🔧 Soldering Defects According to IPC-A-610

✅ 1. Cold Solder Joint

• Description: Dull or grainy appearance; poor wetting between solder and component/PCB pad.

• Cause: Insufficient heat or movement during solidification.

• Impact: Weak mechanical and electrical connection; likely to fail.

✅ 2. Insufficient Solder

• Description: Inadequate amount of solder to form a proper joint.

• Cause: Poor solder paste printing, insufficient solder wire, or poor wave contact.

• Impact: Weak joints; poor conductivity; increased risk of open circuits.

✅ 3. Excess Solder / Over-soldering

• Description: Too much solder creating large, uneven blobs.

• Cause: Excessive solder application during reflow or manual soldering.

• Impact: Possible short circuits or solder bridging between adjacent leads.

✅ 4. Solder Bridge (Short)

• Description: Solder forms an unintended connection between two adjacent conductors or pads.

• Cause: Excess solder or improper solder mask coverage.

• Impact: Electrical short circuits; functional failure.

✅ 5. Non-wetting

• Description: Solder does not adhere properly to pad or component lead.

• Cause: Contaminated surfaces, oxidized leads, or incorrect solder alloy.

• Impact: Weak or open connections; unreliable joints.

✅ 6. De-wetting

• Description: Solder initially wets the surface but then recedes, leaving irregular coverage.

• Cause: Surface contamination or incompatible flux.

• Impact: Intermittent electrical contact.

✅ 7. Lifted Pads

• Description: PCB pad is pulled away from the substrate.

• Cause: Excessive heat or mechanical stress during rework or poor lamination.

• Impact: Open circuit; permanent board damage.

✅ 8. Tombstoning

• Description: One end of a chip component lifts during reflow, resembling a tombstone.

• Cause: Uneven heating or surface tension imbalance.

• Impact: Open connection; component misalignment.

✅ 9. Component Misalignment (Skewed or Shifted)

• Description: Component is not centered on its land pattern.

• Cause: PCB warping, incorrect placement, or solder paste imbalance.

• Impact: Weak joints; aesthetic and functional concerns.

✅ 10. Voids in Solder Joint

• Description: Gas pockets or cavities within the solder joint.

• Cause: Poor paste reflow, moisture in PCB, or trapped flux residues.

• Impact: Reduced thermal and electrical conductivity; may lead to joint cracking.

✅ 11. Pin Holes or Blow Holes

• Description: Small holes visible on the surface of a solder joint.

• Cause: Outgassing from PCB or component during reflow.

• Impact: Generally cosmetic, but may indicate process issues.

✅ 12. Solder Balls

• Description: Small spheres of solder scattered around the joint.

• Cause: Improper reflow profile, excessive paste, or solder splatter.

• Impact: Risk of electrical shorts and contamination.

✅ 13. Cracked Solder Joint

• Description: Visible cracks in solder after thermal or mechanical stress.

• Cause: Vibration, thermal cycling, or improper alloy.

• Impact: High chance of joint failure under operation.

✅ 14. Excessive Solder Fillet (THT)

• Description: Solder fillet rises excessively above the component lead.

• Cause: Too much solder during wave soldering or manual soldering.

• Impact: May hide defects or create mechanical stress.

✅ 15. Incomplete Fill in THT

• Description: Solder does not fill the plated through-hole completely.

• Cause: Insufficient preheat or flux, or wrong soldering parameters.

• Impact: Poor mechanical strength; unreliable electrical contact.

📘 IPC-A-610 Classes of Acceptability

These defects are evaluated differently depending on the class of product:

• Class 1: General Electronic Products – Least stringent.

• Class 2: Dedicated Service Electronic Products – Normal durability and function.

• Class 3: High Performance / Harsh Environment – Highest standards (e.g., aerospace, medical).