1、 Copper foil pinhole and penetration point exceed the standard

main cause:

(1) The cleanliness of electrolyte exceeds the standard, and there are oil, glue and other pollutants;
(2) There are pores or inclusions on the cathode surface;
(3) There is dirt on the cathode surface;
(4) Serious glossy copper powder;

Treatment measures
(1) Strengthen filtration;
(2) Replace filter element or filter bag;
(3) Add or replace activated carbon;
(4) Replace cathode roll or grinding roll;
 

2、 Crater and scratch

main cause:
(1) During edge stripping, copper particles enter the stripping roll and other moving rolls and copper foil to produce indentation. If they enter the idler roll (guide roll that should rotate but not rotate) and copper foil, they will produce scratches.
(2) During edge stripping, copper particles enter the surface of the attached copper foil and get involved in the copper foil roll, resulting in copper foil indentation.
(3) Indentations and scratches caused by foreign sundries are mainly large dust in the air and sand dust falling from the vibration of the traveling crane above the raw foil machine.
Treatment method: For pits and scratches, only dry towels or brushes can be used to clean the guide rollers that produce pits or scratches. It is recommended to clean every 5 minutes during the period of high incidence of faults. Technically, all guide rollers in contact with the copper foil should be rotated as far as possible through technical transformation to eliminate the occurrence of idle rollers and minimize scratch defects.
 

3、 Chromatic aberration

The so-called color difference refers to the inconsistent color of the foil surface. Speckles, ribbons, stripes, etc. can cause color difference on the foil surface. The reasons for color difference production are quite complicated, mainly due to:
(1) The pickling and water washing of the raw foil before (after) stripping from the cathode roll surface is not complete;
(2) The gap between the pressing rollers of the green foil machine is not appropriate;
(3) The acid fog is serious on site, causing a large number of acid fog spots on the foil surface;
(4) Cathode roll surface oxidation;
(5) The raw foil is not dried thoroughly, and the surface of the raw foil is oxidized;
(6) Anode damage;
(8) The washing water is too small, and the electrolyte is not washed clean, which results in the crystallization of electrolyte on the foil surface;
(9) The washing water is polluted, and dirt, oil corrosion, corrosives, salts, grease, etc. may cause color difference on the foil surface;
(10) Mercury pollution. For enterprises that use mercury to conduct electricity, a large number of mercury spots are also a major reason for the color difference on the surface of copper foil.
Handling method:
The causes of color difference shall be analyzed and targeted measures shall be taken. For example, if there are regular brown ribbons on the rough surface of the raw foil, it may be that there is a gap between the press roll of the raw foil machine, which causes the washing water to enter the electrolyte. The press roll should be repaired and adjusted.
 

4、 Fatigue ductility

The low concentration of Cl ion in acid sulfate copper plating solution is not only used as a depolarizer and leveling agent, which is beneficial to obtain better ductility; Moreover, it will also strengthen the crystallographic preferred texture, resulting in a reduction in ductility. On the other hand, too high concentration of Cl ion will lead to the formation of pinholes in the copper coating, which will greatly reduce the ductility of the coating.
In actual production, if problems are found in the ductility and fatigue ductility of copper foil at room temperature and 180 ℃, according to the above analysis, first check whether the Cl concentration in the electromechanical solution of raw foil exceeds the standard; Secondly, check the organic impurities in the electrolyte. If they exceed the standard, they can be filtered by activated carbon adsorption; Then check the additives, Cu, H2SO4, temperature and flow rate.
 

5、 Edge tearing of copper foil

The main reason for the edge tearing of copper foil is that when the foil is peeled off from the surface of the cathode roll, the bonding force between the copper foil and the edge of the cathode roll is too large. On the one hand, because the cathode roller is fully energized and immersed in the electrolyte, it is inevitable to deposit electrolytic copper layer on the end of the roller, which makes it difficult to peel the copper foil on the edge of the roller surface. On the other hand, the poor polishing of the cathode roll edge, the damage of the right angle at the end of the roll surface, and the low end grinding finish will also cause the excessive bonding force between the cathode roll and the copper foil at the edge of the roller.

In order to solve the problem of copper layer deposition at the edge of the cathode roller, the end of the cathode roller is generally sealed to prevent the electrolyte from contacting the end of the roller to reduce copper deposition.
The end sealing of the cathode roll seems to be a trivial matter, but in fact, it is a big problem related to whether the production can be carried out normally. If the sealing is not good, the electrolyte can enter the end face of the cathode roller through the gap, where it is electrolytic deposited. Due to the tip discharge effect, loose copper particles (also called copper beans) are formed on the edge of the copper foil. Since the copper particle is much thicker than the copper foil, and the adhesion is perpendicular to the stripping force of the copper foil, it is like a nail to nail the copper foil on the cathode roll surface. When the copper foil is peeled from the cathode roll, if the strength of the copper foil itself is less than the adhesion of the copper bean on the cathode roll, the copper foil will tear from the vicinity of the copper bean, resulting in edge tearing. If the copper bean is small or the adhesion of the copper bean on the cathode roller is less than the strength of the copper foil itself, the copper bean will be brought down from the cathode roller by the copper foil during stripping, forming burrs, and the burrs (copper beans) will fall on the copper foil, causing pits and indentations. Large copper beans are brought down. If they fall into the anode slot, they will cause shock rolls.
 

6、 Area mass deviation

Causes and solutions:
(1) Calculation error;
(2) The anode is severely damaged or deformed. For DSA titanium anode, if the coating falls off partially, the area of copper foil at the cathode corresponding to the falling off part will be small and thin; If it is a lead anode, due to deformation, some positions will bulge, resulting in a smaller cathode anode distance, an increase in current, and an increase in copper foil thickness. The titanium anode is partially damaged, which can be temporarily solved by shielding the anode, but the anode must be replaced fundamentally; Lead anode deformation is generally corrected manually online, and if it is serious, the anode needs to be removed and corrected through special equipment.
Individual rectifier cabinet trips. Due to the current high current electrolysis, 2-4 rectifier units are generally used for power supply, and each rectifier unit provides 12500A current. If one of the rectification units cannot work and the operator fails to find it in time, it may also lead to deviation in the quality of the copper foil area.