How to Cut Circuit Board: PCB Panel Connections and PCBA Depaneling Methods

In practical electronics manufacturing, “how to cut a circuit board” usually involves more than simply cutting through PCB material.

The actual questions are often:

• How are multiple PCB units connected within a production panel?
• How are individual PCBAs separated after SMT assembly?
• What are the differences between V-scoring, mouse bites, routed slots and machine depaneling?
• How can a PCBA be separated without damaging solder joints, components or the circuit board itself?

To understand how to cut a circuit board correctly, we should first understand PCB panelization and the methods used to connect individual PCB units within a panel.

Why Are PCBs Usually Manufactured in Panels?

Manufacturing and assembling small PCBs one at a time reduces equipment efficiency and increases the cost of handling, positioning and production.

PCB manufacturers therefore usually combine several identical or different PCB units into one production panel. The complete panel can then pass through the following processes:

• PCB circuit fabrication;
• Surface finishing;
• Electrical testing;
• Solder paste printing;
• SMT component placement;
• Reflow soldering;
• AOI and functional testing.

After these processes are completed, the individual PCBAs are separated from the panel.

Therefore, how a circuit board should be cut depends not only on the selected depaneling method, but also on how the individual PCB units are connected within the original panel.

How Are Individual PCBs Connected in a Panel?

The most common PCB panel connection methods are V-scoring, routed slots with solid tabs and mouse-bite tabs.

1. V-Score Connections

V-scoring, also called V-cutting, creates V-shaped grooves on both sides of the PCB while leaving a controlled amount of material in the middle. This remaining material keeps all PCB units connected during fabrication and SMT assembly.

After assembly, a V-score depaneling machine can separate the PCBAs along the scored lines.

The main advantages of V-scoring include:

• High panel material utilization;
• No wide routing channel required between adjacent PCBs;
• Suitable for straight board edges;
• Fast depaneling for volume production;
• Usually a relatively low cost per PCB.

However, V-scoring also has limitations:

• The V-score line normally needs to run continuously across the panel;
• It is unsuitable for curved or complicated board outlines;
• Depaneling transfers some mechanical stress to the PCB and its components;
• Ceramic capacitors, BGAs, QFNs and solder joints near the board edge may be affected.

V-scoring is generally suitable for PCBs with regular outlines, straight edges and sufficient clearance between the components and the score line.

2. Routed Slots With Solid Tabs

For irregularly shaped PCBs, or products that cannot use continuous V-score lines, most of the board outline can be formed by CNC routing while several small solid tabs are left in place.

These tabs keep the PCB units connected during fabrication and assembly. After SMT assembly, the solid tabs are cut to separate the individual PCBAs.

This method offers several advantages:

• Suitable for circular, curved and complex PCB outlines;
• Connection locations can be selected more freely;
• Tabs can be positioned away from sensitive components;
• Suitable for most irregularly shaped PCBs.

The disadvantages are that routed slots consume some panel space, and the remaining tab areas may require additional edge finishing after depaneling.

3. Mouse-Bite Connections

Mouse bites, also called breakaway perforations or stamp holes, consist of a row of small non-plated holes placed through a breakaway tab.

During depaneling, the tab breaks along these holes. The remaining edge resembles the perforated edge of a postage stamp, which is why this structure is sometimes called a stamp-hole connection.

The advantages of mouse bites include:

• Relatively easy manual separation;
• No dedicated V-score machine required;
• Suitable for irregular PCB shapes;
• Flexible panel design;
• Practical for prototypes and low-volume production.

For quick-turn PCB prototypes and low-volume production, mouse bites can be a convenient choice when the assembler does not have dedicated depaneling equipment.

Their limitations include:

• Small protrusions remain on the board edge;
• Grinding or secondary edge finishing may be required;
• Manual separation still creates mechanical stress;
• Hole position and tab strength must be designed carefully.

If the customer does not have a professional depaneling machine, mouse bites are often a practical solution.

If the customer has suitable depaneling equipment, routed slots with solid tabs can usually provide a cleaner finished board edge.

What Methods Can Be Used to Depanel PCBAs?

The correct depaneling method depends on several factors:

• PCB material;
• Board thickness;
• Board outline;
• Panel connection method;
• Component placement;
• Production volume;
• Acceptable mechanical stress.

Manual Breaking

With this method, an operator manually separates the PCBAs along the V-score lines or mouse-bite tabs.

