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Sealing Solutions

Here is a list of some common sealing problems that are encountered, and their possible causes.

Application Torque
No Seal or Weak Seal No Seal or Weak Seal
High Removal Torque
Scorching
Low Removal Torque
Pulp Shears Out of Closure
Other Factors to be considered


Application Torque

To calculate application torque, the standard “rule of thumb” is to take the closure diameter in mm and divide by 2. The result equals the application torque in inch pounds.


No Seal or Weak Seal

  • Output setting too low
  • Conveyor line speed too fast
  • Container / sealing head adjustment
    • coupling distance extreme
    • off-center
    • head not parallel
  • Insufficient cap torque
  • Product contamination
  • Marginal quality container finish
    • Insufficient land area
    • mold marks, flashing, or parting line
    • saddle or taper
  • Bottle treatments and pigments
  • Incompatible liner material

High Removal Torque

  • Insufficient wax absorption due to lack of power or excessive conveyor line speed
  • Bonded backing sticking to closure (single element)
  • Liner quenched by product splashing
  • Excessive application torque
  • Undersized liner disk and plastic from the container finish invading the pulp
  • Excess amount of bonding wax or wrong tem

Scorching

  • Excessive output power setting
  • Closure sealing head alignment
    • not centered
    • not parallel
  • Low application torque
  • Improper liner material

Low Removal Torque


Pulp Shears Out of Closure

  • Insufficient wax absorption (see High Removal Torque)
  • Improper gluing
  • Friction fit liner is undersized

Other Factors to be considered:

  • The proper sealing head for the closure
  • Variations in container height
  • Dimensional conflicts between closure and container
  • Storage considerations of the liner material or container
  • Porosity of the pulp
  • Liner insertion into the closure
  • Package, material, or equipment