Investment Casting

Investment casting has been a crucial manufacturing technique for creating high-precision components with minimal surface defects. The process of molding a wax pattern, casting it in ceramic shells, and then filling the resulting cavity with molten metal allows for the production of intricate and complex parts.

The ability to remove the wax to form an empty space and then fill it with molten metal enables the creation of parts with thin walls, intricate details, and complex geometries. This makes investment casting particularly valuable in industries where precision and intricacy are paramount, such as aerospace, automotive, and medical equipment manufacturing.

Furthermore, the process results in finished parts with limited post-processing requirements, reducing the need for additional machining or finishing. This not only saves time and resources but also ensures that the final components maintain their precise dimensions and surface quality.

Overall, the magic of investment casting lies in its ability to produce high-precision components with minimal surface defects, making it a versatile and valuable manufacturing technique for a wide range of industries.

At KEMING foundry, our investment casting process leverages state-of-the-art technology, positioning us as a leader in China’s investment casting industry. We specialize in the production of high-quality investment castings, offering a diverse range of dimensions and shapes to meet our customers’ needs. Our process accommodates all metal alloys, allowing for customized investment castings based on specific material requirements, including the feasibility of unique material compositions. Quality is paramount, and as such, we implement rigorous quality control measures at every stage of the investment casting process. The following outlines the comprehensive steps involved in our investment casting process:
Step 1: Tooling Production

In order to ensure the production of precise components, the initial step in investment casting involves the creation of tooling. This tooling, or pattern, undergoes precision machining using CNC technology. As a result, when a sample order for a new product is placed, customers will be charged a tooling cost. However, this fee is a one-time payment and will not be required for subsequent orders.


Step 2: Wax Injection and Pattern Assembly

Upon the completion of a set of casting patterns, the next step involves the creation of wax patterns. This is achieved by injecting wax into the patterns, resulting in a model that mirrors the desired product’s dimensions. Subsequently, the injection process is repeated to produce additional wax patterns, which are then assembled onto the sprue. The assembled pattern sets are then left to dry at room temperature.


Step 3: Shell Formation

During this phase, the pattern assembly is immersed in a ceramic slurry and coated with a refractory material. This procedure is repeated multiple times until the ceramic shell achieves the required thickness and strength. Subsequently, the ceramic shell is constructed and subjected to drying within an environment that is atmospherically controlled.


Step 4: Dewaxing

The ceramic shell is subjected to rapid heating within a steam autoclave, causing the wax to melt and flow out through the gate and pouring up under high temperature. Subsequently, the ceramic shell molds undergo firing to eliminate any remaining traces of pattern material and to preheat the mold for casting, typically within the temperature range of 1,600-2,000 degrees Fahrenheit. This process is why investment casting is also referred to as “lost wax casting.”


Step 5: Casting

The casting phase is pivotal in the overall investment casting process. Following the dewaxing stage, the steel ingots are melted to a liquid state, and the molten metal is then poured into the sprue. Subsequently, the metal is allowed to cool at room temperature for a period of time.


Step 6: Removal

During this step, the ceramic shell is fractured, and the individual investment castings are separated from the sprue. Subsequently, any excess metal on the casting body is eliminated through grinding.


Step 7: Heat Treatment

In order to enhance the mechanical properties of the casting blanks, heat treatment is typically conducted after the completion of castings. The primary heat treatment processes include normalizing, tempering, annealing, hardening and tempering, carburizing, and others. It’s important to note that heat treatment is carried out only when specified by customers, and any additional costs will be accounted for accordingly.


Step 8: Shot Blasting/Sand Blasting

To eliminate scales and attain an improved surface finish, the investment castings undergo shot blasting or sand blasting using small steel balls. Therefore, it is essential for all foundries to be equipped with shot blasting machines.


Step 9: Surface Treatments

In order to prevent products from rusting, the castings are immersed in anti-rust water or oil. Additionally, various other surface treatments such as paint spraying, galvanizing, and more can also be carried out during this stage.


Step 10: Quality Control

Quality control is an essential step in ensuring the production of high-quality investment castings. Our engineers conduct dimensional inspections, 100% surface inspections, internal defect inspections, and other necessary checks based on the product requirements. Only after confirming that all products meet the required standards, can we proceed with arranging delivery to our customers.


