Home > Coatings > The Roll Coater Machine and How It Works

roll coater machineIf you’re on this page, you’re probably exploring the concept of the roll coater machine—what does it apply, why do we use it, and how does it work? We frequently use roll coater machines when finishing a variety of different products. That’s why we’re walking you through this equipment, and why it’s so valuable.

What is a roll coater machine?

So, what does a roll coater machine do? How does this machine work in the first place? At its most basic level, a roll coater machine works by applying a liquid solution onto a surface. Usually, these surfaces are industrial parts. Some of the liquid coatings you’ll often see applied by roll coater machines include paints, oils, and varnishes or clear finish coatings.

With a roll coater machine, we must first apply the coating onto the “roller”, before the roller transfers the coating onto the surface. What you’ll notice is that when this process occurs, something called “film splitting” happens. Film splitting provokes the first layer of the coating splits in two. Part of it remains on the original roller, while the other sticks onto the desired surface. How much stays on the roller? It really depends on a number of factors—both the solution and the surface, as well as the coater itself.

How can we control the thickness of the coating?

One thing that’s important to note is that we can control the thickness of the applied layer, and we have a few different options in that sense. Often, this involves a metering blade. When we use a metering blade, we collect the coating solution from a reservoir by the roller. As the roller rotates, a measured amount of the solution itself slips through a gap created by a metering blade and the desired surface. We can adjust the space between the roller and the metering blade, and as such, affect the thickness of the coating.

We must also consider metering rolls. In this case, we still control the thickness of the coating solution by controlling a gap. However, we control the gap through two different rollers, rather than a roller and a metering blade. In this process, we’ll have a metering roller and a coating roller, working in tandem with each other. We pick up the coating from a reservoir yet again with this process, but we carry that coating to a nip point by one roll, with the excess solution being metered away through the second roll.  Why don’t we use this process more often? It’s simply more expensive to build than metering blade systems.

Don’t forget reverse roll coating! This process involves the coated surface being fed across a coating roller in the opposite direction of the surface roller. As such, the coating roll is both an application roller and a wiper roller. In the process, the coating pools, eventually flowing onto the surface as it moves underneath the coating roll.

What do we use a roll coater machine for?

Roll coating is a process that many business owners and manufacturers rely upon, and with good reason. As much as we may know we need a roll coater machine in general, however, many clients don’t fully understand the full range of qualities roll coating covers. That’s why we’re shedding some light on what makes this process so important.

One of the main advantages roll coating provides is the ability to coat a product and protect it against high temperatures. Both the coating solutions used by roll coating machines and the quality of the coating process involved are ideal for applying heat protectants. Additional coating types applied with roll coater machines include:

  • Anti-corrosion coatings. Many of the products we work with end up in highly corrosive environments, and it’s important that roll coater machines so easily apply these coatings.
  • Anti-abrasion coatings. The more your product can withstand abrasion, the longer it lasts. Fortunately, roll coater machines have this covered.
  • Grip coatings. Yes, some coatings actually make it easier for us to grip products, and roll coater machines apply them.
  • Anti-oxidation coatings. One of the worst things that can happen to a product is oxidization, which slowly breaks down the product over time (and leaves it looking unsightly). Fortunately, applying this type of coating is simple with a roll coater machine.

What are the advantages of using a roll coater machine?

So, what are the advantages of using a roll coater machine? We’ve covered one of them above—with the right coating machines, we apply a wide variety of different coatings effectively.

For one thing, when working with any kind of roller coating solution, the uniformity of the coating is one of the most important qualities. You want the thickness and appearance of the coating to be consistent, no matter how many products you’re coating. When we use machines like roll coaters (especially those with metering blades) we’re able to control the thickness of the solution. It doesn’t require much extra effort, and your final results are much more consistent than they would have been otherwise.

Of course, another major benefit of using roll coater machines is that it typically takes less time than alternative systems. (Those systems may include spray applications or screen printing, by the way.) As we all know, time is money—the faster and more effectively we apply coatings, the more time and ultimately money we save.

We’ve just scratched the surface of roll coater machines and how they work—but we’re ready to answer any questions you may have. Call CTI at 419-924-5566 or go here to get in touch with us!