Top Five Things To Remember in Fluid Coating
- Published: February 18, 2014, By Mark Miller
If you'd like to hear from Mark Miller's own lips rather than read his Coating Matters blog post titled, "Top Five Things To Remember in Fluid Coating," click on his podcast below:
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1. Evolution: Liquid coating has come a long way from painting by hand to coating with rolls to pre-metering fluid. The future of fluid coating is housed in the pre-metered enclosure presented by slot die technology. The ability to feed, distribute, and apply a liquid directly to a substrate via slot die provides many advantages. The enclosed nature of the slot die allows for a cleaner liquid to be applied to cleaner substrate than in open pan coating methods. Controlling the fluid through a positive displacement pump eliminates air within the system and reduces air trapped between the fluid and the substrate. The future is now and the technology is available.
2. Trends: Simulations for coating save time and money. Understanding the lot-to-lot variation in fluid and predicting the behavior of the process as entering raw materials change are critical to recipe formulation on a production line. Computer models and operational correlations can be developed over time or through designed experiments. These science-based models can reduce development time and improve performance. Engineers need to make friends with their local statistician.
3. Coating: The coating window is the soul of a coating operation. The more you know the more successful you will be. The well-defined coating window will lead to defect-free coating that reduces operational cost, increases product quality, and improves cost efficiencies. Understanding the coating window requires a comparison of dynamic viscosity, coating profile, slot die design, pressures, substrate speed, surface energy and tension, and forces involved in the adherence of the fluid to the substrate. These will lead to improved defect analysis and coating capability as the product base expands.
4. Curing: Coating variation needs to be coupled with curing models to understand the full effect on the final product. While coating can develop proper fluid placement and adherence, curing models provide insight into defect analysis that goes beyond placement of the fluid on the substrate. This stress/relaxation understanding can provide dividends as the coating forms a final product. The final product performance and coating quality is a constant feedback loop to coating formulation, process development and coating/curing interaction.
5. Converting: The final actor on the product is converting the roll stock into useful components. This may be smaller consumable rolls of tape, or flat panels that need to lay flat for use as components in other products. How the material is cut and the stresses associated can sometimes be contained within their own operational unit, but other times they are critical to the coating and curing decisions in the overall process.
In the end, the evolution trends in coating, curing, and converting for the fluid industry lead the individual process engineer in the direction of choices within boundaries. What slitting method do you choose? What energy source and range is appropriate for the fluid solidification? What factors do you consider when choosing a coating method? What you are looking for are unit operations that create a process that allow for the future. The future of fluid coating includes faster coating, higher quality, thinner coatings, less drying, and reduction of solvent. All while increasing the company's bottom line.
If you are interested in discussing this concept further, contact Mark D. Miller, Founder and CEO of Coating Tech Service, LLC at This email address is being protected from spambots. You need JavaScript enabled to view it. or 612-605-6019.
