Film tension, Testing the web, Operating instructions – GBC 27C User Manual
Page 27
Page 6-11
Operating Instructions
27C
F
ILM
T
ENSION
Proper film tension, known as brake tension, is the
minimum amount required to eliminate wrinkles in the
finished item. Tension adjustments are not necessary
if you are using 1.5 or 3 mil (38 or 75 mic) film unless
the lamination is curling up or down. Generally, 5 and
10 mil (125 and 250 mic) films require more tension.
As the film roll becomes smaller, tension increases,
thus the adjustment needs to be loosened. Film
tension should be checked occasionally to assure
that the adjustment is correct.
The film should be taut with no gaps between the
film and pressure rollers. A properly adjusted roll
of film should not require excessive force to turn by
hand. Film tension should be enough to introduce a
minor amount of drag as the film unrolls. Insufficient
tension causes wrinkles, while too much tension
causes stretching (necking). Uneven tension
between the top and bottom rolls create curl. Too
much upper tension creates upward curl. Too much
lower tension bottom causes downward curl.
Fig. 6-19. Tension Adjustment Knobs.
The machine is equipped with external tension knobs
located on the left side. Turning the knobs clockwise
increases the tension while counterclockwise
decreases the tension.
Testing the Web
After webbing the machine, it is important that the
films run straight and evenly.
To test the web:
Set the roller pressure handle to an appropriate
position.
Press the
RUN button and run approximately
6 in. (10 cm) of laminate.
Press the
STOP button.
Visually inspect the top and bottom films where
they enter the nip.
The films should be tight against the rollers
at both ends. If they are not, use the tension
adjustment knobs to tighten the loose supply film
brake and run another test.
Ensure that the release liner take-up is keeping
the liner tight against the idler bar.
If it is loose, use the tension adjustment knob to
increase the tension.
Run test materials before laminating good
materials.
1.
2.
3.
4.
5.
6.
Tension adjustment
knobs