Functional Printing

Contact cleaning for coated products used in optical applications

By Sheila Hamilton, Teknek Ltd.

Background. Emerging technologies are placing much great­er demands on contact cleaning than its traditional applications. In particular, the size of particles, which pose a risk to the integrity of the product functionality, has become significantly smaller. Also, where the product coating has electrical or chemical functionality, certain types of contamination such as metal particles are extremely detrimental. It is now becoming increas­ingly necessary to be able to tailor the cleaning system to both the size and type of contamination to optimize its efficiency. For any contact cleaning system to be effective, the adhesion force between the elastomer cleaning roller and the particle of contamination must be greater than the adhesion force holding the particle onto the substrate being cleaned. While there are a very large number of variables which affect the adhesion force, one of the most significant ones is the contact area. To maxi­mize the adhesion force, the contact area between the surface of the elastomer cleaning roller and the surface of the particle of contamination must also be maximized. Surface roughness is a key factor in the contact area.

Teknek Limited, Inchinnan, PA4 9RT Scotland UK,