7.3 Compressed Air Standards (ISO 8573)

Pneumatic actuators in pick-and-place heads and screen printers operate at high speeds with tight tolerances. Contaminants in the compressed air supply cause valve stiction, nozzle clogging, and oil deposition on optics. This chapter mandates compliance with ISO 8573-1 air purity classes.

7.3.1 The ISO 8573-1 Class 1.2.1 Standard 

Electronics manufacturing requires air that is dry, oil-free, and particle-free.

• Particulates (Class 1): 0.1 – 0.5 micron size limits. Filters must capture dust to prevent abrasive wear on solenoids.
• Water (Class 2): Pressure Dew Point (PDP) must be ≤ -40°C.
  • Why: Water vapor condenses as air expands in the machine tools. Liquid water washes away lubricants and rusts internal components.
• Oil (Class 1): Total oil content ≤ 0.01 mg/m³. Oil mist coats sensors and lenses, causing vision system failures.

7.3.2 Nitrogen (N2) Generation 

For soldering processes requiring inert atmospheres (to reduce oxidation and improve wetting):

• Purity: 99.99% (4N) minimum for OSP finishes; 99.999% (5N) for wafer bumping.
• O2 Monitoring: Oxygen sensors in the reflow tunnel must actively control N2 injection to maintain < 1000 PPM O2 concentration.

Final Checklist