The poor quality of the plating is mostly caused by plating conditions, abnormal plating equipment or electroplating syrup, and human negligence. It is usually easier to find out the cause when the site is bad, but it is more difficult after a period of plating. However, in the future, it is necessary to pay attention to the contact with sour gas, oxygen, water, etc. in the environment to accelerate the oxidation and corrosion. The following chapter will discuss the causes of the poor plating and the countermeasures for improvement.
1. Rough surface: refers to uneven, non-bright surface, usually rough white
(1) Possible causes: (2) Improvement measures:
1. The surface of the material is severely rough, and the coating cannot be covered. 1. If the material is severely rough, stop production immediately and notify the customer.
2. The surface of the metal transmission wheel is rough and the pressure is too tight, so that it is crushed. 2. If the transmission wheel is rough, you can use it and check the tightness.
3. The current density is slightly higher, some surfaces are not bright and rough (not burnt) 3. Calculate whether the current density is too high, if it should reduce the current
4. Bath temperature is too low, generally nickel plating will occur) 4. Wait for the sharpness to rise and then turn on, or reduce the current, and immediately check the temperature control system.
5.PH value is too high or too low, generally nickel or gold plating (too low) will occur. 5. Immediately adjust the PH to the standard range.
6. Pre-treatment liquid corrosion substrate. 6. Check the pre-treatment agent, dilute the agent or replace the agent
2. Adhesive foreign matter: refers to the dirt attached to the surface of the terminal.
(1) Possible causes: (2) Improvement measures:
1. The washing is not clean or the water quality is bad (if there are micro bacteria). 1. Clean the sink and replace it with new water.
2. Occupy the mechanical oil stain of the receiving system. 2. The oil will be shielded.
3. The material has a similar gel and cannot be removed in the pre-treatment process. 3. It must be soaked in solvent first.
4. When the material is received, it will be stained with dirt and dirt. 4. Avoid landing. If it has been covered with dirt, it can be cleaned with air. If there is a lot of soaking, it is recommended to clean it again.
5. Tin-lead crystals adhered 5. Immediately remove crystals.
6 brush plating wool? Fiber yarn 6. Replace the wool? Check the contact pressure.
7. Paper tape dissolves the fiber. 7. Clear the groove.
8. Belt off-chip. 8. Replace the belt.
3. Poor adhesion: refers to the phenomenon of peeling, peeling, foaming, etc. of the coating.
(1) Possible causes: (2). Improvement measures:
1. Poor pre-treatment, such as stripping nickel. 1. Strengthen pre-treatment.
2. Cathodic contact poor discharge, such as stripping nickel, nickel stripping gold, nickel stripping tin lead. 2. Check the cathode for poor contact, adjust in time.
3. The plating solution is seriously polluted. 3. Change the potion
4. The production rate is too slow, and the bottom layer is oxidized again. For example, the nickel layer is oxidized in the gold bath (or gold reduction), and the lead is stripped. 4. It must be activated again before plating.
5. Washing is not clean. 5. Replace with new water and clean the sink if necessary.
6. The material is seriously oxidized, such as oxidized spots, oxide film after heat treatment. 6. Must be rust and deoxidized film treatment, generally using chemical polishing or electrolytic polishing.
7.caused by chemical shutdown reaction. 7. No stop or cut off defective products
8, the operating voltage is too high, the cathode conductive head and the plated parts are heated, causing the coating to oxidize. 8. Lower the operating voltage or check the wire contact condition
9, poor plating on the bottom layer (such as charring), causing the next layer to peel off. 9. Improve the quality of the underlying plating.
10. Severe. Scrap formed by charring. 10. Refer to NO12 for countermeasures.
4. Reveal copper: can clearly see copper or yellow black at low current (groove)
(1) Possible causes: (2) Improvement measures:
1. Poor pre-treatment, grease, oxides. Foreign matter has not been removed, plating can not be precipitated. 1. Strengthen pre-treatment or reduce production rate
2. Operating current density is too low, resulting in low current area, plating can not be deposited. 2. Recalculate plating conditions.
