Solder paste management

0. Importance of Solder Paste Management

1) If the management of solder paste that is a core element of SMT is insufficient, various soldering failure risks increase such as solder short, cold solder.

1. Income

1) Solder paste is warehoused to producing field & material team

   - Warehousing Status: Store in Styrofoam packing box with Ice Pack

2. Check (Warehousing Status)

1) Check if Styrofoam exterior is abnormal or not

2) Check if packing date on Invoice exceeds over 2 weeks or not.

   - if it is exceeded, notify/return to material operator

3) Check if Solder paste package is damaged and be dented in visual

   - If it is found, notify/return to material operator.

3. Attach controlling tag

1) Included contexts of charts(Date is written as M/D, h:min.)

    - Income date / inputted date to refrigerator / Outgoing date to refrigerator / Mixing 

time / Opened date

2) Controlling Tag should be managed with it attached on solder paste’s container

3) Solder paste should be controlled from income time to discarded time

4. Cold storage

1) Temperature for storing: 1~10℃ (Recommended : 2~8℃)

2) Controlling as “first in, first out.”

 ※ If cold storage is not met, the physical properties of the solder paste are changed due to the volatility of the flux.

     → Increase soldering failure risk

5. Storage in room temperature

1) Solder paste should be neglected in unopened and room temperature(25±3 ℃)

        after taking out quantity of the day shift production

    - Storage in room temperature : 2hr ~ 12hr (Recommended : 2~3hr)

    ※ reason to storage in room temperature: In case of low temperature open, Solder

         ball defect occurs by moisture absorption caused by dew condensation

2) In case of no production, store in cold after unopened and room temperature storage

    - Re-storage should be used  after storing over 12 hours. 

6. Mix

1) Solder paste storage in room temperature is agitated in pocket of mix machine

      - Recommended  : 45sec / 1,000 rpm 

      ※ Details :  Refer Solder paste spec sheet on each Maker / Composition (attachment)

   ※ if you do not meet the mix standards, Increase soldering failure risk because solder and flux do not mix evenly\

7. Open / Review

1) If discoloration/mass after agitated Solder paste open, notify/return to material operator.

8. input to printer

1) Spread neglected Solder paste evenly on Stencil with printing machine using

     designated scoop. (Suggested : thickness 15 ~ 20 mm) 

2) Remainders after inputing printing machine should be stored with cap cover

     and use it within 12hours

• Controlling Solder Paste When SMT Line is not Operated

1. Controlling solder paste in case of not operating line

1) If it is not exceeded 4hours, print after roll Solder paste twice

2) If it is exceeded over 4 hours, discard after raking out with

 ※ After 4 hours are over, Solder characteristics are lower.(viscosity, adhesion, 

oxidation, etc.,)

2. Collecting & storing disposal solder

1) Collect Used Solder Paste with designated scoop on original Solder container and 

record disposal date on management chart on Solder container

2) Attach red sticker on Solder container to manage used Solder and normal one 

separately

3. Writing check sheet of disposal solder paste

1) Production division writes discarded reason and date on check sheet, when 

discarded

solder paste stores

4. Disposal solder paste

1) Environment Safety Team sells stored used Solder to industrial waste specialized

  company or Solder Paste manufacturer at mutually agreed price and collect money 

after checking weight in the presence of both material operator and Environment 

Safety 

operator once a month. Material management team arranges computerized inventory

    ※ Manage after deciding operating department following to national disposal management

         standard and subsidiaries using used Solder recycle should use with separated regulation