The Breyer OptiFlex line allows producers of polycarbonate, PMMA and PET film to retain flexibility in their process, according to Breyer itself.
Side-polished, matte and structured film with optical properties can be produced on a single OptiFlex line. The systems cater for thickness ranges from 50-1000 µm.
The automotive market offers good opportunities for the application of in-mould decoration technology, particularly for illuminated controls. Breyer says that this market places high demands on the optical quality of the film used. It suggests that some extrusion systems and their integrated calender machines may run into problems when processing thicknesses of less than 500 microns.
The bending of the calender rolls and thus the thickness tolerances do not allow for a thinner production in closed roll gap mode.
When pressing the film between the calender rolls too much, tensions can be stored inside the film which can result in shrinkage.
Flat applications naturally require an especially flat film. On the Breyer calender with its third calender roll, the position of the third roll in relation to the center roll can be adjusted exactly to where top and lower side cooling is balanced and the film becomes flat.
The Breyer gap control system includes an automatic film thickness setting. The operation mode allows a precise and automatic adjustment of the gap, simply by changing the extrusion speed (pressure control mode). The operator changes the speed value on the touch screen in accordance with the new product thickness, and within a matter of seconds the product is set to the desired thickness. This saves time and costs compared with conventional gap adjustment systems, which require the operator to adjust the speed separately, after the gap adjustments have been implemented.
With the same system the operator can change between distance control (setting the thickness) and pressure control mode on the fly. The pressure control mode allows users to set a specific gap pressure inside the roll gap. Too much gap pressure generates too much stress inside the film. Shrinkage can occur and result in waste.
With an FSR system (flexible shell roll) low pressure can be applied to the film. Thanks to a quick-exchange device on the first and center calender roll, the machine can be quickly adapted for different types of film.
In combination with the Breyer calender system a film with extremely low retardation rates can be produced, which is essential for the optical characteristics of the film.
Fast set-up is another key advantage, says the group. In one example, in combination with a Breyer calender, a 200 µm two-side-polished film with at thickness tolerances of 2-3 µm was set up in less than 15 minutes.
For applications in the optical field, calendered film at this thickness can act as an alternative to cast film, with Breyer claiming improved tolerances, high gloss on both sides and improved aesthetics.