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Panel

Panelization is a critical process in the economical manufacturing of Printed Circuit Boards (PCBs). By arranging multiple PCBs on a single panel, manufacturers can optimize production efficiency, reduce material waste, and lower costs. This documentation provides a comprehensive analysis of panelization, its design considerations, and its role in modern PCB manufacturing. The content is tailored for advanced users, emphasizing technical precision and practical insights.

Definition and Function​

A panel, also known as a production panel or array, is a large board that contains multiple copies of the same or different PCBs. The primary functions of panelization include:

  1. Economic Efficiency:
    Panelization allows manufacturers to produce multiple PCBs simultaneously, reducing the cost per unit and optimizing the use of materials and machinery.

  2. Automated Assembly:
    Panels are used in automated assembly processes, such as pick-and-place machines and reflow soldering, to increase production speed and consistency.

  3. Material Utilization:
    Clever panelization algorithms can maximize the use of the panel area, reducing waste and further lowering costs.

Panel Design Considerations​

Panel Layout​

The layout of the panel is critical for ensuring efficient production and assembly. Key considerations include:

  1. PCB Arrangement:
    Multiple copies of the same PCB or different PCBs can be arranged on a single panel. The arrangement must optimize the use of the panel area while ensuring adequate spacing for routing and breakaway tabs.

  2. Spacing and Clearance:
    Adequate spacing must be maintained between individual PCBs to allow for routing, breakaway tabs, and handling during assembly. Typical spacing ranges from 2 to 5 mm.

  3. Fiducial Marks:
    Fiducial marks are used to align the panel during automated assembly processes. These marks must be placed consistently and accurately to ensure precise component placement.

Breakaway Tabs and Routes​

Breakaway tabs and routes are used to separate individual PCBs from the panel after assembly. Key considerations include:

  1. Tab Design:
    Breakaway tabs are small bridges of material that connect the individual PCBs to the panel. They must be strong enough to hold the PCBs during assembly but weak enough to allow easy separation.

  2. Routing:
    V-grooves or perforated routes are used to define the breakaway points. V-grooves are cut into the panel to a depth that allows the PCBs to be snapped apart, while perforated routes use a series of small holes to create a weak line.

  3. Drilling:
    In some cases, small holes are drilled along the breakaway routes to facilitate separation. These holes must be placed precisely to ensure clean breaks without damaging the PCBs.

Panel Utilization​

Maximizing the utilization of the panel area is essential for reducing costs and waste. Key considerations include:

  1. Nesting Algorithms:
    Advanced nesting algorithms can be used to arrange PCBs of different shapes and sizes on a single panel, maximizing the use of the available area.

  2. Mixed Panels:
    Mixed panels contain different PCBs, allowing manufacturers to produce multiple designs in a single production run. This approach is particularly useful for low-volume or prototype production.

  3. Panel Size:
    The size of the panel must be compatible with the manufacturing equipment, such as pick-and-place machines and reflow ovens. Common panel sizes include 18 x 24 inches and 21 x 24 inches.

Manufacturing Process​

Panel Fabrication​

The fabrication of panels involves several key steps:

  1. Panel Preparation:
    The panel is prepared by cutting the substrate material to the required size and applying the copper layers.

  2. PCB Layout:
    The individual PCBs are laid out on the panel, with breakaway tabs and routes defined. Fiducial marks are added for alignment.

  3. Drilling and Routing:
    Holes and routes are drilled or cut into the panel to create the breakaway points and define the individual PCBs.

Automated Assembly​

Panels are used in automated assembly processes to increase efficiency and consistency. Key steps include:

  1. Solder Paste Application:
    Solder paste is applied to the pads using a stencil. The stencil is aligned with the panel using fiducial marks.

  2. Component Placement:
    A pick-and-place machine picks components from reels or trays and places them precisely on the pads. The machine uses fiducial marks to ensure accurate placement.

  3. Reflow Soldering:
    The panel is passed through a reflow oven, where the solder paste is melted to form reliable solder joints.

Separation​

After assembly, the individual PCBs are separated from the panel. Key steps include:

  1. Breaking:
    The PCBs are snapped apart along the breakaway tabs and routes. This can be done manually or using a specialized breaking machine.

  2. Cleaning:
    The separated PCBs are cleaned to remove any debris or residue from the breaking process.

Advanced Applications​

High-Density Interconnect (HDI) PCBs​

In HDI PCBs, panelization is used to achieve higher component density and routing flexibility. Advanced techniques, such as laser drilling and microvia technology, are employed to achieve the required precision and reliability.

Flexible PCBs​

In flexible PCBs, panelization must account for the flexibility of the substrate material. Specialized breakaway tabs and routes are used to ensure clean separation without damaging the flexible circuits.

Mixed-Technology Panels​

Mixed-technology panels contain both surface-mount devices (SMDs) and through-hole components. The panel design must accommodate the different assembly processes required for each type of component.

Practical Example​

Example: Hobby PCB Manufacturing​

In the provided example, a single panel contains multiple hobby PCBs. The panel is designed to maximize the use of the available area, with breakaway tabs and routes defined for easy separation. The use of panelization allows hobbyists to have individual PCBs manufactured for just a few dollars, making it an economical option for prototyping and small-scale production.

Conclusion​

Panelization is a critical process in modern PCB manufacturing, enabling economic efficiency, automated assembly, and material utilization. By understanding the design considerations and advanced applications of panelization, engineers can optimize the production of high-quality PCBs. Mastery of panelization techniques is essential for meeting the demands of today's electronic applications, from consumer electronics to industrial systems.