If you’re like any designer, you’ve probably spent more time than necessary trying to hammer out all the kinks of your printed circuit board before you go into making your device. But, especially if you’re not particularly part of the industry, you might wonder how exactly the “printed” gets put into the “printed circuit board”. After you’ve spent time learning the particulars of PCB design and laying out your new dream device, it’s time to bring your board to life.
If you start searching the internet for manufacturers, you will find a long list of companies with varying capabilities, prices, and turnaround times. Production sizes, printing costs, electronic component listings and necessities for audits, suppliers, and turn-around times all may vary.
So how do you pick the right manufacturer for your needs? There are several variables to consider when deciding on a manufacturer and your order size. All manufacturers follow a similar process, but not all manufacturers have the same capabilities or prices.
So You’ve Decided to Print Your Board. Now What?
If you have your heart set on manufacturing your device, it is best to take some time to learn design for manufacturing (DFM) and design of assembly (DFA) practices while you are still in the design phase. Most manufacturers can produce simpler boards without undue costs. Taking some time to learn DFM and DFA practices based on your manufacturer’s capabilities will help prevent delays, redesigns, and unexpected costs.
The next critical question involves quantity. How many boards do you need to order? Do you need them tomorrow, next month, or can deliveries be staggered? Should you order a small prototype run first? These are important questions that can have a big impact on your schedule and your wallet.
Many manufacturers will provide a short-run of PCBs. Their costs vary by geography, manufacturing capabilities, and board complexity. If you live in a moderately sized city, you can likely find a local manufacturer that you can speak with in-person. Short-runs are useful if you want to use a small group of devices for testing, if you want to get opinions about your device from beta users, or if you just want one or two for your at-home purposes.
If you are intending to start selling and distributing your device to wider audiences, you will need to order from a large-run manufacturer. Your fabrication and assembly costs per board will be lower when you order a large manufacturing run. Ordering a large-run is only a good idea if you have already thoroughly tested your board as a prototype. If you order prototypes and thoroughly test them before moving to full production, you’ll have an opportunity to change your design if needed.
If a company is going to charge money for a large manufacturing run, then it needs to work correctly and that will involve testing prototypes in-house. Aside from allowing you to perform some redesigns, prototypes also allow manufacturers to ensure that the fabrication and assembly processes can produce defect-free boards. Some manufacturers will also run basic in-house testing on your prototype.
What Does PCB Manufacturing Look Like?
Once you get your design finished, you’ve validated it with simulations, and you’ve located a manufacturer that can produce the quantities you want, it’s time to prepare your manufacturing outputs. Your manufacturer will need certain documents generated from your design. These documents include Gerber files, Excellon drill files, a CAM draft of your design, and a bill of materials. Your manufacturer will tell you what information they need to plan out the fabrication and assembly process.
Once you get your design to the point where you want to order prototypes, you will need to supply several pieces of information about your design to your manufacturer. Whether you’re manufacturing the next great smartphone or something much simpler, this requirement goes above and beyond the board layout. Your manufacturer needs manufacturing specifications, component sourcing information, suitable component substitutes, and much more.
Some manufacturers will actually give you a discount if you perform DFM checks in advance, as this prevents the manufacturer from having to make last-minute changes to your design to accommodate your order. It also allows you to address any design issues before your information gets sent to the fabrication house.
If you are interested in ordering a larger fabrication run, the last thing you need is to receive your finished boards, only to find that they do not meet your specifications. It is a good idea to order a short run first and check that this short run meets your design specifications. This gives you the chance to implement any last-minute critical redesigns before ordering a large run.
Fabrication and Assembly
Fabrication houses need your manufacturing outputs so that they can build a step-by-step process to build your board. It’s okay if you are not familiar with all the steps involved in fabricating a PCB, your manufacturer will determine the best process to fabricate your board that fits within their capabilities. Your manufacturing outputs will help your fabricator determine the best fabrication process for your circuit board.
Designers that are serious about manufacturing PCBs will panelize their boards, even if they are only purchasing a small run. This involves arranging your PCB into a pattern (called a “panel”). These patterns are arranged through your PCB layout on large boards to have the fabrication house cut or rout the boards from the panel. This increases the number of boards you can manufacture at one and reduce your costs for production.
Once your boards are fabricated, it’s time to assemble components on your board. If your manufacturer will also perform assembly, the manufacturer will be working off of your bill of materials. This document contains component sourcing information, cost estimates, and any suitable replacement components. Effectively, it should serve as a one-stop source for your circuit board’s electronic component needs.
Problems with manufactured boards come primarily from design mistakes, poor communication with your manufacturer and plain old carelessness on the part of manufacturers. Only two of these things are within your control. But, paying enough attention through the start of your manufacturing process will (hopefully) ensure that enough attention is paid from your manufacturer’s end on your circuit board and all required packaging.
Some design choices can incur significant costs and lead to serious design headaches if you don’t communicate with your manufacturer early in the design stage. Even the shape of your board can incur design costs that suddenly make your board unaffordable. Communicating with your manufacturer about how your device can be designed to match their capabilities lets you consider redesigns before your first quote and manufacturing run.
An experienced manufacturer should be able to identify common assembly issues before they begin a manufacturing run. As a typical example, unevenly applied solder paste and slightly misaligned components can lead to tombstoning while soldering components, causing your components stand up vertically and leave an open connection. If your manufacturer can identify problems like this and warn you ahead of time so that you can implement any redesigns as necessary.
No two manufacturers are the same, and finding the right manufacturers can help alleviate all these issues. Not all fabrication houses will offer to help you complete a PCB project from start to finish. If you can find a manufacturer that is prompt with client communications, can point out design issues before fabrication and recommend the best redesign steps, you will increase your chances of receiving the best boards on your first run.
From Beginner Board Design to Advanced PCB Layouts
More complex board designs like rigid-flex and multi-layer PCBs have a more extensive manufacturing process. Both types of boards are becoming the standard in a number of applications. Since these boards are more specialized, they tend to have higher costs and longer turnaround time.
Multi-layer boards allow connections to be routed below the surface layer, allowing you to increase your connection and component density. Fabricating a multi-layer board is similar to fabricating multiple single layer boards and the layers are overlaid and bonded together. Connecting to internal layers requires placing vias at certain points in each layer. Your manufacturer will have certain requirements on how vias should be used in your PCB.
Rigid-flex boards use a flexible conductive ribbon to connect two or more PCBs, and these boards can be used in more complex packages. The important manufacturing step involves applying a coverlay over the flexible part of the circuit, which shields the circuit from damage. As a designer, there are certain design rules you should follow if you when laying out the traces in your flex ribbon.
Just as is the case in fabricating a simple board, your manufacturer should be able to identify any design issues in more advanced boards that will create manufacturing problems. This is where communication with your manufacturer during the design phase is crucial. This gives you the opportunity to understand any design constraints before you finish designing your board and send it to your manufacturer.
If you aren’t a PCB or electronics design guru with a huge budget, you should consider using browser-based design software. With built-in component generators, automatic routers, and an intuitive user interface, IoT 360 helps you streamline your design process without breaking the bank. IoT 360 has a ton of options and allows you to export your manufacturing outputs in an industry standard format.