Question 1

The advantages/disadvantages about SMT

Accepted Answer

SMT is a technology that uses electronic components to mount on the PCB.
SMT is to print solder paste on pad then place the electronic components on it. Next, we heat up to liquefy the solder paste and wait for cool down. After cool down, those electronic components will be mounted on the PCB.
SMT can make electronic product’s design become more delicate because the size of electronic components is small, this can reduce the size of PCB significantly.
SMT is suitable for PCB mass production because SMT supports automated production also the SMT production is a lot more stable than DIP.
SMT can reduce the labor cost and operating hours for manufacturing the PCB.

Question 2

The differences and application of hard gold plating and soft gold plating.

Accepted Answer

Plating gold is a type of PCB surface finish, also known as nickel gold electroplating. In the PCB manufacturing process, plating gold is to deposit a layer of gold plated over a barrier coat of nickel by electroplating.

Plating gold can be divided into ''hard gold plating'' and ''soft gold plating''. The PCB manufacturer has to take the characteristic of the two types of gold into consideration during PCB designing.

In PCB gold plating process, hard gold plating is also referred to as a plating alloy. It has been alloyed with other elements which makes it harder, whereas the soft gold plating is pure gold.

Plating gold application in PCB manufacturing. Hard gold plating is suitable for use in places where the force of friction is needed such as gold finger, keypad. Soft gold, is typically used for aluminium or gold wiring on COB (Chip On Board).

Question 3

Why does V-CUT will be added during PCB design?

Accepted Answer

Because the strength and hardness of PCB.
After finishing the pc board assembly, in order to fit the PCB into the end product. The PCB manufacturer will design V-Cut to de-panel the PCB
Those dividing lines that were cut by cutter on the PCB is called V-CUT and it is commonly seen between break-away rail and unit on PCB.
It is literally impossible to de-panel PCB with your hands.
Even if you do break the PCB manually, the electronics circuit board parts will be damaged.
When bending the PCB, the application of the force will cause PCB deformation which might result in the electronics circuit board parts cracked.
If thickness of PCB is too thin, we do not suggest to do V-CUT because it will damage PCB structural.

Question 4

Why does long stored PCB need to be baked before assembly or running through reflow oven?

Accepted Answer

The purpose of baking is to remove the moisture from the PCB.
No matter the PCB is at production site or still in vacuumed package, both would increase the risk that PCB can absorb moisture.
If PCB is stored at a bad storage condition or over storage period, these would also make the PCB absorb moisture easily.
The high temperature would cause inner board moisture evaporation when assembly the damp PCB.
The PCB will have blister or delamination due to steaming.

Knowledge