CNC drilling is a basic step in the manufacturing process of flexible PCBs. It is mainly used to drill holes on circuit boards to provide the necessary conditions for subsequent electrical connections or mechanical fixation. At Flex Plus, let us understand the importance of CNC drilling in the manufacture of flexible circuit boards
The main role of CNC drilling
Via production: drilling through holes, blind holes or buried holes to achieve electrical connections between different layers.
Positioning holes: Processing positioning holes to ensure accurate alignment of circuit boards in subsequent processes.
Mounting holes: Provide installation locations for screws or other mechanical fixing components.
The importance of CNC drilling in the manufacture of flex PCB
1. Realize electrical connections between layers
Flexible circuit boards usually adopt multi-layer designs, and electrical connections between layers need to be achieved through structures such as through holes, blind holes, and buried holes. CNC drilling can:
Precisely process vias: ensure that the hole diameter meets the design requirements (such as microholes below 0.1mm) to ensure reliable interlayer conductivity.
Precise positioning: sub-micron positioning accuracy is achieved through CNC technology to avoid short circuits or open circuits caused by hole position offset.
Consistency: The position alignment and size consistency of holes in multilayer PCB boards directly affect the electrical performance and reliability of the board.
2. Meet high-density wiring requirements
Flex PCB design tends to be high-density (HDI), requiring more micro-holes and smaller spacing to increase the path of electrical connection.
CNC drilling supports high-density drilling to meet the needs of high-density wiring on flexible boards.
Precisely control the hole diameter, hole depth and distribution to ensure maximum space utilization.
3. Improve product reliability
Hole wall quality: The smoothness and verticality of the hole wall produced by CNC drilling are crucial to the subsequent electroplating process. Hole wall defects can lead to electroplating failure or poor conductivity.
Mechanical strength: The processed holes must ensure mechanical strength, especially flexible circuit boards are often bent during use, and the quality of the holes directly affects durability.
4. Provide a basis for other processes
CNC drilling is not only an independent manufacturing link, but also directly supports subsequent processes:
Positioning holes: Ensure the precise positioning of FPC in subsequent processes such as lamination, alignment, and welding.
Through-hole plating: Provide a basis for electroplating and form a good conductive path.
Cutting reference: In the subsequent cutting process, the positioning accuracy of CNC drilling is used to ensure the accuracy of the sheet shape cutting.
5. Adapt to diverse design needs
CNC drilling can process different types of holes (through holes, blind holes, buried holes) and special shapes (elliptical holes, stepped holes, etc.), supporting the diversified design of FPC products.
Flexibly adjust the drilling path and parameters to adapt to flexible substrates of different thicknesses and materials.
6. Meet the requirements of efficient production
Automation and high efficiency: CNC drilling uses CNC technology to quickly program and efficiently drill holes to meet the large-scale and high-precision production needs of modern electronic manufacturing.
Strong flexibility: Supports multi-variety small-batch production mode, especially suitable for customized flex PCB manufacturing.
7. Ensure the quality of finished products
The quality of CNC drilling directly affects the overall quality of flexible printed circuits:
Electrical performance: hole position deviation or unqualified size will cause the circuit to fail to conduct normally.
Mechanical properties: The shape and smoothness of the hole affect the durability and reliability of the flexible circuit board when it is bent.
Aesthetics: The processing of exposed holes or special purpose holes needs to meet the customer's requirements for appearance and precision.
CNC drilling Process
The process of CNC drilling is an important part of the manufacturing of FPCB. It is mainly used to process through holes, blind holes, buried holes and positioning holes of circuit boards. The following is a brief process flow:
1. Preparation phase
Generate an NC program adapted to CNC drilling equipment based on circuit design files (such as Gerber files), including information such as hole position, hole diameter, and hole depth.
Select a suitable drill bit and set drilling parameters (hole diameter, depth, speed, etc.).
Prepare flexible sheets and pads: The purpose of adding an aluminum base plate or a high-density foam pad under the FPCB is to reduce sheet vibration during drilling.
2. Sheet fixation
Use vacuum adsorption or clamps to fix the sheet to ensure that there is no displacement during drilling.
Alignment confirms the position of the sheet and the drilling path.
3. Drilling processing
CNC automatically executes the drilling program, and the high-speed drill processes through holes, blind holes or positioning holes. Speed (RPM): Usually set to 30,000-100,000 RPM, depending on the material properties.
Equipped with cooling system and dust collection device to prevent overheating and debris residue.
4. Post-drilling cleaning
Remove burrs from the hole wall and clean the plate with an air gun or ultrasonic.
5. Quality inspection
Use a microscope or laser to detect the hole diameter, hole position, and hole wall smoothness.
Sample batch products to ensure processing quality.
6. Subsequent processing
Electroplating or chemical plating is performed to form a conductive layer to achieve electrical connection between layers.
Check and trim, mark the finished product, and send it to the next process (such as lamination or graphic etching).
CNC drilling Process Characteristics
High precision: Through CNC equipment, the drilling accuracy can reach micron level.
High efficiency: Automated processing increases production speed and meets the needs of batch manufacturing.
High adaptability: Supports processing of different hole diameters, hole types and multi-layer materials.
This standardized, automated and high-precision process lays an important foundation for the high-density design and high reliability of flexible circuit boards.
Summary
In the manufacturing of flex PCBs, CNC drilling is a key process that not only affects the reliability of electrical connections between layers, but also affects the mechanical properties of the entire board, functional realization, and stability of subsequent processes. For a flex PCB vendor, this process is critical, as flexible circuit boards develop towards high density, high precision, and diversification. The importance of CNC drilling becomes more prominent, serving as an important technical guarantee for improving production efficiency, reducing scrap rates, and meeting high-end market demands.
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