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Aluminum alloy dyeing common problems and solutions

  • goldapple-alu
  • 2018/12/03
  • 200

Goldapple-alu aluminium extrusion manufacturers supplies aluminium track, aluminium tube, aluminium moulding profiles, aluminum heat sink and so on in the global market. In the meantime, we are also provide some technical information to avoid customer's doubts. For exempla, here are some common problems and solutions about aluminum alloy dyeing.


First, dyeing is not colored

  1. The anodized film thickness is insufficient. The solution is to check whether the anodizing process is standardized and whether the temperature, voltage, and conductivity are stable. If there is any abnormality, please adjust the specification accordingly. If there is no abnormality, the oxidation time can be extended to ensure the film thickness is up to standard.
  2. The pH of the dye solution is too high. At this time, the pH can be adjusted to the standard value with glacial acetic acid.
  3. After the oxidation, the workpiece is placed in the water tank for too long. It is recommended to dye in time. If this has happened, the workpiece can be dyed in the anodizing bath or in the nitric acid and in the tank, and then dyed, the effect will be very good.
  4. Improper use of dyes. A suitable dye is required.
  5. The dye has been decomposed or mildewed, and the dye needs to be replaced at this time.
  6. The oxidation temperature is too low, resulting in a dense film. The oxidation temperature can be appropriately increased.
  7. Poor electrical conductivity. Poor contact in the anode copper rod or cathode lead plate may result in poor conductivity in the batch. Pay attention to cleaning the anode copper rod and the cathode lead plate to ensure good contact.

Second, white spots, white

  1. Washing is not clean and should be washed.
  2. The water used for washing is too dirty, easy to contaminate the film, at this time should replace the water to ensure the quality of washing.
  3. The oxide film is polluted by smoke, acid and alkali mist in the air. Strengthening water washing, timely dyeing, and timely transfer can greatly alleviate this symptom.
  4. The oxide film is contaminated by oil stains and perspiration. The protection must be strengthened and the appearance of the workpiece must not be touched by hand.
  5. There are undissolved impurities in the dyeing liquid, which are contaminated by oil and destroy normal dyeing. At this time, the dyeing solution should be filtered or replaced.
  6. There is residual acid in the gap and deep hole of the workpiece, and the workpiece should be washed with water.
  7. The dye solution is contaminated by Cl-, causing pitting corrosion on the dyed workpiece. At this time, the dye must be replaced. Attention should be paid to avoid introducing impurity ions during the operation.

Third, the color is light, the color difference

  1. The thickness of the film is not uniform. The possible reason is that the temperature and concentration of the anodizing bath are not uniform, and the bath should be stirred by compressed air to solve such problems.
  2. The dyeing temperature or concentration is uneven. A stirring process is introduced.
  3. The dyeing speed is too fast. The bottom of the workpiece enters the dye liquor first and then leaves the dye liquor, so the bottom is easier to dye. The solution is to dilute the dye and extend the dyeing time appropriately.
  4. Poor electrical conductivity. It is possible that the hanger is loose, and paying attention to it can avoid such problems.
  5. The dye is too thin, can add dye to increase the concentration.
  6. The temperature of the dye solution is too low. The dye solution can be warmed to below 60 °C.


Fourth, dyed hair, escape color

  1. The cleaning is not clean. Washing should be strengthened.
  2. The dye is not dissolved properly, or there is an insoluble dye floating, which is easy to produce chromatic aberration. The solution is to improve dye dissolution.
  3. The pH of the dye solution is low, and it can be adjusted to the standard value with dilute ammonia water.
  4. The dye is not completely dissolved, and the dissolution is enhanced to completely dissolve.
  5. The temperature of the dyeing solution is too high to lower the temperature.
  6. The pores of the oxide film are small, because the oxidation temperature is too low, and the film is inhibited from being dissolved by sulfuric acid, and the oxidation temperature can be appropriately adjusted to avoid this problem.
  7. Dyeing and coloring are too fast, and the dyeing time is too short, the dilute dyeing solution can be adjusted, the dyeing temperature is lowered, and the dyeing time is appropriately extended.
  8. The sealing temperature is too low and the temperature is solved.
  9. The pH of the plugging solution is too low and is adjusted to the standard value with dilute ammonia.
  10. The dyed surface is easy to wipe off. The main reason is that the film is rough, generally caused by too high oxidation temperature. Care should be taken to control the oxidation temperature within the specification.


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