Precision casting (investment casting) is a high-precision casting process whose cost is influenced by a variety of factors. Customers face different choices when manufacturing parts. The choice of process typically depends on manufacturing capabilities, product feasibility, and cost. When assessing the cost of precision casting, different customers may experience varying costs due to their specific manufacturing needs (e.g., the number of parts required). However, several key cost drivers need to be considered when deciding on a manufacturing technology.

The following analyzes the core cost drivers from the perspectives of materials, design, process, and equipment, and proposes directions for cost optimization:

 

1. Material Selection

The selected metal is a cost driver in precision casting. Base materials and alloys vary in grade. Therefore, even when using the same metal, a higher purity alloy will be more expensive than a lower purity alloy. Customers typically need to purchase more metal than actually needed to cast the parts. Other cost factors include scarcity and availability. Metals that are difficult to mine and process limit their supply, thus increasing costs.

The following are the specific material costs:

 

1.1 Wax Model Materials

Types and Prices:

Commonly used wax model materials include paraffin-stearic acid-based wax (low cost), medium-temperature wax model materials (e.g., polyethylene wax, high precision but 2-3 times more expensive), and high-temperature wax model materials (e.g., ceramic wax model materials, used for complex structures, highest cost).

Imported high-performance wax model materials can cost 1.5-2 times more than domestic materials.

Loss Rate: Wax model repair and wax recycling result in 5%-15% material loss, with higher losses for complex precision castings.

 

1.2 Shell Materials

Refractory Materials:

Surface materials (e.g., zirconium sand and corundum) are 3-5 times more expensive than backing materials (e.g., silica sand). High-alloy steel castings require special materials such as yttrium oxide, significantly increasing costs.

Binders (e.g., water glass, silica sol): Silica sol has high strength, but is 4-6 times more expensive than water glass, and has a long drying time, affecting efficiency.

Material Consumption: Material consumption for multi-layer shells (typically 5-10 layers) increases with the size and complexity of the casting. Shell material costs for large parts can account for 20%-30% of the total cost.

 

1.3 Metallic Materials

Alloy Types:

Stainless steel and high-temperature alloys (such as nickel-based alloys) are 3-10 times more expensive than ordinary carbon steel, while precious metals (such as titanium alloys and cobalt-chromium alloys) are even more expensive.

Smelting Losses:

The smelting yield in precision casting is approximately 70%-85%, with significant losses for rare alloys.

 

2. Design Complexity

Part design is a crucial factor influencing the cost of investment precision casting. Simple part designs without internal channels, holes, or other features help reduce customer costs. However, when part geometries are more complex and require intricate core designs, these features necessitate that the gating system ensure molten metal reaches all necessary areas to achieve high-quality, defect-free products. These additional steps can increase production costs.

Complex components and large parts may also require additional cores. These additional cores can strengthen already fragile walls (such as elongated holes or slots). Due to the additional cores and complex design, the drying process may take longer, slowing down production. All of these factors increase project costs.

3. Production Process, Heat Treatment, Surface Finishing, and Testing Requirements

 

3.1. Mold Development

Mold Complexity:

Single-piece, small-batch production requires hand-carved wax models, which are low-cost but inefficient; mass production requires metal molds (e.g., aluminum molds, steel molds), with development costs ranging from tens of thousands to hundreds of thousands of yuan, accounting for 30%-50% of the initial cost.

Mold Lifespan:

Aluminum alloy molds can produce approximately 500-1000 pieces, while steel molds can produce tens of thousands. Frequent mold changes increase shared costs.

 

3.2 Process Complexity

Wax Model Making:

Complex castings (e.g., aircraft blades and turbine impellers) require multi-module wax models. Manual assembly is time-consuming, accounting for 15%-25% of labor costs.

Shell Material Preparation:

Silica sol shell materials require multiple coatings and drying cycles (each layer requires 12-24 hours of drying), with a cycle taking 5-7 days. This process is energy-intensive (e.g., requiring a constant temperature and humidity workshop) and labor costs are also high.

Dewaxing and Firing:

Steam dewaxing consumes approximately 500-800 kJ per kilogram of wax, while electric firing furnaces can reach hundreds of kilowatts in power, with energy costs accounting for approximately 10%-15%.

 

3.3 Post-Processing

Sandblasting and Surface Treatment:

High-pressure water cleaning and sandblasting processes increase processing time; precision parts require chemical polishing or electrolytic polishing, which incurs high material and equipment costs.

Inspection Costs:

Non-destructive testing (NDT) costs, such as penetrant testing, X-ray inspection, and coordinate measuring machine (CMM), typically account for 5%-10% of the total cost, and are even higher in high-demand fields like aerospace.

Each manufacturer has its unique manufacturing processes and technologies to meet its operational and service needs. These prices will vary depending on their capabilities. They may also offer certain technologies to help customers create cost-effective solutions.

Rapid prototyping services, heat treatment, surface treatments, and various testing requirements all increase part costs. These optional services can improve part quality and ensure that parts meet application requirements. Many customers choose these surface treatment services because they know the long-term return on the upfront investment is worthwhile.

Ningbo Suijin Machinery Technology Co., Ltd. specializes in the production of various precision castings and machined parts, including carbon steel, alloy steel, and stainless steel, and can perform composite processing of composite materials according to drawings.