Through the use of a new plastics additive, UK-based Sherwood Technology claims that it can now successfully mark plastics using low power CO2 lasers.
Prior to Sherwood’s breakthrough, the successful laser marking of plastics with low powered CO2 lasers was an area of difficulty. Manufacturers had abandoned the use of these CO2 lasers in preference for higher powered versions and YAG lasers particularly for Polyolefins such as Polypropylene and Polyethylene.
Other additives have been used before, but these tend to require higher activation energy and cause a localised change and charring to the surrounding plastic.
Sherwood Technology solved these problems by developing an additive called the DataLase Masterbatch which can be added directly to the polymer to be extruded or injection moulded.
The additive, which is non-toxic and environmentally friendly, produces a positive image when marked by a low power CO2 laser. The additive undergoes a simple chemical colour change and creates an image that is stable and has high contrast.
The laser imaging process does not require any ink or ribbons and is virtually maintenance free according to the company. In sharp contrast to traditional methods, it allows users to mark an expanding range of polymers using CO2 lasers, and is thermally resistant at normal injection/blow moulding and extrusion temperatures up to around 250 degrees C.