What Tolerances could You Design into Your Printed Circuit Board?

PCBMay PCB tolerances can be viewed here. Following printed circuit tolerance guidelines is critical to ensure quality (& feasibility) of final boards.

PCBMay has been implementing circuit boards fabrication procedures stringently conforming to IPC-compliant guidelines and regulations in order to ensure their highest reliability and best performance in our clients’ projects.Therefore,we have to cater to tight tolerances in PCB manufacturing process.For the PCB inspection,we follow IPC6012C Class 2 (advanced Class 3) and IPC600H Class 2 (advanced Class 3) to inspect and ship for customers.

Tolerance is an integral part of any PCB manufacturing process. Although the performance of a PCB depends on various factors, tolerances play a positive role. Most electronics manufacturers know nothing about the correct tolerances for PCBs. PCBMay’s experts here advise them to seek medium tolerances. The advantage of these tolerances is that they can easily source boards from any manufacturer of their choice. Many times, even if the board does not require strict tolerances, they will choose strict tolerances. In this case, manufacturing and assembly time may exceed normal time, which will also be reflected in the price.

PCB drilling

Holes Diameter Tolerance:

There’re many kinds of holes,such as Via’s,Plated Through Hole (PTH), Non-Plated Through Hole (NPTH),blind via, buried via, partial depth holes, countersink holes, back drilling and press-fit holes.

Typically their tolerance are following as below:

Via’s  are ≤0.8mm,the tolerance is +/-0.10mm;                                  0.8mm<PTH≤6.20mm,the tolerance is +/-0.075mm; PTH>6.20mm,the tolerance is +/-0.1mm;                            NPTH≤5.0mm,the tolerance is +/-0.05mm;        NPTH>5.0mm,the tolerance is +/-0.1mm;                                0.4mm8.0mm,the tolerance is +/-0.2mm;                                  NPTH Slot≤5.0mm,the tolerance is +/-0.1mm;                        NPTH Slot>5.0mm,the tolerance is +/-0.15mm;        0.2mm<Pressfit≤6.20mm,the tolerance is +/-0.05mm.

Board Outline Size Tolerance

PCB outline size tolerances include PCB width, height, hole distance, spacing, thickness, arc, diameter, radius, groove, angle, R angle, etc.

General tolerance standard of PCB size:

  1. The tolerance of CNC routing outline is ±0.15MM 
  2. The width or length tolerance of the board with V-cut is ±0.3MM 
  3. The tolerance of punching dimensions is ±0.1MM
  4. The minimum hole or groove width of the punching is 0.8MM, and the tolerance is +0.1MM.
PCB outline

Board Thickness Tolerance:

The thickness of the PCB refers to the thickness after the board is completed. The standard thickness of copper clad laminates is 0.5, 0.7, 0.8, 1.0, 1.2, 1.5, 1.6, 2.0, 2.4, 3.2, 6.4 mm,meanwhile,The thickness of multilayer printed board is related to its number of layers. The thickness of a multilayer board with 8 layers or less can be limited to about 1.6 mm. The thickness of more than 8 layers should exceed 1.6 mm. The standard tolerance of PCB board thickness is as following:

It’s ≤1mm,tolerance is +/-0.1mm;                                            1.0mm <thickness≤1.2mm,tolerance is +/-0.12mm;            1.2mm <thickness≤2.0mm,tolerance is +/-10%;                    Thickness>2.0mm,tolerance is +/-10%.

PCB Manufacturing Tolerance

Thanks to a high degree of automation, the latest machinery, highly qualified staff and seamless control or analysis, we keep our processes stable as the standard tolerance for PCB manufacturing.PCBMay provides you in-house tolerance guidelines to ensure quality manufacturing of your printed circuit boards.   Adhering to these tolerances will allow for proper manufacturing of your PCBs.Some other standard tolerance is as following:

The Hole location tolerence for drilling is +/-0.13mm;                The Hole location tolerence for milling is +/-0.1mm;                  The remain thickness of V-cut tolerance is +/-0.1mm;                The bevelling angle of bevelling tolerance is +/-5 degree;          The depth of countersink tolerance is +/-0.15mm;                      The angle of countersink tolerance is +/-5 degree;                     The soldermask to the lines tolerance is +/-0.25mm.

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