Everything You Need to Know About Circuit Card Assembly

If you are new to electronics manufacturing, you may have heard of circuit card assembly (CCA). A technique that transforms blank circuit boards into practical electronics is what powers the devices you use daily. Learning about the fundamentals will assist you in selecting superior alternatives for your projects and comprehending the significance and difficulty of assembling circuit boards. Let’s take it apart.

What is The Circuit Card Assembly?

Electronic components are combined to form an assembly called a circuit card. This PCB board enables the interconnection of various electronic components in gadgets like phones and computers. To make a working circuit, manufacturers place electronic parts on the PCB.

It involves the process of mounting electronic components such as resistors, capacitors, microchips, and connectors onto a board, creating a functioning circuit. This assembly enables the interconnection of these components, allowing electrical signals to flow between them. Circuit card assemblies are found in a wide range of devices, including smartphones, computers, and other consumer electronics, playing a vital role in their performance and functionality.

Components of a Circuit Card Assembly (CCA)

Printed Circuit Board (PCB)

Elektronische Komponenten

Onboard Connectors

● Substrat: Base material holding components; starre PCBs use fibreglass, flexible ones use Polyimide.

● Copper Traces: Conductive paths connecting components; layers vary by design.

● Lötmaske: Protective layer preventing corrosion and solder shorts.

● Siebdruck: Top layer with symbols and labels for easier component identification.

● Diode: Allows unidirectional current flow; used in rectification.

● Widerstand: Controls current flow; available in through-hole and surface-mount types.

● Transistor: Three-terminal switch; found in actuators and sensor circuits.

● Induktor: Stores energy in a magnetic field; used in power circuits.

● Kondensator: Stores energy electrostatically; used for filtering and DC blocking.

● Board-to-Board: Link two PCBs; common in modular systems.

● I/O Connectors: Interface CCAs with external devices like USB or HDMI.

● Wire-to-Board: Connect sensors and actuators via flexible wires.

● High-Frequency: Maintain signal integrity for RF and microwave connections.

● FPC/FFC: Link flexible circuits and flat cables.

Equipments & Tools Used in Circuit Card Assembly (CCA)

A soldering iron is a device utilized for joining wires and components by melting particular metals.
In reflow ovens, tiny electronic parts are attached.
Circuit boards are aligned using pick-and-place machines to position the components.
A stencil is used to apply solder paste on circuit boards in the process of a solder paste printer.
Insulators can be applied to assembled PCBs using konforme Beschichtung Systeme.
Assess electrical connections and identify issues with ICT testers. Pay attention to solder joints and the positioning of components with optical inspection systems.
Safeguards systems for toxic fumes produced while soldering and ESD-Schutz technology prevent static electricity damage.

Circuit Card Assembly Manufacturing Process

Design Validation

Check the arrangement of your printed circuit board before proceeding with assembly. Issues that may hinder the manufacturing of a product are identified through design-for-manufacturability checks.

Use of Solder Paste

The circuit board is coated with solder paste to place the parts. Considering it as setting up the groundwork for an unbreakable bond.

Placement of Components

Pick-and-place systems are machines that place ICs, resistors and capacitors onto the board. This stage is very precise and will ensure that all parts are placed where they should be.

Soldering Techniques

The act of melting a substance called solder is necessary to connect two metal parts. So, there are three typical methods of utilizing soldering, such as Wellenlöten, reflow soldering and hand soldering. Below we explain each one in detail.

Wellenlöten

Reflow-Löten

Hand Soldering

● Flux application

● Preheat the board

● Use of molten solder

● Solidify the board by cooling it

● Mostly used in through hole technology

● Excellent for large production

● It contains low failure risk

● Due to automatic process it produces highly precise components

● Solder paste application

● Use of pick-and-place machines

● Uses preheat, soaking, reflow and cooling stages

● Mostly used in surface mount technology

● Perfect for bulk production

● It containing hgh soldering skip risks

● It has moderate precision

● By using manual iron

● Risky due to human errors

● Ideal for low volume production

● Time-consuming process

● Low equipment cost

● Not suitable for large production

Inspektion und Prüfung

If any parts of the final circuit board are not present during the reflow, it will be examined to determine if they are defective or lead to loose connections. We must address these issues to pass the final exams. Among the most common ways are automatic optical inspection, manual checks and X-ray examination. Large groups of CCAs may be checked using automated optical inspection.

