There are many benefits to shopping online, and no one can dispute that having the ability to order food and supplies during the pandemic has been convenient. But there is one thing that online shopping can take away from consumers if they aren’t careful, and that is the ability to comparatively shop. It can be effortless to simply choose the first item in a search browser instead of physically examining the different things in a store for the best price.
There can also be different prices for the circuit boards that you want to be fabricated. Many variables can affect how much it will cost to have a raw circuit board fab built, and those prices can also change depending on which vendor you use. We’re going to look at some of these variables and how you can control PCB fabrication methods to reduce supply chain costs.
Circuit Board Fabrication Details that Can Affect Costs
Many circuit boards use the same materials and will even look similar to each other, but the truth is that each board is often very unique. And while a circuit board’s ability to be fabricated differently to fit diverse applications is one of its key attributes, it also directly impacts its cost. Consider the following:
The size and shape of the circuit board
A larger circuit board compared to one that is smaller will cost more simply due to how much material is required to fabricate it. The more contours, slots, and cutouts that have to be formed to create a specific board shape will also add to the final cost.
The number and configuration of the layers in the board
The more layers added to the board, the more it will cost. There is a big jump in price going from a double-sided board to a multi-layer board, after which the cost increases incrementally with each added layer pair. However, a multilayer board’s additional cost needs to be balanced against the board’s performance needs, which often require a specific amount and configuration of layers. Signal integrity considerations often require specific layer stackups for technologies such as controlled impedance routing. Stackups alone can add 20 to 30 percent to the cost of fabricating the board.
The materials used to fabricate the board
There are many different materials used in PCB fabrication, with the most common being epoxy resins like FR-4. Depending on the need, there are many others to choose from, and those usually come at a higher price. There are enhanced epoxies that are better suited for high-speed designs, polyimides that are more durable for harsh environments, PTFE or Teflon used in high-frequency RF applications, and flexible materials for flex circuits.
In addition to these three areas, there are many other aspects of circuit board fabrication that can affect the final cost. These would include whether or not the circuit board rates as RoHS (reduction in hazardous substances) compliant and the type of finishes used on the board.
While many of these costs will be dictated by the circuit board’s performance and operational requirements, there are some ways to reduce costs.
PCB Fabrication Methods to Reduce Supply Chain Costs
The first action to lower costs is to ensure that the board is designed for efficient fabrication. Design for manufacturability (DFM) is a well-known concept, but it is broken up into several sub-categories; design for assembly (DFA), design for test (DFT), and design for fabrication (DFF). Many details should be accounted for during design that can help facilitate the fabrication process:
- Trace widths and spacing: Not every board needs the narrowest lines and spaces. These will contribute to a higher fabrication cost and should be avoided when possible.
- Via types: Blind and buried vias will add a lot to the fabrication cost of the board. Avoid using them if they aren’t required for signal integrity or routing density.
- Routing zones: If you don’t need traces and metal fills next to the edge of the board or slots and cutouts, don’t put them there. They can add to the complexity of fabricating the board, which could lead to higher costs.
- Layer configurations: As we stated earlier, multi-layer boards are often necessary for routing densities, signal integrity, and special needs such as controlled impedance routing. If those aren’t a requirement on your design, remove those fabrication requirements and lower the layer count if possible.
In addition to designing the board for more efficient fabrication, there are other things that you can do to help control costs. For instance, make sure that the board is panelized correctly. Smaller circuit boards are usually fabricated in a production panel that will hold multiple boards. If the individual PCBs aren’t configured efficiently in the panel, or the customer requests that they be built as a single unit, they will cost more to build than larger boards.
Another impact on the cost of PCB fabrication is the volume that the boards are built. It takes time for the fabricator to set up for each run of a new board, and they will charge less if a higher number of boards can be built at one time. While this isn’t applicable for a new board prototype, the customer should plan on ordering a high enough volume of boards during production to reduce the overall cost. Knowing where to find all of the various expenses associated with PCB fabrication is the key to cutting costs. Here is where partnering with someone experienced in PCB manufacturing can be useful.
Working with the Right PCB CM to Help Choose the Right PCB Fabricator
To get an exemplary circuit board built requires working with the right PCB fabrication shop, but making the best choice among fabricators can be daunting. You have to ensure that they have the capabilities and experience for the job while at the same time confident that prices are competitive The printed circuit board contract manufacturer who will be assembling your board can assist with those assurances.
PCB CMs work with circuit board fabricators regularly to build the boards that they will be assembling. They understand the circuit board requirements and the capabilities of the fabricators to get the best results. They can advise you of the best design practices to cut fabrication costs and choose the best PCB fabricator for the job.
At VSE, we regularly work with several PCB fabricators and will explore new alternative sources as needed. Our quality management systems require that the fabricators we work with are ISO compliant. We conduct a site survey of them and validate the first article produced with a rigorous cross-section examination. We will go the extra length to ensure that your circuit boards are fabricated by the best to function as designed.
