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Common circuit board quality problems and improvement measures in multi-layer PCB solder mask process
2021-08-28
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Author:Aure

Common circuit board quality problems and improvement measures in multi-layer PCB solder mask process

    In the multi-layer PCB solder mask process, as smart as you may encounter various problems in the production of circuit boards, the common ones are as follows:
 
  Problem: White spots in printing
 
   Reason 1: The printed multilayer PCB has white spots
 
  Improvement measures: the thinner does not match, use the matched thinner [please use the company's supporting thinner]
 
   Reason 2: The circuit board is dissolved in the sealing tape
 
  Improvement measures: use white paper to seal the net
 
   problem: sticky film
 
   Reason 1: The circuit board ink is not dried
 
  Improvement measures: check the degree of ink drying
 
   Reason 2: Multi-layer PCB vacuum is too strong
 
  Improvement measures: check the vacuum system (the air guide strip may not be added)
 
   Problem: Poor exposure
 
   Reason 1: Poor vacuum
 
  Improvement measures: check the vacuum system
 
   Reason 2: Multi-layer PCB exposure energy is inappropriate
 
  Improvement measures: adjust the appropriate exposure energy
 
   Reason 3: The temperature of the multi-layer PCB exposure machine is too high
 
  Improvement measures: check the temperature of the exposure machine (below 26)
 
   Problem: The ink does not dry out
 
    Reason 1: The exhaust air of the circuit board oven is not good
 
  Improvement measures: check the exhaust air condition of the oven
 
   Reason 2: Less thinner
 
  Improvement measures: increase thinner, fully dilute
 
   Reason 3: The ink is too thick
 
  Improvement measures: appropriately adjust the ink thickness
 
   Reason 4: The thinner dries too slowly
 
  Improvement measures: use matching thinner [please use company supporting thinner]
 
   Reason 5: The oven temperature is not enough
 
  Improvement measures: Determine whether the actual temperature of the oven reaches the required temperature of the product



 

Common circuit board quality problems and improvement measures in multi-layer PCB solder mask process

   Problem: The development is not clean
 
   Reason 1: It takes too long after printing
 
  Improvement measures: control the storage time within 24 hours
 
   Reason 2: The ink runs out before development
 
  Improvement measures: work in the darkroom before developing (the fluorescent lamp is wrapped in yellow paper)
 
   Reason 3: Development time is too short
 
  Improvement measures: extend the development time
 
   Reason 4: Exposure energy is too high
 
  Improvement measures: Adjust exposure energy
 
   Reason 5: Multi-layer circuit board ink is over-baked
 
  Improvement measures: adjust the baking parameters, not to burn to death
 
   Reason 6: Ink mixing is uneven
 
  Improvement measures: Stir the ink evenly before the printed circuit board
 
   Reason 7: Not enough developing potion
 
  Improvement measures: the temperature is not enough to check the concentration and temperature of the medicine
 
   Reason 8: The thinner does not match
 
  Improvement measures: use matching thinner [please use company supporting thinner]
 
  Problem: Excessive development (corrosion test)
 
   Reason 1: The concentration of the potion is too high and the temperature is too high
 
  Improvement measures: reduce the concentration and temperature of the potion
 
   Reason 2: Development time is too long
 
  Improvement measures: shorten the development time
 
   Reason 3: Insufficient exposure energy
 
  Improvement measures: Increase exposure energy
 
   Reason 4: The developing water pressure is too large
 
  Improvement measures: lower the developing water pressure
 
   Reason 5: Ink mixing is uneven
 
  Improvement measures: Stir the ink evenly before printing
 
   Reason 6: The ink is not dried
 
  Improvement measures: Adjust the baking parameters, see the question [Ink does not dry]
 
  Problem: Green Oil Bridge Broken Bridge
 
   Reason 1: Insufficient exposure energy
 
  Improvement measures: Increase exposure energy
 
   Reason 2: The sheet is not handled properly
 
  Improvement measures: check the treatment process
 
   Reason 3: Too much pressure for developing and washing
 
  Improvement measures: check the developing and washing pressure
 
   Problem: Foaming on the tin
 
    Reason 1: Excessive development
 
  Improvement measures: improve the development parameters, see the problem [over development]
 
   Reason 2: The pre-treatment of the board is not good, and the surface is oily and dusty.
 
