Vacuum-molded packaging, which removes air and heat-seals the package, provides an oxygen-free environment for grains, effectively extending their shelf life and creating a neat product appearance. However, this packaging method also presents some notable defects during actual production and transportation. Below are two main defects and their corresponding solutions.
Defect 1: Packaging Bags Are Prone to Puncturing Due to Sharp Grains or External Force
Analysis:
Grains such as millet, oats, and buckwheat often have hard, sharp edges. Under the negative pressure of vacuum packaging, the bag tightly conforms to the grains, causing these sharp points to exert continuous and intense pressure on the packaging film, particularly at the sealed edges. During subsequent storage, transportation, and handling, any squeezing, dropping, or impact can easily puncture the bag, leading to air leakage. This compromises the vacuum protection, causing the grains to spoil quickly.
Solutions:
- Use Multi-Layer Composite High-Barrier Packaging Materials:
Employ packaging films composed of laminated layers such as PET, NY (nylon), AL (aluminum foil), and CPP. The nylon layer offers excellent puncture resistance, effectively withstanding the impact of sharp grain edges, while the aluminum foil layer provides superior barrier properties, preventing oxygen and moisture ingress.
- Optimize Packaging Design and Filling Processes:
Without compromising vacuum effectiveness, avoid over-tight packaging by allowing minimal buffer space. Additionally, implement precise screening and polishing processes before filling to remove impurities and smooth overly sharp grains, thereby reducing the risk of puncture at the source.
Defect 2: Packaging Seal Integrity Compromised by Grain Dust Contamination
Analysis:
During processing and transportation, grains inevitably generate fine dust. During vacuum heat-sealing, this dust can easily disperse and adhere to the sealing area of the packaging bag. The dust particles hinder the pure thermal fusion of the inner packaging layers, resulting in imperfect seals and minute, often undetectable, leaks. Such "false seals" cause the vacuum environment to fail rapidly, leading to higher defect rates and customer complaints.
Solutions:
- Enhance Pre-Filling Cleaning and Dust Removal:
Incorporate robust dust removal and static elimination steps before the grains are filled into the packaging bags. For example, use cyclone separators or vibrating screens to effectively remove dust adhering to the grain surfaces, ensuring the grains are clean and dry when packaged.
- Improve Heat-Seal Design and Equipment:
Employ filling nozzles equipped with dust removal systems or install high-pressure air jets at the heat-sealing station to blow away dust from the sealing area momentarily before closing the molds. Additionally, wider heat-seal designs can be adopted to provide a larger effective sealing area, ensuring reliability even if minor dust contamination occurs.
