Naturally, pillow packaging machines face significantly more complex challenges when packaging products like ice cream than for other common foods (such as biscuits and candy). These challenges primarily focus on three core issues: temperature, material properties, and hygiene requirements.
The following are the main challenges and detailed explanations:
Mechanical and material challenges posed by extremely low temperatures (-25°C to -35°C)
This is the most critical challenge. Mechanical equipment that operates well at room temperature will experience a series of problems in extremely low-temperature environments.
Material embrittlement and shrinkage:
Packaging film: Commonly used plastic composite films (such as OPP/PE) become brittle and shrink at extremely low temperatures. If the film’s low-temperature performance is poor or the formulation is incorrect, tears are likely to occur at the cutters in the longitudinal and transverse seals, leading to package damage.
Mechanical components: Standard seals, rubber components, and plastic guides lose their elasticity at low temperatures, becoming hard and brittle, and easily damaged, resulting in reduced accuracy or failure.
Condensation and Frost (“Freezing Machine”):
When the packaging environment is high in humidity, moisture in the air can instantly condense onto cold machine components (such as the former, sealing blade, and guide rods), forming frost, even thick layers of ice.
Consequences:
Impact on packaging quality: The ice layer alters the shape and smoothness of the former and guide rods, resulting in poor film pulling, poor forming, and crooked or wrinkled packages.
Damage to the sealing blade: Ice on the sealing blade impairs heat conduction, causing a weak seal (false seal) or an uneven seal.
Machine jam: Severe icing can cause moving parts (such as the swing arm and cutter) to freeze, causing machine downtime or even motor overload damage.
Heat sealing difficulties:
The sealing blade must heat the cold packaging film to the sealing temperature in a very short time, which places extremely high demands on the heating system’s response speed and power.
After sealing, the hot sealing line needs to be quickly cooled to set. However, in low-temperature environments, excessive cooling can lead to concentrated thermal stresses, which in turn increases the brittleness of the seal.
Product Physical Properties
Non-fixed shape (soft, sticky, and easily deformed): Ice cream is not a completely solid solid when packaged. Especially right after it comes out of the filling machine, the surface may be slightly softened and sticky.
Blister/film sticking: The product can easily stick to the former or conveyor belt, causing jams or bag inversion.
Deformation: Excessive thrust or overly tight gripping by the robot can leave indentations on the surface of the ice cream, affecting its appearance.
Various Shapes and Sizes: Ice cream comes in a variety of forms, including sticks, blocks, boxes, and family packs. The pillow machine needs to be able to quickly adjust to accommodate the length, width, height, and delivery rhythm of different products.
Extremely High Hygiene Requirements
Waterproof and Corrosion-Resistant
The production environment requires frequent cleaning. Therefore, the equipment must be made of stainless steel and have a good waterproof design to prevent water from seeping into the motor and transmission components.
Easy Cleaning: The equipment’s structural design must be simple and streamlined, avoiding unsafe corners and allowing for quick disassembly and cleaning to prevent bacterial growth.
Lubricant Contamination: All lubrication points that may come into contact with the product or packaging film must use food-grade lubricants and be well-sealed to prevent leakage and contamination.
Stability and Precision Under High-Speed Production
High Synchronicity Requirements: Precise coordination is required for a series of operations, including film pulling, forming, longitudinal sealing, product pushing, transverse sealing, and cutting. Any misalignment can lead to problems such as package misalignment and product damage.
Film Tension Control: The film’s tension properties change at low temperatures, requiring a stable and reliable tension control system to ensure alignment of the packaging pattern and smooth film pulling.
Summary and Solutions
To address these challenges, professional ice cream pillow packaging machines typically employ the following designs and measures:
Special Material Selection:
Use low-temperature-resistant packaging film (such as PE with specific additives).
Use low-temperature-resistant stainless steel and special engineering plastics for parts that come into contact with the product.
Use low-temperature-resistant materials such as silicone for seals.
Targeted Anti-Frost Design:
Anti-Stick Sealing Blade Treatment: Using a Teflon (PTFE) or other anti-stick coating on the sealing blade prevents ice cream particles or film from sticking.
Heating Defrost/Air Knife Purge: Installing a small heater in key areas (such as near the former) or using dry compressed air to continuously purge creates an air curtain, isolates the moist air, and prevents frost formation. This is currently the most effective method.
Powerful Heat Sealing System:
Using fast-response heating methods such as high-frequency induction heating or pulse heating, ensures instantaneous heat delivery for complete sealing.
Strict Hygienic Design:
An all-stainless steel body, an IP65 or higher waterproof motor, and an open, corner-free structure meet food safety standards.
In short, pillow-type ice cream packaging machines are an art form that balances extreme cold and high heat, as well as softness and precision. The challenge lies not in the fundamentals but in achieving stable, efficient, and hygienic long-term operation under extreme conditions.