Common problems and countermeasures of glue in LED packaging process

LED Yellowing

Causes:

  1. The baking temperature is too high or the curing time is excessively long.
  2. An incorrect ratio of A and B components in the epoxy glue, especially when there's more A component, can lead to yellowing.

Solutions:

  1. Cure and demold the AB glue at 120-140°C for 30 minutes. Exceeding 150°C may cause yellowing.
  2. For optimal results, cure at 120-130°C for 30-40 minutes. If the temperature goes above 150°C or the time is extended, yellowing is likely.
  3. When manufacturing large lamp holders, consider reducing the curing temperature to prevent discoloration.

LED Bubble Problem

Causes:

  1. Bubbles inside the bowl: Poor adhesion between the bracket and the glue.
  2. Bracket bubbles: High curing temperature causes excessive reaction of the epoxy resin.
  3. Cracking or bursting on the top: Insufficient curing time, leading to incomplete or uneven curing of the epoxy. This can also happen if the AB glue has exceeded its usable lifespan.
  4. Bubbles on the surface of the lamp head: Inadequate degassing of the epoxy glue or insufficient vacuum during application, along with prolonged glue time.

Solutions:

  1. Improve the process or consult your epoxy supplier for better results based on your specific usage.

LED Bracket Creeping

Causes:

  1. Uneven surface of the bracket leads to capillary action, causing the glue to spread unintentionally.
  2. AB glue contains volatile substances that can affect adhesion and stability.

Solutions:

  1. Contact the supplier for further assistance and recommendations.

LED Package: Short-Baked Off-Die and Long-Baked Discoloration

Causes:

  1. Overcrowding in the oven leads to poor ventilation and uneven heat distribution.
  2. Local temperature in the oven is too high, causing hotspots.
  3. Pollutants or foreign colors in the oven may cause unwanted color changes.

Solutions:

  1. Improve air circulation in the oven.
  2. Clean any color stains and verify the actual temperature inside the oven to ensure it’s consistent.

Uneven Coloring or Gelling Time Across a Row of Brackets

Causes:

  1. Incomplete stirring of the mixture, especially in corners of the container.

Solutions:

  1. Ensure thorough mixing, paying extra attention to the corners of the container.

Difficult to Demold

Causes:

  1. Issues with the AB glue or the glue hasn’t reached the required hardness.

Solutions:

  1. Contact the supplier to confirm the correct curing temperature and time.

Different Colors Even After Same Dose of Lotion

Causes:

  1. Uneven toner concentration or sedimentation of the toner.

Solutions:

  1. Warm up the toner before use and mix thoroughly to ensure even distribution.


Lenovo Chromebook 300E Gen2 AST

Lenovo Chromebook 300E Gen2 replacement parts,Lenovo Chromebook 300E,Lenovo Chromebook 300E Gen2 AST parts

S-yuan Electronic Technology Limited , https://www.syuanelectronic.com