Depanelization is the separation of individual circuit boards from the PCB panel or array. The depanelization method of printed circuit boards (PCBs) directly affects production efficiency and product quality. Stamp hole and V-cut (V-scoring) are two common depanelization technologies. Let's discuss with ALLPCB about the depanelization method of stamp hole connection in detail, analyze its advantages and disadvantages, and compare it with the V-scoring depanelization method to explore its practicality and performance in actual operation.
What is stamp hole?
Stamp hole is a method of drilling small holes on the predetermined dividing line of the circuit board so that the boards remain connected during the production process and are finally separated by simple breaking or cutting with a separation machine. This method is similar to the jagged holes on the edge of a stamp, hence the name stamp hole, also called mouse bites hole.
Design suggestions
The design specifications of stamp holes usually include hole diameter, hole spacing, and the distance between the hole and the edge of the pcb printed circuit board. Common design specifications are as follows:
Hole diameter: usually between 0.6 mm and 1.0 mm. Smaller hole diameters (such as 0.6 mm) are suitable for boards that require higher precision and strength, while larger hole diameters (such as 1.0 mm) facilitate easier separation operations.
Hole spacing: The distance between holes is usually 1.0 mm to 1.5 mm. This distance can be adjusted according to the thickness of the PCB and the required strength. A denser hole spacing (such as 1.0 mm) is suitable for thinner boards, while a sparser spacing (such as 1.5 mm) is suitable for thicker boards.
Distance between holes and board edges: Usually maintained between 0.2 mm and 0.5 mm. This distance must ensure the strength of the board and facilitate subsequent board separation operations.
Advantages of stamp hole board connection
Easy processing: The stamp hole board connection method only requires additional drilling steps during PCB manufacturing, and the operation is relatively simple and easy to implement.
Low cost: Since no special equipment is required during the processing of the stamp hole board connection, only some process steps are added during the drilling stage, so the cost is relatively low.
Reduce stress: This method has less stress during board separation, which is particularly suitable for PCBs that need to protect sensitive components and precision circuits.
High flexibility: The position and number of stamp holes can be flexibly adjusted according to actual needs, and is suitable for PCB designs of various shapes and sizes.
Disadvantages of Stamp Hole Boards
Uneven edges: The edges after board separation may be uneven, requiring additional grinding or finishing, affecting the appearance and assembly accuracy.
Reduced strength: Stamp holes will weaken the overall strength of the board, and it is easy to break or damage during transportation and assembly.
Impact on production efficiency: On high-density circuit boards, stamp holes may occupy limited board space, affecting wiring and component layout.
Mechanical operation limitations: For large-scale production, manual breaking may not be realistic, and board separation machines are required, increasing equipment investment.
Case analysis
For example, a company that produces small batches of customized electronic devices chooses to use stamp hole board separation.
Due to the wide variety of products and small quantities, this method can flexibly adjust the position and number of holes to adapt to different circuit board designs.
The company also noted that this method reduces the stress on precision components during board separation and protects the reliability of the product. However, in order to ensure the aesthetics and assembly accuracy of the final product, they need to perform additional grinding on the edges after board separation.
What is a V-scoring?
V-Cut is a common PCB depaneling method with two main advantages: first, V-Cut can provide smoother and more consistent board edges; second, V-Cut has advantages in material utilization, especially for large-volume or high-layer boards, where every square inch of material is important, so it can bring significant cost savings.
V-Cut Cutting Specifications and Design Suggestions
Panel Boundary: It is recommended to use a substrate of at least 5.00 mm as the panel boundary. Add two parallel edges on the two longest sides of the PCB, and leave no gaps between the boards. The V-Cut will be processed along the shared board outline.
Processing Direction: V-Cut is processed only along the x-axis and y-axis directions, and no diagonal processing is performed. Because the V-Cut will run through the entire board along the array straight line, the board outline should be straight.
Scoring Depth: The scoring depth is about one-third of the total material thickness. The scoring line will be processed on the upper and lower sides of the PCB, leaving a material thickness of about one-third of the total thickness. For example, if the board thickness is 0.062 inches, the remaining material thickness will be about 0.021 inches.
