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Packaging 101 - Heating Sealer

A heating sealer is one type machine used to sealing products, packaging and other thermoplastic materials can be heat. This can be with single layer thermoplastic or with multi layer lamination film. Heat sealing can melt two similar materials together or can melt different materials, one of which has a thermoplastic layer.


Heat sealing process

Heat sealing is the process of sealing one thermoplastic to another similar thermoplastic using heat and pressure. The direct contact method of heat sealing utilizes a constantly heated die or sealing bar to apply heat to a specific contact area or path to seal or weld the thermoplastics together. Heat sealing is used for many applications, including heat seal connectors, thermally activated adhesives, film media, plastic ports or foil sealing.


Applications for the heat sealing process

Plastic bags and other packaging is often formed and sealed by heat sealers. Medical and fluid bags used in the medical, bioengineering and food industries. Fluid bags are made out of a multitude of varying materials such as foils, filter media, thermoplastics and laminates.


Types of heat sealing

Hot bar sealers- have heated tooling kept at a constant temperature (aka Direct Contact Thermal Sealing). They use one or more heated bars, irons, or dies which contact the material to heat the interface and form a bond. The bars, irons and dies have various configurations and can be covered with a release layer or utilize various slick interposer materials (i.e. Teflon films) to prevent sticking to the hot tooling.

Continuous band sealers- (aka Band type heat sealers) utilize moving belts over heating elements.

Impulse heat sealers- have heating elements (one or two) of Nichrome placed between a resilient synthetic rubber and a release surface of film or fabric. The heating elements are not continuously heated; heat is generated only when current flows. When the materials are placed in the heat sealer, they are held in place by pressure. An electric current heats the heating element for a specified time to create the required temperature. the Jaws hold the material in place after the heat is stopped, sometimes with cooling water: this allows the material to fuse before stress can be applied.

Induction sealing is a non-contact type of sealing used for inner seals in bottle caps.

Ultrasonic welding uses high-frequency ultrasonic acoustic vibrations to workpieces being held together under pressure to create a weld.

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