EcoMark offers various solutions for laser branding the following materials:
Laser labelling or laser branding is suitable for many materials and applications. Individual details such as text, numbers, graphics and codes can be applied directly to workpieces. This may often preclude the requirement for other expendable materials such as labels or packaging. Another advantage of laser labelling is its resistance to mechanical stress and chemicals. Due to the very low running costs and ease of maintenance, laser branding is very often superior to other systems. Labelling lasers therefore increasingly prevail in the industry, and they are among the most reliable branding systems.
How does laser marking work?
The workpiece(s) is/are placed on the conveyor belt of the EcoMark machine. The workpiece is measured three-dimensionally at the first station. The position and alignment of the marking is calculated and transmitted to the laser. The branding is then carried out completely automatically. The QR code is checked for legibility at the final station. The machine automatically recognises whether one or more workpieces is placed on the conveyor belt and it adapts the processes.
New workpieces can be placed and set up. No setting up time or investments are required for new workpieces. You can store any number of different workpieces in the database and retrieve them again in no time.
Procedure for laser labelling
A fibre laser is used for laser engraving as a high energy density is required for the process. With laser engraving, material from the surface of the workpiece being processed is melted out and evaporated. The laser beam penetrates the material and carries this away. The resulting laser engraving is visible and can be felt. It is used in particular for tool labelling and mould-making. The interaction of the heated material with the ambient air creates a discolouration in the engraving area, which is also emphasised by the laser engraving.
Colour removal / material removal
CO2 and fibre lasers are used for colour removal or material removal. This type of laser labelling is used in particular for anodised aluminium and painted materials. The laser beam removes parts of or the entire topmost colour, paint or surface layer so that the basic material underneath becomes visible. Laser labelling works via the absorption of the laser beam by the topmost layer, which then heats up and vaporises. The differences in the basic material are usually fairly major, so that colour / material removal is one of the most contrasted types of laser labelling. It is the method of choice in the automotive industry for day / night design in particular.
Laser labelling by annealing, also known as annealing branding, is carried out using a fibre laser or CO2 laser. An oxide layer is created on ferrous metals and titanium through local heating of the material. The thickness of the oxide layer therefore depends on the depth at which the oxygen atoms can diffuse. This oxide layer is abrasion-resistant as the heat from the laser labelling penetrates around 20-30µm into the surface. The surface also remains even, as this involves a colour change occurring on the surface with no application or removal. The “standard” annealing colour is black, but there are also other colour options such as green, yellow or red. The colour depends on the temperature of the heated layer.
Colour change / foaming
Colour change / foaming is only deployed for plastics with the use of fibre, UV and YAG laser marking. The light absorbed creates local heating. This destroys and evaporates the colour pigments in the plastic along with the carbon. The carbon oxidises into CO2 which leaves the plastic and forms a layer of foam. The colour change then becomes visible, and the foaming of the material noticeable, as the molten gas bubbles increase the volume and are firmly integrated into the material structure when cooling. The resulting colour depends on the composition of and additives in the plastic in question. Dark plastics take on white laser branding and light plastics display dark laser branding. This provides an excellent contrast.
With carbonisation, the plastic bonds are broken open with the help of a fibre, YAG or CO2 laser. Therefore, the pigments of the plastic burned always create dark-coloured laser branding due to the release of the carbon. The colouring is thus always grey to black. The carbonisation laser labelling process is used for light plastics as well as organic material. Due to the locally restricted heating, the surface remains largely undamaged so that this type of laser labelling is very gentle on materials.