1: The higher the temperature, the cleaner the pre-treatment degreasing, but it is necessary to prevent the degreasing liquid from evaporating and exposing the degreasing parts to the liquid surface. The alkali film on the cover of these exposed parts that dries quickly is very difficult. It is difficult to remove cleanly and can easily lead to bubbling and peeling of the coating.
2: Iron materials and copper materials cannot be degreased in the same degreasing tank, nor can they be pickled, activated or neutralized in the same tank. This is because iron materials and copper ions will be replaced. , copper ions are adsorbed on the surface of iron materials, causing peeling due to poor bonding during electroplating. If it has occurred, the copper replacement layer must be stripped off in a deplating solution of sodium cyanide and anti-staining salt before plating. In a similar way, the copper pickling solution will accumulate copper ions after being used for a certain period of time. When the copper ions exceed a certain concentration, they will crystallize and precipitate on the surface of the workpiece, causing pitting after electroplating. Therefore, the copper pickling solution must be replaced regularly. .
Three: For non-ferrous metal plated parts such as copper and zinc, we generally use an alkaline solution that does not contain sodium hydroxide to remove oil by cathode electrolysis (reduction reaction, high oil removal efficiency, and does not corrode parts. The disadvantage is Steel parts are prone to hydrogen embrittlement and dust staining). For high-strength steel, thin steel sheets and spring parts, in order to avoid "hydrogen embrittlement", generally only anodic degreasing (oxidation reaction, low efficiency, highly corrosive to non-ferrous metals, can peel off a layer of material surface ). For the electrolytic degreasing of general steel materials, we first use cathodic electrolytic degreasing, and then conduct a short period of anode electrolytic degreasing, which can not only remove impurities on the surface of the workpiece, but also remove hydrogen.
Four: The most practical way to check whether the oil removal is clean is to remove the oil, wash with water, pickle, then wash with water, and then check whether the water film on the surface of the plated parts is evenly moist. If there are water droplets on the surface of the plated parts, , that is, the degreasing is not complete, and you need to continue degreasing and degreasing.
Five: When using PH test paper to measure the pH range of a solution, the test paper should be immersed in the solution being measured for 0.5 seconds. Take it out and quickly watch for comparison.
Six: Calculation formula for the actual consumption of additives --- (actual current A÷1000A) × (plating time m÷60m) × kiloamp hour consumption.