Minimum line width: 6 mil (0.153 mm). In other words, if the line width is less than 6 mils, it cannot be manufactured. If the design allows, it’s better to use a larger line width. A wider line width improves PCB production, increases yield, and enhances manufacturability. Typically, the general design practice is around 1,000 mils. This is a critical factor, so it must be taken into consideration during design.
Minimum line spacing: 6 mil (0.153 mm). This refers to the spacing between traces and the distance from a trace to a pad. From a manufacturing perspective, it should not be less than 6 mils, and the larger the spacing, the better. Normally, it is kept within 10 mils, depending on the design requirements. Again, the larger the spacing, the better, and this is an important design consideration.
The line spacing for paired traces is 0.508 mm (20 mils).
Two: Through-holes (commonly referred to as conductive holes)
Minimum hole diameter: 0.3 mm (12 mils).
1. The minimum via hole (VIA) aperture should not be smaller than 0.3mm (12mil), and the single-sided pad size must not be less than 6mil (0.153mm), ideally exceeding 8mil (0.2mm). The maximum limits (see Figure 3) are crucial, and must be carefully considered during the design phase.
2. The hole spacing (distance from hole edge to hole edge) of each via hole (VIA) must be no less than 6mil, preferably greater than 8mil. This is very important and must be considered in the design.
3. The distance between the PCB pad and the molding line is 0.508mm (20mil).
4. Hole spacing:
– NPTH (Non-Plated Through Hole, no solder ring): Hole compensation should be 0.15mm, with a backline distance greater than 0.2mm.
– PTH (Plated Through Hole, with solder ring): Hole compensation should be 0.15mm, with a backline distance greater than 0.3mm.
5. Hole spacing:
– PTH (with solder ring): Hole-to-hole distance should be no less than 0.45mm, with backline compensation of 0.15mm.
– NPTH hole: Hole-to-hole distance should be at least 0.2mm or greater, with hole compensation of 0.15mm.
6. VIA: Slightly spaced.
7. PAD-PAD (commonly referred to as the insertion hole, PTH):
The size of the insertion hole depends on the component, but it must be larger than the component pin. It is recommended to have a hole size of at least 0.2mm, or larger (i.e., 0.6mm for the component pin). You should design a hole size of at least 0.8mm to accommodate processing tolerances and avoid difficulty during insertion.
8. The outer ring of the insertion hole (PTH) pad on one side should not be less than 0.2mm (8mil). Of course, the larger the better (as shown in Figure 2 for solder entry). This is a critical factor that must be considered in the design.
9. The hole spacing (hole edge to hole edge) for the insertion hole (PTH) should not be smaller than 0.3mm, and ideally, the larger the better (as shown in Figure 3). This is very important and must be factored into the design.
10. The distance from the pad to the edge of the table is 0.508mm (20mil).
11. Other considerations:
The shape of the PCB, including the board frame, slots, and V-CUT, should be placed on the KEEPOUT or mechanical layer, and not on other layers such as the silkscreen or signal layers. Any grooves or holes that need to be mechanically processed should be placed on a single layer whenever possible to avoid missed cuts or holes.
12. If the shape of the mechanical layer and KEEPOUT layer do not match, please specify that in addition to the required shape, if there is an inner groove that intersects with the outer shape, the sector of the outer shape to be removed will be impacted by the grooves and holes. The mechanical layer should correspond to the KEEPOUT layer to avoid interference. This usually follows the copper-free PCB approach (copper should be removed during the fabrication process). If there are metallic holes to be processed, please take special note.
13. If you need to create a metalized slot or hole, the most reliable method is to use multiple pads together; this method ensures proper processing without errors.
14. Special attention should be given to whether diagonal chamfering is needed when ordering golden finger boards.
15. For GERBER files, please ensure there are no small layer phenomena in the files. Our department typically produces the board directly based on the provided GERBER files.