Sand casting and investment casting are two distinct casting processes, with significant differences in several aspects. Below is a detailed comparison of these two casting methods:

Material Usage

Sand Casting: Primarily using sand molds as molding materials, such as quartz sand, gypsum sand, clay sand, and others. These materials offer great value in terms of cost and availability, making sand casting a relatively low-cost production method.

Investment Casting: This process requires refractory materials to create molds, which are typically made of materials such as gypsum, ceramics, and even fusible materials like wax. Although these materials are relatively expensive, they enable the production of higher quality and more precise castings.

Process Flow

Sand casting: The process is relatively simple, mainly including mold making, casting, cooling, mold removal, and sanding. This casting method offers high production efficiency and is suitable for manufacturing small to medium-sized castings.

Investment Casting: This method involves greater manufacturing complexity and a more intricate process. It begins with creating an easy-melting model (such as a wax model), then applying multiple layers of refractory material over the model's surface. After hardening and drying, the model is heated to melt away, resulting in a shell that matches the model's shape. The shell is then fired, followed by casting, cooling, and cleaning the casting. This process encompasses several steps, including making the gypsum model, dipping in paint, oiling, drying, wax burning, melting wax, casting, cooling, and removing the cores.

III. Application Scope and Accuracy

Sand casting: Suitable for producing complex shapes, especially patterns with intricate internal cavities, but not particularly suitable for high-precision casting. As the casting size increases, larger molds and more gates are required, significantly increasing costs.

Investment Casting: This method enables the production of high-precision, complex-shaped castings, with no limitations on the casting alloys. Consequently, it is suitable for manufacturing parts with high precision and complexity in industries such as aviation, aerospace, and automotive.

Section 4: Production Efficiency and Costs

Sand casting: It offers high production efficiency and, due to relatively low material costs, overall costs are manageable. This makes sand casting a common casting method in many industries.

Investment Casting: Although it can produce high-quality castings, the overall cost is relatively high due to the complex process, high material costs, and the need for precise design and manufacturing techniques. Additionally, the production cycle for investment casting is also longer.

In summary, sand casting and investment casting differ significantly in terms of material usage, process flow, application scope and precision, as well as production efficiency and cost. In actual production, the choice of casting process should be based on specific product requirements, cost budget, and production cycle factors.