3 Excessive nickel gloss agent, resulting in low current zone, the coating can not be precipitated 3. Treat the syrup, remove too much brightener or update.
4. Serious scratching caused copper exposure. 4. Check the plating process, (refer to reference NO5)
5. Not plated. 5. Adjust current position.
5 scratches: refers to horizontal lines, generally more likely to occur in tin-lead plating.
(1) Possible causes: (2) Improvement measures:
1. The material itself is in the process of stamping, and caused scratches. 1. Stop production, and contact customers.
2. Metallic tools in the electroplating equipment, such as cathode head, oven positioner, guide wheel, etc. 2. Check the plating process, adjust the equipment and tools in a timely manner.
3. Scratch by electroplated crystals. 3. Stop production and immediately remove crystals.
6. Deformation (scraping): The shape of the terminal has deviated from the original size or position.
(1) Possible causes: (2) Improvement measures:
1. The material itself is deformed during stamping or transportation. 1. Stop production and wait for contact with customers.
2. Electroplated equipment, manufacturing scraping (such as blowing. Positioner, oscillator, notch, slewing wheel) 2. Check the plating process, adjust equipment and tools in a timely manner.
3. The plate is too small or poorly wounded, causing scraping when entering the material. 3. Stop production and adjust the plate at the right time
4. The drive wheel turns 歪, 4. Correct the drive wheel or change the transmission mode.
7 crush injury: refers to the irregular shape of the hole
Possible causes: Improvements:
1) It has been crushed during the processing of the punching machine, and the coating cannot cover the flat layer
2) Loose or faulty drive wheel, causing injury when pressing 1) Stop production and wait for contact with customer
2) Check the transmission mechanism, or replace the spare parts
8 white fog: refers to the surface of the coating is a layer of cloud, not bright but flat
Possible causes: 1) Poor pre-treatment
2) The plating solution is contaminated
3) The tin-lead layer is loved by acid corrosion, such as corrosion by tin-lead solution during shutdown.
4) The temperature of tin-lead syrup is too high
5) Tin-lead current density is too low
6) Insufficient gloss agent
7) Passing the force wheel is dirty
8) The long-term advancement of tin-lead electricity causes foam adhesion. Improvement measures: 1) Strengthen pre-treatment
2) Change the syrup and purify the contaminated fluid
3) Avoid downtime, if it is unavoidable, cut off poorly
4) Immediately check the temperature control system and reset the temperature
5) Increase current density
6) Make up the trapping agent drive wheel
7) Clean the drive wheel
8) Immediately remove the foam
9 pinholes: refers to groups, small round holes (like bell-shaped)
Possible causes: Improvement measures:
1. The current density of the operation is too 1. Reduce the current density
2. The surface tension of the plating solution is too large and the humectant is insufficient. 2. Replenish the humectant or check the syrup.
3. Plating time mixing effect is poor. 3. Strengthen the mixing.
4. Tin bath temperature is too low 4. Adjust bath temperature
5. Electroplating syrup is contaminated. 5. Purify the potion or update it.
6. Poor pretreatment. 6. Strengthen the pre-treatment effect.
10. Tin-lead remelting: The surface of the coating is as plain as a hill (like foaming, but good adhesion), and only tin-lead plating will occur.
(1) Possible causes: (2) Improvement measures:
1. The tin-lead cathode is overheated (the voltage is too high), causing the tin-lead layer to re-melt. 1. Reduce the voltage and understand why the bath voltage is too high and correct the plating conditions.
2. The oven temperature is too high, and the baking time is too long, resulting in remelting of the tin-lead layer. 2. Lower the oven temperature and check the temperature control system.
11. Terminal melting: refers to the surface of the surface is heated into a concave shape, usually caused by copper material (before nickel plating) or tin-lead plating.