Board Thickness Requirements: It is recommended to use V-scoring technology only on panels with a minimum board thickness of 1 mm to ensure stability. However, in practice, the thickness of the inner mesh material of the V-scoring can vary from 0.15 mm to 0.4 mm depending on the length of the scoring. If the scoring length is less than 25 mm, the mesh thickness can be 0.15 mm; scorings with a length of 100 mm can have a mesh thickness of 0.25 mm; scorings longer than 100 mm can have a mesh thickness of 0.4 mm. These values ??are guidelines only and should be discussed with your assembly shop to confirm the mesh thickness for your board design.
Board Material: Standard PCB material is basically fiberglass. Even if the board has a V-scoring, it will still be strong, so be careful when separating the boards. Expect some degree of flexing before the scoring line breaks. It is normal for some fiberglass filaments to appear along the edge of the V-scoring. Light sanding with a belt sander can take care of any rough areas.
As shown in Figures above, the V-scoring cutting selection is very important. With the difference in drill bit and cutting angle, all wires and circuit boards should be arranged within a range of at least 1 mm from the top of the V-scoring edge to prevent damage during the depaneling process. The middle layer should be pulled back 1 mm from the V-scoring to maintain a ratio of 1/3 in the upper, middle and lower parts.
Advantages of V-scoring
1. Flat edges: The edges of the V-scoring after depaneling are relatively flat, which reduces the subsequent processing steps and improves the product appearance and assembly quality.
2. High production efficiency: The V-scoring is suitable for mass production, and the mechanical operation is simple and fast, which improves production efficiency.
3. Stable structure: Even before depaneling, the overall strength of the circuit board is high, reducing the risk of damage during transportation and assembly.
4. Strong adaptability: Suitable for PCBs of various thicknesses, especially thicker multilayer boards.
Disadvantages of V-scoring
1. Complex processing: The processing of V-scoring requires special milling cutters and equipment, which increases the process complexity and equipment cost.
2. Stress concentration: Large mechanical stress may be generated during the depaneling process, resulting in damage to components or deformation of the circuit board.
3. Low flexibility: The design and processing position of the V-scoring are not easy to change, and the adaptability is not as flexible as the stamp hole.
Case analysis
A company focuses on mass production of consumer electronic products, such as smartphones. In this case, the V-scoring depaneling method is more suitable. By using automated equipment for V-scoring processing and depaneling, they can greatly improve production efficiency and ensure the edge flatness of each circuit board, improve the appearance quality and assembly accuracy of the product. However, the company also noticed that this method will cause stress to some sensitive components during depaneling, so special attention should be paid to the layout and protection of components during design.
What are the differences bewteen V-Scoring or Stamp Hole?
Processing complexity and cost
Stamp hole: simple processing, low cost, suitable for production of all sizes, especially small batches or rapid prototyping.
V-scoring: complex processing, high equipment cost, more suitable for mass production.
Depaneling quality
Stamp hole: uneven edges, need additional trimming, suitable for products that do not require high appearance quality.
V-scoring: flat edges, high quality, suitable for products with high quality requirements.
Depaneling stress
Stamp hole: low stress, suitable for sensitive and precision components.
V-scoring: high stress, need to pay attention to the protection of components.
Design flexibility
Stamp hole: flexible design, can adapt to various shapes and layouts.
V-scoring: limited design, suitable for regular shapes and fixed layouts.
Applicable scenarios
Stamp hole:
Small batch production or single piece production.
Beginners or hobbyists do not have complex equipment.
The board has various shapes and needs to be flexibly adjusted.
The finished product does not require high edge flatness.
Recommended examples:
Small circuit boards such as Arduino expansion boards and sensor modules.
DIY electronic projects, such as simple LED driver boards, audio amplifiers, etc.
V-scoring:
Massive production or high production efficiency.
Hobbyists have the conditions to use special equipment or tools.
The board design is relatively regular and suitable for fixed layouts.
The finished product has high edge flatness requirements.
Suggested Reading: V-Scoring vs. Stamp Hole Depaneling: Choosing the Right Method for Your PCB
Summary
Stamp hole connected boards and V-scoring each have their own advantages and disadvantages. In actual applications, engineers usually consider factors such as custom PCB cost, production efficiency, product quality and design flexibility, and choose the most appropriate board separation method to achieve the best production effect and product performance. Close cooperation with PCB manufacturers should be carried out according to specific project requirements and equipment conditions to ensure the best design and processing results.