Step 11: Packaging

Since all products are destined for the overseas market, the standard practice involves packaging the investment castings in polybags and then placing them into standard wooden cases. It is crucial that all packaging is executed to ensure the products remain undamaged. Additionally, we are able to provide customized packaging services to accommodate any special requirements from our customers.


Advantages of Investment Casting Process

Exceptional Detail and Precision:
Investment casting is renowned for its ability to produce parts with intricate detail and precision. This method allows for the creation of complex geometries, intricate forms, and undercuts that are challenging to achieve using other casting techniques. Additionally, it delivers high dimensional accuracy, reducing the need for extensive secondary machining.

Superior Surface Finish:
Investment casting results in a smooth surface finish, often superior to other casting methods. The high-quality surface finish minimizes the necessity for additional treatments or finishing processes, leading to cost savings and expedited production cycles.

Material Flexibility:
Investment casting accommodates a wide range of metals and alloys, including steel, stainless steel, aluminum alloys, bronze, and more. The versatility of materials allows for the selection of the most suitable option to meet specific product requirements, such as strength, heat resistance, or corrosion resistance.

Ideal for Complex and Intricate Designs:
The investment casting process is well-suited for the production of complex and intricate parts, offering a level of detail and complexity that may be challenging to achieve through other manufacturing methods. The use of wax patterns and ceramic molds enables the creation of intricate designs with precision.

Cost-Effective for Small to Medium Production Runs:
Investment casting is particularly cost-effective for small to medium production runs. This process requires fewer steps and generates less waste compared to alternative methods. While the initial tooling cost may be higher, it is often offset by lower per-piece production costs.

Near-Net-Shape Parts:
Investment casting is known for producing near-net-shape parts, reducing the need for extensive additional machining or finishing after the casting process. This efficiency saves time and costs, particularly for complex-shaped components or hard materials that are challenging to machine.

In summary, the investment casting process offers numerous advantages, making it a valuable option across various industrial applications. Its precision, material versatility, and ability to produce intricate details in components make it a highly effective manufacturing method.

Tips for Selecting the Investment Casting Process

The investment casting process is highly efficient and can yield impressive results, but it’s crucial to carefully consider its suitability for your project’s specific requirements. Here are some tips for selecting the investment casting process, particularly when considering Keming Machinery as your manufacturing partner:

Evaluate Your Design Requirements:
Begin by assessing the design of your part. Investment casting is well-suited for intricate and complex designs that may pose challenges for other manufacturing methods. Evaluate the complexity, details, and features of your design to determine if investment casting is the most suitable option.

Consider the Material Selection:
Keming Machinery offers a range of metals and alloys, allowing you to select the material that best aligns with your project’s needs. Factors such as strength, heat resistance, and corrosion resistance should be taken into account when choosing the material for your project.

Assess Production Volume:
Determine the production volume for your project, whether it involves small or large quantities. While investment casting can be cost-effective for production runs, consider the initial costs for mold making and the efficiency of wax pattern creation. Discuss the production volume with Keming Machinery’s team to ensure it aligns with your budget.

Factor in Lead Time:
Although Keming Machinery is known for its efficiency, the investment casting process involves multiple stages that require time to complete. Communicate your project’s timeline to the foundry and ensure they can meet your specific deadlines.

Review Post-Processing Requirements:
While investment casting ensures high surface quality and dimensional accuracy, some projects may require post-processing techniques such as machining, heat treatment, or specialized coatings. Keming Machinery provides these services, so be sure to discuss your post-processing needs to ensure they can be accommodated.

Partner with an Experienced Foundry:
Keming Machinery is a professional and experienced foundry with a strong background in investment casting. They can provide guidance on design optimization and material selection. Partnering with a reliable foundry like Keming Machinery will streamline project management and ensure quality results.

By considering these factors collectively, you can effectively determine whether the investment casting process, in partnership with Keming Machinery, is the right choice for your project. Our commitment to quality, customer support, and advanced technology makes us the ideal partner for your investment casting requirements.