From kitchen gadgets to games to smartphones to cars, we use devices every day that contain electronic components. Those components are assembled on a printed circuit board (PCB), also known as a circuit card assembly (CCA), during the manufacturing process. The market value for PCBs is projected to be USD 75.72 billion by 2026, registering a CAGR of 1.53% from 2021 to 2026. Let’s take a look at what goes into the multi-billion dollar circuit card assembly process.
1. Circuit Card assembly manufacturing process: PCB assembly is not PCB fabrication
How is a fabricated board different from an assembled one?
Fabricating a PCB and assembling a PCB are two separate processes.
PCB fabrication is the first part of the production process and starts with circuit board design, followed by its production and testing.
At the fabrication stage, the PCB consists of a flat sheet of insulating material and a copper foil layer laminated to the substrate. The flat sheet consists of several layers.
At this stage, it is a bare circuit board that is a blank canvas! There are no electronic components—capacitors, inductors, transistors, and resistors—that make the gadget work. Components are soldered to the board at the PCBA or circuit card assembly stage.
The PCB assembly process (PCBA) transforms the bare circuit board into a functioning unit by soldering the components onto the board. But first, a DFM review (Design for manufacturability) ascertains that the PCB design is, in fact, manufacturable. Doing this cuts costs and eliminates unforeseen delays due to design issues that would require re-engineering.
Next, a process called surface encapsulation assembles all electronic components on the circuit board. Manufacturers use mounting technologies like Through Hole Technology (THT), Ball Grid Array (BGA), or Surface Mount Technology (SMT) to place and solder the components to the board. A thorough quality check follows to ensure proper component alignment and integrity of all joints.
Both PCB fabrication and PCB assembly must be undertaken by a reputed, experienced PCB manufacturer to maintain quality and reliability. Any faults or errors in these processes cause the device to fail or malfunction. Error-proof fabrication and flawless assembly together is the key to a successful electronic device.
2. SMT, THT, BGA: Which mounting works best?
In PCBA, placing and fixing small electronic components is a critical operation. Of the options available–SMT, THT, BGA–what works best? Let’s understand each of these methods a little more in detail:
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SMT is a technique used for mass production. An automated machine picks up the surface mount devices (SMD) and places them on the board’s surface, fastening them with soldering paste in a reflow oven. In SMT, components can be placed on both sides of the board, so SMDs take up less space on the circuit board, making it easier to manufacture more compact PCBs.
Ball Grid Array (BGA)
BGA is a type of surface-mount packaging used mainly for integrated circuits and microprocessors, which require permanent mounting using a grid of solder balls on pins under the components. BGA boards have more interconnections than standard PCBs allowing for high-density smaller boards like those in CPUs or mobile phones.
Through-Hole Technology (THT): In this technique, components with leads or wires run through holes drilled in the board. The extra lead part is soldered manually or by using a wave soldering machine on the other side of the board.
So which works best? For high volume production, SMT is usually the best choice. SMDs take up less space on a board and are conducive to automated picking and placing. SMT also lets you place components on both sides of the PCB.
BGA packages are suitable for cases where the assembly must be thinner with the denser placement of electronic components–for example, integrated circuits.
For low-volume production or prototyping, THT may work best. It is also more suitable for front connectors. It may, however, have limitations on multilayer boards.
3. Soldering—the most crucial step in circuit card assembly
Why is soldering the most crucial step in the circuit board assembly process? Because a soldering flaw can cause the device to malfunction or fail. Different soldering techniques come into play depending on the mounting technology adopted.
Soldering Surface Mount Components: The first step in SMD soldering is to apply solder paste to the board with great precision. After mounting, the board goes through a reflow oven on a conveyor, and the solder paste melts to create strong solder joints. The board is then visually inspected by AOI (Automated Optical Inspection) machines to check that joints are correctly soldered. Faults are corrected using manual soldering.
Wave soldering for high-volume THT: When production volume is high, and there are many through-hole components, wave-soldering is the right choice. The process uses a pool of liquid solder to stick metal parts to the bottom of the board. A solder mask prevents the solder from sticking to areas where soldering is not required.
Manual soldering is ideal for prototypes and low production runs. Set up and configuration costs of automated machines are too high at low production volumes. Manual soldering, however, works well for intricate work in small areas where the use of automated machines is problematic.
Modern factories use automated IoT devices for testing and quality control throughout the soldering process. X-ray machines come into use in cases where the solder joints are not visible.
4. Benefits of using a turnkey circuit card manufacturer vs. consignment assembly
OEMs prefer to work with one-stop PCB assembly manufacturers to provide services at every production stage.
There are many advantages to using a single company end-to-end.
- It is cost-effective: With all processes under one roof, there are no shipping costs and Bill of Materials (BoM) costs are optimized.
- Quality assurance: With multiple vendors, errors at one stage may not get communicated to the next, leading to quality issues in the end product. Who is at fault can end up in a time-consuming finger-pointing match that usually ends with no clear party to blame—and therefore no clear recourse to fix the situation. This usually translates into added costs. A single company avoids this situation, with all responsibility resting on one shoulder and quality assured at each stage, correcting errors before proceeding to the next.
- Single point of contact: When you have a single point of contact, not only does this smooth out kinks, but there is better collaboration between designers, engineers, and testing teams.
- Faster go-to-market: When you work with a single partner, there is better collaboration, greater control on quality, accessible communication, no transit time between phases.
If you choose consignment assembly, you are responsible for a large part of the process, including parts procurement, ordering, warehousing, inventory management, right up to packing and shipping. Whew!
That’s why electronic manufacturers prefer engaging PCB assembly companies like MIS Electronics that provide end-to-end services. MIS is committed to fulfilling customer requirements in a way that exceeds expectations.
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When looking for a circuit card assembly provider, the biggest question is whether to go with a local Canadian company or an overseas manufacturer.
Many assume that choosing an overseas manufacturer will keep costs down. While this may or may not be true, you may end up with a low-quality product that costs you more in the end. Additional charges such as shipping, import duties, and taxes offset initial apparent savings.
Choosing a local Canadian PCBA manufacturer like MIS Electronics means you get a cost-effective circuit card assembly and an end-product that meets our highest-quality standards. When you take the five points mentioned in this post into consideration, it becomes obvious that time, quality, and cost savings are gained by choosing a reputable turnkey PCB supplier to handle your circuit card assembly. With MIS, you enjoy a great experience from start to finish that ends with a product you’re proud of that brings peace of mind to you and your customers.
Get a free quote from MIS Electronics today, your one-stop PCB shop.