Particle Selection (2)

Question 1

Three main considerations when choosing the type and colour of particle for inspection

Answer 1

1. type of defect (dry is more sensitive to subsurface defects)
2. size (wet for small surface defects)
3. convenience (potability + environmental conditions)

Question 2

Wet Fluorescent Particle Inspection

Answer 2

• Fluorescent dyed
• wet (small, uniform)
• darkened area
• UV lighting

Question 3

Wet-Visible or Black-on-White Particle Inspection

Answer 3

• black dyed particles
• wet (small, uniform)
• used with white contrast aid paint

Question 4

Dry-Visible or Dry-Powder Particle Inspection

Answer 4

• better location of sub-surface defects
• larger and irregular in size
• coloured
• low cost
• purchased in bulk