How to Troubleshoot Poor Adhesion in Inkjet Printing
In inkjet printing, poor adhesion can lead to smudging, flaking, or fading of printed codes, barcodes, or graphics. Identifying the root causes and applying the correct solutions ensures your print stays intact throughout handling, storage, and distribution.
Common Causes of Poor Ink Adhesion
1. Incompatible Ink and Substrate
Explanation: Different materials have different surface energies. Some inks are formulated for porous materials (e.g., cardboard), while others are needed for non-porous materials like plastic or metal.
Solution: Match the ink chemistry (solvent-based, UV-curable, pigmented) to the substrate. Use adhesion promoters if needed for challenging materials.
2. Surface Contamination
Explanation: Dust, oil, moisture, or mold release agents on the surface prevent proper ink bonding.
Solution: Clean the substrate before printing using appropriate methods (air blowing, wiping, plasma treatment if needed).
3. Incorrect Drying or Curing
Explanation: If the ink does not dry or cure properly, it remains vulnerable to smudging and peeling.
Solution: Adjust drying temperatures, add IR dryers, or switch to fast-drying inks if line speed is too fast for proper setting.
4. Low Surface Energy of Substrate
Explanation: Materials like polyethylene (PE), polypropylene (PP), or Teflon have very low surface energy, making it hard for inks to adhere.
Solution: Pre-treat surfaces using flame treatment, corona treatment, or switch to specialized inks designed for low surface energy substrates.
5. Incorrect Printer Settings
Explanation: Incorrect firing voltage, print distance, or drop size can affect how well the ink wets and bonds with the surface.
Solution: Calibrate printhead parameters based on substrate characteristics and ink type.
Checklist for Improving Ink Adhesion
- Verify substrate type and select compatible ink formulation.
- Clean substrates thoroughly to remove contamination before printing.
- Optimize curing or drying systems to match production speed.
- Apply surface treatments if necessary to increase surface energy.
- Adjust printer settings like firing voltage, print distance, and droplet size.
Substrates That Commonly Cause Adhesion Problems
- Flexible films (PE, PP, PET)
- Glass and glossy ceramics
- Metal surfaces with oil residues
- Rubber and silicone-based materials
- Recycled plastics or textured surfaces
FAQs
- Can I add a topcoat to improve adhesion? Yes. Applying varnishes or protective coatings after printing can improve abrasion and chemical resistance in tough environments.
- What is surface energy and why does it matter? Surface energy determines how easily a liquid (ink) spreads on a surface. Higher surface energy improves ink wetting and bonding, essential for good adhesion.
Conclusion
Poor ink adhesion can be frustrating, but it’s often solvable with correct ink selection, substrate preparation, and printer calibration. Proactively addressing surface and environmental factors ensures clean, durable, and reliable coding. Need help selecting the best inks or tuning your inkjet printer for better adhesion? Contact Cheef Inkjet today at sales@cheef.cn!
