Laser marking metals : principles and applications
Metals can be easily marked with a laser beam, making it an efficient and precise process for many applications. The principles of laser marking metals will be discussed and some of the most common applications. There are various factors to consider when choosing the best laser marking system for your needs, so be sure to do your research!
1. What is laser marking, and what are the benefits of traditional methods?
Laser marking is the process in which laser light is used to change or alter the properties of a material by creating markings or etching into it. The laser beam is transmitted through optical elements mounted on a laser system and focused onto the material to be marked.
The laser processing enables marking metals with high precision, thus increasing productivity compared to traditional manufacturing methods. It also allows increased automation in different industrial stages, such as production lines. Furthermore, laser marking can offer environmental benefits since no toxic chemicals are involved during the process.
2. What materials can be laser-marked?
Many metals can be laser-marked successfully with laser technology, including steel, titanium alloy, aluminum alloy, and superalloy. Typical laser marking systems can operate in a temperature range of -30 to 400°C (-22 to 750°F), depending on the laser wavelength, allowing them to mark metals with high surface hardness.
3. What laser parameters should be considered while laser-marking metals?
When laser processing stainless steel and other metals that contain iron (Fe) and nickel (Ni), two significant factors need to be taken into consideration: laser type and laser beam energy (the respective wavelengths).
These two laser parameters will determine what laser system or source is best for your application. For example, a shorter pulsed Nd: YAG laser wavelength can be considered if you require deep marking with a minimal heat-affected zone. The laser’s laser beam energy, measured in joules, should also be chosen depending on the laser marking depth required.
4. Laser marking metals with laser power
The laser power needed for laser marking varies greatly depending on the properties of the metal being marked and even which type of laser is being used. For example, if the material you are working with has a low absorption coefficient, it may require more laser power to heat up faster. More laser penetration depth may be needed if your application involves marking alloyed materials more commonly found in aircraft or satellites.
As a general rule, consider using higher laser powers when processing hard alloys (up to HRC 50) along with stainless steel. However, laser power should be lowered if marking aluminum alloys as it may lead to unwanted laser-induced effects such as dross formation or roughening on the surface.
5. Laser marking metals with laser beam scanning
When laser processing metals, a laser beam scanning system can decrease production time by moving the laser at faster speeds across the material’s surface. For example, a laser beam that scans horizontally and vertically can laser mark a fixed spot up to six times faster than a fixed laser power. In addition, suppose the metal part being processed has a complex shape with tight tolerances. In that case, this feature will allow for increased operational flexibility due to its ability to adapt to different workpieces sizes and shapes.
6. How laser marking materials is different from laser cutting
The laser parameters used for laser cutting are very different than those required for laser marking. The laser beam energy level should be higher for laser cutting, as it removes material by vapourising it. This allows the laser to process metals with high surface hardness; however, this can cause more heat-affected zone during the laser processing. On the other hand, when laser marking materials, there is no need to consider laser power levels as changes on this parameter do not alter the metal being processed. The wavelength of the laser, which determines how deep or shallow a mark will be created on a metal’s surface, needs to be considered instead.
7. What laser marking method is best?
The best laser marking method will depend on the laser parameters and laser type you choose, in addition to how your laser-marked product will be used in its final application.
8. What is laser surface treatment?
Although laser marking metals can produce a permanent mark on their surfaces, laser surface treatment can further enhance part functionality by making it wear-resistant. For instance, heat treating is conducted with lasers operating at high power or broadband wavelengths such as carbon dioxide or neodymium-doped yttrium aluminum garnet (Nd: YAG) lasers. Laser-induced fusion processes are also used to treat metal alloys by adding nanoparticles to create an ultra-hard material layer. In addition, such laser surfaces can be employed for medical implants or cutting tools to increase laser beam machining efficiency.
9. How laser marking metals can benefit manufacturing?
Laser marking metals is a tool that any manufacturing industry or individual users can utilize to get their desired laser-marked effect on metal surfaces. It allows manufacturers of devices, components, and products to differentiate themselves from competitors better. It also enhances product quality by producing laser marks featuring complex logos, texts, and barcodes that are not easily replicated. By laser processing the surface of materials instead of laser cutting them, laser marking offers reduced risk for safety hazards caused by sharp edges around laser-cut parts. Laser surface treatment processes using lasers with high power or broad wavelengths can also produce wear-resistant coatings on workpieces for greater operational reliability.