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An Overview On Printed Circuit Board Assembly

by: Jan 10,2014 1334 Views 0 Comments Posted in Engineering Technical

PCB Design PCB components Printed Circuit Board Assembly

We all know that in order for a gadget or equipment to work, it has to be connected to an electric source. However, not many of us know that in order for these devices to work, they need to have a printed circuit board. A printed circuit board or pcb is used to electrically connect and mechanically support electronic parts using conductive pathways and signal traces that are etched from copper sheets that are laminated to turn into non-conductive substrate. A pcb that is filled with electronic parts is called printed circuit board assembly. They are usually made from fiberglass or ceramics. All electronic devices or gadgets require a printed circuit board assembly in order for them to work. In addition, all electronic components of a device can’t just be put into the phone. They need a foundation to sit on and that’s how a PCB printed circuit board works. It serves as a strong base for every part and conductive pathways in an electronic gadget.

What is printed circuit board assembly, or PCBA? When we say, Printed Circuit Board Assembly, we actually refer to a working or functional PCB, which forms a functional assembly together with the electronic components. Also known as printed circuit assembly, the components connect to the board using conductive tracks and paths. The electronic components, including integrated circuits (chips), resistors, and capacitors are attached to the circuit board electrically and mechanically. The connections are generally done using surface-mount and/ or through-hole construction technologies. In fact, though mostly the surface-mount technology is used, connection is done by combining the two technologies. The reason behind combining the two is that the two technologies impart different features to the circuit board, and are used for connecting different components to the board.

In order for the printed circuit board to form, there are actually two processes that are used for it. The first process is the through-hole construction wherein the component leads are inserted in holes. The other process used in making printed circuit board assembly is the surface-mount construction in which the components are situated on pads located on the outward surfaces of the printed circuit board. These two processes have component leads where they are fixed electrically and mechanically to the board through a metal solder that has melted.

To further understand how printed circuit board assembly works, there are various methods in soldering that are being used for the PCB components to connect. When it comes to mass production of a printed circuit board, it’s crucial that it must be done through machine placement or bulk wave soldering types, to ensure that there are no mistakes in soldering them. However, if there is only a number of PCB assembly that is needed, expert technicians are able to solder very small parts by their own hand and under a microscope. This is done with the use of a soldering iron with fine tip and tweezers that are designed for small volume prototypes.

After the parts of the PCB have been soldered, it will have conformal coating that is either dipped or sprayed. This coat helps to prevent corrosion and leaking of current shorting due to condensation. It’s also important for one to know that printed circuit board assembly is very sensitive to static so it should be placed in bags that are antistatic while it is being transported or shipped. If improper techniques are applied to it, it could transmit static charge to the board and may damage the component.

Producing circuit boards is often a process that takes time and is not regarded as a “simple thing” to do. Even though, you’ll find enthusiasts who are able to make their unique boards at home with the best materials, but they normally have a tendency to be not as complex as machine made printed circuit boards. Also, it may be quite time consuming to hand make 20,000 Printed circuit boards. Below, I will briefly walk you through the actual Pcb Assembly course of action and what is required at each stage. Pcb Assembly, which also is known as Printed Circuit Board Assembly is when you will solder electronic elements to a PCB or printed circuit board. A circuit board that has not yet been assembled with the electronic components are called PCB or Printed Circuit board and when the boards have soldered components upon them, they are technologically termed as Printed Circuit Assembly or Printed Circuit Board Assembly. Needless to say circuit board assembly is not necessarily similar to circuit board manufacturing. After you manufacture PCBs, it requires multiple processes that include PCB Design as well as making the PCB prototype. Ahead of the board is often predesigned in electronics or devices, the correct components need to be added by soldering all of them upon. The kind of components together with the procedure for the actual assembly rely on the sort of circuit board it actually is, sort of electronic components that ought to be connected, as well as what electronic device the board will probably be combined with. So, after the PCB is carried out being made, it is time for the various electronic components to be attached to it so as to actually be functional.

This is certainly sometimes termed as PCBA or Printed Circuit Board Assembly. There are two forms of construction methods useful for the assembly.

