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Slot Die Coating 101: How It Works and Why It’s So Popular

slot die coatingSlot die coating is the process of depositing thin liquid films onto various substrates. This unique coating technology was first used in the 1950s to produce photographic films. Today, industries including electronics, packaging, and pharmaceuticals use slot die coating for countless products.

Slot die coating involves dissolving your selected film material into a thin coating fluid. Next, the coating is put into the specialized coating machine, which can then uniformly distribute the coating onto the substrate.

Fortunately, at Conversion Technologies International (CTI) the viscosity of the coating can be customized so that it is as thin as necessary for your product.

Major Components of a Coating Machine

Coating technology can seem rather complex, but it’s a relatively uncomplicated technique. As mentioned, the first step involves selecting the coating fluid, and then dissolving it into a coating solution, often called the fluid or film.

Once the fluid has reached the desired thickness, it goes into what is known as the slot die head. The slot die head is comprised of a front plate, backplate, meniscus guide, and shim. First, the front and back plates receive the coating liquid. Subsequently, it fills up in the interior of the slot die head. Incidentally, the interior is also known as the cavity, reservoir, distribution chamber, or manifold.

Once the cavity is full, the shim guides the coating solution downward to the coating edge of the slot die head. During this process, the shim will dictate the stripe pattern of the film or fluid on the substrate beneath it.

All the while this is taking place, the meniscus is stabilizing the fluid between the slot die head and the moving substrate beneath it. Additionally, the meniscus guide facilitates the flow of the coating fluid from the slot die head.

Benefits of Slot Die Coating at CTI

Because of the highly sophisticated coating apparatus we boast at CTI, the coating speed is expedited. This helps keep your production schedule on time.

Likewise, when you partner with CTI Technologies, you have access to a state-of-the-art coating machine, and our years of expertise in all facets of the slot die coating process. As such, you have excellent control over your coating thickness and wet film thickness. If you need incredibly thin films, we’ve got you covered.

Slot die coating is appropriate for a wide variety of substrates. Moreover, it offers a great deal of choice in coating thickness. Furthermore, because we use only the most sophisticated coating machines, customization provides even greater control over things like coating width, coating accuracy, dry times, and more.

Because of the precision offered with slot die coating, it is incredibly scalable to large areas requiring coating. For that reason, slot die coating is often preferable to blade coating which lacks the versatility and precision of slot die. Some people also deem it superior to spin coating, which is a slower process, that can generate excess waste.

Pre-metered coating in slot die cutting reduces waste. Because it is a continuous process, which can coat hundreds of meters within just a minute, and boasts significant material efficiency, it prevents wasteful mistakes.

What Industries Use Slot Die Coating?

From precise coating for highly sophisticated applications including ceramic capacitors and Li-ion batteries to crude application of adhesives, slot die coating serves a myriad of industries. Some of the many industries that rely on slot coating include:

  • Medical

Diagnostic equipment including perovskite films for x-ray machines and medical lab chip devices may use this type of fluid delivery system.

  • Micro-electronics

Thin circuits and flat panel displays are perfectly suited for this coating solution.

  • Food and Beverage

Liquid film coatings are in a wide array of food and beverage items.

  • Batteries and Capacitors

Lithium-ion batteries and multilayer ceramic capacitors frequently rely on slot die technology.

  • Solar

Perovskite solar cells require thin coatings, making slot die the coating system of choice.

FAQs about Slot Die Coating at CTI

Below please find answers to frequently asked questions. If you don’t see your question, please feel free to contact us directly. We’d love to answer any questions you have. You can send us a message or call us at 419.924.5566.

What Substrates Are Appropriate for Slot Die Coating?

Substrates that are suitable include:

  • Glass
  • Metal
  • Polymers
  • Paper
  • Fabric
Which Coating Technique is Right for My Product?

There is a lot to consider when it comes to choosing a coating method. We will be happy to speak with you to learn more about your product, your needs, your production timeline, and present all options available from CTI. That way, you’ll be able to make the best choice for your needs.

What Other Services are Available at CTI?

At CTI, we offer a variety of services at our West Unity, Ohio facility including:

  • Belt Laminator
  • Hot Gravure
  • Hot Melt Spray Coating
  • Hot Roll Lamination
  • Knife-Over-Roll Coating
  • Meyer Rod Coating
  • Powder Coating
  • Roll Coating
  • Slot Die Coating
  • Water-Based Gravure Coating and Printing

We are immensely proud to work with small businesses and global corporations alike. Some of the household name companies we’ve had the opportunity to work with include:

  • Carlisle
  • Clorox
  • DuPont
  • Firestone
  • Ford
  • General Motors
  • Hanes
  • Henkel
  • Kimberly-Clark
  • Lear Corporation
  • Owens Corning
  • Steinway & Sons
  • Uniroyal
  • Valspar
  • And More!

Our friendly team at CTI would love to work with you, too. So please give us a call today at 419.924.5566. Or, request a quote online!