As you may have noticed at first glance, WPR machines are distinguished by their high-quality industrial design: a tidy arrangement of components, ergonomic styling, clean lines, and premium materials. For the designers at WPR, ensuring that quality is visually reflected in the product design is paramount. The value of these systems is equally significant for their future owners, who appreciate an aesthetically pleasing machine park in their production facilities.
More than just a slot nozzle support
Let’s take a closer look at what might initially seem like an unremarkable component and discover the extensive expertise, experience, and innovative ideas embedded in its design.
The slot nozzle support unit is the central component of all WPR machines. It serves as the workstation for the machine operator and is specifically designed for flexibility and user-friendliness. The operator finds all essential control elements conveniently located in one place, enabling swift and professional execution of tasks.
WPR prioritises a compact and centralised arrangement of the film holder, slot nozzle, and film guide. This allows all settings, positions, and process parameters to be monitored efficiently from a single operating position, eliminating the need to move repeatedly around the machine.
The slot nozzle glue head
The hot melt coating head is the heart of every wrapping system. It applies the hot melt adhesive to the decorative film, making it crucial to have a straightforward method for adjusting centring and width settings of the adhesive application. This is achieved through infinitely adjustable nozzle slides, which can also enable off-centre adhesive coating. The handwheels of the nozzle slides are integrated into the slot nozzle support and equipped with position indicators, allowing the operator to set and adjust the application width quickly and precisely, even during operation, while maintaining a direct view of the glue pattern.
When “Glue Start/Stop” is activated via the central control panel, two pneumatically controlled guide rods move towards the slot nozzle opening to press against the passing decorative film, ensuring that the expelled adhesive is properly transferred onto the film. In the event of an emergency stop or foil break, the system automatically and reliably halts the adhesive flow and releases the pressure rods, preventing uncontrolled adhesive leakage and foil melting at the heated slot nozzle.
Foil holder and foil guide
Ensuring the smooth and precise guiding of decorative film from the film unwinder onto the profile is an essential process in lamination. Two key aspects are fundamental: correct foil tension and precise foil alignment. The foil tension is regulated either manually via rotary switches with pressure indicators on the slot nozzle holder or automatically via an integrated foil brake system.
Furthermore, the machine’s film guiding system and all deflection rods must be designed to facilitate frictionless, secure film processing. Proper alignment is necessary to ensure correct adhesive application while positioning the foil precisely onto the profile. Adjustable flanges assist in centring and securing the foil on the slot nozzle, preventing displacement and ensuring consistent adhesive coverage along the edges. Additionally, the foil must be aligned as it transitions from the slot nozzle onto the profile, ensuring that only the intended surfaces are laminated.
To streamline this process, WPR has developed an exceptionally user-friendly system. Once the foil is correctly aligned at the unwinder, the entire slot nozzle assembly group, including the foil holder, can be adjusted to the profile via a crank with a position indicator. This eliminates the risk of losing the correct alignment during setup or operation. This stepwise adjustment method allows for a rapid and precise alignment of the film guiding system. If your production involves frequent use of variable film rolls that may be unevenly wound or telescoped, you may wish to consider installing an optional automatic film edge control system—the slot nozzle assembly is already designed for such upgrades.
Integrated foil preheating
The slot nozzle support design also allows for the installation of an IR lamp for foil preheating. Should you decide to process particularly thick and/or rigid films, an IR lamp with automatic temperature regulation can be easily retrofitted. This system measures the actual foil temperature and adjusts the heating mechanism to maintain the recommended or programmed temperature. Automatic film preheating is particularly beneficial in profile lamination involving rigid foils, as preheating enhances their elasticity, making them easier to process.
Film trimming before the slot nozzle
Another possible expansion of the slot nozzle assembly is the integrated foil trimming function before adhesive application. If your production frequently involves leftover film rolls that exceed the required profile width, an optional foil cutter can be installed above the slot nozzle. This allows for precise trimming of excess foil before the adhesive is applied. While using pre-cut films tailored to each job is typically more efficient, this integrated trimming system offers a practical solution for utilising leftover foil efficiently in production runs.
Retrofitting onto older lamination machines
Thanks to its compact construction, WPR’s advanced slot nozzles can also be retrofitted onto older wrapping machines. WPR customises the slot nozzle support unit to match the width of your machine bed and manufactures the complete assembly to fit seamlessly onto the existing structure. This cost-effective upgrade enables you to modernise ageing equipment or even convert wrapping systems previously using two-component solvent-based adhesives to process reactive polyurethane hot melt adhesives. You can read more about this under “Upgrades.”
Do you have an old profile wrapping machine that you’d like to modernise with a new hot melt coating head? Contact us—we offer seamless integration upgrades, even for systems from other manufacturers. Interested? Get in touch with us using the contact form below.
