Fin Seal vs. Lapse Seal

Fin seal

A fin seal is created by folding a single piece of packaging material around a product and sealing the two inner layers together. This creates a vertical, raised seam that sticks out like a "fin" on the back of the package before being folded flat. 

• Seal construction: The two internal, heat-sealable sides of the film are bonded together.

• Material: It is a more versatile sealing method because it only requires the inner layer of the film to be heat-sealable.

• Appearance: Creates a visible, raised seam on the back of the package. This can be a design consideration, as it may break up continuous artwork.

• Benefits: Generally offers a stronger, more tamper-resistant, and hermetic (airtight) seal, making it ideal for products that require a high barrier against oxygen and moisture.

• Drawbacks: Uses more material since it requires a wider film to create the fin, which makes it less cost-effective than a lap seal. 

Lap seal

A lap seal is made by overlapping one edge of the packaging film over the other and sealing the outer layer of one side to the inner layer of the other. This forms a clean, flat seam on the back of the package. 

• Seal construction: The outside of one film edge is sealed to the inside of the other.

• Material: This method requires the film to be heat-sealable on both the inner and outer surfaces, which can limit material choices.

• Appearance: Creates a smooth, almost invisible, flat seam that doesn't disrupt printed designs or branding on the back of the package.

• Benefits: Uses less packaging material, making it a more economical option. The flat seam also provides a cleaner aesthetic.

• Drawbacks: It may not offer the same level of tamper resistance or barrier protection as a fin seal, especially when used for heavy products.