Choosing the right laser for marking specialist materials and techniques

Choosing the right laser for marking specialist materials and techniquesWhen permanently marking a material, for branding or to facilitate tracking through your manufacturing and supply chain, it is very important to find the balance between having enough power to create a mark and not having too much power which could damage the area.

Hundreds of kilowatts of power are needed to create the chemical reaction in a material to change its colour and provide enough visual contrast to leave a strong mark; however, the longer the energy is hitting the material, the heat can start to dissipate into the surrounding material – the heat-affected zone (HAZ) – which could change the properties of a larger area. For materials that have high thermal gradients and heating and cooling rates – such as special plastics, ceramics, glass, dielectric materials, polymers, resins and semiconductors – this can result in residual stresses and distortion, which may then affect the product's integrity.

Depending on the material being processed you need to apply specific marking techniques and use the right laser, with the right power and pulse duration, to mark the material without damaging or deforming it from thermal stresses or fluctuations.

Marking techniques and lasers

Technique

Description

Material

Laser marking product(s)

Annealing

Using laser irradiation to thermally induce local oxidation without noticeable material ablation. This process creates an indelible, permanent black mark without any cracks, depressions or burrs.

Ferrous metals
(iron, steel)

Titanium

Sol DPSS laser
(Bright Solutions)

Surface etching

Using laser irradiation to alter the superficial finish of a metal and creating contrast by enhancing the way it reflects ambient light. Laser etching is probably the most widely used high-speed, laser-marking process.

Metals

Sol DPSS laser
(Bright Solutions)

Coating ablation or paint stripping

The partial or complete removal of one or more coating layers which exposes the contrasting colour of a substrate material.

Any, depending on coating

Sol DPSS laser
(Bright Solutions)

Colour change, blackening or bleaching

On some thermoplastic materials, green and UV lasers can be used for bleaching and photo-reduction marking processes. This effect is also called 'cold marking' for the reduced thermal footprint on the substrate. Laser-sensitive additives in plastics can increase outline sharpness, colour contrast and the variety of colours available.

Thermoplastic materials

Wedge DPSS laser
(Bright Solutions)


Onda DPSS laser
(Bright Solutions)


Sol DPSS laser
(Bright Solutions)

Carbonisation

One or more specific pigments, flame retardants or other additives, this technique is typically used to create dark markings as a sharp contrast on light-coloured thermoplastic materials.

Thermoplastic materials

Wedge DPSS laser
(Bright Solutions)


Onda DPSS laser
(Bright Solutions)

Sub-surface laser engraving (SSLE)

Focusing intense laser radiation below the surface of a glass object creates a mark made of micro-cracks. As a result the microscopic cracks create multiple internal light reflections, which makes the spot look white without affecting the polished surfaces. Two- and three-dimensional images can be created inside of the glass. This technique is popular for decoration as well as tamper-proof traceability.

Glass

Transparent materials

Wedge DPSS laser
(Bright Solutions)


Onda DPSS laser
(Bright Solutions)

Colour marking on ferrous metals and titanium

Laser colour marking is based on surface oxidation. Varying different laser parameters will result in different oxide coatings that can be seen as different colours by the viewer. For ferrous metals you need specialised lasers with the capability to exert a high level of control over a laser's pulse width to create the right colour results.

Ferrous metals
(iron, steel)

Titanium

Onda DPSS laser
(Bright Solutions)


Sol DPSS laser
(Bright Solutions)

Black marking on anodised aluminium

A technique widely used by mobile-device manufacturers to mark logos and serial numbers on the anodised aluminium case with a high-contrast, pleasing appearance and no damage to the protective oxide layer.

Anodised aluminium

Onda DPSS laser
(Bright Solutions)


Sol DPSS laser
(Bright Solutions)

Get in touch

If you would like more information on how we can help with your design challenges, or to speak to one of our experts, please get in touch.



From sensors to the cloud – everything you need to succeed in the Internet of Things

From sensors to the cloud – everything you need to succeed in the Internet of Things

ulteriori informazioni
Turning great ideas into customer success – how Acal BFi are solving IoT design challenges

Turning great ideas into customer success – how Acal BFi are solving IoT design challenges

ulteriori informazioni