Top 10 Tips to Improve PCB Drilling Quality

Drilling is the most expensive and time-consuming process in PCB manufacturing. The PCB drilling process must be carried out with great care, as even the smallest mistake can lead to significant losses. The drilling process is the most critical step in PCB manufacturing. It forms the basis for the connection between through-holes and different layers, making drilling techniques extremely important.

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1. Drill a Guide Hole for Proper Drilling

The first step before performing any drilling is to create a guide hole. This prevents the drill bit from "walking," which occurs when the bit starts in one position and then moves in an unintended direction while drilling. The guide hole can be made manually with a small drill bit or automatically with a tool called a drill machine.

If the pilot hole is made using a drill machine, the drill bit is pulled out one by one from the tool. The number of bits used in this process depends on the size of the PCB being drilled. For example, a 0.2 mm drill bit can pull out four holes. When each bit is removed, the process usually leaves a small metal mark on the PCB.

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2. Use a Straight PCB Drill Bit When Drilling at an Angle

When drilling at an angle, use a straight drill bit. Drill bits usually come in sets and vary in size. The sizes include:

? Gauge Drill Bits: Used for wires 0.8 to 1 mm thick.

? Small Drill Bits:?Suitable for holes with a thickness or diameter between 0.7 and 2 mm, including flat and round shapes.

? Medium Drill Bits:?Used for drilling holes with a thickness or diameter ranging from 2 to 10 mm, typically including flat and round shapes.

? Large Drill Bits:?These are used for holes 5 mm or larger, and can be flat or round, depending on the manufacturer.

3. Use the Correct Drill Bit Size

Ensuring that the drill bit size is appropriate for the PCB is crucial. If the bit is too large, it may damage components within the circuit board. Conversely, if it is too small, the wires won’t fit through the drilled holes.

4. Use a Drill with the Appropriate Speed and Power

The power and speed of the drill determine how quickly it can penetrate metal. The most common options are:

? High-Speed Drill Bits:?These drill through metal quickly and efficiently but can cause issues if used for too long at once.

? High-Speed Steel Drill Bits:?Used for larger holes and suitable for drilling multiple, not-too-thick PCBs.

? Plated Drill Bits:?These are used in circuit board drilling and plating processes, as well as for punching holes in thick boards or with high-frequency air hammers.

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5. Use a Drilling machine

A drill machine is the best option to ensure accurate hole drilling. They are at least four times more efficient than handheld drills and typically use industry-standard drill bits.

6. Understand Drilling machine Operation

Drill machines?vary in cost and capability, but they all work by applying just enough pressure to drill through metal. The more pressure applied, the faster the drilling process. There are also different types of drilling, such as “cross drilling,” “jack drilling,” “vent drilling,” and “beveled edge drilling.” The most common drill machine?type has a vertical panel (a metal plate drilled at an upward angle). When using this type, ensure the drill bit is facing upward and the angle matches the hole on the PCB.

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7. Use a Drilling machine to Drill PCBs

Every stage of PCB drilling can be done using a drill machine, especially when precision is required. Although setting up a drill machine takes some time, it yields excellent results when used correctly.

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8. Exercise Caution When Drilling

Drilling into a circuit board can be challenging without the right tools and materials. Take your time and be patient, as rushing this process can damage the board. Always ensure the drill bit rotates at a speed that is neither too fast nor too slow. Wearing safety goggles while drilling is also important to protect your vision.

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9. Clean the PCB After Drilling

After drilling the circuit board, it’s essential to clean the holes with a brush and solvent. The solvent will remove any metal shavings that may have formed during the drilling process, ensuring the board is ready for use after completion.

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10. Apply Solder to the Drilled Holes

After completing the PCB drilling, you must apply solder to the new holes and use a soldering iron with a fine tip to melt it. To ensure the solder adheres properly, thread a wire through one of the holes and heat it. This will prevent the solder from dripping out of the hole. Then, gently press down to ensure it is securely connected.

After acquiring the correct drill bits, ensure that no debris or chips are present when drilling or slotting the PCB. Any chips or debris on the drill bit can cause issues during the drilling process, leading to undesirable results.

PCB drilling, when done correctly, can be completed without damaging the drill bits. If mechanical parts come into contact with the drill bits while the machine is operating, it can damage them.