Introduction

Ordering Printed Circuit Boards (PCBs) as panels is a common practice in the electronics manufacturing industry, especially for high-volume production. Panelization allows multiple PCBs to be fabricated and assembled on a single larger board, which is then separated into individual units after assembly. This approach offers several advantages, including reduced manufacturing costs, improved handling during assembly, and increased throughput. However, panelizing PCBs requires careful planning and adherence to specific design and manufacturing guidelines. This guide provides a detailed overview of how to order PCBs as panels, covering everything from design considerations to communication with manufacturers.

1. Understanding PCB Panelization

1.1 What is PCB Panelization?

PCB panelization is the process of arranging multiple PCB designs onto a single larger board, known as a panel. This panel is then used for fabrication and assembly, after which the individual PCBs are separated (depanelized). Panelization is particularly useful for small PCBs, as it allows manufacturers to handle and process multiple boards simultaneously, improving efficiency and reducing costs.

1.2 Benefits of Panelization

1. Cost Efficiency: Panelization reduces material waste and optimizes the use of manufacturing equipment, leading to lower costs per unit.
2. Improved Handling: Smaller PCBs can be difficult to handle during assembly. Panelization makes it easier to transport, place, and solder components.
3. Increased Throughput: By processing multiple PCBs at once, manufacturers can achieve higher throughput, reducing lead times.
4. Consistency: Panelization ensures that all PCBs are fabricated and assembled under the same conditions, leading to consistent quality across all units.

1.3 Types of Panelization

1. Tab Routing: PCBs are connected by small tabs of material, which are later broken away. This method is cost-effective and suitable for most designs.
2. V-Scoring: V-shaped grooves are cut into the panel, allowing the PCBs to be easily snapped apart after assembly. This method is ideal for rectangular boards.
3. Perforated Panels: Small perforations are made along the edges of the PCBs, allowing them to be separated by breaking the perforations. This method is less common but can be useful for specific applications.

2. Design Considerations for Panelization

2.1 Board Size and Shape

1. Standard Panel Sizes: Manufacturers often have standard panel sizes (e.g., 18″ x 24″) that they prefer to work with. Design your PCBs to fit efficiently within these dimensions.
2. Board Shape: Consider the shape of your PCBs when designing the panel. Rectangular boards are easier to panelize than irregularly shaped ones.

2.2 Spacing and Clearance

1. Spacing Between Boards: Ensure adequate spacing between individual PCBs to allow for routing or scoring. Typically, a spacing of 2-3mm is recommended.
2. Clearance for Components: Account for the height of components when designing the panel. Ensure that there is enough clearance between boards to prevent interference during assembly.

2.3 Fiducial Marks and Tooling Holes

1. Fiducial Marks: Place fiducial marks on the panel to assist with automated assembly. These marks help machines accurately place components on the PCBs.
2. Tooling Holes: Include tooling holes in the panel design to aid in alignment during fabrication and assembly. These holes should be placed in consistent locations across the panel.

2.4 Breakaway Tabs and V-Scores

1. Breakaway Tabs: If using tab routing, design breakaway tabs that are strong enough to hold the PCBs together during assembly but can be easily broken afterward. Typically, tabs are 2-3mm wide and placed at intervals of 50-100mm.
2. V-Scores: For V-scoring, ensure that the grooves are deep enough to allow easy separation but not so deep that they weaken the boards. The angle of the V-score is usually 30-45 degrees.

2.5 Panelization Software

1. Using CAD Tools: Most PCB design software, such as Altium Designer, KiCad, and Eagle, includes panelization tools that allow you to arrange multiple PCBs on a panel. These tools can automatically generate breakaway tabs, V-scores, and fiducial marks.
2. Manual Panelization: If your software does not support panelization, you can manually arrange the PCBs in a new design file, ensuring that all necessary features (tabs, scores, fiducials) are included.

3. Communicating with Manufacturers

3.1 Providing Design Files

1. Gerber Files: Generate Gerber files for each layer of the PCB, including the panel design. Ensure that the files clearly indicate the location of breakaway tabs, V-scores, and fiducial marks.
2. Drill Files: Provide drill files that specify the location of tooling holes and any other required holes in the panel.
3. Assembly Drawings: Include assembly drawings that show the placement of components, fiducial marks, and any special instructions for the manufacturer.

