Incorporating DFM for Panelization in Your Electronics
Oftentimes, in a larger production environment, companies seek small tips and tricks along the manufacturing route in the hopes of significant cost savings. As a ‘low hanging fruit’ of costs savings, manufacturing is (or at least should be) a highly discussed topic early on in the design phase. Keeping manufacturing principles and specifications in mind at the design stage is what is known as design for manufacturing (DFM).
There are a handful of DFM practices that can lead to huge savings in the long run. My favorite DFM practice is to simply ensure early coordination with your selected manufacturer(s) in order to truly understand their capabilities, challenges, and even the way they conduct business. From there, you can begin to detect which aspects of your designs will be easy (i.e. cheaper), challenging (i.e. more expensive), and so on.
For instance, when I was designing an amplifier circuit for a speaker project of mine, I was set on a simple (or so I thought) circular printed circuit board form factor that would look awesome mounted directly behind the speakers’ driver. When involving the manufacturer early on and opening up discussions, I quickly realized that something even as ‘simple’ as a circular shaped PCB panel would incur enough cost for the design feasibility (from a profit standpoint) to significantly drop.
In the end, I opted for a more standard rectangular shape that significantly decreased manufacturing costs. Ultimately, I was able to make timely adjustments to enhance profitability and pleased with the end design and cost.
What is Panelization?
One DFM trick that folks tend to use these days is a method known as panelization. Panelization is simply when manufacturers use a single, larger substrate to manufacture and assemble multiple circuit boards at once. This is an effective technique due to the time savings associated with creating a circuit board.
Once each collection of boards is assembled on the single, large substrate, they are then depanelized into an individual circuit board. You are then left with a slew of fully assembled and (hopefully) functional circuit boards ready to be installed and sold to the world. Sounds easy enough, right? Hold your horses, cowboy. The processes of PCB panelization are employed to maximize cost savings over a large production scale but there are some important nuances involved in this process.
Example of a v-groove panel cut
Various PCB Panelization Methods
As with most things in the PCB layout universe, there are a plethora of ways to accomplish a single task. Manufacturers have their own methods and processes that will either dictate your design or send you searching for another manufacturer.
V-Groove Panelization: This process involves an angled ‘v-groove’ to be taken from ⅓ of the top of the board. The cutting is performed by a machine that performs best on straight lines. This method is best suited for a PCB array with no overhanging components, decent edge clearance, and no rounded edges.
Tab Route Panelization: As the name implies, PCB board shapes are routed out with a handful of tabs left to hold the board secure while assembling/manufacturing. This process isn’t ideal for heavier components such as large transformers, as they may make depanelization far more difficult. This method does, however, reduce stress on the board and lowers chances of splintering.
Perforated Tab Panelization: This process is similar to tab routing; however, in this technique, small holes are drilled into the tabs, which makes depanelization much easier and more intentional as you can direct the exact location of breakout. As you may imagine, this method is even less ideal for heavy components, as they may even break tabs under their own weight.
Where Costs and Challenges Come Into Play
Putting aside qualitative descriptions of how each technique is accomplished, the added costs and challenges behind each are what most folks will be searching for. Keep in mind that the more challenging you make a design, the more likely it is that the overall cost will synonymously rise.
Depanelization: When separating the assembled boards using a router, there will inevitably be particles left all over each board, which will require extra hands and time (i.e. cost) to properly remove. If a saw is your tool of choice for depanelization, keep in mind that you’ll be limited to straight lines, which may impact shape-related decisions. A laser, on the other hand, is a terrific piece of technology but will require your board thickness to be around 1 mm or less. This may again limit the multilayered boards you are allowed to use.
Break-away Holes: During most depanelization situations, you’ll likely be left with a handful of rough edges (depending on your method) especially if you are using perforated tab panelization. This will inevitably require time and effort to sand and remove, assuming your PCB isn’t designed to cause pain while handling.
Manufacturing capabilities will often determine your method of design for a specific method of panelization.
Overhanging : As mentioned earlier, you may be limited in panelization techniques depending on your choice regarding having overhanging component. These overhanging components may, furthermore, induce headaches during depanelization, as even a routing machine could knock into them, causing irreparable damage to the array of PCBs. This would incur a huge remanufacturing cost, not to mention the time lost during production.
How to Anticipate and Mitigate Potential Issues
There are a few commonly practiced techniques in the PCB design industry that actively work to subdue any potential issues far before they become actual problems.
As mentioned earlier, following DFM is the most effective way to ease your design into a cost-effective solution for manufacturing or panelization. Including the right manufacturer early on in your design stage will ensure you are meeting all their capabilities, or designing around their challenges.
Additionally, utilizing great design software will alleviate many automated manufacturing issues. Speaking in terms of panelization design; Altium Designer® delivers strong support for PCB panelization through its embedded board array feature. This feature makes it easy to define a panel of the same or different board designs. And because the source boards in the panel are linked rather than copied into the embedded array, design changes made on a source board are immediately reflected in the panel.
While there are many ways to save on manufacturing tasks, panelization certainly deserves attention as there are many ways to quickly run into higher-than-expected quotes, or worse, a non-manufacturable PCB.
Keeping some general guidelines in mind during the process will help reduce these costs and possibly save some cash while you’re at it. Ultimately, this article is one of hundreds attempting to convince you to adopt a DFM-oriented mindset during design. If you always keep DFM in mind, you will save boatloads of time while minimizing unnecessary costs and hassle down the road.
If you’re interested in learning more about how Altium Designer’s features can assist you in your PCB panelization challenges and PCB manufacturing, talk to an Altium Designer expert today.