In egg tray production, the vacuum holes and water spray holes on the molds play a critical role.
Vacuum holes are responsible for evenly absorbing pulp onto the mold surface to form the product.
Water spray holes assist in washing and demolding, ensuring smooth release of finished trays.
However, during continuous operation, pulp fibers and impurities often block these holes. This leads to weak suction, incomplete forming, or difficult demolding, which directly affects product quality and production efficiency.
This article explains the causes, symptoms, solutions, and preventive measures for mold clogging in egg tray machines.
Common Causes of Mold Clogging
Excessive pulp impurities – waste paper contains dust, film, and fine fibers that accumulate in the holes.
High pulp concentration – overly thick pulp deposits around hole openings.
Insufficient vacuum pressure – weak suction leaves fibers inside the holes.
Small hole design – fine apertures are more prone to fiber blockage.
Lack of regular cleaning – buildup worsens if molds are not cleaned routinely.
Symptoms of Clogged Molds
Weak suction: pulp cannot adhere evenly, resulting in incomplete forming.
Uneven product weight: trays are thin in some areas and thick in others.
Demolding problems: trays stick tightly to the mold, slowing down automation.
Lower productivity: frequent shutdowns for cleaning reduce output.
Solutions
1. On-line Quick Cleaning
Reverse air blowing: use compressed air from the back of the mold to blow out fibers.
High-pressure water washing: spray the mold surface to flush away pulp deposits.
2. Deep Cleaning During Shutdown
Ultrasonic cleaning: immerse molds in an ultrasonic tank to loosen pulp fibers.
Chemical soaking: use diluted alkaline cleaning solution (e.g., sodium hydroxide) to dissolve residues.
Manual brushing: clean hole by hole with fine brushes or cleaning needles.
3. Process Optimization
Adjust pulp concentration: keep within an optimal range (typically 0.8%–1.2%).
Enhance vacuum system: ensure stable suction to reduce fiber deposits.
Upgrade mold design: adopt anti-clog molds with smoother surfaces and optimized apertures.
Preventive Measures
Pulp pretreatment: install pressure screens or cleaners to remove impurities before pulping.
Scheduled cleaning: daily washing and weekly deep cleaning extend mold lifespan.
Automatic cleaning devices: advanced egg tray machines integrate online spray cleaning systems.
Better raw materials: use cleaner waste paper or bleached pulp to reduce clogging risk.
Standardized operation: maintain consistent pulp mixing and avoid concentration fluctuations.
Conclusion
Mold clogging is a common challenge in egg tray production. The key to solving it lies in:
Short-term measures: quick cleaning with air or water to restore operation.
Long-term strategies: pulp treatment, mold optimization, and regular maintenance for sustainable production.
By applying scientific cleaning methods and preventive solutions, manufacturers can improve product quality, stabilize production efficiency, and extend mold service life—ultimately achieving greater profitability.
