Handling of common abnormal problems in screen printing process

Common problems of silk screen printing :

Bonding sheet.

a) The screen height is too low or the screen variables are insufficient, the adjustment method: increase the screen height, increase the pressure

b) When lifting the screen and changing the pressure is invalid, you can loosen the limit screw on the top of the print head and turn the knob counterclockwise to readjust the pressure and the height of the screen.

Incomplete printing/virtual printing.

a) Incomplete printing is usually manifested as the height of the screen is too high. At this time, reduce the height of the screen appropriately

b) Appropriately reduce the height of the feed plate to avoid excessive adjustment and damage to the screen

c) Virtual printing is a form of incomplete printing. Virtual printing is mainly caused by poor slurry permeability or partial blockage of the screen. The printing pressure can be appropriately increased and the printing speed can be reduced.

d) Treatment of poorly printed products: When the back electrode and the back electric field are slightly incompletely printed, use the broken silicon chip to take the pulp to supplement the unprinted position. When the incompletely printed area is large, use the waste silicon chip to remove the backside as much as possible. If the printed paste and the reprinted positive electrode are incompletely printed, reprint directly.

Cut off the fence.

a) Generally speaking, wipe the screen with a cleaning cloth to return to normal

b) The broken grid of slurry permeability and virtual printing performance can extend the mixing time and change the slurry dilution. When printing, you can wipe the screen with terpineol, and wipe the upper and lower screens of the virtual printing dots with a clean cloth.

c) Too high a screen is also an aspect of network disconnection, which is similar to incomplete printing.

Raw edges.

Burr refers to that the edge grid printing is not smooth, it is fluffy, and the fluffy part is printed with excess paste.

a) Adjustment method: increase the screen version, and the adjustment range is large, and the effect of slight adjustment is not obvious

b) If the screen is too low, it will also cause burrs. The difference lies in the direction of the burr-like deflection, which is usually biased towards the liftable screen inside the battery panel, and the height of the screen can be appropriately lowered if the screen is biased towards the outer edge of the battery panel.

Background printing quality.

Several problems in background printing: uneven thickness, thick edge printing

a) The uneven thickness here shows that the printing humidity near the back electrode is very high. The main method now is to maintain the uniformity of the printing. The stability of the device electrode is also an important aspect to ensure that the printing table will not shake during printing.

b) The adjustment method of the edge printing thickness includes increasing the screen (decreasing the height of the squeegee and increasing the pressure have the same effect) and replacing the squeegee.