Fibre lasers (or lasers with a similar wavelength) are traditionally used for metal marking. This is due to their energy being absorbed more efficiently. In this example we are looking at laser marking stainless steel using Thermark.
OneLife iD evolved from the desire of the co-founders to create a dynamic personal ID, that looked good and appealed to a broader market, than purely sports and medical emergency users. The information is accessed by using a smartphone to scan the QR code, located on the top surface of the bracelet.
The requirement to have the information automatically read moved us to utilise Thermark – a laser receptive additive for materials. The energy of the fibre laser is used to permanently fuse the material to the substrate. Generally the process is used where the laser wavelength and the materials do no combine to provide acceptable levels of mark contrast or durability. In this case, the customer wanted to get as close to perfect black, as was possible without any issues with viewing angle distortion. Laser marking stainless steel using Thermark, did reduce issues associated with the code reading capability.
The Thermark application process
The laser marking process requires for the materials to be coated in a thin film of the Thermark material. Once dry, the laser is used to reproduce the image required onto the material surface – in this case a unique QR code depicting the customers URL address and a few lines of data, such as name or ICE number as required. Once the operation is complete, the Thermark is removed with a light water clean. Where the laser has interacted with the Thermark coating, the Thermark becomes thermally bonded and remains permanent to the substrate surface.
Fibre laser processing
One of our LightWriter products with a 20 watt fibre has been used to process the Thermark. The laser used in a high pulsed mode to create the heat energy that fuses the materials together. The focal position is critical when using Thermark. Too much curvature weakens the bonding process. Specialist tooling was designed in order to better control focal position and date placement. To find out more about our fibre based marking systems visit the LightWriter product range page.
What is a QR code?
A machine readable code, consisting of an array of black and white squares, typically used for storing URL’s or other information, that can be read by a camera on a Smartphone device.
It is popular for its fast readability and storage capacity, sitting in the middle between traditional barcodes, and 2D matrix codes seen in many industrial applications. Growing in popularity in areas such as general marketing, the code format is also used for product tracking, time identification, time tracking and document management.
Invented in the early nineties, its original application was to track vehicles during manufacturing and today is one of the most used types of two dimensional codes.
If you would like further information on this laser application, or any other application, please request a call back or talk to one of our laser marking specialists on 01737 826902.
