CNC Machining Tolerances
When creating parts through CNC machining, the level of precision depends on how accurate your design needs to be. Tolerances are important because they define how much variation is acceptable in the size and shape of the finished part. In CNC machining, we can measure and control tolerances in two ways:
- Coordinate Tolerances: Basic measurements like length, width, and diameter
- Geometric Tolerances: Focuses on shapes, positions, and alignments
Why Tolerances are Important
Choosing the right tolerance depends on accuracy, cost, and purpose. A part that requires very high precision will take more time and resources to make. However, not all parts need such tight control.
Parts that must fit perfectly together in assemblies may require premium or ultra-precision. On the other hand, less critical parts may only need standard precision.
Tolerance Standards
- Levels of Precision
- Tolerances by CNC Process
We offer three levels of accuracy including standard, premium, and ultra-precision. Each level allows different range of tolerance.
| Standard Precision | The part can vary within +/-0.005 inches (0.13mm) |
| Premium Precision | The part is more accurate within +/-0.001 inches (0.025mm) but greater than +/-0.005 inches. |
| Ultra Precision | This is the highest accuracy, within +/-0.0001 inches (0.0025mm) up to +/-0.001 inches (0.025mm) |
Different CNC processes also have their own tolerance ranges.
| Router | +/-0.005 inches (0.13mm) |
| Router (cutting gaskets) | +/-0.030 inches (0.762mm) |
| Engraving | +/-0.005 inches (0.13mm) |
| Surface Finish | 125RA (measure of roughness, where lower values mean smoother finishes) |
