22/09/2012

Package Evaluation
T i i
Training
Transversal Sealing (TS Seal)

PE-03/2012-04-01

Agenda
1. Principle of Transversal sealing
2. Evaluation - Tear down method + Practical
3. Evaluation - Dissolving test method + Practical
4. Evaluation - Heat Pattern + Practical
5. Evaluation - TS integrity by red ink + Practical
6 Example of TS defect
6.

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1. Principle of TS
sealing
li
Transversal Sealing (TS Seal)

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1. Principle of TS sealing
What do we need to seal?

Too short sealing time will affect proper heat diffusion through
the polymer
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1. Principle of TS sealing
Polyethylene Sealing – Microscopic Scale

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1. Principle of TS sealing
General information on TS Sealing

The heat required to melt the sealing layer of the packaging
material is generated by induction in the aluminium foil in the
packaging material
► TPIH sealing systems can produce short pulses with sufficient heat
► The heat is transferred directly to the sealing area
►

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1. Principle of TS sealing
Jaw System

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1. Principle of TS sealing
Definition

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1. Principle of TS sealing
Thermograph of Transversal Seal

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1. Principle of TS sealing
Induction Network

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1. Principle of TS sealing
TS sealing components
TPIH 2000

TPIH 2500

Generator
Transformer

Inductor
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1. Principle of TS sealing
TBA/19 – Component of the jaw system

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1. Principle of TS sealing
TBA/19 – Sealing jaw components


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1. Principle of TS sealing
TBA/19 – Pressure jaw components

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1. Principle of TS sealing
Chain – Sealing jaw components

Inductor

Busbar

Carbon Brush
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1. Principle of TS sealing
Chain – Pressure jaw components

Knife

Spring
Bushing


Dolly

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1. Principle of TS sealing
Principle of ridge induction heating (IH)

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2. Evaluation - Tear
d
down
method
th d
Transversal Sealing (TS Seal)

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2. Evaluation - Tear down
Evaluation concept

The method consists of
pulling TS (1) apart using
the stretch pliers (2) and
examining how the seal
separates.
► Seal must be mechanically
stronger than the materials.
If the sealing
g is g
good,, the
packaging material/strip
layers (plastic film, Al-foil or
paperboard) break while the
seal does not separate.
►

Seal is stronger than materials

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2. Evaluation - Tear down
Definition
►

Blocked seal
Blocked seals, or cold seal, is
when the inner packaging material
layers have not completely
merged. Separation takes place
between the sealing layers.


►

Plastic lump
Plastic lump is a plastic residue
that solidifies out of the dolly area.
Plastic lumps are a potential
danger, the hard residue might
punch the packaging material
layers during distribution of the
package compromising package
integrity.
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2. Evaluation - Tear down
Preparation of the samples – TS rough check

Unfold the top and bottom flaps of the packages
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2. Evaluation - Tear down
Check of the samples – TS rough check
►

Checking the integrity of

the TS by gently
squeezing the package
with the fingers.

►

If there is product leakage,
the TS has a gross defect
(most likely a dolly is
missing)

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2. Evaluation - Tear down
Preparation of the samples – TS accurate check
St 1:
Step
1 Cut
C t off
ff the
th top
t and
d
bottom of the packages at a
distance of about 25 – 30

mm, from the top and bottom
fin creases.
Rinse the samples and dry
p
them with either compressed
air or soft tissue.
Note! Use compressed air with care
since it might damage the sample.

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2. Evaluation - Tear down
Preparation of the samples – TS accurate check
Step 2:
St
2 Cut
C t off
ff 1 mm max
from the edges (at the
corner).
Note: It is recommended to start
cutting from the outside in order
to have control over that
important section.

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2. Evaluation - Tear down
Check of the samples – TS accurate check
Step 1: Run your finger over
the TS and check if there are
plastic lumps or ridges.
Plastic lumps show that the
sealing is not correct.

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2. Evaluation - Tear down
Check of the samples – TS accurate check
Step 2: Place the sample in
the stretch pliers and gently
squeeze the handles to
stretch the seal.

Good light is important when
evaluation the seal quality
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2. Evaluation - Tear down
Check of the samples – TS accurate check

Step 3: Stretch by pressing
the plier handles along the
whole length of the sample.
Stretch a little bit at a time,
both ends (1) towards the
LS/TS cross (3), stretch the
LS/TS cross last.
last

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2. Evaluation - Tear down
Critical points of the transversal seal are:

1. The cross : which is the
point where the TS and LS
meet
2. The corners : which are
at the ends of the package.

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2. Evaluation - Tear down
Evaluation of the samples


Defective seal
“Plastic lump”
Before pulling the seal
apart, check that there
are no plastic lump in
the sealing. Use your
fingernails to detect
plastic lump.
p
p
Plastic lumps (1) are a
potential danger, hard
residue might punch
the PM layers during
distribution of the
package.
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2. Evaluation - Tear down
Evaluation of the samples

Good seal
The wave (1) is
still encapsulated
in the heated
area and will not
d t
determine
i
integrity issues.


