Solution40

Defect : Solder balls

Process/machine infomation :

Board type - Single sided

Solderability protection - OSP

Flux carrier - Alcohol

Preheat type - Infrared

Process solutions

• Conveyor speed too slow.

  a. Time over preheat too long causing flux to be burned
  off.

  b. Dwell time too long causing flux to be destroyed before
  exiting the wave.

• Conveyor speed too fast.

  a. Time over preheat not long enough to dry flux
  carrier.

• Flux not active enough or solids percentage too
  low.

• The use of nitrogen may increase solder balls.

• Not enough flux.

• Flux carrier is not being completely dried by the
  preheat.

• Too much flux.

Board and design solutions

• Lead length too long.

• Solder mask type or curing.

  a. Matte finish is preferred.