As a result of many unknown variables which may significantly impact sealing results of an induction machine, an induction sealing process validation is highly advised.
The sealing machine could be bumped on a small angle, a slight height adjustment might have been made, large bottle height variations, and conveyor speed variations can all drastically impact the induction sealing results.
Visual Inspections Process Validation for Induction Sealing
For properly trained operators, this process can be the best of all; in particular when they are competent exactly how induction foils look like when they have obtained the precise conditions for a good seal.
Some things to look for include:
a) A Concentric heat pattern in the foil; when you hold the foil to some light source with the accurate position you should observe a smaller sized circle where material was not heat affected. This implies the seal has heated externally then inwards in an even pattern; therefore a good seal.
b) Overheating – there are numerous of aspects to point out if there have been overheating including visual discolouration of one or more layers of the induction foil, bubbling or creasing, a flattening of the bottle neck, melting of a backing resealing foam (if there are any).
c) Unequal heat sealing; associated in some ways to (a) above; a foil can look nicely sealed but an unequal heat seal can result in aspects of the seal being too tightly “welded” or very lightly welded and more likely to “pop loose with some pressure on the side walls of the bottle/container.
So long as you have operators in each shift that happen to be properly trained in the above areas to consider, then the “subjectivity” of a visual process validation is reduced and the validation will hold more benefit.
2.0 Basic version – Linepatrolman™ Process Validation for Induction Sealing
Should you have doubts that you’re going to always have operators properly trained or experienced enough to cover what exactly is required for a
reliable visual process of validation for induction sealing then there is the straightforward option of a Linepatrolman™ which has no additional controls than a reset button.
This unit needs absolutely no programming and simply provides an built-in count of the energy seen by the testing cell moving about the same path as the products.
The Benefel site has a good animation of the Linepatrolman™
In this animation, the count gets up to “50”. If that reading worked for the last batch and was verified being a good reading by a very comprehensive visual assessment (as well as some leak screening), operators would look to obtain equivalent readings in next production runs of the same product.
Many organisations need an induction sealing measurement since the whole process is a time and position dependent. When there is speed variance as the product passes through the induction machine the outcome is likewise different. For an operator a 10% alteration of the speed of a product conveyor may not be found. To an operator a 1mm height adjustment of the sealing head most likely is not noticed or a 5 degree angle difference in guide rails could possibly be missed. The induction sealing setting on the induction sealing machine may not have changed at all, but the sealing effects would have changed considerably!
The Line Patrolman™ is a unique process validation device that can pick up changes in energy transfer in what may seem like an identical set-up to the last time an induction machine has been operated. This eliminates guess work on the energy transfer and give confidence that the machine is set to the ideal settings.