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2. Evaluation - Tear down
Evaluation of the samples

Good seal
The seal does not
come apart; the plastic
film stretches and
breaks, leaving the
paperboard uncovered.

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2. Evaluation - Tear down
Evaluation of the samples

Good seal
At the cross where TS and LS
meet, the LS must be considered
as additional plastic multilayer.
Below picture shows the LS
which stretches and separates.


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2. Evaluation - Tear down
Evaluation of the samples

Good seal
The seal does
not come part;
the plastic film
breaks leaving
Al-foil uncovered.

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2. Evaluation - Tear down
Evaluation of the samples

Good seal
The seal does
not come part;
the plastic film
stretch.

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2. Evaluation - Tear down
Evaluation of the samples

Defective seal
“Bl k d seal”
“Blocked
l”
The seal separates; no rupture
occurs in the material layers.
The seal appears mattish or
greyish.

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2. Tear down method and practice
Evaluation of the samples

Defective seal
“Blocked seal”
The seal separates;
no rupture occurs in
the material layers.
The seal appears
mattish or greyish.
greyish


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2. Evaluation - Tear down
Evaluation of the samples

Defective seal - “Overheated”
The seal is overheated; the two PE layers are burnt and the
Al-foil shows micro cracks and cuts.
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2. Evaluation - Tear down
Evaluation of the samples

Good Seal - At corner, seal
above the ridge

Blocked Seal - At corner, seal
below the ridge
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3. Dissolving method
and
d practice
ti
Transversal Sealing (TS Seal)

PE-03/2012-04-01

3. Dissolving method and practice
Introduction
► Procedure application:
− During production
− Quality control
− Troubleshooting
► Procedure:
− Chemical reaction, from the multilayer structure to the
inside pouch, via acid or alkali reaction
− Heat pattern assessment and red ink tightness of each
sealing jaw

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3. Dissolving method and practice
Dissolving packaging


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3. Dissolving method and practice
Dissolving Package Purpose
► Information gained:
− Monitor sealing components state and performance
− Control settings over time
− Monitor each sealing link over time
− Allow archiving and traceability
• plastic lumps
• product residue

p
Evaluation of the samples

• overheated seal
• channels (unsealed spots)
• cuts in the ridge area
• Bending off
• sealing symmetry
• abnormal heat pattern
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3. Dissolving method and practice

Preparation of the sample
Step 1:
►

Unfold all the flaps and
flatten the packages. Cut
the package in a I shape,
as shown in the picture
(app. 25 – 30mm, from the
top and bottom fin creases).

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3. Dissolving method and practice
Preparation of the sample
Step
p 2:
►

Mark each sample in order
to distinguish the TOP and
BOTTOM seal after
dissolution.

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3. Dissolving method and practice
Preparation of the sample

Step 2: cont…
►

Cut with a distinctive cut
type (3) part of the
sample to identify from
which jaw pairs the
package comes

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3. Dissolving method and practice
Preparation of the sample
Step 3:
►

If possible, cut the top of
the package using the
pinking scissors for an
easy identification of the
top. This step still remain
6 layers. (1 – 6)

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3. Dissolving method and practice
Preparation of the sample
Step 4:
►

Peel off the external
packaging (outer PE, a
part of PB layer will come
off). The PM layers left at
the stage on the sample
are the following: (2 – 6)

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3. Dissolving method and practice
Fast methods :
Use HCl acid

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3. Dissolving method and practice
Alternative VERY FAST/ FAST methods : Use
HNO3 acid and alkaline NaOH

Alternative – Acid &
Alkaline agent (very fast)
Solution
used

Advantages

Disadvantages

Alternative – Acid &
Alkaline agent (fast)

- HNO3 60-65%
- NaOH 15%

- HNO3 30-35%
- NaOH 15%

- very fast (sample ready in
20 min)
- Room temperature
temperature, no
need water bath

- fast (sample ready within 1
hr)
- Room temperature
temperature, no
need water bath


- risk of spoiling of the
sample with too long
immersion in solution

- risk of spoiling of the sample
with too long immersion in
solution

3. Dissolving method and practice
Dissolving Method – Chemical Warning
Warning !
Risk of personal injury!
Ob
Observe
safety
f t regulations
l ti
when
h working
ki with
ith ACIDS
ACIDS. P
Preparation
ti
and handling of HCl, HNO3 and NaOH solutions must be carried out
in a well-ventilated environment, as fumes may be given off. It
should be carry out in an Exhaust cabinet. Always wear protective
goggles and gloves. Use heat resistant beakers for preparation and
storage. Exhausted chemical must be disposed of in accordance
with current regulations.


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