River City’s Emulsion Trouble Shooting Guide – Emulsion Troubleshooting Guide
To achieve optimal emulsion results, utilizing an exposure calculator tailored to your specific setup is essential. Exposure times can vary based on factors such as your coating technique, light source, emulsion type, thickness, and more. No one can accurately determine your exposure time without these specific details. Utilizing an exposure calculator ensures precise and customized exposure times, enabling you to fine-tune your emulsion process for exceptional screen printing outcomes.
Achieving flawless screen printing results can sometimes encounter challenges. Refer to this comprehensive troubleshooting guide to address common issues and solutions with emulsion-related problems:
WASHOUT BREAKDOWN (LOSS OF ADHESION DURING DEVELOPMENT) – Washout Breakdown, also known as Loss of Adhesion During Development, refers to a problem in the screen printing process where the adhesion between the emulsion and the mesh weakens or breaks down during the developing stage.
- Contaminated Mesh Type of Stencil:
- Inadequate or Inconsistent Exposure Type of Stencil:
- Excessive Water Pressure and/or Washing Type of Stencil: ALL Solution:
- Reduce water pressure and/or adjust washout time accordingly.
- Water Temperature Range Too Hot Type of Stencil:
- Solution: Maintain an optimum water temperature of 90° to 100°F (32° to 38°C) during washout.
- Improper Adhesion of Capillary Film Type of Stencil:
- CAPILLARY FILM Solution: Degrease appropriately with a screen degreaser and consider using a wetting agent.
- Transfer Emulsion Has Inadequately Sensitized Film Type of Stencil:
- DIRECT/INDIRECT Solution: Allow approximately 10 minutes of dwell time after coating with transfer emulsion before exposing to heat or a fan.
- Screen Not Dry Enough for Exposure Type of Stencil: ALL Solution:
- Follow proper drying directions, and consider using a dehumidifier in the drying area.
- Pre-Exposed or Outdated Film or Emulsion Type of Stencil:
- Solution: Work in yellow or subdued lighting for screen making, and ensure the screen is dried in complete darkness. Check the lot number on the packaging for freshness.
- Poor Coating Methods Type of Stencil:
- EMULSION Solution: Refer to the user’s guide for correct coating instructions and utilize an appropriate scoop coater with a straight edge.
SCUMMING OR HAZE – Scumming or Haze in screen printing refers to the appearance of unwanted residue or faint marks on the screen, often visible after the emulsion has been washed out and dried
- Incomplete Washout and/or Underexposure Type of Stencil:
- Solution: Increase exposure time and washout until foaming ceases. Use a wet vac to remove water and scum.
- Excess Moisture in Screen Making Area Type of Stencil:
- Solution: Implement a dehumidifier to maintain relative humidity below 50 percent.
- Poor Positive and/or Contact with Coating Type of Stencil:
- Solution: Ensure high-quality positive and proper contact with the coating by checking the vacuum frame and blanket for leaks.
- Pre-Exposure of Film or Emulsion Type of Stencil:
- Solution: Work under yellow or subdued lighting for screen making, and avoid exposing the screen to natural sunlight during development.
- Light Scatter Type of Stencil:
- Solution: Use dyed or tinted fabric or reduce exposure time. Consider replacing scratched glass.
WEAK STENCIL – A weak stencil in screen printing refers to a stencil that lacks the necessary durability or thickness to withstand the printing process.
- Underexposure Type of Stencil:
- Solution: Increase exposure time according to the Chromaline Exposure Calculator. Check for sliminess or color transfer during washout as an indicator of underexposure.
- Film Too Thin for Mesh Count Type of Stencil:
- DIRECT/INDIRECT, CAPILLARY FILM Solution: Consult the user’s guide for recommended film thickness per mesh count.
- Emulsion Coating Too Thin Type of Stencil:
- EMULSION Solution: Apply additional coats on the print side after initial drying. Alternatively, use higher solids emulsion or the rounded edge of the coater.
- Screen Not Fully Dry During Exposure Type of Stencil:
- Solution: Adhere to proper drying instructions and use a dehumidifier in the screen drying area to maintain below 50 percent relative humidity.
- Stencil Too Thin for Mesh Type of Stencil:
- ALL Solution: Refer to the user’s guide for film/emulsion recommended for mesh count and adjust accordingly.
By referring to this emulsion troubleshooting guide, you can effectively address and overcome challenges that may arise during your screen printing process. Achieve consistent and high-quality results by implementing the appropriate solutions to enhance your printing experience.
If you have tried all these items listed above and are still having trouble, feel free to reach out to your emulsion manufacturer listed below for additional support: