PCB panelization is the final step in PCB design. Although it is essential to manufacturing, it is often overlooked because designers naturally focus on product functionality, performance, and customer requirements. From a manufacturing and soldering perspective, however, the panelization strategy directly affects production efficiency and cost. A well-designed panel can improve downstream operations, while a poorly designed panel can create expensive manufacturing problems.
Panelization was once understood mainly as combining small boards into a larger panel or filling irregular shapes to create a rectangle. As manufacturing strategies and production processes evolve, the design considerations become more complex. When PCBA production changes from outsourcing to in-house manufacturing, panelization issues become more visible because the design must account for production equipment, process capability, tooling, depanelization methods, and production volume.
More comprehensive consideration generally improves the design, but it also introduces more variables and can make the preferred solution difficult to determine. Different engineers may reach different conclusions for the same PCB because they evaluate equipment utilization, process risk, tooling cost, material cost, and depanelization efficiency differently.
Design engineers are usually focused on delivering a functional, high-performance product that meets customer and market requirements. At an early stage, the difference between a board cost of 5 RMB and 10 RMB, or a production time of 10 minutes and 20 minutes, may not be their primary concern. Manufacturing engineers, on the other hand, want the panelization design to be correct the first time. Later changes may require scrapping or reworking stencils, carriers, fixtures, and other tooling. Avoiding a change may preserve existing tooling but leave a clear opportunity for cost reduction and productivity improvement unrealized. Panelization therefore often involves a trade-off between immediate rework cost and long-term production cost.
1. PCB Panelization Concepts, Benefits, and Methods
The basic concepts and methods of PCB panelization are familiar throughout the industry, but they are summarized here to establish the engineering context.
1.1 Definition and Purpose of Panelization
PCB panelization combines multiple identical or different individual boards into one larger manufacturing panel. The purpose is to improve production efficiency and reduce cost. In some manufacturing environments, different board designs may be combined on the same panel, although that approach is not used in the design practice described here.
In the early development of PCB manufacturing, panelization was primarily used to make production feasible. With improvements in PCB design and fabrication capability, designs that cannot be manufactured have become relatively uncommon. Modern panelization is therefore better understood as a manufacturing optimization strategy. A suitable panel can improve production efficiency, reduce material consumption, and simplify subsequent handling.
Key benefits include:
- Meeting production requirements: Small or irregularly shaped boards can be arranged into a panel that is more suitable for volume production.
- Improving production efficiency: Panelization can increase SMT placement efficiency, balance the capacity of printing, placement, and soldering operations, improve equipment utilization, and increase overall throughput.
- Reducing PCB procurement cost: This is particularly relevant to irregularly shaped boards, where a suitable arrangement can reduce the required PCB area.
- Reducing the number of board outlines: Different board shapes and sizes can sometimes be integrated into a smaller number of standardized panel or handling formats. This can reduce cost and improve efficiency in manufacturing, carrier fabrication, packaging, and workstation transfer.
1.2 Main Panelization Connection Methods
The three primary methods for connecting boards in a panel are V-scoring, mouse-bite perforations, and tab routing or bridge connections. V-scoring and mouse bites are the most commonly used methods, while bridge connections are generally reserved for specific designs.
- V-scoring: Suitable for boards with regular outlines and straight edges.
- Mouse bites: Suitable for irregular outlines, curved edges, and other cases in which V-scoring cannot be applied.
- Bridge connections: Commonly used for boards with plated half-hole structures. This method is similar to mouse-bite panelization, but the connecting section does not contain drilled perforations.
Figure 1 | Examples of V-scoring and mouse-bite panelization
Figure 2 | PCB panel connection examples
In one example, an individual board uses both V-scoring and mouse bites. Actual implementation may be adjusted according to the product characteristics and board details. For example, some designs leave a 0.3–0.4 mm gap between two boards, while others use a zero-gap arrangement. When the distance between the copper routing and the V-score is greater than 1 mm, a 30° blade can be used to avoid damaging the traces during fabrication.
