PCB Panelization: A Comprehensive Technical Guide for PCB Designers
Printed circuit boards (PCBs) play an integral role in the development of electronic components. Almost all electronic devices contain PCBs. But have you ever tried to dig deeper into the technology behind these essential components?
Unfortunately, most designers have little understanding of the PCB panelization process. This is a big miss, considering the importance of a correct design in the PCB assembly. Even a minor mistake in PCB panel design can create severe faults in the end product, prolong lead times, and hinder productivity.
This technical guide contains all the panel requirements you should know as a PCB designer.
What is PCB Panelization?
So you have just finished sketching your PCB design. You carefully placed your parts and traces to allow maximum EMI/EMC and thermal aspects. You even ensured your board aligns well with the tight enclosure of your target product.
However, you may experience a single but detrimental issue. After contacting your preferred PCB manufacturer, you realize that the conveyors of their equipment cannot handle single boards with less than a 2.0-inch conveyor width. As a solution to your problem, the salesperson will advise you to either expand it or try panelization.
Your PCB design enclosure may lack adequate margins for the expansion of your board width. Still, even if it did, the cost associated with single PCB processing may be too high for you. In this scenario, PCB panelization is the most effective and low-cost solution.
PCB panelization is a manufacturing method where smaller circuit boards are processed in a group or as one array. The technique facilitates easy movement through the assembly process. You can easily remove the individual PCBs from the array for packaging and installation purposes.
Advantages of PCB Panelization
PCB panelization enables smaller boards to fit in standard manufacturing processes and makes manufacturing more effective. The primary benefits of PCB panelization are:
- Mass production: if you want to create a large number of boards, panelization will minimize costs and condense your lead times.
- Product safety: panelization shields the board from shock and vibrations produced during assembly.
- Speed and efficiency: from paste printing to component placement, soldering, and quality inspection, it is faster and more efficient to handle several boards simultaneously.
- Standard panel sizes: it is cheap to produce PCBs using the manufacturer’s standard processing panel.
Factors to Consider in PCB Panelization Design
There are multiple factors of PCB panelization design you need to consider. In this article, we will discuss only three of them:
Circuit Board Design
A PCB design plays a major role in determining the right panelization technique you will use. Basically, you can establish the most suitable panelization technique based on the clearance size between parts and the PCB edge. Alternatively, you can consider the presence of edge-hanging factors.
Circuit board components are the essential elements of the whole panel. Every element comes with its own function. Components give the board unique features that make it suitable for its intended application. Therefore, the components you choose are as important as their placement. Highly sensitive parts and connectors play a crucial role during a breakout.
Your circuit board materials can influence the panelization method you use because some materials appear to splinter during a breakout. Another essential factor you should consider is the PCB thickness. Thin boards are more vulnerable to breakouts during PCB assembly, while thick boards are not easily broken during breakouts.
PCB Panel Design Guidelines
One of the most typical and detrimental mistakes designers make is taking primary circuit board guidelines as an afterthought. Most PCB designers only concentrate on the part selection and circuit design. Why do we consider this habit a significant problem? If you fail to dedicate adequate time and energy to the essentials of the printed circuit board layout, you will create a low-quality circuit design, which is hard to manufacture.
So how do you make a design that is digitally and physically practical? First, you should understand that there is nothing like a standard board. Every board plays a unique role in its intended application.
You should use a computer-based design system with unique design software to create your circuit patterns. You should also mark your holes’ location for contact points and parts using the design software. This mostly applies when you are using a computerized drilling machine during PCB processing.
When you complete the circuit pattern, the computer-based system will print a negative picture, often referred to as a mask, on transparent plastic material. The mask has similar size dimensions to your PCB. The circuit pattern is clear, while the non-circuit pattern areas are black.
PCB Panelization Methods
1. V-Score Panelization
Here, a circuit board is divided by a V-shaped groove. Generally, the slots consume almost one-third of the PCB thickness from the upper and lower sides. Most PCB service providers use a machine to breakout a circuit board since the remaining portions between the upper and lower grooves is considerably large. If you manually break out the section, you will apply too much stress on the PCB and adjacent components.
