Laser etching machine for industrial marking of metals and plastics

Laser etching machines are indispensable in most industries. They can be used in a variety of ways and mark or engrave almost all materials with high precision and efficiency. Different methods are used for industrial product labeling, depending on the desired effect, material or quality requirements.

Which laser etching machines are used for laser marking?

For direct laser etching (Direct Part Marking, DPM) of industrial products, such as medical devices, components for the automotive industry or electronic components, fiber laser markers, UV lasers and CO2 lasers are generally used. Which laser etching machine is suitable depends on various factors like the material, the surface quality and the desired marking effect. It is also crucial how the product will be used and if the marking has to withstand extreme conditions such as disinfectants and cleaning procedures or environmental influences.

Additionally, there is a difference between laser etching machines for integration in production lines and laser etching machines as workstations for stand-alone operation in laser class 1. The following laser etching machines are used both integrated in production lines and as stand-alone workstations in various industries:

Fiber laser markers: powerful, efficient, flexible

Common fiber laser (in the background) compared with the very small version of a fiber laser (in the foreground).

The economic fiber lasers are used for precise etching of plastics and metals in almost all industries: from automobile manufacturing to the electronics industry and medical technology. For etching medical devices, the fiber laser is considered as a universal laser because it is versatile and marks medical stainless steel reliably and corrosion-free.

A vision system that is integrated into the marking head ensures highest quality and process reliability for laser etching.

Particularly suitable for integration into production lines are very small fiber lasers with the size of a CIJ (Continuous Inkjet).

CO2 laser markers: fast and flexible

CO2 lasers mark a variety of materials with highest precision and razor-sharp, including coated metals, paper, cardboard, glass and many plastics.

The lasers achieve marking speeds of up to 2,000 characters per second and line speeds of up to 900 meters per minute. With options for customer-specific configuration, they offer highest flexibility.

UV laser marker: high-contrast markings on highly sensitive products

UV lasers achieve high-contrast etchings on sensitive products through a photochemical effect. The heat input is very low so that sensitive materials such as medical plastics, silicones, white polyamides, colored tubes, cables or glass can be etched without damaging the product surface.

What are the advantages of a laser etching machine with an integrated vision system and innovative software?

Vision systems integrated in the laser etching machine increase accuracy, economy, manufacturing efficiency and processing quality during laser marking and engraving. Small and large components can be etched with the same laser so that manufacturing processes are optimized. Operating costs are reduced because only simple fixtures are needed – or, with appropriate software features, fixtures even become unnecessary for part marking. Integrated vision enables inspection steps before and after the laser marking directly in the laser etching machine, such as the Holistic Enhanced Laser Process (HELP) which drastically reduces scrap and provides almost zero-defect marking quality:

With the help of the marking software, marking contents can be created quickly and efficiently, high-quality laser marks are applied precisely. Innovative software features offer further advantages, such as the above-mentioned possibility of marking without product fixtures:

Additional user interfaces optimize production efficiency, lower costs and increase throughput in laser marking. Such interfaces minimize user intervention and clearly visualize the essential steps of the marking process. This ensures fast, intuitive, safe and error-free operation of the laser etching machine. The etching process is thus accelerated and scrap is reduced.

For which processes can a laser etching machine be used?

A laser etching machine can be used to mark a variety of materials. Different methods are used:

Annealing

Laser annealing means that an oxide layer is applied to metals by local material heating, resulting in a high-contrast, perfectly readable marking. No material is removed, the material surface remains flat. Usually the oxide layer is black, but also other color effects are possible.

This procedure is particularly suitable for etching medical devices because it does not harm the surface and withstands multiple cleaning, disinfection and passivation cycles. With the right settings and laser parameters, the marking is corrosion resistant.

Color laser etching on stainless steel.
UDI code, marked with a fiber laser (annealing on medical stainless steel).

Foaming/Frothing

Laser-marked plastic housing of a temperature sensor from the automotive industry.

Carbon and color pigments (from additives, paints or similar) contained in plastics are heated locally by the laser. As the carbon in the plastic oxidizes to CO2, a foam layer is created during foaming, which appears as an embossed mark that can be felt on the surface. The small bubbles that settle on the surface reflect diffusely and create light colored marks on darker materials. The color depends on the composition of the plastics.

Color removal/paint removal and day-night design

In the layer removal process, the laser causes the removal of thin layers of the plastic surface by superficial melting. Either the material itself or its coating, which was usually applied with the aim of achieving a certain marking effect, is removed. In this way, coatings can be removed with high precision in the desired thickness from the underlying, differently colored plastic layer, which then becomes visible.

This marking process is also used for lacquered materials and color-coated aluminum. Previously applied layers of paint, varnish and cover layers are partially removed.

Paint removal on aluminum can lids.
Day/night design for automotive interiors.

In the automotive industry, this procedure is used for creating day/night designs on control elements and keyboards. The coating is removed from a transparent material and the resulting sharply defined symbols can be backlit in the dark, e.g. for switches in the automotive industry. Also through the precise layer removal, several layers of differently colored paints/lacquers can be individually removed to produce desired labeling effects still with high exactness and without damaging the underlying layers.

Carbonizing

Injection moulded part with color change through carbonisation.

Carbonization is a darkening effect. The laser burns some components resulting in a dark discoloration. This process is mainly used for plastics. The plastic composition and the basic color of the material determine the contrast. Materials that show a poor reaction to the laser can be optimized by using laser additives. Carbonization is also used for organic materials such as paper, cardboard, wood or leather to achieve a dark effect.

Engraving

Engraving with a laser is done by removing material causing a deep mark. The advantage is the robustness of the mark against wear. This procedure can be used for almost all materials. Even in case of possible downstream coating processes the mark remains visible.

Melted engraving on an automotive venting valve.
Laser engraved hatchings.

Further information

Laser etching machines for integration in production lines
Laser etching workstations
Laser etching of silicone elastomers with a UV laser
Corrosion resistant laser etching of medical stainless steel
Day/night design in automotive industries