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OPTIMISED SOLUTIONS FOR REGISTERED EMBOSSING
Dieffenbacher Zaisenhausen now offers the coating industry even greater
scope for design in the form of newly developed systems which deliver an
extremely high level of positioning accuracy, thus ensuring that the
finished products are more vivid and natural in appearance.
Suppliers of laminate
flooring have succeeded in boosting the appeal of their products and
increasing their market shares by continually developing attractive
patterns and surface finishes, giving consumers exactly what they want,
namely high-quality products with a realistic look and feel. The design of
the surface structure is decisive. It is now possible to produce a
three-dimensional appearance and, therefore, create the natural and
authentic-looking products that the market demands. On a technical level,
manufacturers face the stiff challenge of matching the decorative pattern
to the surface structure as precisely as possible. If there is a slight
discrepancy, the customer's illusion of authenticity is shattered and the
value of the product is diminished considerably. One example of this would
be a tile pattern with non-matching grout lines.
In series production, modern, high-quality coating plants of conventional
design allow near- perfect congruence in pattern and structure, within
certain tolerances. However, for many products, the requirements are far
more stringent than even this. The Dieffenbacher Zaisenhausen plant
concept is designed for those stages of the production process, which are
decisive with respect to the quality and the accuracy of the embossing on
the finished product. In the loading area, for example, the specially
developed positioning belt has an optical detection system for determining
the exact position of the decorative film, with a resolution of upto
O.O3mm. Motor-driven correcting elements enable any deviations from the
desired position, lengthways or crossways, to be put right immediately.
One of the main features to be modified was the motion sequence in the
loading and pressing area, which is critical with regard to positioning
accuracy in conventional plants. Here all the guides and bearings were
designed using highly precise, state-of-the-art components. Positioning in
the limit positions is highly accurate. All of the drives are asynchronous
servomotors with low-backlash gears and frequency converters. When it came
to developing a system for depositing the press material in the press, the
main aim was to find an innovative ant viable solution to maintain the
high degree of positioning accuracy already achieved up to this point in
the production process. To this end, the entire loading and depositing
system had to be re-designed and re-engineered. The kinematics of the
depositing process was modified to incorporate an additional loading tray
tilting function in conjunction with extremely precise control and
position strategies.
Even the short-cycle press itself underwent major changes. Firstly it was
equipped with a precision guide for the stroke movement. Furthermore, the
guide is hydraulically preloaded, thus ensuring an extremely low degree of
play. In extreme situations, it yields hydraulically and thus allows the
press ram to re-align itself automatically. The caul plate holders were
designed to allow extremely precise locating of the caul plates on the one
hand and safe, simple caul plate changes (semi-automatic caul plate
changes) on the other hand, all in keeping with Dieffenbacher's high
quality standards. Dieffenbacher opted to use the tried-and-trusted
SIEMENS S 7 system for the control duties. For the program developers, an
effective plant concept needs an easy-to-understand and user-friendly
visualization system. Great importance was also attached to keeping the
system open for corrections from outside so that it is always possible to
influence the process and its individual parameters.
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