Manual breaking requires almost no equipment and may be acceptable for prototypes or simple products. However, the bending stress generated during manual separation is difficult to control.

It may cause:

• Cracking of ceramic capacitors;
• Microcracks in solder joints;
• Stress on BGA solder balls;
• Damage to copper traces or plated holes;
• PCB deformation;
• Damaged or uneven board edges.

A PCB that can be broken apart by hand is not necessarily suitable for reliable volume production.

V-Score Depaneling Machine

A V-score depaneling machine uses circular blades, linear blades or other dedicated cutting mechanisms to separate PCBAs along the scored lines.

Compared with manual breaking, its advantages include:

• More controlled cutting paths;
• Lower mechanical stress;
• Better board-edge consistency;
• Suitability for volume production;
• Higher operating efficiency.

However, this equipment is mainly suitable for straight V-score lines and cannot follow complex board outlines.

PCB Router Depaneling Machine

A PCB router follows a programmed path to cut through solid tabs and separate individual PCBAs.

It is particularly suitable for:

• Irregularly shaped PCBs;
• High-value PCBAs;
• Components positioned close to the board edge;
• Products requiring low-stress depaneling;
• Volume production requiring consistent edge quality.

Its disadvantages include higher equipment and fixture costs and, in many cases, a lower depaneling speed than a simple V-score machine.

For a high-reliability PCB, the additional cost of controlled router depaneling may be justified by the reduced risk of component cracking and solder-joint damage.

Punch Depaneling

Punch depaneling uses a dedicated die to separate the PCB or PCBA from the panel in a single operation.

Its main characteristics are:

• Very high production speed;
• Suitable for high-volume manufacturing;
• Low depaneling cost per unit;
• Good dimensional consistency.

However, a dedicated die is required, creating a higher initial tooling cost. The process also imposes restrictions on the board outline and component layout.

Laser Depaneling

Laser depaneling does not require a mechanical blade to contact the PCB directly. It provides high cutting accuracy and very low mechanical stress.

It is commonly used for:

• Flexible circuits;
• Ultra-thin PCBs;
• Small precision circuit boards;
• Products sensitive to mechanical stress;
• Complex cutting paths.

The disadvantages are higher equipment costs and the need to control heat effects, carbonization, fumes and cutting residues.

How to cut circuit board (bare PCB)?

If the circuit board has not yet been assembled with components, common cutting methods include:

• CNC routing;
• V-scoring;
• Punching;
• Shearing;
• Diamond saw cutting;
• Laser cutting.

For prototypes or personal projects, some users may use a small rotary tool, saw or scoring method to cut a bare PCB.

However, FR-4 contains glass fibers and generates fine dust when it is cut.

At a minimum, manual PCB cutting should include the following precautions:

• Use suitable eye and respiratory protection;
• Provide dust extraction or local ventilation;
• Avoid inhaling FR-4 dust;
• Secure the PCB before cutting;
• Avoid damaging copper traces;
• Remove burrs and finish the board edge after cutting.

Uncontrolled hand tools are not recommended for volume production, high-reliability products or PCBAs that have already completed SMT assembly.

What Should Be Considered During Depaneling Design?

Reliable depaneling should not be considered only after PCBA assembly is complete. It should be addressed during the PCB panel design stage.

Maintain Sufficient Clearance Between Components and Board Edges

MLCC ceramic capacitors, BGAs, QFNs, large connectors and other brittle or stress-sensitive components should not be placed too close to a depaneling line.

The closer a component is to the board edge, the more easily the bending and vibration created during depaneling can reach the component body and its solder joints.

A single fixed clearance value cannot apply to every PCB. The appropriate distance depends on:

• PCB thickness;
• Depaneling method;
• Component orientation;
• Component size;
• Panel-tab strength;
• Product reliability requirements.

This consideration becomes increasingly important for dense multilayer PCB designs, where components, vias and internal copper structures may all be located close to the finished board edge.

Control the Number and Position of Breakaway Tabs

If there are too few tabs, the panel may deform, move or break during fabrication, transportation or reflow soldering.

If there are too many tabs, or if the tabs are too wide, depaneling becomes more difficult and produces greater mechanical stress.

A properly designed tab arrangement should ensure that:

• The panel has sufficient mechanical strength;
• PCB units remain stable during SMT handling;
• The panel can pass through reflow without separation;
• Depaneling positions remain away from sensitive components;
• The remaining board edges can be finished easily.

