PC Board Fabrication, V-Scoring-Purpose and Benefits

PCB or a printed circuit board has different holes, cuts, and elements, and V-scoring is one of them. V-scoring pre separates the PCB and designers also call it V-groove because a groove resembling V is cut on the circuit board’s top and bottom. Generally, the depth of the groove is 1/3 of the board depth and there is a thin layer between two Vs for the board processing.

The boards with V-grooves are either end to end or side by side with adjacent edges. The groove helps break boards with a little force, and you can divide a single panel into several parts with the help of V cuts.

Purpose of V-Scoring

Manufacturers use V-scoring while combining an array’s circuit boards for an effective assembly. It makes the assembly process less hectic, and you can easily set apart the assembled PCBs.

V-scoring helps to reduce pressure during the placement of SMD components on the circuit board by an SMT machine, and while separating the assembled PCBs.

The PCB panel helps manufacturers to insert the components at a high speed, using one panel at a time, rather than one circuit board.

The panel boards are loaded with their parts through an automated machine that performs the pick-and-place function.

These uses motivate PCB engineers, manufacturers, and buyers to use the V-grooves.

Specifying V-Scoring

Engineers specify V-scoring according to the groove depth, or a distance between the two grooves or Vees through a cross-section. The residual material in this case is known as Web. Each measurement has to be equal, including 1/3rd on the top, bottom, as well as a 1/3 web in the center.

The practice of the 90 degrees or the 30 degrees scoring is also there in some cases. However, the 90 degrees scoring is easy to break compared to the 30 degrees scoring.
You can alter these measurements according to your needs, depending on the array size and the ease of separating the boards later on.

You have to use a 30-degree cutter for a score-line cutting with a certain depth. You can calculate the rest of the web based on the material thickness. However, the tolerance of +/- .002″ is essential in this case.

When to Use a Jump Score

Jump score is used in some conditions though it is not that common. In jump score, the score does not go from one end to another, instead, it ends before the circuit boards end. Like, the cutting blade stops before another end comes. The jump scoring provides a firm array while assembly.

Some V-Scoring Terms

There are certain terms to consider while making PCBs with V grooves, and we will discuss them one by one.
• PCB board has some borders or extra material that helps in making a panel, and they are called Rails or Waste Tabs. They enhance a panel’s mechanical strength, allowing an extra material or borders that help to clamp a panel while assembling.
• Another term used in V-scoring is Fiducials which are marks being etched on the borders or a PCB’s inner surface, like on upper and lower layers of copper. Fiducials help the SMT assembly to identify the position of the PCB and SMD components.
• The other important elements are tooling holes located on a PCB’s four corners. The manufacturers use these holes to align a PCB during drilling and routing. Like, the alignment that involves the SMT carriers, solder plate printing, and PCBs’ final assembly.

Process of V-Scoring

It involves two blades being beveled at 30o, or 45o, or 60o, and the blade resembles a wheel with several gears or knives that make V-grooves. Both top and bottom blades rotate while cutting. When the PCB assembly is over, an individual assembly of the board occurs by dividing the sub panels.

Rules To Follow In V-Scoring

Some fabricators think that the perfect size of the board is compatible with an 18”×24” sheet of CCL, but this is not so. Because the fabricator has to use some part of the sheet while processing. Both customer and manufacturer should discuss the kind of a PCB they require, besides, it should be the best.

Some Rules for Exceptional Circumstances

1. There should be zero space between two circuit boards
2. If you opt for V-scoring, your PCB’s size should be at least 75×75 mm, and it can go up to 450 x1250 mm. So, the scoring won’t be successful if the board size is not as per the rule.
3. Make sure the V-scoring path or line is straight, whether it’s continuous like end to end, or discontinuous like jump scoring.
4. For a perfect V-groove, the minimum thickness of the board should be 0.6mm.
5. You can choose the groove angles from 30o, 45o, or 60o.
6. The space between the PCB edges and parts should be a minimum of 6.35 mm
7. The minimum distance between the PC Board Fabrication outline and V-grooves’ line has to be 0.35mm.

Benefits of V-Scoring

• V-scoring helps to use a PCB surface effectively
• It helps reduce the manufacturing cost by fabricating many boards on one PCB.
• It helps to place more than one circuit through one assembly, helping in precise sub-assembly.
• V-scoring tools are cost-effective, portable, and require minimum maintenance.
• It helps save time as it allows you to separate different parts from a final assembly.

