Friday, July 04 2008
Home
Products
About RMI
Samples
Laser Marking 101
Applications
     
RMI Login
Visitors: 138898
Who's Online
Laser Marking Types Print E-mail

LASER MARKING Types

Laser ENGRAVING / Etching /

Metals are the most common substrate marked in this manner although ceramics and some plastics also engrave well. The material is removed when the intense power density of the laser vaporizes the material leaving a contrasting impression – the depth of which can be varied by adjusting the power density. When engraving certain metals, oxides are formed on the surface on and around the mark adding further contrast due to their natural color. It is important to note that while much of the removed material is vaporized, there is usually some amount of debris remaining on the surface of the material. While this may increase the definition of the mark, it might also be necessary to remove the debris depending upon the application.

 		  photo
Applications
 

Laser ABLATION

This type of mark uses the energy of the laser beam to alter or destroy the structure of surface molecules by which a visible change in the color of the substrate is made without damaging the material.

When engraving certain metals, oxides are formed on the surface on and around the mark adding further contrast due to their natural color. It is important to note that while much of the removed material is vaporized, there is usually some amount of debris remaining on the surface of the material. While this may increase the definition of the mark, it might also be necessary to remove the debris depending upon the application.

Many paints and coatings ablate easily, however the color of the paint or coating is an important factor to consider when selecting ablation as a marking function. Generally, a high contrast between the substrate and the paint color yields the best results. The process is so accurate that it is often used to remove the lower layer of paint from backlit panels for automotive day/night displays. 		 photo
Applications

Laser COLOR CHANGE

This type of mark uses the energy of the laser beam to alter or destroy the structure of surface molecules by which a visible change in the color of the substrate is made without damaging the material.

Again, the color of the substrate plays a significant role here as some plastics mark very well while others require the addition of pigments to attain an acceptable level of contrast.

 		 photo
Applications

Laser ANNEALING

Compared to engraving, annealing is achieved by using lower power densities and a slower marking speed and works best with a limited number of substrates including steels, titanium, and some other metals. The low power setting does not melt or vaporize the substrate but creates enough surface heat to oxidize the surface of the metal substrate. These oxides have a different color than the material itself providing the necessary contrast required for a visible mark.

 		  photo
Applications
 
  

Traditional Marking Methods for Manufacturing and Engraving 

Scribing

Definition: A process utilizing a hard-tip (like diamond)pen or pointed device to scratch or scrape off the surface of a material to generate a mark.  

Advantages: It is possible to generate deep engravings with this type of process. Being a traditional marking method, scribing is generally an inexpensive process. 

Disadvantage: Compared to Laser Marking, scribing is a slow and crude process. Precesion, high resolution marking is impossible with scribing. Also, many materials can be damaged or deformed through this process, which includes anchoring the part using clamps or fasteners. Scribing involves purchasing replacement tips when they wear out. 

Inkjet Printing

Definition: A process whereby inks and/or dyes are sprayed through nozzles onto the surface of the part to create a mark.  

Advantages: Being a traditional marking method, scribing is generally an inexpensive process. Also, high speed (although low resolution) marking can be achieved with inkjet printing. 

Disadvantage: Compared to Laser Marking, inkjet printing is a messy process with many comsumables, including, replacement nozzles, ink refills and clean up materials. Although inkjet printing does not generally damage the part, the marking will fade or rub off over time, making it illegible. In general, high resolution, permanent marking is a challenge for inkjet. Inkjet printing poses another key disadvantage in the medical field where sterility is important, particularly in implantable medical parts and devices. Most inks are considered to be harmful contimants to the body.   

Chemical (Acid) Etching

Definition: A process where acid is applied through a stencil to corrode the part, leaving a mark.  

Advantages: It is possible to generate permanent marks with this type of process.

Disadvantage: Compared to Laser Marking, chemical etching is a messy and caustic process. Users are constantly exposed to acids and chemicals which are harmful to touch and breate in. Precesion, high resolution markings are nearly impossible with chemical etching and there are numerous consumables such as replacement stencils and acid refills. 

Stamping

Definition: A process where a single metal stamp or series of pin stamps is struck into the part to leave a physical impression, thereby leaving a mark.     

Advantages: Stamping is generally very fast. It is also possible to generate deep permanent markings with this process. Being a traditional marking method, scribing is generally an inexpensive process. 

Disadvantage: Compared to Laser Marking, scribing is a crude process where part damage and resolution are a constant challenge. Precesion, high resolution markings nearly impossible with stamping, particularly on smaller parts. Also, many materials can be damaged or deformed through this process, which includes anchoring the part using clamps or fasteners. Stamping involves purchasing replacement stamps when they wear out. 

  
    
     
 
.
Site and all contents © 2008 RMI Laser