Sand casting is widely used in various industries due to its adaptability and cost-effectiveness. Sand casting is a metal casting process that utilizes non-reusable sand molds to form metal products of different shapes. It is the simplest metal casting method. However, every foundry must take more precautions and quality control measures. This metal casting method is suitable for all types of metals and can produce metal products ranging from ounces to tons.
The tools for sand casting are simple. Sand molds with exquisite exterior details and interior cores of any shape can be created. However, complex objects are difficult to process with sand casting. Other casting methods such as investment casting can be considered methods.
Overall, sand casting is good for small batch production of large parts because it is able to create large, complex parts or parts that require cores. This method can be started and completed quickly, faster than many other casting techniques.
Production Steps
The sand casting method is easy to operate and requires less tools. But it follows a continuous production step, where the operator's skills focus on better quality. We have summarized the complete sand casting method into the following seven steps.
Step 1: Mold Making
Mold making is the most critical step that guarantees the accuracy of the final casting dimensions. A container filled with special sand contains the pattern of the original object. In this case, the casting model replicates the actual product. It can be made of wax or other materials. However, the upper and lower halves of the sand mold container are called the upper and lower molds respectively.
Step 2: Mold Preparation
After the sand mold is ready, the operator prepares it to pour the molten metal. In this case, the cavity surface needs to be lubricated. Each metal type has a different type of lubrication. Subsequently, the operator closes the two halves of the container and clamps them together. Clamping is also a critical step that requires proper precautions to achieve defect-free metal casting.
Step 3: Pouring the Molten Metal
Gating system is one of the essential terms in this step. The operator pours the molten metal through these gates. In this case, the gate refers to the gap between the casting cavity and the outside of the mold.
Step 4: Cooling
After pouring the metal into the casting cavity, the operator puts the container into a cooling chamber. In this case, proper cooling temperature is required to minimize shrinkage defects in the casting. When the liquid metal turns into solid metal and reaches the right temperature, it is ready to be removed.
Step 5: Removing the casting from the mold
At this stage, the operator breaks the sand mold and removes the casting from the mold. At Dawang Metals, first, skilled operators use a vibrating machine to gently remove the sand from the casting. Finally, the remaining sand and the oxide layer adhering to the surface of the casting are removed using a hot sandblasting method.
Step 6: Machining
It is worth noting that sand castings have high dimensional tolerances. At this stage, proper machining is required to make them precise. Some excess material may adhere to the surface and needs to be removed to obtain the original shape of the casting.
Step 7: Finishing
After finishing and other machining stages, the casting enters the finishing stage. The finishing stage includes polishing, painting or powder coating. The type of finishing depends on the casting material and application.
Applications
The sand casting method is widely used. Popular products of sand castings are pistons and valves, engine blocks, cams, bearings, bearing balls, hydraulic pumps and housings, agricultural equipment, automotive equipment, lever arms and pulleys, electrical equipment electrical parts, railway equipment, petrochemical engineering equipment, engineering machinery.
Although the types of metal casting may vary according to the complexity. The popular industries it serves are medical, agriculture, automobile, defense, marine, mining, power plants, etc.
Advantages
As we all know, sand casting is the most commonly used metal casting method in every industry. Due to its wide range of advantages, this method is prevalent in every field involving metals. Compared with other metal casting methods, sand casting has the following advantages.
1. Sand casting is widely used and suitable for all types of metals. It can produce metal products of various sizes.
2. It can create relatively complex parts in a budget option.
3. This metal casting method can produce relatively precise metal castings. However, additional processing is subsequently required to minimize dimensional tolerances.
4. Sand casting is undoubtedly the best budget option for precision metal casting. Investment casting, shell casting are more expensive compared to sand casting.
5. This metal casting method is the fastest in the world. It takes less time for processing and formulation compared to other metal casting methods.
6. Sand molds are recyclable but not reusable for casting. These are easily recycled for multiple production cycles.
7. Casting sand can usually withstand extremely high melting points.
Disadvantages
Despite the many advantages of sand casting, it still has some disadvantages. Depending on different factors of the desired application, sand casting may present some disadvantages.
1. Sand casting method produces higher porosity defects in castings compared to other metal casting methods. Therefore, it is better to determine the porosity level for metal casting applications.
2. Another casting defect often found in sand casting is surface inclusions. During the casting process, the molten metal picks up the loose sand from the mold. As a result, it creates surface inclusions in the form of sand particles.
3. We know that sand casting requires less mold cost. However, on the other hand, since the process is manual, it will eventually increase labor costs.
4. Sand casting requires special cleaning and additional machining to minimize dimensional tolerances.
5. This casting method is not suitable for large orders. In these cases, reusable permanent molds are common in most foundries.
For more information, please feel free to contact us.
Whats App number:19050516721
Phone: 19050516721
E-mail: Judy@haozhifeng.com