(1) Possible causes: (2) Improvement measures:
1. The cathode contact between nickel plating or tin-lead plating is poor, and the discharge spark melts the copper into a cavity. 1. Check the cathode and adjust it as appropriate.
12. Coating burnt: The surface of the coating is severely dark and rough, such as carbon. (refers to the high current density zone)
(1) Possible causes: (2) Improvement measures:
1. The operating current density is too high. 1. Reduce the current density.
2. The bath temperature is too low. 2. Increase the bath temperature and check the temperature control system.
3. Poor mixing. 3. Increase the stirring effect.
4. Insufficient gloss. 4. Make up the gloss.
5. The pH is too high. 5. Correct the PH value to the standard range.
6. The plating position is improper. (Electronic flow curve) 6. Re-correct the plating position and pay attention to the current distribution line.
7. Rectifier filter is poor. 7. Check if the filter is in compliance with the standard. If it is offset, the rectifier must be sent for repair.
13. The plating thickness is too high: it means that the actual plating thickness exceeds the expected thickness.
(1) Possible causes: (2) Improvement measures:
1. The transmission speed is slow, not accurate or the speed is unstable. 1. Check the transmission system and check the production speed.
2. The current is too high, not allowed or the current is unstable. 2. Check the rectifier and anode and cathode and correct them in time.
3. Select the plating position variation. 3. Check if the plating position is deviated and readjust.
4. The metal concentration of the syrup is increased, and the gold plating is generally sensitive. 4. Adjust the current or drive speed.
5. The PH value of the potion is too high. 5. Adjust the pH to the standard range.
6. The fluorescent film thickness tester deviates, or the test method is wrong. 6. Calibrate the instrument or determine the test method.
7. The bath temperature is high. 7. Check the temperature control system.
14. Insufficient plating thickness: the actual thickness of the plated film is lower than the expected thickness
(1) Possible causes: (2) Improvement measures:
1. The transmission speed becomes faster, not accurate or the speed is unstable. 1. Check the transmission system and check the production speed.
2. The current is too low, not allowed or the current is unstable. 2. Check the rectifier and anode and cathode and correct them in time.
3. Select the plating position variation. 3. Check if the plating position is deviated and readjust.
4. The metal concentration of the syrup is lowered, or the syrup is diluted. 4. Adjust the current or transmission speed and stop production if necessary.
5. The PH value of the syrup is low. 5. Adjust the pH to the standard range.
6. The fluorescent film thickness tester deviates, or the test method is wrong. 6. Calibrate the instrument or determine the test method.
7. The bath temperature is low. 7. Check the temperature control system and stop production if necessary.
8. There is gold in the plating structure, which consumes part of the current. 8. Remove gold deposits or replace the tool.
9. Electroplating syrup stirring, uneven circulation or metal replenishment is not enough. 9. Improve the circulation or supplementation of the syrup.
15. Uneven plating thickness: It means that the actual plating film thickness is high and low, or unevenly distributed.
(1) Possible causes: (2) Improvement measures:
1. The transmission speed is unstable. 1. Check the transmission system and check the production speed.
2. The current is unstable. 2. Check the rectifier and anode and cathode and correct them in time.
3. The terminal is severely deformed, resulting in unstable plating position. 3. Check if the plating position is deviated. If the material cannot be improved due to severe deformation process, it must be stopped.
4. The terminal structure causes uneven distribution of high and low currents. 4. Adjust the plating position and increase the mixing effect.
5. Poor mixing effect. 5. Increase the stirring effect.
6. There is a problem with the film thickness test position, resulting in large errors. 6. The test position must be reworked.
7. The plating mechanism is unstable. 7. Improve the plating mechanism.
16. The coating is dark red: usually the golden color is dark and reddish.
(1) Possible causes: (2) Improvement measures:
1. Gold plating syrup deviates. 1. Readjust the plating solution.
2. The coating is rough, and the white layer is covered with red and red. 2. Improve the nickel layer.
3. Washing water is not clean, causing erythema. 3. Replace the washing water.
4. The plated parts are not completely dry and will oxidize red in the future. 4. Check the drying system to determine that the plated parts are dry and the reddish terminals are cleaned with dilute cyanide.
