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In the PCB manufacturing process, you’ll frequently come across the term “PCB depaneling,” which refers to the process of cutting, routing, drilling, and scribing printed circuit boards to divide them into individual parts.
V-Cut, or V-scoring, is a technique used in PCB depaneling, and ELE PCB will provide a comprehensive guide to the technology, including definition, production, design, and comparison with stamp holes, to help you master V-cut board separation method!
What is V-Cut PCB Scoring Technology ?
V-cut is a dividing line cut in advance with a rotary tool at a specific location on the PCB, with the goal of making it easier to break between the boards and facilitating the subsequent assembly of the SMT circuit boards after the depaneling is completed.
V-scoring method is applied widely for its outstanding benefits:
Easy separation of V-cut boards: break along the groove for quick, simple disconnection from individual PCB boards.
Neat edges for assembly and use.
Reduced stress: V-cut de-panelling generates less stress on PCB boards thanks to reasonable design.
Simple design: You only need to draw a V-shaped groove where the PCB boards connect.
V-Scoring Manufacturing Process
- Drawing V-Cut Shapes
Use PCB design software to connect two boards and add 2D lines and characters to the Drill Drawing layer to represent the V-cut position and shape. Export the right Gerber file to the board manufacturer, who will process the V-scoring based on the file.
2. Milling
The PCB is machined with a V-cut milling cutter to create V-grooves. The depth and angle of the milling cutter must be adjusted based on the thickness and material of the PCB board, commonly retaining about 1/3 of the circuit board’s thickness.
3. Inspection
Use a V-groove residual thickness gauge to measure the V-cut’s depth and ensure the residual thickness of the V-cut meets the standards. If the groove is too deep, it may lead to breakage or deformation of the PCB board in the placement process; if too shallow, it may be difficult to separate the boards or not be neatly separated.
4. Separation: separate the board into individual PCB boards after the circuit board patch is complete.
Rules for V-Cut PCB Design
When designing the V-scoring, consider the following principles:
-
Conforming Residual ThicknessThe remained thickness of v-groove is defined within certain limits as below:
- IPC-2221B: the residual thickness of V-cut ≥ 1/3 of the board thickness;
- IPC-6012E :the residual thickness tolerance should to be ± 0.1mm.
Considering the equipment, the minimum residual thickness requirement of 0.4mm for manual board splitter; 0.5mm for automatic board splitter; 0.3mm for laser board splitter system.Generally, the recommended residual thickness is of 0.5-1.0mm.If the board thickness is thin(≤1.0mm), the residual thickness can be appropriately reduced, but should not be less than 0.35mm, otherwise it will be easy to break in the process before breaking time.
If the board thickness is thicker(≥1.6mm), the residual thickness can be appropriately increased, but should not be more than 0.8mm, otherwise the V-cut machine may not be able to cut off immidiately, it will also increase the risk of machine’s damage.
- Suitable Angle SelectionV-cut has three types of angles: 30°, 45°, 60°, the most commonly used is 45°.The larger the angle, the more board edges are eaten by the V-cut, the more boards, the line must be more inward; the smaller the angle, the more favourable to the spatial design of the PCB, but not conducive to the life of the V-cut saw blades. And the thicker the board, the larger the V-cut angle is usually.
- Avoid critical areas: The cutting line should not pass through important circuit lines or components to avoid damaging the circuits or components during the V-cut process.
- Consider stress distribution: The V-cut position should try to avoid the weak area or stress concentration area of the board, such as board edges with arcs, protruding edges or grooves in the area, these places are not suitable for V-Cut, to avoid cracks or breaks in the process of sub-panel or use.
Restrictions
- Because the V-Cut’s grooves are cut using a chainsaw with two discs, it can only cut in a straight line from beginning to end; it cannot spin to change direction or cut a small section and then jump off the section.
- If the board thickness is less than 1.0mm, it is not suggested to do V-cut because the V-cut groove will undermine the original PCB structural strength. Additionally, when there are heavier items on the circuit board, the V-groove design may cause the board to flex easily.
PCB Separation Methods Comparison: V-Cut vs Stamp Holes
There are various methods of PCB depaneling, the most common of which are v-cut and stamp holes, but also the use of lasers, high-pressure water flow and other cutting methods. Should I choose V-cut or stamp holes？Here we will show a comparison with V-cut and stamp holes to help you make a choice.
| V-Cut | （Breakaway Holes/Mouse bites） | |
| Special Equipments | specialised milling cutters and equipments | only additional process steps at the drilling stage |
| Manufacturing Complexity/Cost | Complex/ Expensive | Simple/ Low-cost |
| The Quality of Depaneling | Flat edges | Uneven edges |
| The Stress of Depaneling | High | Low |
| Flexibilty | Suitable for regular shapes and fixed layouts | Adaptable to various shapes and layouts |
| Suitable Application | High-volume production Regular board designs, fixed layouts Edge flatness required | Batch or single-piece production No complex equipment needed No high-fidelity edge flatness required |
Conclusion
V-cut PCB separation technology has become the mainstream solution for PCB separation with its advantages of high efficiency, low stress and neat edges. The design should strictly follow the IPC standard, reasonably plan the residual thickness (0.5-1.0mm is recommended) and V-angle (45° is commonly used).
V-Cut is more suitable for linear depaneling and automated production than stamp holes. By optimising the design and manufacturing process, PCB depaneling efficiency can be significantly improved and losses reduced.
ELE PCB provides a one-stop solution for V-Cut depaneling, covering design review, precision machining and quality inspection, to help customers achieve efficient and high yield production. We are dedicated to providing high-quality PCB products to all our customers. Contact ELE PCB for a free design guide now!
FAQs
A1:
You can break a V-cut PCB by hand, although we generally do not recommend it. Due to the PCB’s extreme precision, even a minor external strain might cause it to bend resulting in cracks and other issues with the electrical components. Normally, we choose machinery for depaneling to ensure the quality of our products.
A2:
No. The angle depends on the material and thickness of the board but usually we choose 45°. If the board is thicker, the angle is correspondingly larger to ensure that it can be easily broken when splitting the board.
A3:
IPC-2221B: the residual thickness of V-cut ≥ 1/3 of the board thickness;
IPC-6012E :the residual thickness tolerance should to be ± 0.1mm.
A4:
Flexible PCBs are recommended to use laser depaneling or stamping process due to structural characteristics.
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