In Part 3 of the Web Guiding Systems Series we discussed Web Displacement Guide.Read more
Category Archives: Blog
In Part 2 of the Web Guiding Systems Series we discussed web steering guides.Read more
Web Displacement Guide[caption id="attachment_2699" align="alignright" width="200"] 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...
In Part 1 of this series we introduced web guiding systems in roll-to-roll winding.Read more
Web Steering Guide[caption id="attachment_2698" align="alignleft" width="200"] 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...
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...Read more
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"] Read more
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...Read more
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[/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...Read more
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...Read more
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
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...Read more