One of the most frustrating issues that screen printers face is the breakdown of their screens during the printing process. Screen breakdowns can lead to poor print quality, wasted materials, and increased downtime, all of which can impact the efficiency and profitability of a print shop.

Understanding the common reasons behind screen breakdowns is essential for mitigating these issues and ensuring smooth production runs. In this comprehensive blog post, we'll delve into the primary causes of screen breakdowns during the screen making process and on-press, along with practical solutions to address each issue effectively.

Common Mistakes When Making Screens for Screen Printing

It all starts in the screen room. When your screen breaks down on press, nine times out of ten it is because of something that was done (or not done!) in prepress. Understanding the common reasons behind screen breakdowns and implementing proactive measures to address these issues are essential for maintaining optimal print quality and production efficiency in screen printing operations.

1. Underexposing Your Screen

Problem: Underexposure of the screen emulsion is a the most common culprit behind screen breakdowns. When the emulsion isn't adequately cured during the exposure process, it can lead to incomplete hardening and weakened stencil integrity.

How To Fix It: Incomplete or uneven exposure can result from various factors, including improper mixing of emulsion, uneven application onto the screen, or insufficient exposure time. To ensure proper exposure, it's crucial to follow best practices, such as thoroughly mixing the emulsion, applying it evenly onto the screen, and using an Exposure Calculator or Guide to determine the optimal exposure time for your specific setup.

2. Using The Wrong Emulsion

Problem: Using the wrong emulsion for your ink type and printing job can significantly impact the longevity and durability of your screen stencils.

How To Fix It: Different emulsions are designed to withstand varying types of inks, solvents, and printing conditions. Using the right emulsion not only enhances stencil durability but also improves print quality and overall efficiency. If you're not sure which emulsion to use, reach out to the Chromaline team or your Chromaline distributor to help ensure you're using the correct emulsion for your specific printing needs.

3. Low Quality Artwork

Problem: Poor quality artwork can lead to sawtoothing and may necessitate underexposure, further compromising stencil integrity.

How To Fix It: Artwork with fuzzy edges or low contrast can result in sawtoothing, where fine details are lost or distorted in the final print. To prevent this, it's essential to start with high-quality, crisp artwork with a density Dmax over 3.0. Additionally, ensure that your artwork is sufficiently opaque; holding it up to the light should reveal no visible light passing through.

4. Bad Screen Tension

Problem: Insufficient tension in the screen can cause it to move or vibrate during printing, leading to premature breakdowns.

How To Fix It: Low screen tension compromises print registration and can result in blurred or distorted prints. Regularly check and maintain proper tension in your screens using a tension meter. Proper tensioning not only extends the life of your screens but also improves print consistency and registration accuracy.

5. Using Chemicals Incorrectly

Problem: The use of harsh or improper cleaning chemicals can weaken the screen emulsion or mesh, making it more prone to breakdowns.

How To Fix It: Using recommended cleaners and following proper cleaning procedures is essential for preserving screen integrity. Be sure to degrease screens thoroughly with a suitable cleaner like Chroma/Wet iSC before coating to remove any residual chemicals that could interfere with emulsion adhesion. While on press, avoid cleaning screens with harsh solvents. Using a common hard solvent cleaner will likely damage the screen and degrade the emulsion faster, affecting the longevity of the stencil and the quality of subsequent prints. Instead, use press washes specifically designed for screen printing like Chromaline’s Textile Press Wash iSC. Finally, before reclaiming your screen, be sure to remove ink with a screen wash specifically designed to break down screen printing inks. A screen wash such as Chroma/Screen Wash iSC removes ink more effectively and is easier on your mesh than common hard solvents.

6. High Humidity & Temperature

Problem: Fluctuations in humidity and temperature can impact emulsion curing, ink consistency, and screen tension, leading to screen breakdowns.

How To Fix It: Maintaining a stable and controlled environment in your printing area is crucial for consistent results. Aim for temperatures between 60-80°F and humidity levels between 30-40% to optimize emulsion curing and ink performance. Investing in climate control equipment or implementing measures to regulate environmental conditions can help minimize the impact of external factors on your printing process.

7. Poor Reclaim Practices

Problem: Aggressive reclaiming practices can gradually degrade screens over time, reducing their lifespan and increasing the likelihood of breakdowns.

How To Fix It: Gentle handling during the reclaiming process is essential for preserving screen integrity. Thoroughly rinse and dry screens before re-coating to remove any residue that could compromise stencil adhesion. Consider using a reclaiming solution like Chroma/Strip iSC, specifically formulated to effectively remove emulsion and ink residues without damaging the screen mesh.

Common Mistakes On-Press When Screen Printing

Premature breakdown of your stencil or screen on-press is most commonly caused by an issue during the screen making process, however if you have your screen room dialed in and you are still having issues, here are some on-press things to consider.

8. Thick Ink Consistency

Problem: Thick or improperly mixed inks can increase the pressure needed to push the ink through the mesh, contributing to screen breakdowns.

How To Fix It: Maintaining the correct ink consistency is crucial for achieving optimal print results and prolonging screen life. Follow ink manufacturer recommendations for mixing ratios and viscosity adjustments to ensure smooth ink flow and minimal stress on the screen.

9. Damaged Squeegees

Problem: Damaged or worn squeegees can apply uneven pressure across the screen, accelerating stencil breakdown.

How To Fix It: Regularly inspect and replace worn or damaged squeegees to maintain consistent print quality and prolong screen life. Ensure that squeegees are properly set for angle and pressure to distribute ink evenly across the screen surface.

10. Press Setup Incorrectly

Problem: Improper press settings, excessive pressure, or aggressive printing techniques can strain the screen and lead to premature breakdowns.

How To Fix It: Optimize press settings to minimize stress on the screen while still achieving satisfactory print results. Adjust off-contact settings, pressure levels, and printing speeds to strike the right balance between print quality and screen longevity. Gentle handling and adherence to proper printing techniques can help prevent unnecessary wear and tear on the screen.

Dial in Your Screen Room & Press Conditions for Screen Durability

By paying attention to factors such as emulsion exposure, artwork quality, screen tension, environmental conditions, and on-press variables, printers can minimize the risk of screen breakdowns and maximize the lifespan of their screens.

Regular inspection, maintenance, and adherence to best practices throughout the prepress, coating, printing, and cleaning processes are crucial for identifying and rectifying potential issues before they escalate into costly problems. By prioritizing quality materials, proper techniques, and diligent equipment maintenance, printers can optimize their screen printing workflow and achieve consistent, high-quality results.

Additional Tips:

• Conduct regular inspections of screens, equipment, and printing environment.
• Invest in quality materials and equipment to ensure reliable performance.
• Provide ongoing training for staff to promote adherence to best practices and techniques.
• Keep detailed records of production processes and any issues encountered for future reference and troubleshooting.

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