Weitmann & Konrad GmbH & Co KG (WEKO, Leinfelden-Echterdingen/Germany) will come well-equipped with solutions for plastic film and sheeting web coating to the K Düsseldorf (hall 4, stand E25).
Today, many plastic films are equipped with specific functional characteristics changing the physical properties of the film surface. So the market demands films with specific sliding properties, antistatic surfaces, with non-stick additives, anti-fog equipment or antibacterial surfaces.
In addition to the option of using specific additives for the batch, more and more customers have relied on WEKO coating technology in recent years. It equips the plastic film or material web with a thin functional coating directly after the extrusion process. Such coatings do not affect the barrier characteristics or the processing of the used plastics. They are effective immediately after application and thus they can be applied flexibly so that also small batches can be produced in a cost-effective manner. Another advantage is the fact that plastic films cannot become cloudy and loose their transparency by used additives.
WEKO has specialized in applying finest surface films on material webs. Rotors arranged in a row within a rotor carrier and rotating at high speed ensure a non-contact application of liquids.
This specific technology allows the application of even the smallest amounts of fluid precisely and reproducible. In addition to its wide dynamic range, this system excels by an outstanding service-friendliness.
A further interesting option to reduce sticking is the application of a very fine evenly distributed powder film. WEKO powder application (WPA) systems can take these functions. Powder, mostly starch powder, is used as a separating agent and is applied upstream of the roll winder in film extrusion facilities.
WEKO application systems are available for both highest industrial requirements and also cost- and ecology-minded production.
THE WEKO-FLUID-APPLICATION (WFA) SYSTEM
Application system for liquids onto material webs or continuously conveyed products
The system consists of a liquid supply module with control and a rotor carrier as the application module. Application occurs by specifically designed spray disks, called rotors, which are located one next to each other within a rotor carrier. The supply module provides them with the desired liquid quantity. Rapid rotor rotation produces a uniform flow of microscopically small droplets.
Adjustable sliders create a defined spray fan for each rotor. The individual spray fans are seamlessly arranged side by side providing uniform application.
Coating and finishing of plastic films and other material webs
WEKO-SIGMA ROTOR CARRIERS
For this new generation long-term stability, easy operating and maintenance have been brought into focus.
The WEKO WFA at a glance:
WEKO-FLOW Fluid Supply Unit
The WEKO-FLOW fluid supply is used to provide the rotor carrier with the liquid required for the desired application.
A frequency-controlled centrifugal pump lifts liquid from the store tank to the WEKO-SIGMA rotor carrier via a prefilter. A flow meter monitors the supplied quantity according to the quantity specification and the rotary pump's speed is controlled. The quantity applied is automatically adjusted to the machine speed.
Liquid not sprayed by the rotors in the rotor carriers is returned to the supply unit via a return filter. As a result it does not get lost and remains within the liquid circuit.
WEKO-FLOW fluid supply and WEKO-SIGMA rotor carrier– Team work of a new generation.
The perfect interaction of both components
This combination allows you to tailor the WEKO fluid application (WFA) system to a variety of application-specific requirements. That is why an ideal extent of convenience and automation can be achieved.
Applications - more and more
This well-proven liquid application system is used in a variety of applications and can be adapted to many different requirements thanks to its variability and modular design. It is an application system providing a large dynamic range without system adjustments. Even minimum quantities of liquid can be applied in a reproducible and uniform manner.
The WEKO powder application (WPA) system
Application system for powder or powdry materials on continuously conveyed material webs.
Designed as a modular system, the WEKO powder application (WPA) system mostly consists of a powder sprayer, an encapsulated application module and an extraction module for purpose of plastic film production.
The powder sprayer from the AP series is the heart of this system. It produces a consistent and exactly reproducible powder-air mixture that is then conveyed to the spray bar. Through specific nozzles, the spray jet is applied finely and evenly distributed on the film web. The spray bar is located within an encapsulated spray chamber that is connected to an extraction system. In this way, excessive and fine dusts are efficiently extracted and cannot come to the production hall.
Separating material application on plastic films and other material webs
WEKO-AP powder spray systems
Thanks to the Precision Metering System (PMS), all powder spray systems of the AP range produce an exact reproducible powder application adjusted to the machine speed. Systems of the AP100 range are inexpensive alternatives for standard applications. From the AP200 range, the systems can be combined with the encapsulated spray chamber (ESC) system and an extraction system for excessive powder. In addition, both the AP200 and also the AP300 have an automatic format adjustment. Both systems are equipped for an easy powder change using the VARIOBOX.
The WEKO-AP900 is specifically designed for systems where a large amount of powder is to be applied. With up to 48 nozzles it supplies webs with widths up to 4 metres.
WEKO-ESC encapsulated spray chamber
At first, the surface of the material web to be sprayed passes an ionization module and is there prepared for powder application. Subsequently, an evenly distributed fine film of powder is applied within the encapsulated spray module. Non-sticking powder particles are efficiently sucked off and filtered out from the ambient air.
The WEKO WPA at a glance: