Investment casting is known for its high degree of accuracy and precision, making it suitable for applications where tight tolerances and intricate geometries are essential.

However, the accuracy of investment casting can vary depending on several factors, including the casting process, the quality of pattern and mold preparation, and the expertise of the casting supplier.

Here are some key considerations regarding the accuracy of investment casting:

1. Pattern and Mold Preparation: The accuracy of investment casting begins with the creation of the wax or wax-like pattern and the ceramic shell mold. The precision and quality of these components are crucial. Patterns must faithfully replicate the desired part, and the ceramic shell mold must be dimensionally stable to maintain the intended shape and dimensions.
2. Casting Process Control: Investment casting foundries must carefully control the entire casting process, including metal pouring, solidification, and cooling. Proper gating and riser design are essential to minimize shrinkage and maintain dimensional accuracy.
3. Tolerances: Investment casting can achieve tight dimensional tolerances, often within a range of ±0.005 to ±0.015 inches (±0.13 to ±0.38 mm) per inch or ±0.1% to ±0.5% of the linear dimension, depending on the size and complexity of the part. Achieving these tolerances requires precision in every stage of the process.
4. Surface Finish: Investment casting typically produces parts with excellent surface finishes. The surface roughness can vary depending on factors like the mold material and the quality of the ceramic shell. In many cases, investment casting results in a surface finish of 125 to 250 microinches (3.2 to 6.3 micrometers) Ra or better.
5. Design Considerations: The accuracy of investment casting can also be influenced by the design of the part. Features such as thin walls, sharp corners, and undercuts may present challenges that affect accuracy.
6. Post-Casting Processes: While investment casting can produce near-net-shape parts, some post-casting finishing processes like machining or polishing may still be required to achieve the desired specifications.
7. Quality Control: Rigorous quality control measures, including dimensional inspections and non-destructive testing (NDT), are essential to ensure that castings meet the specified tolerances and quality standards.
8. Casting Expertise: The expertise and experience of the casting supplier play a significant role in achieving accurate results. Experienced foundries with a history of successful investment casting projects are more likely to produce accurate and high-quality castings.

In summary, investment casting is capable of achieving a high level of accuracy and precision, making it suitable for applications in industries such as aerospace, automotive, and medical devices, where precise and complex parts are required.

However, achieving this level of accuracy requires attention to detail in every stage of the casting process, from pattern and mold preparation to final inspection and quality control.