17. Interface black line, fog line: This phenomenon usually occurs at the interface of the semi-tin-plated lead layer.
(1) Possible causes: (2) Improvement measures:
1. The cathode reaction is too large, and a large amount of hydrogen foam floats on the liquid surface. 1. Reduce the current.
2. Poor cathode stirring. 2. Adjust the frequency and amplitude of the oscillator.
3. The plating height is not adjusted uniformly. 3. Check the plating height and correct it.
4. Poor design of the plating tank, causing the foam to remain in the plating bath surface and cannot be eliminated. 4. Improve the plating structure.
5. Tin-lead syrup low-current zone white fog. 5. Correct tin-lead syrup to the best tank condition.
6. Rectifier filter is poor. 6. Measure the filter with an oscilloscope to determine the fault when the filter is poor, and repair the rectifier.
18. Poor soldering: Refers to the poor tin-lead coating of tin-lead coating.
(1) Possible causes: (2) Improvement measures:
1. The tin-lead plating solution is contaminated. 1. Replace tin and lead syrup.
2. Excessive amount of gloss agent, resulting in excessive carbon content of the coating. 2. Immediately filter the activated carbon or change the potion.
3. Poor handling after plating (residual acid, poor water quality, salt formation, foreign matter adhesion). 3. Improve processes and improve water quality
4. Poor adhesion 4. Solve the problem of poor adhesion.
5. The voltage is too high during electroplating, causing the plated parts to be thermally oxidized and passivated. 5. Improve the conductive equipment.
6. The current density is too high, resulting in poor plating structure. 6. Reduce the current density.
7. Poor mixing results in poor plating structure. 7. Increase the stirring effect.
8. The bath temperature is too high, resulting in poor plating structure. 8. Immediately lower the bath temperature and check the cooling system.
9. The coating is poorly placed and the time is too long, causing oxidation and aging of the coating. 9. Strengthen packaging and improve storage environment.
10. The coating is too thin. 10. Increase the thickness of the plating layer.
11. The solder temperature is incorrect. 11. Check the solder temperature.
12. Influence of the shape of the plated part. 12. Change the decision method.
13. The flux is too high. 13. Replace the flux.
14. Effect of plating material (tin > tin lead > gold > copper > phosphor bronze > brass) 14. Explore the material.
15. There are foreign objects on the surface of the plated parts, such as oil stains. 15. Remove foreign matter.
16. The bottom layer is rough. 16. Improve the underlying flatness.
19. Blackening of the coating: Black lines that do not contain charred black and tin-lead interfaces.
(1) Possible causes: (2) Improvement measures:
1. Tin-lead plating has been white mist and will turn black in the future. 1. Refer to section 8, to deal with tin-lead white fog.
2. The nickel bath has been contaminated and there will be black plating in the low current zone. 2. Do activated carbon treatment, or weak electrolytic treatment.
3. The plated parts are severely blackened and oxidized by oxidation. 3. It is necessary to analyze and discuss the reasons.
4. Shutdown causes corrosion or reduction. 4. Cut out bad and avoid downtime.
5. The tin-lead coating is blackened by the spark released by the cathode conductive head. 5. Adjust the cathode contact head to make good contact with the terminal.
20. Tin slag: refers to the tin-lead metal on the surface of the tin-lead layer with intermittent fineness, usually with the most material.
(1) Possible causes: (2) Improvement measures:
1. Tin-lead syrup brings out crystallization at the cathode conduction seat. 1. Improve the delivery of potions and strengthen the cleaning process.
2. Rub in the oven and scrape off the high temperature metal. 2. Adjust the tool in the oven to avoid rubbing to the terminals and adjust the oven temperature.