Smart PCB Array Design for Higher Yield and Lower Production Costs

Ever wonder why, when you go from the prototype stage to volume production, the cost of your per-unit PCB falls through the roof? One decision that plays a big part in cost savings is how you lay out your boards on a manufacturing panel. It is known as PCB array design and is the key to a profitable production run versus a bleeding production run due to wasted materials and failed separations.

From a few small sensor modules to thousands of LED driver boards, how your individual PCBs are arranged on a production panel directly affects throughput, yield, and unit cost. A poor design wastes laminate, creates handling problems when putting the array together, and can even damage the laminate mechanically when depaneling. In this lesson, we will go over all the basics of designing a PCB array. Starting with the basics of what a PCB array is, to spacing, scoring, and tab routing best practices.

Why PCB Array Design Matters in Modern Manufacturing

What a PCB Array Is and Its Role in Panelization

A PCB array, also known as a PCB panel or sub-panel, is a collection of identical (or sometimes different) individual PCBs that are arranged in a grid on a single manufacturing panel. Manufacturers treat the entire array as a single board and go through the entire manufacturing process of etching, drilling, solder paste printing, and reflow.

Most fabricators use 18 x 24” (457 x 610 mm) and 21 x 24” (533 x 610 mm) standard manufacturing panel sizes. These panels have a usable area in which your individual PCB designs are tiled and then a tooling strip (also known as a rail or border) that contains fiducial marks, tooling holes, and other alignment features.

Imagine cutting out cookies from a cookie sheet. The task is to put as many cookies as possible on each sheet of paper, but leave enough space between them so they can be easily cut. Your copper-clad laminate is the “dough,” and any leftover bits are wasted product and money.

Impact on Production Efficiency and Material Utilization

Your PCB array layout is directly related to cost and efficiency. With a well-optimized array, it is possible to get 20-30% more boards per panel than with a naive layout. Multiply that improvement by hundreds or thousands of panels, and the material savings alone can be huge.

In addition to material utilization, array design has an influence on all subsequent processes. The pick and place machine can process the whole panel in one go during SMT assembly, and more boards per panel means higher throughput per machine hour. In the wave soldering or selective soldering process, the panel is moved through the machine as a whole. AOI inspection will take place on the camera, and one panel will be scanned, not individual boards.

Here is a quick look at how array optimization affects key production metrics:

Key Benefits of Well-Designed PCB Arrays

Increased Throughput and Reduced Waste

The first advantage of a well-designed PCB array is increased throughput. The more boards you pack on each panel, the more boards each machine in the production line is processing per cycle. The stencil printer allows more boards to be printed per stencil. The pick and place machine places more boards per load of the panel. More boards can be cured in a single pass with the reflow oven.

This is particularly important for small PCBs as it allows for the increase of throughput gain. For instance, a small Bluetooth module measuring just 10 x 15 mm could accommodate more than 100 in a single manufacturing panel. If those small boards were not panelized, it would be difficult, if not impossible, to handle and assemble them individually. The array enables automation of assembly.

Some of the main advantages of key throughput are:

• Faster machine setup per unit (amortized over all boards in the array)
• Increases solder paste printing speed (one print covers the whole panel)
• Simultaneous placement and inspection of all boards in parallel.
• Reduce handling defects in relation to the processing of individual small boards

Improved Handling and Depaneling Ease

Handling of individual small PCBs can be a nightmare. They will block conveyor systems, slide through equipment, and are susceptible to edge damage. Panelization overcomes this by providing you with a larger standardized form factor that can easily pass through automated equipment.

However, the design of the array also affects the ease of separation of the boards at the end of the line. If not designed well, a depaneling operation can result in fractured solder joints, stressed components around the edges of the board, or rough/uneven edges on the board that can affect enclosure assembly. The spacing, separation, and location of breakaway features must be carefully considered at the outset. As a general guideline, components should be kept a minimum of 1.5mm from any V-scores and 2.0mm from any routed tab edges. This clearance helps to avoid mechanical stress upon separation that would otherwise occur at the sensitive solder joints.

Best Practices for Creating Effective PCB Arrays

Optimal Spacing, Orientation, and Panel Size Selection

You need to make three key decisions to get your array layout right: spacing between boards, the orientation of the boards, ds, and the targeted size of the panels.

The spacing between boards will vary based on how you are separating them:

1. V-scoring: Minimum V0.0 mm between boards required as the scoring line is across the entire panel. There should be a gap, however, of 0.4-0.5 mm between the copper features and the board edge.
2. Tab routing with mouse bites: Needs 1.6-3.0 mm space between boards, for the routed channel and breakaway tabs.
3. Full routing with breakaway tabs: Needs 2.0 – 3.0 mm spacing for the routing bit (usually a 1.6 mm or 2.0 mm diameter end mill).

You might be surprised by the difference orientation can make. For rectangular or irregularly shaped boards, occasionally it is possible to turn the boards 90 degrees or mirror alternate rows to substantially boost the count/board. Always make several orientations and compare the results. Here is a general guideline for common panel sizes:

Using V-Scoring, Tab Routing, and Mouse Bites Effectively

V-Scoring is the process of making a V-shaped cut at the top and bottom surfaces of the panel along the separation line. The thickness of the board is reduced by approximately one-third on each side by the groove, and the thin web of material snaps cleanly when bent. V-scoring is best applied to straight-edged rectangular boards, as the score line needs to extend across the width or length of the panel.