Final Functional Testing

Finally, a circuit board is created through functional testing. The board is evaluated to ensure its functioning is dependable. Periodic inspections are necessary during the construction of the circuit board to ensure its proper functioning. Functional tests are conducted to evaluate the PCBs electrical and mechanical functionality, and to demonstrate its practical applications.

Types of Circuit Card Assembly

1) Box Build Assembly

Box build assemblies are called combining systems. A basic PCB or CCA is enclosed as part of it. The standard box assembly incorporates a range of electronic and electromechanical components, such as heatsinks, cooling parts, Netzteile, and special cable setups.

2) Surface Mount Technology (SMT) Assembly

Electronic parts are placed directly onto a circuit board in surface mount technology. The approach facilitates the process of reducing complexity and increasing efficiency in creating small Leiterplatten. The parts are not required to be inserted into holes on the circuit board because they are directly connected to the metal areas. High-density PCBs are produced by utilizing SMT, which can be used to manufacture more intricate and smaller circuits.

3) Through-Hole Assembly

Through-hole assemblies are characterized by the use of holes in circuit boards to allow for the passage of components. When the metal parts are glued, the other side of the board is covered with solder. Double-sided boards replaced single-layer boards. Later, multi-layered boards were introduced. The use of SMT is not yet feasible in certain areas, such as through-hole assembly for transformers and electrolytic capacitors.

Comparison Chart

Eigenschaften	Oberflächenmontagetechnik (SMT)	Durchstecktechnologie (THT)	Box Build / Ball Grid Array / Technology
Komponenten	Surface-mounted	Durchgangsbohrung	Combination of SMT und THT
Platzierung	Automatisiert	Manual or wave	Both automated and manual
Kosten	High setup and low volume cost	Higher volume cost	Varies
Anwendungen	Used in Compact, and high-density PCBs	High-durability connections	Hybrid designs combining strengths of SMT and THT

Materials for CCAs

Polyimid
Bismaleimide triazine (BT
Cyanate ester

Compared to regular FR-4 laminates, these materials are more resistant to heat, have a higher glass transition temperature (Tg), and can resist breaking down at higher temperatures. The use of laminates is beneficial in challenging circumstances, such as in cars, gas stations, and airplanes.

Circuit Card Assembly Issues and Solutions

Putting together circuit boards can cause several problems. In this section, we will examine common issues and suggest ways to resolve them.

Soldering Issues

Some soldering problems include dry (not connected) soldered spots and parts not being fully sold together, and poor amounts of solder paste, or the wrong temperature used can cause problems like these.

Lösung: Altering the temperature as directed by the solder paste manufacturers is a viable solution to this problem.

Component Placement Issues

Komponentenplatzierung issues arise when parts are not aligned or lined up correctly. The cause of these problems could be either incorrect machine settings or improper placement of parts.

Lösung: You can either modify the machine’s settings or manually manipulate the parts to solve the problem.

Designing Problems

Problems with design can arise when parts are not designed properly due to a mismatch in size or rules. Errors or incomplete information about parts in the design documents could be responsible for these problems.

Lösung: There are two options available: improving the design files and repairing the component data.

Thermal Management Issues

The heat generated within the device increases as a result of the number of parts and power required. The consequence was reduced performance, decreased reliability and overheating of parts.

How is this achieved? The solution is to design the power parts separately and make them more space-efficient.

Fazit

Indeed, CCA technology has revolutionized electronics by making it possible to create compact and potent devices that are used in various applications. This has enabled the development of smaller and more powerful devices that are now widely applicable in various fields. Every system, from everyday gadgets to aircraft, relieses on CCA. They are smaller in size but still deliver exceptional performance and dependability. The use of High-density interconnect (HDI), printed circuit boards (PCB), and 3D packaging is resulting in improved designs that make devices more efficient. The complexity of circuit card assembly makes it hard to quickly manufacture a large quantity of them but FS PCBA is here to assist you. We are continuously delivering high quality excellent PCBs by using CCA process.

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