Knife over roll is a method used by manufacturers to apply a covering to a substrate while filtering it before direct application to ensure small particles do not disrupt the end result. A knife over roll coater is often used for pressure sensitive applications because they have a broad range of weights. With this application method, the coating is fed through a knife and roll to maintain consistency regardless of weight as the process determines the factor based on the gap between these items. The process may be used to apply various qualities to a substrate including:
- Pressure Sensitive Adhesives
- Barrier Coverings
- Printable Topcoats
- Custom Saturation Options
Each portion of a knife over roll coater is adjustable and movable to ensure the right application consistency. It may also be used to feed several narrow webs of coating by applying spacers along the box bed. Since every portion is removable for most machines, they are easy to clean and prepare as covering needs change.
A knife over roll coater provides a few advantages for certain covering requirements including lower costs, the ability to handle high viscosity coats, and the ability to handle higher weights. The application method is highly flexible and can be used for a number of materials. Additionally, it may be adjusted based on weight, viscosity, or application requirements quite easily. In situations where knife over roll is not the best approach, the provider should recommend another application method to ensure exceptional quality.
Is Knife Over Roll the Right Option?
The knife over roll method is a flexible option because it can be used on films, foils, or other types of substrates such as textiles or rubber. It offers a lower cost, effective choice for many production scenarios. Companies with exceptional experience are able to produce dependable coatings for flexible or rigid substrates without significantly increasing costs. Common applications for this particular method are:
- Food Grade Casting
- Hot Melts
- Heavy Coverings
- Shear Sensitive Adhesives
- Pharmaceutical Strips
A knife over roll coater consists of a reservoir, knife, and roll that work together to provide a continuous feed of the covering material while at the same time scraping off any excess. Determining if this choice is the best option requires careful evaluation for any product or quality. Most companies turn to a professional in these situations because they have a deeper understanding of the process. Here are a few things to evaluate with a dependable provider:
- Will this method deliver the needed accuracy?
- Does it offer the best results for the coating weight?
- Is there a better option for the viscosity of the coating?
- Would a different application method be more dependable?
- Is it able to be used for the required substrate and covering material?
Many factors go into making the decision to use a knife over roll coater, which makes having the advice of a professional with years of experience beneficial. Be certain to use a provider who has worked with countless substrates, coatings, and application methods to prevent low quality or costly results. The more experience the provider has, the better the results and advice you will receive.