For mouse-bite connections, the hole diameter is commonly 0.6–1.0 mm. The pitch is generally the hole center-to-center distance plus 0.4 mm or 0.5 mm, and each connection group commonly contains two to five holes. One design practice uses 0.6 mm holes, a 1.0 mm pitch, and two to four holes per connection group.
Figure 3 | Bridge connection for a board with plated half holes
A board with plated half holes along three edges may use bridge connections. The bridge dimensions must balance connection reliability against the ease of depanelization.
1.3 Selecting the Connection Method
Each connection method has advantages and limitations. Selection should consider the PCB characteristics, component placement, sensitivity to mechanical stress, board outline, depanelization method, production capacity, and the requirements of the assembly process.
2. Key Factors Affecting Panelization Design
Panelization is not governed only by PCB design rules. It is also closely related to production equipment, assembly processes, manufacturing strategy, product lifecycle stage, and depanelization methods.
2.1 Product Stage and Panelization
The product stage directly affects the appropriate panelization strategy.
2.1.1 Research and Development
Products in the research and development stage contain many uncertainties and are more likely to undergo design changes. Panelization should focus primarily on satisfying equipment requirements, and the number of boards in each panel should generally not be excessive.
2.1.2 Small-Batch Production
The research and development panelization scheme may be retained, but it should be evaluated from the perspective of efficiency and cost. The evaluation should determine whether optimization is necessary and whether sufficient savings can justify changes to carriers and fixtures. The design and quantity of related tooling should be based on this assessment.
2.1.3 Mass Production
For PCB mass production, panelization should focus on production efficiency and cost optimization. The objective is a solution that provides the best overall balance among material utilization, equipment throughput, tooling requirements, process stability, and depanelization efficiency.
2.2 Assembly Process and Panelization
The soldering and assembly process is one of the most important factors determining the panelization scheme. Different processes impose different requirements.
For double-sided mixed-technology assemblies, possible process combinations include:
- Two reflow operations followed by wave soldering for an in-house production line.
- Reflow, red-glue assembly, and wave soldering for an outsourced production model previously used.
The panelization design must reflect the actual process flow rather than assuming that one panel format is suitable for every assembly line.
2.3 Carrier Strategy
Carrier usage also affects panelization. One production strategy may use carriers for all wave-soldering operations, while another may avoid carriers unless they are essential. These different strategies can lead to different decisions regarding panel dimensions, tooling edges, support structures, and board spacing.
2.4 Depanelization Method
In one production model, manual depanelization was the default and a depanelization machine was used only in selected cases. In another, machine depanelization became the default, with manual separation reserved for special cases. Because V-scoring, mouse bites, and bridge connections behave differently during separation, the depanelization method must be considered during the initial panel design.
2.5 Manufacturing Strategy
Panelization requirements also change when PCBA production moves from outsourcing to in-house manufacturing. Outsourced production may prioritize compatibility with the supplier’s existing equipment and tooling, while in-house manufacturing may place greater emphasis on internal equipment utilization, standardized carriers, machine depanelization, and long-term process efficiency.
3. Panelization Design Cases
Case 1: Adding a Process Edge to Support SMT Transfer
For Board III, the original panelization was Scheme A, and Scheme B was proposed as an alternative. The alternative was questioned by the design engineer.
Figure 4 | Comparison of panelization Schemes A and B for Board III
Case 2: Removing an Unnecessary Process Edge
For Board IV, the original panelization was Scheme A, and Scheme B was proposed.
Figure 5 | Comparison of panelization Schemes A and B for Board IV
In Case 1, the original design used V-scoring between the two boards. The revised design introduced a 2 mm gap between the boards and connected them through a process edge. In Case 2, the original design used a 2 mm gap and a process edge, while the revised design removed the process edge and connected the two boards directly with V-scoring.
