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13.3
Lack of Edge Seal Down
Lack of edge seal is the result of insufficient down pressure from the nip rollers.
Possible Solution
The article being laminated is too thick to achieve a satisfactory seal (See Section 9.5, Thick stock,
Page
15).
Possible
Solution
Side by side lamination of any heavy article may prevent satisfactory seal down in the area between
the sheets. Mount narrow film and run one up (See Section 9.4, Side by Side lamination, Page 15).
13.4 Creasing
Problem
: Creasing of the laminated article.
Creasing of laminated articles usually occurs with large posters (particularly light weights) and often
relates to poor feeding technique.
Possible Solution
Creasing beginning at the centre of the front edge and running longitudinally through the centre of
the poster usually indicates that the item has been held on the feed table close to the heat shoes for a
short period of time. The radiant heat from the heat shoes will dry out the leading edge of the poster
and cause it to buckle on entry. Do not delay your feeding - he who delays is lost.
Possible Solution
Arc shaped creasing occurring at the leading edge usually indicates that the poster has been forced
into the nip. Try to develop the knack of feeding the article into the nip a little slower than the film
moves (See Section 9.3, Feeding Techniques, Page 15).
13.5
Longitudinal Wrinkling of Film
Problem:
The film, rather than the poster, is wrinkling in the direction of the film path.
This fault usually indicates that there is insufficient tension on the laminating film.
Possible Solution
Tighten brake knob on the appropriate film mandrel and ensure that the film passing over the heat
shoe is wrinkle free as it leaves the lower section. Caution do not over tension the film.
Possible Solution
Check that you have the correct thread path for the films i.e. ensure that the film passes under each
idler bar and in particular ensure that the lower idler bar is in the "run" position.
Possible Solution
Check heat shoes for any resin build up or surface contamination that may be effecting the smooth
flow of film over their surface. Any contamination may snag the film and cause fluctuating tension
entering the nip. Clean the heat shoe when hot.
Possible Solution
Ensure that the rolls of film are firmly locked onto the core grippers on the film mandrels. Test by
winding brake on hard and seeing whether the film is firmly locked onto the core grippers. If the
film is not firmly "caught" on the grippers, remove the film and inspect the grippers. The spring
position may need adjustment with a screwdriver. Remember to release the brake afterwards.
13.6 Film
Sweating
Problem:
Film sitting on the heat shoe begins to "sweat" with dribblets of molten resin running
down the face of the film. Most common on the lower film web and may deposit on the lower idler
bar.
Film once heated and then left to cool, then reheated again, breaks down the key bond between the
outer plastic and inner and causes the resin to run.
