Optimizing Off-Contact Distance in Manual Screen Printing

Understanding and adjusting the off-contact distance is crucial in manual screen printing for achieving quality prints. This article addresses common issues and solutions related to off-contact settings, ensuring your screen printing process runs smoothly. We'll discuss the importance of off-contact, how to measure and adjust it, and share practical tips for different garment types.

The Importance of Off-Contact Distance

Off-contact distance refers to the gap between the screen and the printing surface (platen). This distance is vital for preventing ink smudging and ensuring a clean transfer of the ink onto the garment. If the screen is too close, it can lead to ink smearing; if it's too far, the ink might not transfer properly, causing uneven prints and screen clogging.

How to Measure and Adjust Off-Contact

1. Basic Measurement Techniques:
   • The off-contact distance should generally be around 1/8 inch (approximately 3mm) off the garment. For thicker garments like sweatshirts, you might need to increase this slightly.
   • Use common items like quarters or a sheet of plexiglass to measure and maintain consistent off-contact distances. Place a quarter on the platen without a garment and adjust the screen to touch the quarter lightly. Alternatively, use an 1/8 inch thick plexiglass sheet to ensure even off-contact across the entire screen.
2. Adjusting the Press:
   • Ensure your press has an adjustable mechanism to raise or lower the screen height. Adjust the screen to snap back up immediately behind the squeegee as it moves across the print, pushing the ink through effectively.
   • Level your platen and screen bracket to ensure there is no warp. Use a flat sheet of aluminum or plexiglass to check for any discrepancies.

Troubleshooting Common Issues

1. Ink Not Clearing the Screen:
   • If the ink isn't clearing properly, check your off-contact distance first. A common mistake is setting it too high, causing incomplete ink transfer.
   • Use screen opener spray and ensure you’re using the right amount of extender in your ink. Overflashing or using too much adhesive spray can clog the screen.
2. Garment Lifting:
   • This issue often occurs when the off-contact is too high. Ensure you’re using adequate but not excessive adhesive spray.
   • Flashing too long can reverse cure the ink back into the screen, so monitor your flash times carefully.

Practical Tips for Different Garment Types

1. T-Shirts:
   • For standard t-shirts, maintain a 1/8 inch off-contact distance. Adjust based on the ink and screen condition during the printing process.
2. Sweatshirts and Thicker Garments:
   • Increase the off-contact distance slightly for thicker materials to ensure proper ink transfer without smudging.
3. Small Details and Thick Letters:
   • Balance the off-contact distance to accommodate both small details and larger letters. Use a mix of screen tension and off-contact adjustments to get the best results.

Final Thoughts

Adjusting and maintaining the correct off-contact distance is essential for achieving high-quality screen prints. Regularly check your equipment, use practical measurement tools, and adjust based on the type of garment and ink. By following these guidelines, you can improve your screen printing results and reduce common issues like ink smudging and garment lifting.

For more detailed tutorials and tips, follow our YouTube Channel BCH Technologies and our tech blog. If you're local to Greensboro, North Carolina, visit us for in-person support and demonstrations.