3.4 Ionization & Insulator Control

Grounding straps and conductive floors have a fatal physical limitation: they only work on conductors. They are chemically incapable of draining charge from insulators (plastics, epoxy, glass). When an ungrounded insulator—like a plastic connector housing or a circuit board substrate—accumulates charge, it creates an electrostatic field. This field can induce voltage onto nearby conductive traces without contact (Field-Induced Charging), leading to CDM failures the moment the board touches a grounded tool. Ionization is not optional "air blowing"; it is the only way to neutralize insulators.

Insulator Management Strategy

You cannot eliminate all insulators (the PCB itself is one). You must manage the risk based on proximity.

Decision Logic: The 30 cm Rule

1. IF the insulator is "Process Essential" (e.g., connector bodies, PCB fiberglass, specialized jigs) → THEN Neutralize with Active Ionization.
2. IF the insulator is "Non-Essential" (e.g., coffee cups, scotch tape, standard paperwork, plastic binders) → THEN Ban from the EPA entirely.
   • Constraint: Maintain a strict > 30 cm exclusion zone from any ESDS (Electrostatic Discharge Sensitive) component.

Active Neutralization (Ionization)

Ionizers flood the air with positive and negative ions, neutralizing any static charge on surfaces that cannot be grounded.

Selection Logic

• Overhead Blowers: Use for general workbench coverage.
  • Risk: Airflow blockage. Ensure objects don't block the "line of sight" to the product.
• Point-of-Use (Snake) Ionizers: Use for focused, high-static activities (e.g., inside a wave solder machine or automated tape-and-reel).
• Ionizing Guns: Use for cleaning dust off optics or sensors.
  • Warning: Standard compressed air generates massive static friction. Only use ionized air guns.

Pro-Tip: Ionizers are not "set and forget." Emitter points erode and collect silica/dust, causing the electrical balance to drift. A dirty ionizer often becomes a static generator, pumping thousands of volts of positive charge onto your product.

Packaging & The "Faraday Cage"

Protection during transport relies on creating a shield that external fields cannot penetrate.

Material Standards

• Silver "Metal-In" Bags (Shielding): * Requirement: Mandatory for all PCBAs and sensitive components moving outside the EPA.
  • Physics: The metal layer creates a Faraday Cage, blocking external electrostatic fields.
• Pink Poly Bags (Dissipative):
  • Usage: Only for "Low Risk" items (screws, brackets, non-sensitive hardware).
  • Limitation: Pink poly is NOT a shield. It merely prevents the bag itself from generating charge. It offers zero protection against external fields.

Transport Logic

• IF moving material on a cart → THEN The cart must be electrically bonded to the floor via drag chains or conductive casters.
• IF the cart wheels are dirty → THEN The cart is an isolated floating conductor. Clean wheels monthly.

Final Checklist