Shell mold casting is a common metal casting process, which belongs to the consumable casting process. Like sand casting, shell mold casting is a sand-based casting method that uses sand coated with resin to form the mold. Its mold is a thin-walled shell formed by applying a sand-resin mixture around the model.
In the following content, we will deeply introduce the shell mold casting process and its application in the industrial field, so that readers can have a deep understanding of shell mold casting.
Shell Mold Casting Process
Shell mold casting is a relatively simple process consisting of only six steps.
Creating the Pattern
Creating a model is the first step in shell casting. The shell casting pattern is usually composed of two parts, and its shape is customized according to the needs of the finished casting.
Creating the Mold
In the steps of creating a mold, it can be divided into three steps:
1. Heat both parts of the model.
2 . Coat the surface of the model with lubricant.
3 . Then insert the model parts into a container that needs to be filled with resin-covered sand. And make sure the model parts themselves are covered in sand.
Assembly of Pattern Parts
During the assembly of the model parts, the top and bottom parts of the mold are joined together and secured. Once fully set, insert the mold into the flask.
Exposure to Molten Metal
In this step, molten metal is poured into the cavity of the mold to form a hardened shell. Different types of metals and alloys can be used in this process, including steel, iron stainless steel, aluminum alloys and other alloy metals.
Wait to Cool
The molten metal must cool to form a hardened shell, which creates a casting. Typically, model parts can be cooled at room temperature. As the molded part cools, the molten metal hardens to form the shell.
Ejecting the Casting
The last step in shell mold casting is to eject the casting from the mold cavity. Since the casting process uses a two-piece mold, the top and bottom mold parts are separated from each other, and the casting can be easily removed.
After the casting is removed, some post-processing procedures can be carried out according to the needs. Including removal of the gating system, removal of surface burrs, machining, surface coating, heat treatment, etc.
Shell Mold Casting Application
Shell mold casting is a casting process that can be used in various industrial fields. It can be used in automobile manufacturing, aerospace, machinery manufacturing, and other fields.
In automobile manufacturing, shell mold casting can be used to produce various key components. Including engine block, cylinder head, crankcase, steering gear housing, transmission case housing, etc.
Shell mold casting can be used in mechanical equipment, industrial equipment and instruments and other fields and is also widely used. Including textile machinery parts, printing machinery parts, medical equipment casings, etc.
Pump and Valve Manufacturing
Shell mold casting can be used to manufacture shells and fittings for various pumps and valves.
Shell mold casting can produce high-precision accessories, so it is also widely used in the aerospace field. Including key components such as aero engine parts, aerospace structural parts and aero turbines.
In the energy industry, shell mold casting can be used to produce various parts of gas turbines, steam turbine blades, generator casings, burner parts, etc.
In addition to the above fields, shell mold casting can also be used in ship parts, railway transportation equipment, petroleum, and chemical equipment, building structural parts, etc.
Advantages and Disadvantages of Shell Mold Casting
As a casting process, shell casting has many advantages:
- High Precision and Dimensional Stability
Shell mold casting can produce various high-precision parts, and can guarantee good dimensional stability. This is very important for some parts with strict size requirements. Such as engine blocks, turbine blades, etc.
- Complex Shapes and Internal Structures
Shell mold casting can be used to produce accessories with complex shapes and internal structures. Such as curve, thin wall and hollow structure accessories.
- Surface Quality and Finish
Shell mold casting can provide a higher quality surface and finish, which can minimize some common defects, such as trachoma and sand scars. This also makes subsequent machining and surface treatment of shell mold casting parts easier.
- Flexible Choice of Materials
Using the shell mold casting process, the appropriate metal material can be selected according to different performance requirements. Including iron, aluminum, stainless steel, aluminum alloy, nickel-based alloy, etc.
While shell mold casting has several advantages, there are also some limitations and disadvantages to consider. Such as longer manufacturing cycle, higher cost, and restrictions on part size and weight.
- Long Manufacturing Cycle
The shell mold casting process involves multiple steps, including model making, shell mold coating, drying, and model burning. Therefore, it has a relatively long production cycle and is not suitable for urgent needs or short lead times.
- Higher Cost
The cost of shell mold casting and other additional materials is relatively high. Therefore, compared with other casting processes, the cost of the shell mold casting process is relatively high.
- Limited by Part Size and Weight
Shell mold casting is suitable for relatively small and medium-sized parts, and this is one of its biggest limitations. If used to produce larger size and heavier parts, shell mold casting may not be the best choice.
When we choose the casting process for the product, we can choose the appropriate casting process according to the performance requirements of the part, the production quantity, and the budget.
The Difference Between Shell Mold Casting and Sand Casting
Shell mold casting and sand casting are two different casting processes. They both use sand molds as the basis, but there are some differences in specific operation steps and application ranges.
Shell Material and Manufacturing Method
- In shell mold casting, the shell is formed by coating the surface of the model with a special high-temperature-resistant coating. The shell-type coating has better high-temperature resistance and adhesion and can withstand metal casting at high temperatures.
- Ordinary sand molding sand is used in sand casting.
Complexity and Precision
- Shell mold casting is usually suitable for manufacturing more complex parts and parts with higher precision requirements because the shell shape can achieve more complex inner cavities and surface details.
- Sand casting is suitable for relatively simple parts and applications that require less precision.
Production Cycle and Cost
- The production process of shell mold casting is relatively complicated and the production cycle is long. And the cost of shell mold casting is usually higher.
- The production process of sand casting is relatively simple and the production cycle is short. Compared with shell mold casting, the cost of sand casting is relatively low.
- Shell mold casting can provide a higher quality surface, and can reduce blisters and other defects because the shell mold coating can better fix the filling material.
- The surface quality of sand casting is relatively poor, and defects such as sand holes and sand scars may appear.
𝑺𝒉𝒆𝒍𝒍 𝑴𝒐𝒍𝒅 𝑪𝒂𝒔𝒕𝒊𝒏𝒈 𝑴𝒂𝒏𝒖𝒇𝒂𝒄𝒕𝒖𝒓𝒆𝒓𝒔
As an investment casting manufacturer, EASIAHOME can provide shell molds to complement other casting processes to provide the best quality and cost solution. The shell and membrane castings we have completed include flange mounts, impellers, gearboxes, cylinder heads, pump casings, pump covers, etc. If you have shell casting needs, please contact us.