Category Archives: Blog

Part 3: Web Displacement Guide in Roll Coating Systems

In Part 2 of the Web Guiding Systems Series we discussed web steering guides.

Web Displacement Guide

[caption id="attachment_2699" align="alignright" width="200"]Web Displacement Guide Figure 3 - Web Displacement Guide[/caption] When a sufficiently long entry span is not available, a displacement guide may be a better choice. The displacement guide, as seen in Figure 3, is a system of four rollers. The first and last are fixed, while the center two rollers...
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Part 2: The Web Steering Guide in Roll to Roll Systems

In Part 1 of this series we introduced web guiding systems in roll-to-roll winding.

Web Steering Guide

[caption id="attachment_2698" align="alignleft" width="200"]Web Steering Guide Figure 2 - Web Steering Guide[/caption] The web steering guide, as shown in Figure 2, is a roller that has ends which are mounted on a pair of angled linear bearings. As the actuator pushes the roller sideways, the raceways cause the guide roller to pivot about an imaginary point called the instant center. The principles of...
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Part 1: Web Guiding Systems in Roll to Roll Winding System

Webs do not always track down through a machine in a consistent location. On a roll-to-roll operation, for example, any offsets in the unwinding roll will cause the web to get started through a machine in a variable CD (cross direction) position. However, even if a web starts out in the position, it may take slightly different paths through the machine depending on several factors. First, a variably baggy or cambered web will cause the web to track toward the variably tighter side. Second, variabilities in roller traction or drag can cause a steering...
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Part 5: Position of Corona Treating Station

In Part 4 of the Corona Treating Series we discussed watt density. Most roll coating and laminating is done today using water-based adhesives and coatings. The use of water-based materials requires a substrate with a higher surface energy than when solvent-based coatings are used. Therefore, pre-treated substrates should be used whenever possible and the pre-treated polymer should be treated again at the time of coating or lamination. Table 5 shows typical treatment levels for various materials. [caption id="attachment_2963" align="alignnone" width="244"]Figure 4 Read more

Part 4: Corona Treating Watt Density

In Part 3 of the Corona Treating Series we discussed power supply. The most significant design criterion involved in corona treatment equipment selection is sizing the system to meet the specific application requirements. Power supply size in kW is determined by the treatment power required by the most difficult-to-treat substrate to be coated. Treatment power is measured in Watt Density (Watts/Square Foot/Minute), which takes into consideration not only power level, but also the length of time the power is applied. If a given material...
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Part 3: Corona Treating Power Supplies

In Part 2 of the Corona Treating Series we discussed driving and nipping the treater roll. [caption id="attachment_2962" align="alignright" width="294"]Figure 3 - Power Supply Diagram Figure 3 - Power Supply Diagram[/caption] All corona treating installations require a source of controlled electrical power. Low-voltage 60 hertz electrical power is fed into an electrical device which raises the frequency. This high-frequency electrical power is applied to a step-up transformer that increases the voltage. The high voltage, high-frequency...
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Part 2: Driving and Nipping the Corona Treater Roll

In Part 1 of the Corona Treating Series we discussed the corona treating station. The requirement to nip or to drive the Corona treater roll is more often dictated by machine or substrate characteristics than by technical treatment demands. For example, treatment of substrates, especially ultra light weight substrates running under light tension, is seriously complicated by the tendency for these substrates to wrinkle under the corona discharge. The wrinkling not only causes a problem with the quality of the wound roll, but also produces backside treatment...
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10 Best Roll Coating & Laminating Articles of 2013

PFFC (Paper, Film & Foil Converting) announces their 10 Most Popular Stories of 2013. Here are the highlights. Claudia Hine started the year off with a recap of the Top 11 New Products of 2012. The previous year's innovations focused on improvements in web coating and laminating processes mostly in the packaging industry. Mark Miller of Coating Matters began the year trying to explain fluid coating technology to people familiar with extrusion technology. In his blog, Read more

Part 1: Corona Treating for Coating Applications

Maintaining high quality coating on paper, film, metalized film and foil substrates at production line speeds requires a method of enhancing substrate surface energy. Corona treatment promotes bond sites and increases surface energy without sacrificing the positive properties of the substrate. In coating applications, treater system design has undergone significant changes to accommodate lighter webs, higher line speed operation and advanced substrates. The range of developments has included the requirement for handling conductive substrates, nips at the treater roll, using the treater roll as a "pull roll," and modifying the treater station design...
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Part 8: Mechanical Design of the Reverse Roll Coater

Reverse Roll Coaters must be of Uncompromised Precision

In Part 7 of this series on reverse roll coating we discuss the use of hydraulic force to control Metering Roll Ratio and Capillary Number. The mechanical design of the Reverse Roll Coater must be uncompromised when it comes to precision. Rolls must be made of high strength steel or cast iron of sufficient diameter and wall thickness to provide substantial resistance to the gap separating forces encountered...
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