Drawbacks of V-Scoring

There are some restrictions of V-scoring like it is not suitable for PCBs with components placed near edges.
V-scoring can affect the PCB structure, reducing its strength due to the mishandling of a solder machine. However, fabricators apply jump scoring to maintain a PCB’s strength. You can read the above section to understand the jump scoring.
In the case of V grooves, you have to allow a 0.05 inches clearance between the grooves and components. The blade should not come between the components, especially for taller parts. Likewise, you should keep enough clearance for components located on the wide connection surface.

Difference Between PCB Scoring and PCB Panels With Tab-Routing

The PCB design determines if you should choose V-scoring or tab-routing. However we have a guideline for better selection, but you have to follow it.
1. The circuit board shape helps to select the right scoring. Like, V-scoring is suitable for rectangular or square PCBs, whereas the tab-routing goes well with an irregular shape.
2. You should choose a tab-routing if the components are hanging on the PCB edges. Besides, the tab-routing does not affect the edge quality. Whereas V-scoring makes edges rough.
3. V-scoring works faster than tab routing, besides, it is cost-effective than tab-routing in terms of labor.
4. At the same time, there is less wastage of material in V-Scoring compared to the tab-routing, which also reduces the total cost.
5. It also depends on the number of boards in an array and the number of PCBs in both directions, including the X and Y planes.

Frequently Asked Questions

What Is The Difference Between The PCB And PCBA?

The process is the same, but it involves two stages. Like, PCB is just a circuit board with components, whereas PCBA is an assembled board with necessary components, and it is ready for application.

What is Jump-Scoring and Its Use?

Jump scoring involves a cut that starts from one end of PCB but it stops before the other end, unlike V-scoring. Jump scoring strengthens a board for multiple processes.

What Is Tab-Routing In PCBs?

Tab routing helps you to process different circuit boards on one panel. It also helps you to isolate boards by breaking the tabs that exist between various boards.

What Is The PCB Penalization?

A process of connected small boards in a single array is called the PCB penalization. It helps fabricators to move the circuit boards while assembly.

What SMT Stands For In PCB?

SMT stands for Surface Mount Technology, and it’s a process of installing the electrical components on the PCB directly. Whereas the component installed through SMT is known as SMD or Surface Mount Device.

Final Thoughts on V-Scoring

PCB fabrication becomes economical by adopting cost-effective processes, including V-scoring. The boards with V-grooves are either end to end or side by side with adjacent edges. The groove helps break boards with a little force, and you can divide a single panel into several parts with the help of V cuts.

It involves less routing space, so you can add several rows in the PCB panel to be fabricated. It eliminates the wastage of the laminate, besides, V-grooves also save money and time by streamlining the PCB processing and manufacturing.

V-scoring helps to reduce pressure during the placement of SMD components on the circuit board by an SMT machine, and while separating the assembled PCBs.

V-scoring tools are cost-effective, portable, and require minimum maintenance. Moreover, it helps save time as it allows you to separate different parts from a final assembly.
But, V-scoring can affect the PCB structure, reducing its strength due to the mishandling of a solder machine.

Interested to know more about V-scoring or PCB assembly services, email us at sales@pnconline.com

Written by Sam Sangani

Sam Sangani is the President & CEO of PNC Inc., a Nutley, NJ based Printed Circuit Board manufacturer. Sam graduated from L. D. Engineering College with a BS Degree in Mechanical Engineering. He also continued his education and graduated from Steven’s Institute of Technology where he acquired a Master’s degree in Computer Science.

After completion of his BS, Sam worked as a QC Manager, for Xerox, Romania and London. He was responsible for the Quality Control of Cable and Wire Harness imports from Romania. After completing his Master’s Degree, he worked as a Senior Programmer with IBM, Tucson, Arizona. Sam was responsible for leading the Mainframe System Programming Team.

In 1997, Sam acquired PNC INC., a Nutley, NJ based PC Board fabrication Shop. From 1997-2013, Sam has made tremendous improvements and changes within PNC INC., as he added many new Products and Technologies in PNC’s portfolio. With his proven track record and leadership, PNC has never had an unprofitable year and has continued its growth yearly since 1997.

His current responsibilities are Strategic Planning, Corporate Management, New Business Ventures, Sales & Marketing, Trade Shows, Professional Services and leading productive teams to achieve peak potential. He has also utilized Lean Management techniques which have built a foundation for PNC’s high-paced growth. Sam also enjoys real-estate investing, web design & SEO, trading stocks, options, futures and Forex markets.