1) Through-Hole building: Component leads are inserted to the holes?

2) Surface-Mount construction: Components are placed upon lands or pads on the outer surfaces of the PCB. Interestingly, throughout construction types, the component leads continue to be electrically and mechanically fixed to the PCB using molten metal solder. Depending on volume of boards that need to be assembled will determine how the components can be soldered. If it is for a substantial production quantity, then soldering components to the Printed Circuit Board is best done by piece of equipment placement. Machine placement is performed along with volume wave soldering or reflow ovens. Or else, in case the production quantity ideal for small number prototypes, soldering by hand works just fine in most cases (Ball Grid Arrays are actually impossible to solder by hand). Usually, through-hole and surface-mount construction should be performed in one PCB assembly mainly because some needed electronic components only available in through-hole packages, while others are only easily obtainable in surface-mount packages. Also, this is a valid reason to utilize each of the methods in the course of the same assembly due to the fact through-hole mounting will essentially provide more strength for the electronic components which have been more likely to bear some physical stress. Knowing that a Pcb isn’t going to go through any physical stress, then it is often techniques in order to consider less space on your board.

Starting wholly engineered over the PCB, normally it is better to examine to verify the board correctly as well as the particular functioning needed. Here I will discuss the strategy they are examined when they have been produce.

1) A fairly easy visual examination to ensure that is perhaps no electrical components abnormal on the circuit board. It is also the best time to be sure all of the soldering. (energy is off)?

2) Analog Signature Analysis: in case you applie something-limited AC sine wave throughout 2 points inside electrical components as well as circuit. (energy is off)

3) Undertaking an In-Circuit Test: investigating various physical dimensions when using the board such as current, frequency, etc. (energy is on)

4) Undertaking a practical Test: making sure the particular circuit board truly does indeed what it is intended for. (energy is on) Just in case your number of within the printed circuit boards are unsuccessful these assessments, only a few sheds. You’ll find a way to discover the location where the issue is happening and change the failing components and/or board allowing it to provide. This really is regularly generally seen to concerning as reworking. Circuit boards alongside the manufacturing process on their own account is not only complicated, however an essential part for individuals firms throughout the world. With developments within technology and capabilities of outsourcing, US symptom in the art pcb manufactures possess required to surpass to stay operating and deliver support that is unmatched to local and globally competition.

The advanced printed circuit boards assembly connections are done using high-end machine or manually. The assembly is done in stages, where one stage should be compatible with next, and there should be feedback from output to input. This ensures that problems are easily detected and the process is adjusted accordingly.

During the process, solder paste is added to the area where solder is needed. This is done using solder screen. The screen is made with the help of PCB files, and has holes wherever solder pads are positioned.

The amount of solder that is added is controlled for ensuring correct amount of solder is applied.

This is followed by placing of the components with the help of a machine at appropriate position on the circuit board. The design information of the PCB is used to program the picking and placing of components by the machine. Further, soldering or reflow soldering is done. In case of usage of solder paste, soldering is not done and vice-versa.

After this, automatic optical inspection of the boards is done. After passing the inspection, the board is tested and the output is monitored, and if failures are detected, investigations are done to find the cause of it. The assembly work is very critical as it is not just the demand which is high, but the number of components and solder joints is also very high.

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Since 2003 PCBWAY has been the leading PCB quick turn manufacturer specializing in both Prototype and Production quantities, Initially produced single-sided and double-sided printed circuit boards for the consumer electronics market. PCBWAY is ranked among the top 4 board fabricators in asia and is well-known for its expedited turn time capabilities and its reliable best on-time shipping record.

Today, we have over 450 operators with high modern facilities to manufacture multi-layer PCB up to 12 layers. Backing up with a group of professional engineers, and well established quality system. PCBWay has grown to become a major PCB manufacturer in Asia to serve in diverse customers base such as electronics appliance, communication, educational electronics, power supplies, Automationsetc.

Our mission is to become one of leading PCB manufacturer that provide in high quality product with total customer satisfaction.

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