38
3.6
Top film unwinding unit
The top film unwinding unit is fitted to the control cabinet (see Figure 3.12).
There are two types of top film unwinds, the WP400 and the CK400.
The film that is unwound here travels via the top film infeed roll onto the bottom film. Its
functioning is the same as described in paragraph 3.3.2
3.7
Photocell and film brake
When a printed top film is used a photocell and a film brake (see Figure 3.13) ensure that the
print is in the correct position on the package.
The photocell detects the position of print marks and the film brake corrects the distance with
reference to the bottom film.
Figure 3.13 Photocell
Photocell
Figure 3.12 WP-400 top film unwind