  Improvement measures: do a good job of pre-treatment of multi-layer PCB boards to keep the surface clean
 
   Reason 3: Insufficient exposure energy
 
  Improvement measures: check the exposure energy and meet the ink usage requirements
 
   Reason 4: Abnormal flux
 
  Improvement measures: adjust flux
 
   Reason 5: Insufficient post-bake
 
  Improvement measures: Baking process after inspection
 
  Problem: Poor upper tin
 
   Reason 1: The development is not clean
 
  Improvement measures: improve several factors of poor image development
 
   Reason 2: Post-baking solvent contamination
 
  Improvement measures: increase oven exhaust or machine cleaning before spraying tin
 
   problem: post-baking and exploding oil
 
   Reason 1: There is no segmented baking
 
  Improvement measures: stage baking
 
   Reason 2: Insufficient viscosity of multi-layer PCB plug hole ink
 
  Improvement measures: adjust plug hole ink viscosity
 
   Problem: Ink matte
 
   Reason 1: The thinner does not match
 
  Improvement measures: use matching thinner [please use company supporting thinner]
 
   Reason 2: Low exposure energy
 
  Improvement measures: Increase exposure energy
 
   Reason 3: Overdeveloped circuit board
 
  Improvement measures: improve the development parameters, see the problem [over development]
 
   Problem: Ink discoloration
 
   Reason 1: Insufficient ink thickness
 
  Improvement measures: increase ink thickness
 
   Reason 2: Multilayer circuit board substrate oxidation
 
  Improvement measures: check the pre-treatment process
 
   Reason 3: The post-baking temperature is too high
 
  Improvement measures: the time is too long to check the baking parameters
 
   Problem: Ink adhesion is not strong
 
   Reason 1: Ink type selection is inappropriate.
 
  Improvement measures: Change to appropriate ink.
 
   Reason 2: The ink type selection is inappropriate.
 
  Improvement measures: Change to appropriate ink.
 
   Reason 3: The drying time, temperature is not correct, and the exhaust air volume during drying is too small.
 
  Improvement measures: use the correct temperature and time, and increase the exhaust air volume.
 
   Reason 4: The amount of additives is inappropriate or incorrect.
 
  Improvement measures: adjust the dosage or switch to other additives.
 
   Reason 5: The humidity is too high.
 
  Improvement measures: improve air dryness.
 
   Problem: Blocking the Internet
 
   Reason 1: Drying is too fast.
 
  Improvement measures: add slow-drying agent.
 
   Reason 2: The printing speed is too slow.
 
  Improvement measures: increase the speed and slow down the drying agent.
 
   Reason 3: The viscosity of the multilayer PCB ink is too high.
 
  Improvement measures: add ink lubricant or extra slow drying agent.
 
   Reason 4: The thinner is not suitable.
 
  Improvement measures: use designated thinners.
 
   problem: penetration, blur
 
   Reason 1: The ink viscosity is too low.
 
  Improvement measures: increase the concentration without adding diluent.
 
   Reason 2: The circuit board silk screen pressure is too large.
 
  Improvement measures: reduce stress.
 
   Reason 3: Bad squeegee.
 
  Improvement measures: Replace or change the angle of the squeegee screen.
 
   Reason 4: The distance between the screen and the printing surface is too large or too small.
 
  Improvement measures: Adjust the spacing.
 
   Reason 5: The tension of the silk screen becomes smaller.
 
  Improvement measures: Re-make a new screen version.
 
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