Marking, engraving

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  • Laser assisted machining
  • Laser machining

Marking :

Marking can be done with many different techniques. Mechanical engraving or hot stamping are mainly adapted to metallic materials. Ink jet, stamp printing, screen printing are techniques commonly used in all industrial sectors for their low cost and their fast marking speed. These technologies are more and more in competition with laser marking that offers flexibility and permanent marking. The principle is based on the implementation of a laser beam that acts on the surface of the material to be marked.

Marking by image transfer :

This process consists in lighting the surface of the piece to be marked through a mask placed on the way of the laser beam. CO2 pulsed lasers are generally used because they deliver high output pulses. For each pulse one piece is marked.

Laser		Masque     Miroir     Lentille de focalisation

Marking by beam moving :

Another process uses the focussing of a solid-state laser (Nd-YAG generally) on the surface to be marked. A combination of several galvanometric mirrors of low inertia guides the beam.

Laser		Axe X miroir galvanométrique                   Lentille de focalisation

Characteristics

Most lasers available on the market (CO2, Nd-YAG, Excimer, .) can be used for the marking of nearly all kinds of materials (diamond, metallic materials, plastic, glass). Engraving depths can be of several microns (surface marking) to a few tenths of millimetres (deep marking). Marking by mask gives rates of several pieces per second whereas marking by beam moving requires a few seconds per piece but offers a better flexibility.

Marking of use-by date on beer cans

Industrial applications

Deep marking is used mainly in automotive industry: gear transmission parts, engine block, car body identification.

Superficial marking concerns all sectors :

• Packaging : Marking by CO2 or Nd-YAG of bar codes or use-by dates on many packagings of consumer goods
• Medical : Marking of prosthesis
• Food industry: Marking by mask with a CO2 laser of cheese rind for Bongrain
• Electronics, electricity: electronic components by Nd-YAG laser, electric cable by TEA CO2 Laser.
• Optics : micro-engraving of spectacle glass moulds
  
• Miscellaneous: plastics, business gifts, medals.

Colour marking on steel