Laser marking and screen printing have grown in popularity as government and industry regulations require clearly marked product and part identification on items. Lasers are used frequently in material processing, from product development to high volume manufacturing. Laser marking can be done on all metal materials, making it a popular option for a range of industries.

Product manufacturers have two options when they need to mark a surface with an image, text, or pattern (like a barcode)—laser marking and screen printing. Each method has its own benefits, depending on the application.

Laser Marking

Laser marking is when the pattern created from the laser beam either oxidizes or removes the material, which leaves a mark where the beam touches the surface of the material. Patterns are created on the product with a laser beam directed by mirrors or a fixed position laser mounted above a table that can move.

Some advantages of using laser marking include: 

• Faster Production: Setup is quick, there is no cleanup, and marking is faster, so production time will move more smoothly.
• Cleaner and More Environmentally Friendly: No paints or solvents are necessary with this method. 
• Very Precise Marking: The precision of laser marking is useful for tiny objects and in tight spaces. 
• Ability to Mark in Three Dimensions: With laser marking, you can mark on round and other three-dimensional objects. 
• Can Be Autoclaved: This is necessary for items such as medical or dental instruments that must be sterilized regularly.
• More Durable: Laser marking does not rub off after repeated use. 
• Less Chance of External Contamination: Since the pattern is marked directly onto the surface of the material, you do not have to worry about contamination from outside sources such as pigments.

Screen Printing

Screen printing is when the pattern is painted on the surface of the product. During this process, a squeegee presses ink onto the surface of the material. The squeegee moves across the back of a mesh, causing it to become ink-soaked. A stencil attached to the mesh allows the ink to only follow through its openings, which creates the desired pattern.

Advantages of screen printing include: 

• A larger variety of colors for your design
• Greater material options

Types of Laser Marking Processes

All laser marking processes cause a material to transform in some way as the energy of a laser beam interacts with the material. To achieve each laser process, the wavelength, power, duty cycle, and repetition rate of the laser beam must be regulated with extreme precision. Laser marking changes the appearance of the metal surface without removing material, while laser etching and engraving will remove part of the surface as it marks. 

The four most common types of laser marking include:

• Annealing: Suitable for carbon-containing metals
• Carbon Migration: Suitable for metals and metal alloys
• Foaming: Suitable for plastics
• Coloration: Suitable for both metals and plastics

There are several methods used for laser marking metal: 

• Direct Laser Marking: Direct marking uses either a Fiber laser or a CO2 laser. It is called direct marking because the metal surface is heated by the laser beam energy causing oxidization. This will cause the area exposed to the laser beam to darken, creating a permanent black mark. A Fiber laser can create a bright or polished mark on the surface as well. 
• Indirect Marking: Indirect metal marking can be done by either adding a coating to the surface, like a marking compound, or removing a coating from the surface, such as paint. 

Material Attributes

When choosing the right laser for a marking application, there are many factors to consider, including material attributes, such as:

• Material Color
• Surface Finish
• Reflectivity
• Thermal Conductivity 

When deciding whether laser marking or screen printing is best, you must first look at the application, as each has its own advantages.

Contact Hai Tech Lasers for More Information

Hai Tech Lasers are specialists in precision industrial laser marking and laser engraving for the medical, automotive, aerospace, and electronics industries. To learn more about laser marking, or to request a quote for our metal engraving services, contact us today.