Investment Casting

Investment casting, also known as lost wax casting, is a traditional manufacturing process that originated thousands of years ago. This process is utilised to create metal parts and components with complex shapes and intricate details. It is a cost-effective method to produce complex parts.  

The process commences with the crafting of a wax or plastic pattern, an exact replica of the desired part. Our experienced engineers excel in designing tooling for creating these patterns. Once the tools are devised, we utilise 3D printing for initial rapid prototyping, which undergoes testing before the production phase. Subsequently, the pattern is coated with a ceramic slurry to form a shell around it. After the shell has hardened, the wax or plastic is melted out, leaving behind a cavity in the shape of the desired part. Molten metal is then poured into the cavity, filling the space vacated by the melted pattern. Following solidification, the ceramic shell is removed, revealing the finished metal part. Investment casting is esteemed for its capability to produce parts with tight tolerances, excellent surface finish, and intricate geometries.

Here at Taiyuan Simis Investment Casting Co., Ltd, we possess the capability to manufacture metal parts and components with extremely tight tolerances and complex and intricate shapes and designs, both internally and externally. We can cast metal parts and components with a wide range of materials using the investment casting technique, including stainless steel, carbon steel, cast iron, aluminium, and many more.

The investment casting process commences with pattern creation, where a master pattern, typically wax but occasionally plastic or frozen mercury, is formed to replicate the desired part, allowing for material shrinkage. 

Next, multiple wax patterns are assembled onto a central wax sprue to form a tree-like structure, facilitating efficient casting of multiple parts. This assembly is then coated with ceramic slurry and fine sand, repeating the process to create a robust ceramic shell around the wax patterns, ensuring strength and thickness. 

After drying, the wax is melted out, leaving a hollow cavity, followed by firing the ceramic shell to remove residue and fortify the mould. Molten metal, such as steel or aluminium, is then poured into the preheated ceramic shell, assuming the precise shape of the patterns. 

Upon cooling and solidification, the ceramic shell is removed, often through vibration or blasting, revealing the metal casting. The castings are then cut off from the central sprue and finished, which may involve grinding and machining for accuracy. 

Finally, inspection and quality control ensure dimensional precision, surface finish, and structural integrity, employing techniques like X-ray and ultrasonic testing to detect any defects.

Taiyuan Simis Investment Casting Co., Ltd employs one of the world’s most advanced silica sol investment casting techniques, revolutionizing the process through the complete implementation of silica sol binders. This shift not only replaces environmentally harmful curing agents, improving the working environment and enhancing casting quality, but also reduces drying time for silica sol shells from 8 hours to just 1 hour per layer, significantly boosting production efficiency and shell strength. 

The innovation has broadened the application of silica sol technology to a wider range of materials, including carbon steel and various alloy steels, enabling the production of larger investment casting parts weighing up to 50 kg and reducing costs, especially for traditionally expensive materials. Our fully automated shell-making process, which includes mechanical handling and automatic drying, can create up to 8 layers of shells with precise control, resulting in stronger shells that are nearly half the thickness of conventional silica sol binders, thus improving permeability and achieving high-quality surface finishes. 

In addition to offering silica sol investment casting services, we provide tooling design and manufacturing support. Capable of producing castings ranging from 1g to 50kg, we ensure top quality and dimensional accuracy for diverse applications, including aerospace, agricultural machinery, automotive, and more. Our experienced engineers tackle manufacturing challenges such as gas porosity and shrinkage defects, accommodating all order volumes with an annual capacity exceeding 5000 tons across a range of materials and alloys, including stainless steel, high-strength steel, and titanium.