Coating/Laminating
Hot Topics: Adhesive Coating | Extrusion Coating | Metallizing | Curing | Drying | Green Converting | Primers | Coatings
Nordmeccanica Machinery and Novacote Adhesives by COIM Group Partner for Adhesive Technology Solution
- Published: February 14, 2019
Nordmeccanica and COIM Group joined forces in a cooperation targeted to the development of an adhesive technology.
Pack Ready Lamination PE Sealant Films: Charter NEX Collaboration With HP Indigo
- Published: February 13, 2019
Charter NEX Films announced the launch of a new family of PE thermal lamination sealant films.
Vetaphone ICE-USA 2019 Preview
- Published: February 09, 2019
Vetaphone is planning to exhibit one of its Corona stations at the upcoming ICE expo in Louisville, Ky.
Davis-Standard Announces First Quarter R&D Additions
- Published: February 05, 2019
The Davis-Standard Technical Center has announced two additions to its lab capabilities in Pawcatuck, Conn.
AGL 64” Foam, Felt and Gasket Industry Laminator
- Published: January 24, 2019
Advanced Greig Laminators recently announced a 64” laminator for the automotive gasket market.
AIMCAL Organizes Technical Program at ICE USA and Issues a Call for Papers
- Published: December 12, 2018
AIMCAL organizes a technical program for ICE USA and calls for papers to be submitted on the AIMCAL Website until Jan. 16, 2019.
Will it Process?
- Published: December 12, 2018
The benefits associated with modified substrates vary but can include improved physical strength, thermal stability, permeability as well as optical strength.
Mark Andy Print Products Strengthens Partnership with RotoMetrics
- Published: November 19, 2018
Product portfolio expands to support magnetic and print cylinder tooling.
Color and its Role in Defining Embossed Product Surfaces
- Published: November 07, 2018
Packaging may be the mainstay of business for the majority of converters, but there can be more to converting than packaging
Premier™ Slot Die from Nordson Can Get ROI in Months
- Published: November 07, 2018
Digital tool for modeling cost inputs of fluid coating operations enables manufacturers to calculate the payback time for switching to a slot die system
Dürr Completes Acquisition of MEGTEC/Universal
- Published: October 11, 2018
This will create the world’s leading supplier of environmental systems for industrial exhaust-air purification.
Emsur Russia Eximpack Increases Printing Capacity
- Published: September 20, 2018
The St. Petersburg facility invested in a new line of gravure printing and a Combi laminator.
E-Commerce Comes to Cast and Cure™ Films
- Published: September 10, 2018
The Cast and Cure™ process for achieving holographic effects on labels and packaging is fully explained in Breit Technologies’ new web site.
Coating Matters | Rigid Panel Coating with Slot Die Equipment
- Published: August 30, 2018
Panel coating is a unique application of fluid coating technology that provides capability and functionality to a discrete substrate. But what is important to understand and what tradeoffs exist?
Unlike continuous coating application against a moving substrate, we are trying to develop steady state control over an intermittent process. The fluid needs to exit the slot die only when we want it to and stop flowing before a mess is made. In intermittent
Like continuous coating, the math and physics involved to control flow and predict behavior for
FLUID RHEOLOGY
Many fluids can be coated onto rigid panels, so what are the key factors to be aware of in the fluid chemistry, surface energy
There are two main techniques for coating rigid panels – proximity and curtain coating. Both utilize slot dies, but each has a different set of criteria to develop successful performance.
In proximity coating, the gap maintained between the slot die lip face and the rigid panel is 1-2 times the wet coating thickness. So, the lower the wet coat weight, the closer the slot die gets to the substrate. For rigid panels that have variation in
For very light coat weights (less than 1 mil or 25.4 microns), curtain coating should be considered. For curtain coating, the critical calculation of success is the Weber number. No heavy math is required, just a simple understanding of the fluid and the equipment setup.
We = ρQV/σ
We = Weber number
ρ = density
Q = volumetric flow rate
V = impingement velocity
σ = surface tension
This simple equation helps us determine the success of coating based
One of the big differences between proximity and curtain coating is the area coated. In proximity
EQUIPMENT DESIGN
How about the equipment utilized? First of all, the slot die is going to be positioned vertically. Why does this matter? Air. Evil air. When the fluid initially fills the manifold of the slot die, the air in the system wants to rise to the highest point. For a vertically oriented slot die, this means that the air will travel to the back of the manifold or the joint of attachment for the fluid delivery pipe or tube. If the air has no release mechanism, then the air will slowly release over time, causing coating defects. Ideally, a purge valve will be placed either in the back line of the manifold or the fluid delivery tube, whatever the highest point in the system is. Once the slot die is filled and purged, the air will release and then operate correctly. Without a purge mechanism,
OPERATION
After the equipment is set-up correctly, the coating of the rigid panel can still have issues. These issues can include the variation in the substrate, control of the travel and potential environmental factors. Let’s break these down a little.
Especially in glass substrates, the surface flatness can vary tremendously. If the final product requires micron level control, and the equipment is precisely manufactured to deliver micron level performance, the product may still fail if the substrate variation exceeds the coating specification. Make sure that the substrate flatness meets or exceeds the flatness requirement for coating caliper control both cross web and down
Another key factor in the coating of rigid panels is how to properly handle the substrate. Should the slot die move over the panel or should the panel move under the slot die? Can the panel be held stable with a vacuum table, or will the suction cause damage to the substrate? These factors need to be considered to properly design the equipment. Consider the stability and weight of the equipment traveling during the process.
Environmental factors come into play for both proximity and curtain coating, but more so in curtain coating. Because of the larger gap created in curtain coating we have to be concerned with air in the room disrupting the curtain. With proximity coating, room air won’t cause a fluid disturbance to the same extent as curtain coating, but mechanical vibration and environmental debris can cause coating defects. Make sure the fluid and substrate are clean before coating.
CONCLUSION
Rigid panel coating is becoming more and more commonplace. Understanding the variables to consider will help your company attack this multi-variable process with the right tools for success. If you work through the questions presented here, you will have a deeper understanding of how to successfully coat panels and limit coating defects.
Mark D. Miller,
Maan Engineering Introduces HYBRID Laminating Coating Line in America
- Published: August 29, 2018
Because the adhesive and silicone are applied simultaneously, it is possible to make special laminates that are truly distinctive.