The apparently opposite recommendations result from the process-edge requirements. On Board III, SMT components are close to the board edge, so the available conveyor edge is insufficient. A process edge is therefore required, regardless of whether a gap exists between the boards. Because the process edge must be present, V-scoring between the two boards can be eliminated and the boards can be connected through the existing process edge. This improves efficiency.
On Board IV, the SMT conveyor edge is wide enough and no additional process edge is required. Adding a process edge merely to replace the V-score would increase the panel area and reduce production efficiency. In that case, the modification is not beneficial.
Case 3: Evaluating Cost Against Depanelization Risk
There is no universally optimal panelization scheme. Although Scheme B was better than Scheme A for Board IV in the preceding example, that conclusion cannot be applied blindly to every board or production environment.
Board V has dimensions of 196 × 25 mm. The two proposed schemes were:
- Scheme A: A 1 × 10 panel with a 2 mm gap between boards, 5 mm process edges on the left and right sides, and V-scored connections between the boards.
- Scheme B: A 1 × 10 panel with direct V-scored connections between the boards.
Figure 6 | Comparison of panelization Schemes A and B for Board V
Compared with Scheme B, Scheme A has a larger panel area and increases procurement cost by approximately 12.7%. For a panel containing ten boards, the additional cost is approximately 3.1 RMB. However, Scheme A reduces the number of depanelization actions by seven and permits machine depanelization, while Scheme B can only be separated manually.
The better solution cannot be determined from cost alone. The evaluation must compare the additional 3.1 RMB against the labor associated with seven additional depanelization actions and the reduction in depanelization risk. Different factories may reach different conclusions because their equipment, labor costs, process capability, and quality risks differ.
Case 4: Preventing Damage to an Irregular Board Outline
Board VI has an irregular outline. The original 2 × 2 panelization added a 4 mm process edge along the lower side and filled the missing outline region to create a rectangular panel.
Figure 7 | Original panelization of the irregular Board VI
Figure 8 | Damage to the process edge during PCB profiling
The lower-left supplemental section was connected only to the 4 mm process edge. Its mechanical support was insufficient, so it could move during profiling and cause an outline deviation. Although the damage did not affect the functional board area, the delivered board had an unacceptable external defect. The resulting scrap rate exceeded 50% per lot, prompting the PCB fabricator to propose an improvement.
After reviewing additional information about the board, a second improvement scheme was developed.
Figure 9 | Improved panelization design for Board VI
This case demonstrates that panelization must consider the mechanical stability of every section that will be supported, routed, separated, or handled. Creating a rectangular panel is not sufficient if the added regions are inadequately supported during PCB profiling.
4. Practical Panelization Control and Optimization
The cases above illustrate a central principle: PCB panelization is affected not only by the board’s own design rules but also by external manufacturing conditions. In the four cases, Case 4 contained an inherent panelization weakness, Cases 1 and 2 changed because external process conditions changed, and Case 3 did not have a universally superior solution.
It is unrealistic to require the first panelization design to remain optimal throughout the product lifecycle. External conditions are dynamic. A scheme that is suitable during research and development may not be the best option for mass production, and a scheme that works well in one factory may be unsuitable for another.
The ideal approach is to match the panelization scheme to the product stage. When the product stage, production volume, manufacturing site, assembly process, or depanelization method changes, the panelization design should trigger a new evaluation. The manufacturing process used by the factory handling the greatest proportion of soldering work should normally be treated as the default process during scheme development.
For organizations without panelization software, an integrated product-development system, or complete design rules, the following control and optimization measures are practical:
- Assign panelization to a dedicated person or team. Centralized ownership reduces unnecessary variation among engineers, helps control the number of panelization schemes, and allows experience to accumulate in a reusable knowledge base. A process based only on individual judgment and temporary decisions can result in one board having multiple panel sizes and inconsistent manufacturing results.
