Sometimes you may see film detach from an item along one edge (the edge
that was put in first). This happens when the material is put all the way into
the nip before the machine is started. The area of film between the shoes
and the nip can cool off too much while the machine is idle. The adhesive
may not be hot enough to stick.
The way to prevent this is to let a few inches of film go though before putting
in sheets to be laminated. This serves other purposes besides ensuring the
front edge of the piece will be properly sealed. It gives the machine a chance
to take up the slack that develops in the film whenever the machine is
stopped and it prevents the following problem as well.
PROBLEM:
A laminated item comes out with a large “oily” spot on or near
the leading edge.
SOLUTION:
It’s not oil that causes this effect but excess adhesive. When a
machine is left heated but idle for a few minutes or longer the adhesive from
the film over the shoes can form droplets if material is put in immediately.
This excess adhesive saturates an area of paper creating what looks like an
oily spot. The solution, as mentioned above, is just to let a few inches of film
go through before feeding in your work.
Anytime you are laminating unfamiliar or costly items it is a good idea to start
with an expendable sample or test piece. Laminating a test piece first gives
you an indication of the results you’ll get and also takes care of any pooled
adhesive.
PROBLEM:
A milky, hazy line about an inch wide appears periodically
across the width of the web immediately after initial warm-up.
SOLUTION:
The rollers are not evenly heated, and the cold side of the
rollers is preventing the adhesive from melting. When warming up the
machine, keep the rollers open and keep the forward drive on at low speed.
PROBLEM:
The machine produces a continuous squealing noise when
laminating.
SOLUTION:
To a certain extent, it is normal for some laminating film to
squeal as it is pulled over the heat shoes under tension. This noise is
produced via the same principles that make a violin squeal. Some of the
compounds put on film to keep it from sticking to itself seem to act like resin
on the bow of the violin—they enhance the noise.
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