7/28/2019 Laser Processing Laser Marking

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Answer shortly to following question:

I. Explain why scanner optics is so often used in Laser marking?The scanner optics is so often use because the scan field diameter determines many of the

overall lens specifications. Once a scan field diameter is determined, it is along with the

focal length defines the deflection angle required, since the focus position is proportional

to the product of F x .

II. List 3 advantages of using Laser beam in markingThe three advantages of using beam in marking are:

- Very high flexibility in automation;- Constant high quality and durability of the result;- Very high processing speed and low cost (no use of consumable).

III. Describe the basic principle of Laser marking?A laser marker uses a laser beam to apply heat to the surface of metal or plastic objects to

mark characters, symbols, or logos without contact. The laser beam is reflected between

the mirrors inside the oscillator and is amplified. The amplified laser beam is emitted from

the output mirror, passes through the f- (f-theta) lens, and is focused onto the target

surface. This focused point is moved with scanning mirrors along the X- and Y-axes to

represent a character, and the character is marked by removing, chemically changing, or

engraving the target surface.

IV. Which laser type is the most common marking Laser?Most metals are highly reflective and therefore, an Nd: YAG (Neodymium: Yttrium

Aluminum Garnet) would be most suited. The wavelength being much shorter means there

will be less reflection of the beam on the surface, therefore less loss of energy and

consequently easier working of the metal.

Organics materials such as wood, acrylics, plastics, fabrics, and transparent objects are

better suited to the CO2 as the wavelength is longer and has more latitude. However the

Nd: YAG lasers can be used to mark some non-metals too. But if the object is transparent

(e.g. glass) then the YAG / Fiber laser light will pass through it without marking it.