2. Solid Tab Panelization
To enhance the general strength of the board, you can place solid tabs between the PCBs. Nevertheless, it will be best to have laser cutting equipment, a depaneling router, or a hook-shaped device to break a solid tab panel. Solid tab panelization is not commonly used since the depaneling appliances are not as efficient as manufacturers. For example, the router generates vibrations and dust. The laser-cutter is a bit expensive and is not efficient with thicker boards.
3. Tab Routing Panelization
PCB manufacturers use tab routing panelization as an alternative to V-groove panelization. You need to pre-cut boards from the array and hold them correctly on the circuit diagram with perforated tabs. Most PCB service providers use 3-5 holes in the perforation patterns.
Tab routing panelization technique is instrumental in designs with hedge-hanging tools. In addition, it allows both manual and machine breaking.
Important Points to Consider During PCB Panelization
You should ensure that your board has adequate strength. Besides, there are other essential factors you should consider like:
Leave a gap of 0.05 inches between parts and V-grooves to avoid damaging components during breaking. If your PCB has taller components, you can increase the gaps. Besides, if your parts require bigger connection areas, position them far from the groove. Depanelization stress can break solder joints that are too close to the V-groove.
Label Placement Consideration
Tab placement is necessary for maintaining the quality of the board array design. It is advisable to place your tabs at a spacing of 2-3 inches along the PCB edge for a five-hole perforated tab. For a three-hole perforated tab, position your tabs at a spacing of 1.5 inches along the border.
Do not place perforations in the middle of the tab to avoid creating projections from the PCB sides. Instead, place them near the PCB edge.
Board Array Arrangement
Break all collinear tabs when arranging your boards. This will ensure that the break-lines are reliable throughout the array.
Issues that Commonly Arise During PCB Panelization
Even with a good PCB array design, some issues may arise during the breakout process. Here are some tips for preventing such problems:
Hand Breaking of Tabs
You can break a tab routed panel with hand tools. To avoid creating more mistakes, apply wide-nose pliers to bend checks in a break-line. Ensure you turn them in the opposite direction to detach them on the break-line completely.
You can manually break V-scored panels based on the PCB’s design and the proximity of the parts to the PCB. Use the hand-breaking method to break tabs.
You can also use a depaneling machine to break V-scored panels. The computer comes with a cost-effective blade. The primary disadvantage of this technique is that it leaves rough PCB edges.
Panel Wiring Methods
Establishing the right puzzle panel wiring technique depends on various factors like:
Your PCB shape influences the PCB panelization technique you will use. For example, use the V-scoring method for rectangular and square boards.
For boards that depend on edge-hanging parts, you should apply tab-routing panelization instead of V-scoring.
Apply the tab routing method when you need to consider the quality of PCB edges. While this method leaves some laminate cruxes, you can easily remove them with sandpaper.
Typically, tab routing is time-consuming and demands more labor. On the other hand, the V-scoring method is time-intensive since it is automated.
When you want to save on materials, apply the V-scoring method as it produces fewer wastes than the tab-routing method.
Other Considerations for PCB Panel Design
You will conduct a visual and automated quality inspection throughout the printed circuit board design and fabrication process. The checks will enable you to identify defects and resolve them before mass production of PCBs. Some of the common flaws include wrongly placed parts, excess solder, and others. When the PCBs are complete, you should also pass them through a rigorous function test to confirm whether their performance meets the specifications.
Some PCB materials contain lead – a hazardous material harmful to life when consumed in large quantities. For this reason, it is essential to put on the right personal protection gadget throughout the PCB manufacturing process. A long exposure to lead is harmful to your health.
The PCB array design plays a significant role in the overall quality and cost of the circuit board manufacturing process. That is why you should carefully consider the above PCB design considerations.
The panel requirements we have discussed above will be essential in your future PCB assembly processes. Perhaps more critical to your circuit board design’s success is partnering with a reputable and professional PCB service provider. That is where MKTPCB comes into play.