What is Roller Wave?
Heating float glass creates soft pliable glass which is then rapidly cooled to create heat-strengthened or toughened glass. Unfortunately, this process can create forms of optical distortion in the surface of the glass.
Roller wave is a common form of this optical distortion. Roller wave is caused during the heating process as the glass sags slightly when being transported through the furnace between the carrier rolls used. The glass then passes through the quench, rapidly cooling the glass after the heating process. This heating and cooling creates a compression and tension in the glass thickness that is what creates the additional strength and safety in a glass unit to create toughened or heat-strengthened glass.
Although this process allows us to create impressive architectural glazing and technical glass installations, it can also result in a slight inconsistency to the surface of the flat glass, usually seen as ripples or a roller wave. The amount of distortion can be affected by the glass thickness and size. If the glass is thicker, the glass will remain flatter than if thinner glass was used. Larger glass sizes will also show more distortion than smaller sections. Roller wave is also normally only visible in the reflections of the glass.
This optical distortion can be reduced in the heat-treating process. Many issues must be addressed in this process such as the conveyor system, furnace temperature uniformity and the quench design which can all affect the outcome of the quality of glass. However, due to the nature of roller wave distortion, it cannot be completely eliminated, only reduced.
IQ Glass are required to follow the Glass and Glazing Federations standard guidelines as to what is accepted as an acceptable level of optical distortion for an architectural glass installation.