Key V-scoring specifications:

• Score angle: 30, 45, or 60 degrees (30 degrees is the most popular).
• Remaining web thickness: Usually 0.3-0.5 mm for a 1.6 mm board.
• Board-to-board gap: virtually none (the score line is the gap)
• Only works for straight lines that are extended across the entire panel length.

Tab routing is the process of cutting around the perimeter of each board in a panel, leaving small tabs (usually 3-5) on each board that keep the boards in the panel. The tabs are snapped or cut during de-paneling.

A refinement of tab routing is called a mouse bite (also known as a perforated tab or breakaway tab). The router leaves small tabs with a series of non-plated holes (usually 0.5-0.6 mm diameter, spaced 0.7-0.8 mm apart) drilled along the connection point, in place of the solid tabs. These perforations form a planned weak point that breaks easily without the need for excessive force.

The following comparison will help you decide:

Manufacturing Considerations for High-Yield PCB Arrays

Precision Alignment and Process Stability

To achieve high-yield array production, precise registration throughout the panel is required. With dozens of boards per panel, any registration issues with layers, solder mask, or silkscreen are compounded with each board. The 0.1mm registration error may be acceptable on a single board, but on a panel of 50 units, it could be enough to move edge-case designs out of spec.

Fiducial marks are the key to your alignment. Placing fiducials on the tooling strip (global fiducials) and on or near individual boards (local fiducials) creates a global alignment for the whole panel and fine-tuning for each individual board. Local fiducials on each individual board in the array are highly recommended for arrays with fine-pitch components (0.5 mm pitch or less).

Fiducial placement is done as follows:

• Set up at least two global fiducials on the diagonal corners of the panel tooling strip.
• If required by your assembly house, add a 3rd global fiducial for rotational correction.
• Near fine pitch components: Use local fiducials (QFP, BGA, QFN packages).
• Fiducial diameter: 1.0-1.5 mm, clearance area is 2.0-3.0 mm without copper and solder mask.
• Avoid positioning fiducials near the edge of the panel where they can be hidden by clamping.

Quality Control During and After Panelization

Arrayed panels have two levels of quality control: panel and individual board. Both are of importance to sustain high yield.

Manufacturers certify at the panel level:

• Size and straightness of panels as a whole
• Accuracies in tooling hole position (usually within ± 0.05 mm)
• V-score depth consistency for the entire length of the panel
• Tab positioning and mouse bite hole positioning
• Panel warpage (IPC-A-600 calls up to 0.75% bow and twist in surface mount board)

Standard quality checks are in place at the individual board level:

• Continuity and isolation testing (flying probe or bed of nails)
• AOI for solder joint quality (after assembly)
• Impedance Check for controlled impedance design
• Radiographic inspection (X-ray) of BGA and/or hidden joints (if applicable).

However, one factor that is often overlooked is depaneling damage. The requirements of IPC-A-610 Class 2 state that the separated edge of the board should not contain any cracks, delamination, or exposed copper that would hinder reliability. Upon post-depaneling inspection, the clean separation shall be verified with no fractures that extend into the functional area of the board.

JLCPCB's Strength in Efficient PCB Array Production

Expert Panel Layout Optimization for Maximum Material Utilization

If you're considering setting up a PCB array, a deep understanding of panelization by your manufacturing partner can be a game-changer. JLCPCB's engineering team will process all the array submissions and conduct a review to ensure the best utilization of materials, while the ordering system on their website will offer instant feedback on the panel configuration.

They provide standard and custom panel sizes, so you can select the panel that will fit the most boards. If you prefer to work on your own panelization, JLCPCB supports pre-panelized Gerber files. If you prefer to let the professionals do the work, they can design an optimized array layout for your specific board design, which they are likely to fit more units into than a manual layout.

Seamless Support from Array Design Review to Final Delivery

The practical benefits of using JLCPCB include the seamless process from design to delivery. Their system automatically checks your Gerber files for potential panelization problems such as insufficient edge clearance for V-scoring, positioning tabs too near components, copper features that enter routing channels, and more.

In the event of problems, their engineering team offers constructive comments instead of simply saying no. The collaborative process results in fewer revision cycles and a quicker time to production. With their 1-2 day turnaround on PCBs and the competitive pricing that starts at $2, the cost of getting a good panelized design into production is quite low.

FAQ about PCB Array

conclusion

Mastering smart PCB array design is one of the most effective ways to transition smoothly from prototyping to high-volume production. A well-optimized panel layout not only maximizes material utilization and boosts manufacturing yield by 20-30%, but also improves throughput, reduces handling defects, and lowers overall production costs. By applying the right panelization techniques — whether V-scoring for rectangular boards or mouse bites and tab routing for complex designs — along with proper fiducial placement and component clearance, you can achieve cleaner edges, higher reliability, and smoother assembly.

Ultimately, thoughtful array design turns your PCB panel into a competitive advantage. Partner with an experienced manufacturer like JLCPCB to refine your panelization strategy and bring your boards to market faster and more profitably. Start optimizing your next production run today.