Tips for prolonging the service life of silk inkjet nozzle of PCB

There is a case.

Phenomenon: As shown in the figure below, the zigzag deformation of the silk line is unrecognizable, and it is accompanied by flocculent dot scattered ink on the pad. The silk lines appear jagged deformation and can not be recognized, accompanied by dot scattered ink on the pad.

The reason

The investigation found that the abnormal phenomenon of ink scattering occurred in the same area on the same side. Through the investigation of this location and the corresponding nozzle location, it was found that the nozzle damage in Group 1 and Group 9 was caused.

Corresponding location

Why were the nozzles damaged?

Because the ink is in liquid state during printing, a UV light is needed to pre-cure it to make it stable. Meanwhile, a slight of UV light stablize the ink through reflection of white table. Among them, a small amount of UV light is reflected on the white table top (white contains the color of all the light in the spectrum, and generally reflects the light of all wavelengths) to solidify the ink on the nozzle, and the hole curing accumulates and blocks the hole position, making the ink unable to shoot normally, thus causing the abnormality of the silk.

In addition to routine spot check, we also need to change the color of the table on which the board is placed. It is suggested that black is the main color. This will not only improve the yield, but also prolong the service life of the nozzle and reduce the cost.