PCB Drilled-Hole Quality: Drill Bits, Cutting Fluid, Feed Rate and Hole-Wall Roughness

Drilling of PCB boards is one of the crucial processes in PCB manufacturing, and the quality of drilling directly affects the performance and reliability of the entire PCB board. Next, let's discuss some of the key factors that affect the drilling quality of PCB boards.


Quality of the Drill Bit	The drill bit is one of the key elements determining the drilling quality of PCB boards. Poor-quality drill bits are prone to blunting, wear, and breakage, resulting in problems such as smaller and non-circular holes.
Quality of the Cutting Fluid	Cutting fluid plays a role in cooling, lubricating, and flushing chips during the drilling process, so its quality directly affects the drilling effect. If the cutting fluid contains impurities or inappropriate moisture, it may cause uneven hole walls, small hole diameters, and burrs on the circuit.
Control of Pressure and Speed	When drilling, it is necessary to control the pressure and feed rate of the drill bit properly. Different PCB boards and hole sizes need to be matched with different processing parameters; otherwise, problems such as hole lifting and drilling bridge fracture may occur.
Control of Hole Wall Roughness of Drilled Holes	Generally speaking, the hole wall roughness of PCB holes after drilling should not exceed 1.2 mils, and after electroplating, it should not exceed 0.8 mils.
Performance of PCB Board Materials	Hard and brittle PCB board materials, such as FR-4, are prone to internal hole cracking, especially in high-density multilayer boards, which affects drilling quality. In this case, methods such as using backup boards are needed to avoid such problems.
Other Factors	In addition to the above factors, the processing environment and machinery and equipment can also affect the drilling quality of PCB boards.

In conclusion, the quality of PCB board drilling is affected by multiple factors. Adequate preparation before processing and strict adherence to procedures are required. During processing and inspection, problems should be promptly investigated and resolved to prevent deviations in drilling quality.