3.2 Specifying Panelization Requirements

1. Panel Size: Clearly specify the desired panel size, including any preferences for standard sizes.
2. Panelization Method: Indicate whether you prefer tab routing, V-scoring, or another method. Provide details on the size and placement of tabs or V-scores.
3. Fiducial Marks and Tooling Holes: Specify the location and size of fiducial marks and tooling holes.
4. Material and Thickness: Specify the type of material (e.g., FR-4) and the thickness of the PCB. Ensure that the material is suitable for the chosen panelization method.

3.3 Discussing Depanelization

1. Depanelization Method: Discuss with the manufacturer how the panels will be separated into individual PCBs. Ensure that the chosen method (e.g., breaking tabs, snapping V-scores) is compatible with your design.
2. Handling Instructions: Provide any special handling instructions for the depanelized PCBs, such as avoiding excessive force or using specific tools.

3.4 Quality and Testing

1. Quality Standards: Specify any quality standards or testing requirements that the manufacturer should follow. This may include electrical testing, visual inspection, or functional testing.
2. Prototyping: Consider ordering a prototype panel before full production to verify the design and panelization process.

4. Cost Considerations

4.1 Material Costs

1. Panel Size: Larger panels may reduce the cost per unit but require more material. Balance the panel size with the number of PCBs to optimize material usage.
2. Material Type: The choice of material (e.g., FR-4, high-frequency laminates) will affect the overall cost. Choose a material that meets your performance requirements without unnecessary expense.

4.2 Manufacturing Costs

1. Panelization Method: Different panelization methods have different costs. Tab routing is generally less expensive than V-scoring, but the choice depends on the design and manufacturing requirements.
2. Quantity: Higher quantities typically reduce the cost per unit due to economies of scale. Discuss volume discounts with the manufacturer.

4.3 Assembly Costs

1. Component Placement: The complexity of component placement and the number of components will affect assembly costs. Optimize the design for automated assembly to reduce costs.
2. Testing and Inspection: Additional testing and inspection requirements may increase costs. Ensure that these are necessary for your application.

5. Common Challenges and Solutions

5.1 Warping and Twisting

1. Cause: Warping and twisting can occur during the panelization process, especially with larger panels or thin materials.
2. Solution: Use a balanced stackup design and ensure that the panel is adequately supported during fabrication and assembly. Consider using stiffer materials or adding stiffeners to the panel.

5.2 Component Interference

1. Cause: Components placed too close to the edge of the PCB or near breakaway tabs can interfere with the depanelization process.
2. Solution: Ensure adequate clearance between components and the edges of the PCB. Avoid placing tall components near breakaway tabs or V-scores.

5.3 Inconsistent Depanelization

1. Cause: Inconsistent depanelization can result from poorly designed breakaway tabs or V-scores.
2. Solution: Follow manufacturer guidelines for tab and V-score design. Test the depanelization process with a prototype panel to ensure consistency.

6. Best Practices for Ordering PCB Panels

6.1 Collaborate with Manufacturers

1. Early Communication: Engage with the manufacturer early in the design process to discuss panelization requirements and constraints.
2. Feedback and Iteration: Be open to feedback from the manufacturer and be willing to iterate on the design to optimize for panelization.

6.2 Optimize for Manufacturing

1. Design for Manufacturability (DFM): Follow DFM guidelines to ensure that the design is easy to fabricate and assemble. This includes optimizing component placement, trace routing, and panel layout.
2. Standardization: Use standard panel sizes and materials whenever possible to reduce costs and lead times.

6.3 Test and Validate

1. Prototype Testing: Order a prototype panel to test the design and panelization process before committing to full production.
2. Quality Assurance: Implement quality assurance processes to ensure that the final PCBs meet your performance and reliability requirements.

Conclusion

Ordering PCBs as panels is a strategic approach that offers numerous benefits, including cost savings, improved handling, and increased throughput. However, successful panelization requires careful planning, adherence to design guidelines, and effective communication with manufacturers. By following the steps outlined in this guide, you can ensure that your PCB panelization process is efficient, cost-effective, and results in high-quality products. Whether you are a seasoned engineer or new to PCB design, mastering the art of panelization will enhance your ability to deliver reliable and manufacturable electronic products.