How to Choose Between Investment Casting and Sand Casting?

The term "precision casting" generally excludes sand casting and primarily refers to processes such as investment casting (also known as lost wax casting), ceramic mold casting, permanent mold casting, die casting, Lost Foam Casting, and vacuum casting. Among these casting processes, investment casting and sand casting are the most common and widely used in manufacturing. Although they differ significantly in production methods and product requirements, these two processes are most easily confused. The following two images illustrate their respective processing techniques (for reference only). Today, we can discuss whether to choose investment casting or sand casting based on factors such as cost considerations, precision requirements, and surface finish requirements:

5. 1.      From a cost perspective
   Sand casting features a relatively simple and easy-to-operate process, with lower material costs as the molds are reusable and raw materials like sand are inexpensive; in contrast, investment casting requires costly materials (such as wax patterns and coatings) and involves a more complex, multi-step production process, resulting in higher costs and lower efficiency. Therefore, if cost is the primary consideration, sand casting is the more practical choice.

   2.      Accuracy requirements for workpieces

   Sand casting offers a simple process and high production efficiency, but the resulting parts have relatively low dimensional accuracy and often require additional CNc Machining. In contrast,investment casting produces high-precision components that typically need no post-processing, though some high-precision assembly applications may still necessitate subsequent CNC machining.

   3.      Surface smoothness requirements for workpieces

   Sand casting produces parts with poor surface finish and is prone to gas porosity in certain structural components, while investment casting yields products with superior surface quality and smoothness that can generally be used as finished products without further processing. For applications requiring even higher surface standards, polishing treatment can be applied to achieve a mirror-like surface finish.

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The selection of an appropriate casting process for a product requires comprehensive consideration of multiple factors. Sand casting is more suitable for producing large, structurally complex castings with relatively lower precision and surface finish requirements, as it offers cost savings and higher production efficiency. Conversely, investment casting is better suited for manufacturing small to medium-sized castings that demand high precision and superior surface quality. However, investment casting involves more complex manufacturing processes and requires advanced precision design and production techniques, resulting in higher overall costs compared to sand casting. Therefore, choosing the optimal casting process based on specific product requirements and application scenarios is crucial to ensure both production efficiency and casting quality. For any inquiries regarding custom metal casting processes, we welcome discussions and knowledge sharing - please contact us at info@dgsxltd.com.