PCB Manufacturing Tolerances
What Are PCB Manufacturing Tolerances?
In PCB manufacturing, tolerances define the acceptable variation for features like thickness and drilling. These variations ensure components fit properly and the board functions as intended. It's the wiggle room given to manufacturers for precise board creation.
PCBX Manufacturing Tolerances
Inner Layer Line Width and Line Spacing
| Copper Thickness (OZ) | Trace Width/Spacing (Conventional Process) (mil) | Trace Width/Spacing (Non-Conventional Process) (mil) |
| 0.5 | 4/4 | 4/3 |
| 1 | 5/5 | 5/4 |
| 2 | 7/7 | 6/6 |
| 3 | 9/9 | 8/8 |
| 4 | 11/11 | 10/10 |
| 5 | 13/13 | 11/11 |
| 6 | 15/15 | 13/13 |
Outer Layer Line Width and Line Spacing
| Copper Thickness (OZ) | Trace Width/Spacing (Conventional Process) (mil) | Trace Width/Spacing (Non-Conventional Process) (mil) |
| 0.3 | 4/4 | 4/3 |
| 0.5 | 5/5 | 5/4 |
| 1 | 6/6 | 5/5 |
| 2 | 7.75/7.5 | 6/6 |
| 3 | 9/9 | 8/8 |
| 4 | 11/11 | 10/10 |
| 5 | 13/13 | 11/11 |
| 6 | 15/15 | 13/13 |
Hole Copper and Surface Copper Thickness
| Deposited Copper Thickness | Hole Copper Thickness (um) | Plating Thickness (OZ/um) | |||
| oz | um | Conventional Process | Non-Conventional Process | Conventional Process | Non-Conventional Process |
| 0.33 | 12 | 18-20 | >25 | 1（35） | ＞1(35) |
| 0.5 | 18 | 18-20 | ≥30 | 1-1.5 | ＞1.5(53) |
| 1 | 35 | 18-20 | ≥30 | 1.5-2 | ＞2(70) |
| 2 | 70 | 18-20 | ≥30 | 2.5-3 | ＞3(105) |
| 3 | 105 | 18-20 | ≥30 | 3.5-4 | ＞4(140) |
| 4 | 140 | 18-20 | ≥30 | 4.5-5 | 4.5-5(157-175) |
The charts provided above are for simple reference purposes only. For further information on PCB tolerances, please feel free to contact our professional service team for more details.
PCB Drill Tolerances
Every step in PCB manufacturing has tolerances, and sometimes what you specify isn't enough.
Hole sizes are tricky. Components dictate the drill size needed, but there's a twist! The drill chart guides production, and you need to specify the finished hole size you want. Here are the key tolerances:
- Plated holes: Allow +/- 0.003 inches for tolerance.
- Non-plated holes: Allow +/- 0.002 inches for tolerance.
Component Tolerances
In addition, component tolerances are also crucial. It is often specified as a percentage of a nominal value.
Tighter tolerances increase costs due to precise manufacturing. Specific tolerance levels are necessary for different electronics applications. When creating a bill of materials for production, using a manufacturer's part number is common. Including detailed component data like electrical parameters, footprint, and tolerances is essential. This information aids in meeting technical requirements and facilitates part sourcing and replacement if needed. Manufacturers' information requirements should be consulted before finalizing the bill of materials.
Conclusion
Tolerances play a crucial role in our manufacturing process of circuit boards, enabling us to produce them consistently to high standards. An excellent data package should specify tolerances and provide detailed information, thereby minimizing errors or production delays.
