Laser Marking

Laser Marking Processes

Everything you ever wanted to know about what we do:

The actual processes are called (alphabetically): 

Ablation

This is where one material is removed by laser from the top of another, dissimilar material. Common example are "Day/Night" lighted switches in automobiles. These are commonly translucent white plastic bodies which are dipped in paint. The paint is then selectively burned off to expose some pattern or symbol which appears white during the day and which is illuminated from the rear at night. 

Annealing

Annealing is a heating process used on steel and titanium alloys where the surface of the material is selectively heated with the laser to near the melting point. This has the effect of discoloring the material to a black color, which gives excellent contrast against the surrounding steel. This process when properly done does not remove material. It is very commonly used for surgical tools and implants where there is high contrast and permanence and no trenches or crevices are created for bacteria, etc., to hide. Annealing has the disadvantage that if the material is exposed to extreme heat the annealed mark will disappear. Also, annealing only works on steel and titanium. 

Color Change

Color change is a process in plastic where the color of the material changes under the laser light. Some plastics do this naturally, and others have additives which absorb specific laser wavelengths in order to achieve this effect. Typically, no material, or a trivial amount of material, is removed from the surface of the target. One of the classic examples, photos of which can be found on nearly every laser website in the world, is marking on ear tags for cattle. Many consumer electronics products have this kind of marking on their cases.

Cutting

Lasers can be used to cut certain materials. Very thin materials (up to a few thousandths thick) can be cut by normal marking lasers, although some materials exhibit unsightly heat-effect zones on the material. Thicker materials can be cut with higher power lasers, and sheet steel, fabrics, fiberboards, etc., are all cut in industrial situations with lasers. These lasers can have power in the many thousands of watts.

Deposition

Commercially available ceramic paints and films can be applied to the surface of a material and then melted in place with a laser beam, leaving behind a raised and very permanent laser mark. Often used with decorative glass items. Somewhat labor-intensive process to apply the material and then remove the excess. Also can be expensive. However, the mark can be very attractive when done properly.

Engraving, light

Probably the most common kind of laser marking is engraving. This is where the laser beam is used to remove material from the surface of the device being marked, but the material is homogeneous. The laser acts like a chisel in this case and blows away pieces of the subject material. Light engraving is where a relatively shallow trench is created, between .0001" and .005". The depth achievable depends on the material, the power of the laser and the dwell time of the laser. 

Engraving, deep

Deep engraving is something that only high power lasers can do. Deep engraving is used for making molds and dies, stamps, etc. The depth that can be achieved is entirely dependent on how the material absorbs the laser, how much energy the laser has, and how long the laser can dwell on the target. Deep engraving is usually a fairly slow process.

 

Marking

The generic term for making some kind of readable marking on the surface of a component.  Marks are technically one of the following kinds of effects: engraving, ablation, annealing, color change or foaming.

 

Micromachining

Another generic term used to describe marking on the surface of a target where the purpose of the mark is not to make a part number or logo or other readable mark, but to engrave a pattern for mechanical reasons. These reasons may include liquid conduits through a metal block, antennae patterns on metal parts, etc.

Polishing

Similar to annealing is polishing. In polishing, the laser beam is used to selectively melt the very top few molecules of material, and when it cools, which is usually instantaneously, the surface finish will appear different from the surrounding finish. This will then reflect light differently and while there is no real color change, it will appear different. This is often used in electronics for nickel and gold packages.

Welding

Lasers can be used to create weld joints in many materials, including metals, plastics, and certain ceramics. Typically, weld lasers are higher power and are used in systems where the laser beam is stationary and the product moves underneath the laser - similar to the table travel of a milling machine.

 

How the laser works: