PCB Panelization Explained: Tips and Techniques

PCB panelization is a crucial process in modern electronics manufacturing, designed to streamline production and reduce costs. In this way smaller circuit boards are produced in bulk and joined to one another to form a single array. This bulk production fosters the easy movement of PCBs through an assembly line. CNC (Computer Numerical Control) machines are utilized in PCB production and assembly facilities. These CNC machines can design PCBs that are rather large in size. But typically, electronic products use small-sized PCBs.

Therefore, several copies of the PCB design are given to the CNC machine to fully leverage its capability. PCB Panelization is the most commonly used PCB manufacturing technique, as it saves both time and cost. In this guide, we'll explain what PCB panelization is, why it's important, and provide essential tips and techniques to optimize the process.

What is a PCB Panel?

A PCB panel, or array, consists of multiple smaller boards connected together. During assembly, the panel is processed as a whole, and later separated into individual PCBs through depanelization. This method reduces defects by streamlining automated assembly, improves material efficiency, and lowers costs. Panels can contain either a single design (single-up) or multiple designs (multi-up), making them ideal for high-volume production.

How to Select Between Different Penalization Methods

There are several PCB panelization methods, each with its own pros and cons. The design of both the individual boards and the panel greatly influences the most suitable method for a given application. Key factors to consider include:

• Design: The board's layout is crucial in selecting a panelization technique. The spacing between components and the board edge can make some methods less suitable, especially if there are edge-hanging components.

• Components: The types and placement of components are equally important. Fragile components or connectors may influence which breakout method is best.

• Materials: The materials used in the PCB can limit panelization choices. Some materials are prone to splintering during breakout, and board thickness also plays a role—thin boards can break during assembly, while thick boards might pose challenges during the breakout process.

Given these factors, some projects may require a mix of panelization techniques to ensure both the structural integrity of the panel and smooth breakout.

Why is PCB Panelization Important?

PCB panelization is important because it optimizes manufacturing efficiency, reduces production costs, and minimizes material waste. By grouping multiple boards onto a single panel, it streamlines assembly, handling, and testing processes, ensuring better alignment, reducing errors, and enhancing productivity in mass production.

1. Increased Efficiency: Multiple boards to be fabricated and assembled at once, reducing overall manufacturing time.

2. Cost-Effective: It reduces material wastage and minimizes costs related to handling, setup, and equipment usage.

3. Simplified Handling: Tiny individual PCBs are difficult to handle during assembly and can lead to errors.

4. Better Component Placement: Panelization allows machines to place components accurately on a larger area, reducing errors and ensuring uniformity across all boards.

PCB Panelization Techniques

Different techniques are used to panelize PCBs, depending on the design requirements and manufacturing processes. The most common techniques include:

1. V-Scoring (V-Grooving)

V-scoring involves creating a shallow groove on both sides of the PCB panel, typically at 30° or 45° angles. The grooves weaken the material along the lines, allowing the boards to be snapped apart manually or with the help of a machine. V-scoring is best for straight-edged boards but may not work well for irregularly shaped designs. See our fully detailed article covering all the main aspects of V-Scoring technique.

Advantages:

Efficient for straight-line designs.

Clean edges post-separation.

Minimal material wastage.

Limitations:

Only allows straight cuts.

Limited to rectangular or square board shapes.

2. Tab-Routing (Mouse Bites)

Tab-routing, also known as mouse bites, is a technique where small tabs hold the individual PCBs together in the panel. The tabs are perforated with tiny holes (mouse bites) that make it easy to break the boards apart. This method offers greater flexibility for irregularly shaped designs compared to V-scoring. See our fully detailed article covering all the main aspects of Tab Routing technique.

Advantages:

Suitable for irregular shapes.

Boards can be easily separated by breaking the perforations.

Provides more design flexibility.

Limitations:

Rougher edges after separation.

May require post-processing to smooth the edges.

3. Breakaway Rails

Breakaway rails are non-functional extensions added to the panel’s edges to facilitate machine handling during assembly. They provide extra support, ensuring the PCBs remain stable throughout the process. Once assembly is complete, the breakaway rails are removed. This method is often used in combination with V-scoring or tab-routing.

Advantages:

Adds mechanical stability during assembly.

Simplifies automated handling for smaller or irregular PCBs.

Limitations:

Increases material usage.

Requires additional steps to remove the rails.

4. Solid Panel with Custom Cutouts

This method involves creating a solid panel with custom cutouts for individual boards. The boards are separated later using advanced techniques like milling or laser cutting. Milling can result in dust and vibration, while the laser-cutter is extremely expensive and ineffective on boards over 1mm thick. The hook-bladed option is less expensive but inefficient and prone to blade rotation. This method tends to be less common than the other two.

Advantages:

High precision for complex designs.

Minimizes panel stress during manufacturing.

Limitations:

Higher manufacturing costs.

Requires advanced machinery for separation.

V-Score and Tab Routing are the most commonly used panelization methods. For PCB designers, the key is determining which method best suits their application, followed by designing the array for optimal strength and breakout success.

V-groove panelization is often preferred for its efficiency and reduced surface stress. Depaneling machines for V-groove arrays are cost-effective, portable, and require minimal maintenance. While this method may produce slightly rougher board edges, it is generally not an issue in applications where V-groove is used.

Tips for Effective PCB Panelization

Consider Assembly Constraints: Ensure the panel layout fits within equipment specs, leaving enough space between boards for depaneling.

Use Fiducial Markers: Add fiducials to guide automated machines for accurate placement and alignment.

Plan for Depaneling: Choose the best panelization method (V-scoring, tab-routing) based on board shape and design needs.

Account for Tooling Holes: Place tooling holes in non-critical areas to avoid interference.

Optimize Board Orientation: Align boards to reduce material waste and minimize cuts.

Ensure Thermal Relief: Include proper thermal relief to prevent warping during reflow soldering.

Balance Flexibility and Strength: Provide adequate support for rigid-flex designs to avoid damage during assembly.

Key Factors to Keep in Mind while V-Scoring:

While V-groove panelization is efficient for many applications, it poses design limitations. It’s unsuitable for designs with components too close to or hanging over edges, and introduces manufacturing concerns:

• Clearance: Maintain at least 0.05 inches between components and V-grooves. Taller components, like multilayer ceramic chip capacitors, need 1/8 inches clearance to avoid cutter interference and prevent solder joint fractures.

• Jump-Scoring: V-grooves can weaken PCB arrays, causing warping in wave-solder machines. Adding jump-scoring on the leading and trailing edges (with a ½ inch breakaway) strengthens the array and prevents sagging.

By addressing these considerations, V-scored panels can avoid issues during manufacturing.

Instructions for Breaking Out PCB Boards

Even with a perfectly designed PCB array, the breakout process can still mess up things like splintering, tearing, or component damage. Here’s how to keep those breakouts smooth and avoid unnecessary costs:

Breaking Tabs by Hand: If your panel is tab-routed well, you can break it with hand tools. Grab some wide-nose pliers and bend each tab along the break-line until you hear a satisfying snap. For a clean break, bend in the opposite direction to finish it off.

Breaking Tabs by Machine: If the board's too thick for hand tools, no worries! A hook blade or depaneling router can do the job, especially for solid tab panels.

Breaking V-Grooves by Hand: V-scored panels? Yep, those can be broken by hand too, using the same technique as tab-breaking.

Cutting V-Grooves: For these, you'll need a depaneling machine with a pizza-cutter-style blade. which is cheap, low-maintenance, but the edges might be a little rougher.

Conclusion

PCB panelization is a key factor in efficient manufacturing, offering numerous benefits in terms of cost, time, and production quality. By understanding the different panelization techniques and following best practices, designers and manufacturers can optimize the production process, reduce errors, and ensure high-quality PCBs.

With the right approach, panelization not only simplifies assembly but also enhances the overall performance and durability of the final product. By using techniques like V-scoring, tab-routing, and breakaway rails strategically, you can maximize production efficiency and minimize post-processing steps. Whether you're working on prototypes or high-volume production, mastering PCB panelization is essential for delivering reliable and cost-effective electronics.