- For new products, prioritize production feasibility. The number of boards in a panel should be based on research and development needs and should not be excessive. A simple, flexible scheme is often more appropriate than a heavily optimized mass-production panel during this stage.
- For derivative products, reference existing products. A derivative product is based on an existing product and has a similar outline and component arrangement. The existing panelization may be retained or optimized after considering the scope of the changes and the likelihood of further board revisions.
- Review key decision points before changes become expensive. Important review triggers may include production transfer, a production release quantity reaching a defined threshold, or the quantity of carriers required in one production release reaching a defined threshold. The threshold values can be established by the review team and adjusted later. The essential purpose is to trigger an evaluation at the right time.
- Introduce supporting design tools. Panelization tools can improve design efficiency, but their more important benefit is the accumulation of reusable knowledge. Design experience can be converted into digital rules and structured data, improving consistency, repeatability, and engineering decision quality.
5. The Future of PCB Panelization
As electronics manufacturing becomes more intelligent and flexible, PCB panelization is likely to evolve from a late-stage task attached to individual board design into a formal part of product lifecycle cost and efficiency management.
With digital manufacturing systems and supporting engineering tools, panelization can gradually move from experience-driven decisions to data- and rule-driven decisions. Governance can shift from individual judgment to rules and system control. As manufacturing systems accumulate more data and improve their ability to evaluate alternatives, the amount of manual decision-making required for routine panelization may decrease significantly.
Digital manufacturing platforms increasingly connect PCB design, manufacturing constraints, process preparation, SMT programming, standard operating procedure generation, product lifecycle management, manufacturing execution, and factory resources. Such integration allows design engineers to receive manufacturing constraints earlier and enables production data to feed back into design and process decisions.
Digital Factory Architecture
A digital factory may combine several types of systems and tools:
- Simulation systems: Tecnomatix includes platforms for plant planning and simulation, quality analysis and simulation, assembly planning and simulation, intelligent manufacturing, human factors engineering, and value-stream simulation.
- Placement and manufacturing management: Valor includes PCB and PCBA solutions, manufacturing execution functions for placement, design-for-manufacturing analysis, process preparation, and electronic component libraries.
- Manufacturing process management: Teamcenter Manufacturing provides centralized management, collaboration, and interoperability for product digital models, linking products, processes, factories, and resources.
- Equipment modernization: Production equipment can be upgraded and connected to digital systems to improve data collection, control, and traceability.
Research and Design Platforms
- Electromechanical and software collaboration: Application lifecycle management systems support coordination among mechanical, electrical, and software development activities.
- Three-dimensional design: NX is an interactive CAD/CAM system capable of constructing complex solids and shapes.
- Product lifecycle management: Teamcenter provides product lifecycle management and supports coordination across design, manufacturing, and related engineering activities.
Simulation and Verification
- CAE simulation: Simcenter 3D provides an integrated environment for 3D CAE and can connect design, one-dimensional simulation, testing, and data-management environments. It can be used independently or integrated with NX.
- Experimental testing: Dedicated test systems can connect physical verification results with digital design and manufacturing processes.
In a digital factory, the effects of system integration can be observed in production speed, flexibility, quality, and efficiency. Digital-twin technology can support the introduction of many new products into volume production, frequent production-line changes, and continuous delivery. Flexible lines can accommodate a broad range of products and materials, while integrated data collection can improve transparency and traceability from finished products to individual components.
In such an environment, panelization becomes one element of a larger digital manufacturing workflow. Manufacturing constraints, product configuration, equipment capability, process data, and historical results can be connected to the panelization decision. Routine panelization tasks can consequently become more consistent, easier to review, and less dependent on individual experience.
PCB panelization should therefore be treated as an engineering activity that connects design with manufacturing. The best scheme is not necessarily the one with the smallest panel area or the largest number of boards. It is the scheme that provides the best balance among manufacturing feasibility, production efficiency, material cost, tooling investment, depanelization risk, quality requirements, and the current stage of the product.