Consider Component Orientation

Long ceramic capacitors positioned parallel to a depaneling line may be more vulnerable to tensile stress when the PCB bends.

For stress-sensitive components located near a board edge, the depaneling direction, component orientation and expected PCB bending direction should all be evaluated.

Include Suitable Process Rails

SMT equipment usually requires sufficient process rails for conveyor transport, positioning and clamping.

The process rails may also include:

• Tooling holes;
• Fiducial marks;
• Test structures;
• Barcodes or traceability markings.

If the individual PCB does not provide enough handling space, panel rails should be added to support the assembly process.

How Should a PCB Depaneling Method Be Selected?

No single depaneling method is suitable for every product.

Product or production condition	Commonly used method
Straight board edges and volume production	V-score with a depaneling machine
Irregular PCB outline	CNC-routed slots with breakaway tabs
Prototypes or low-volume production	Mouse bites or routed breakaway tabs
High-value PCBA requiring low stress	PCB router depaneling
Very high volume with a fixed design	Punch depaneling
Flexible, ultra-thin or precision PCB	Laser depaneling
No dedicated depaneling equipment	Mouse bites, with controlled manual separation

The selection should not be based only on depaneling cost. Potential component damage, repair costs and long-term reliability risks must also be considered.

A low-cost depaneling method that causes microcracks in ceramic capacitors may create failures that are not detected during factory testing. The product may fail only after it has been operating in the field for some time.

How Can a PCB Manufacturer Help?

An experienced PCB manufacturer should do more than manufacture according to the supplied files. Before production, the manufacturer should also review:

• Panel material utilization;
• V-score direction;
• Breakaway-tab positions;
• Mouse-bite design;
• Process-rail width;
• Fiducial marks and tooling holes;
• Distance between components and board edges;
• Finished outline tolerances;
• The intended depaneling equipment.

SQPCB can evaluate V-scoring, CNC routing, mouse bites and other panelization options according to the PCB outline, board thickness, component layout and the customer’s assembly conditions.

A DFM review before production can reduce depaneling risks and help balance manufacturing cost, assembly efficiency and finished-product reliability.

Conclusion

“How to cut a circuit board” may appear to be a simple question, but in actual manufacturing it involves two closely related stages:

1. How individual PCB units are connected within a production panel;
2. How the PCBAs are safely separated after SMT assembly.

V-scoring is suitable for straight board edges and volume production. Routed slots and breakaway tabs work well for complex outlines. Mouse bites are convenient for prototypes, low-volume production and manual separation. Router, punch and laser depaneling each serve different requirements for accuracy, production volume and mechanical stress.

The correct depaneling method should be considered during the panel-design stage—not after the PCBAs have already been assembled and someone is deciding how to “cut them apart.”

Frequently Asked Questions

1. Can a PCBA Be Broken Apart by Hand?

Some PCBAs with V-scores or mouse bites can be separated manually. However, the mechanical stress generated by hand breaking is difficult to control.

For products containing MLCCs, BGAs, QFNs or other stress-sensitive components, a suitable depaneling machine is recommended.

2. Is V-Scoring Better Than Mouse Bites?

Neither method is always better.

V-scoring is suitable for straight outlines and volume production and usually provides better material utilization. Mouse bites are more suitable for irregularly shaped PCBs, prototypes and assembly lines without V-score depaneling equipment.

3. Can Depaneling Damage Electronic Components?

Yes.

Bending, vibration and impact during depaneling may cause ceramic capacitors to crack, solder joints to develop microcracks or the PCB itself to become damaged.

Proper panel design and a controlled, low-stress depaneling process can significantly reduce these risks.

4. Can an Assembled PCBA Be Cut With an Ordinary Saw?

It is generally not recommended.

The vibration, dust and positioning accuracy of an ordinary saw are difficult to control. The process may also damage components, solder joints and copper features.

Volume-production or high-value PCBAs should be separated using a V-score depaneling machine, PCB router or other suitable equipment.

5. Who Should Design the PCB Panel: the Customer or the Manufacturer?

Ideally, the customer, PCB manufacturer and PCBA assembly provider should review the panel design together.

The customer understands the product structure, the PCB manufacturer understands fabrication capabilities, and the PCBA provider understands the SMT line and available depaneling equipment.

Combining these three perspectives usually produces a more reliable and cost-effective panel design.