CNC machining tolerance levels vary depending on the specific machining stage and process requirements, with an overall range spanning from ±0.5 mm down to micron-level precision.
- Rough Machining Stage
The tolerance range typically falls between ±0.2 mm and ±0.5 mm. This stage is primarily focused on rapidly removing excess material to achieve the preliminary shape of the part, and consequently, the precision requirements are relatively low. - Semi-Finishing Stage
Tolerances can be controlled within the range of ±0.05 mm to ±0.2 mm. This stage serves to further refine the part’s geometry and improve its surface finish, thereby preparing it for the subsequent fine finishing process. - Fine Finishing Stage
Tolerances can reach ±0.01 mm to ±0.05 mm. This level is suitable for the majority of standard mechanical components that require specific precision, such as shafts, gears, and hardware connectors. - High-Precision Machining Stage
Tolerances can be controlled within ±0.005 mm to ±0.01 mm—or even tighter. This typically necessitates the use of high-end precision machining equipment and specialized processes, and is predominantly applied in fields with extremely stringent precision requirements, such as aerospace, precision instrumentation, and medical implants.





