Powder Clumping or Bare Spots

medium
powder
static
humidity

Uneven powder adhesion from static, humidity, or wet ink timing.

Likely Causes

  1. Static on film: Repels/attracts powder unevenly.

  2. Humidity too low/high: Affects charge and wetting.

  3. Powder has absorbed moisture: Clumped powder does not distribute evenly.

  4. Ink is too dry before powder application: Powder won't stick to dry ink.

Quick Checks

  • Wipe film with anti-static cloth.
  • Set RH 40–55%, ionize if available.
  • Sift powder through a fine mesh screen.
  • Check time between printing and powdering; reduce delay.
  • Observe the powder application curtain for consistency.

Step-by-Step Fix

  1. Install ionizer at powder station — Neutralizes static.

  2. Store powder in an airtight container with desiccant — Prevents moisture absorption.

  3. Adjust printer/shaker speed to minimize time between print and powder — Ensures ink is wet enough for powder to adhere.

  4. Clean shaker and vacuum any old powder residue — Prevents clumps from being recirculated.

  5. Increase shaker vibration slightly to break up small clumps — Improves powder flow and uniformity.

Acceptance Criteria
  • Uniform powder coat; no bald patches.