The purpose of FQC: FQC is final quality control, final quality control. In this process, the appearance of the PCB is mainly inspected.

Check the appearance, you may think that there is no process, right? In fact, there are, because different projects require different inspection methods, let’s explore together below.

1. Appearance inspection of the surface treatment of solder resist lettering.

The inspection items, as the name suggests, are related to these processes, such as ink stains, sundries, blurred and incomplete text, ink deviation, burrs and white spots on the edge of the board, uneven surface treatment, oxidation, etc., as shown below Several common types of defects. (Surface treatment does not cover exposed copper, sundries, offset of solder mask ink, incomplete text). The inspection method can be manual visual inspection (need to be equipped with standard illumination), or AVI automatic appearance inspection machine can be used for inspection. Before using the appearance inspection machine for inspection, it is necessary to make inspection data in AVI based on the data of graphics, solder mask, and text, and then the automatic inspection can be performed, and the NG points detected will be re-judged later. The picture below is a common device pattern for AVI.

2. Through-hole quality.

Through-hole inspection is mainly to check whether the through-hole is blocked (plug-in hole), whether there is plugged hole as required, etc. Usually, the inspector takes the product and inspects it against the light. Of course, it is also possible to input the drilling data through the hole inspection machine. Program, input the allowable tolerance, and then the machine automatically checks, and then manually checks the products that have detected NG, which is mainly suitable for batch orders.

3. Board bending inspection.

Board bending and warping have a great impact on the downstream placement of PCB. If it exceeds the standard, it may cause problems such as virtual soldering, tombstone, and poor tinning. Therefore, the FQC process also needs to correct the PCB board warpage. to test. The figure below is the measurement method of board warpage explained in IPC. Of course, batch products can also be automatically inspected by using the board warpage inspection machine.

Most of the appearance inspection items in the FQC process can find the corresponding standards in the IPC, but there are still some items that are not clear and need to be determined through negotiation between the customer and the supplier. The above pictures are not all unacceptable, and need to be compared The IPC standard or the judgment between the two parties, in short, whether the appearance problem can be judged, according to the application scenario of the product, the standard is relatively flexible, but the bottom line is that it cannot affect the function.