No solder mask problem in PCB board edge area

1. When generating the solder mask output data, there is no need to increase or compensate the solder mask pad.

It is best to leave the solder pad in the same size as the copper pad. Then we will set up the solder mask to meet the technical requirements for the correct production and assembly of circuit boards.

The preferred version without oversize is bad: the gasket is too big

2. We use the solder mask preparation rules:

We set the value of the solder mask preparation according to the PCB pattern category. The figure shows different functions:

MAR (mask ring) - Clearance between solder mask and copper pad

MSM (Mask SegMent) - Solder Mask Bridge between Adjacent Pads

MOC (mask overlap gap) - solder mask between track or plane and adjacent solder mask window

We always apply the standard values ​​to the complete solder mask. Based on the design, we can reduce these standard values ​​at specific locations to the minimum acceptable value to generate the optimal solder mask.

The standard values ​​for MAR, MSM and MOC for all pattern classifications are 0.1000mm (4mil).

MAR, MSM and MOC MINIMUM acceptable values depend on the pattern classification according to the table (only a value in mm)

important:

If the mask segment between masks (MSM) is less than 0.0800 mm (3.15 mil), it will be removed as a mask segment of less than 0.0800 mm (3.15 mils). If mask segment (MSM) is less than 0.0800mm (3.15mil)

For NPTH drills without a copper pad, the masking ring (MAR) is always 0.125 mm (4.92 mil) regardless of the pattern grade.

3. Depressed vias: The copper pads of the vias are covered by a solder mask .

Fur Eurocircuits, when we spray all of our solder masks, technical support does not mean that the vias are completely enclosed or covered with solder masks.

Only use ViaFilling to ensure that the vias are completely closed (see section ViaFilling below)

IMPORTANT: If you need to support vias, make sure that the solder mask data you generate does not have a solder mask for vias.

4. The NPTH hole without copper pad should always have a pad gap pad.

5. When the output is generated, the board outline is included in the solder mask. It is best to use a small line - such as 0.50mm (20mil) wide - the center of the line is the exact board outline. We will remove the production line from the final production preparation data.

IMPORTANT: If you need PCBs with no solder mask on the edge of the board, use thick lines to indicate the board outline. The line width should be at least 2.00 mm (79 mils), resulting in 1.00 mm (39.5 mils) no solder mask boundaries. It is also advisable to point out the non-resistive border in the mechanical plan.