As shown in the figure below (figure 1), this printed circuit board assembly is an electronic cigarette product. Currently in the research and development stage, the picture is the second test item. Finished product as shown in figure 2.

(Figure 1)

(Figure 2)

The product has a size of about 10*44mm and is a 4-layer printed circuit board, green solder mask with white silk print.

Electronic Cigarette PCBA Features:

1. Can used with the filter to make the user have the same effect as smoking, and no harm to the body

2. You can connect to the mobile app to set user-specific preferences.

3. Set the smoking frequency according to the Bluetooth connection and slowly reach the effect of quitting smoking.

Electronic Cigarette PCBA difficulties:

A. Poor Bluetooth connection

B. Need programing and test

C. USB only recognizes one side

D. The battery always has a short circuit

E. Design the case, not too large and ensure that the battery and PCBA can fully assembled in the case.

For the first sample order, we find several problem as follows:

• The connected Bluetooth display does not respond to the green light.
• USB only recognizes one side 
• The wire inside the product is too long to completely close the case.
• The shell design has less buckle function and needs to be temporarily tied with rubber bands.
• The motor has a lot of bad contact
• Connect the wrong type hardware.
• After connecting the battery, several parts short circuit 

Therefore, we studied the above problems one by one, the process is as follows:

• The connected Bluetooth display does not respond to the green light.

It needed to add diode to control the current. Otherwise, if the current is too large, the green LED light is easily burned out without protection.

• USB only recognizes one side

USB only recognizes one side, there are similar cases in 2 sets of good 100 sets.

This phenomenon is very strange, it is reasonable to say that the USB of this C-type port should be recognized on both sides, the second side should be identify when identifying the good side. Because this USB pad is under the component itself, the soldering state is not visible to the naked eye, as shown in Figure 3. We then use the X-ray machine to detect the welding state, as shown in Figure 4. The picture shows that the welding condition is good and there is no offset.

(Figure 3)

(Figure 4)

Next, we swap the USB-related ICs and resistors with the well-tested USB products, but only recognize one side of the USB product or only recognize one side. After trying another PCBA, I found that it would not work, and the customer could not find the reason. Later, when we discussed, a person in charge of another project sent a picture to solve our problems. As shown in Figure 5, it turns out that the pad floats. Because the X-ray is taken from top to bottom, so the picture shows that the welding has no offset but is actually floating.

(Figure 5)

Therefore, we replaced the USB as shown in Figure 6, to avoid similar situations in the future PCBA mass production.

(Figure 6)

• The wire inside the product is too long to completely close the case.

After discussion, we shortened the external extension cord from 10cm to 5cm. It ensures the assembly of the outer casing is good, and at the same time ensures the convenience of the welding and testing workers.

• The shell design

The housing has less buckle function and needs to temporarily tied with rubber bands.

After discussed with the customer designer, it was found that there is no buckle function, because the final PCBA and a shell will be perfectly assembled.

• The motor has a lot of bad contact

At the beginning of the IQC, we detected the motor is not good quality, after the power turning on, some motors did not vibrate. After communicating with customers, we found that customers want to save costs, the original motor was replaced, which led to this bad situation.

Later, after consultation, we replaced the model and manufacturer that the original designer requested, and solved the problem perfectly.

• Connect wrong type hardware

The customer specifies the hardware for the connection, and the connection and picture sent are related to the model. They purchased the connection looks like the same model as the picture, so some size can not meet customer’s request.

• Battery short connect

Several circuit board are shorted after connecting the battery. During the test, we found that after the battery was connected, the product would overheat or even have a short circuit. We connect with the customer designer video to check one component. Finally, it was found that the polarity of the Zener diode was wrong.

After the above communication test, we conducted a good second PCBA production.  See the test Video at 86PCB

Although there were many problem in this process, we confirmed our professionalism through repeated communication with customers. Moreover, the designer became a good friend with our engineers. This product lays a good foundation for further cooperation in the future.