The chrome surface is the face of a gravure plate-making company, which can directly win the trust of customers for the company. The smooth chrome surface, extraordinary print resistance, and satisfactory blade consumption all have a huge attraction for customers. The chrome layer comes into direct contact with the printing material during printing and must effectively protect the copper layer from scratches and damage, so the chrome layer must achieve a certain hardness. The high hardness of the chrome layer and uniform surface hardness are key to improving the print resistance of the gravure cylinder. If the print count reaches 500,000, the chrome layer hardness should be between HV750 and HV950, and the print resistance should ideally be between 800,000 and 1,000,000 times. Many high-end plate-making companies use the German chrome plating additives provided by MaiTuo Technology.chrome plating additivesgood wear resistance and chemical stability, thereby improving the print resistance of the printing plate cylinder, allowing it to withstand frequent friction from the ink blade and pigments in the ink. Currently, gravure plate-making companies across the country deeply feel that the quality of chrome plating is an everlasting issue and a major factor causing rework. There are many complex factors affecting the quality of chrome plating, closely related to the hardness of the chrome layer, temperature, current density,chromic anhydrideand the content of sulfuric acid. In summary, the author believes there are three main influencing factors: first, poor conductivity; second, unstable chrome plating solution; third, inadequate cleaning. Some companies have established quality standards and control data, but employees do not execute them carefully and strictly, leading to rework. Therefore, it is necessary to strengthen management and implement strict controls.

Strengthen cleaning management

Before chrome plating, the cylinder should be thoroughly cleaned to remove any oxidized impurities from the copper surface, and there should be no rust stains. This is an important step to ensure the quality of chrome plating. If cleaning is not thorough, it can easily lead to chrome peeling failures. The manual cleaning of the cylinder is divided into the following steps.

(1) Mix powdered cleaning agent with water to form a paste, and scrub with a sponge (5-10cm thick).

(2) Rinse with tap water.

(3) Neutralize with 3%-5% sulfuric acid (H₂SO₄) to increase activity.

(4) Rinse thoroughly with distilled water.

(5) Electrolytic degreasing, which is an important step involving both anode and cathode degreasing. The anode current density is 1-5 A/dm², and the cathode current density is 5-7 A/dm². The degreasing solution consists of three components: first, sodium hydroxide (NaOH) 7g/L; second, sodium carbonate (Na₂CO₃) 20g/L; third, trisodium phosphate (Na₃PO₄) 20g/L. The time is: anode 1 minute, cathode 6 minutes, anode 1 minute, totaling 8 minutes. It is standard to change the bath solution once a week.

(6) Finally, neutralize with 3%-5% diluted sulfuric acid (H₂SO₄) and then rinse thoroughly with distilled water before proceeding with chrome plating.

  Regarding the choice of cleaning agents,MaiTuo Company has specifically developeda dedicated cleaning agent for gravure copper layers,which isthe top choice for many plate-making factories.This cleaning agent uses imported raw materials, mainly composed of anionic and non-ionic surfactants, efficient cleaning agents, and roughening agents,which can effectively remove grease and also roughen the surface of the workpiece to a certain extent, improving the bonding strength of the subsequent coating with the copper layer. It has slight polishing ability on the copper layer surface, effectively removing fingerprints, watermarks, and other corrosion, improving the local quality defects of the subsequent coating, and also extending the service life of functional coatings.