is more affordable when engaging in low volume production.
Additionally, it is worth noting that both sand casting and die casting are highly efficient, widespread, and useful in making metal parts.
With some planning, both sand casting and die casting can produce complex shapes. The two techniques have been used to produce metal parts that can be challenging to machine in the past. However, die casting is most preferred if the part is more complex. This may not mean that sand casting is less desirable. For instance, engine blocks are often created through sand casting.
Conclusion
This article has briefed you about the differences and similarities between sand casting and die casting. Consider looking into your needs to determine the process that best suits your projects if you are caught between options.