Laser marking is a manufacturing process that uses focused laser beams to create permanent marks on surfaces. The process involves transferring heat energy to a material through a system comprising a laser generator, oscillator, scanning mirrors, and focusing lenses. This non-contact technique prevents mechanical wear and preserves material integrity.
Key marking methods include black annealing, which forms oxidation layers on metals; white etching, achieved by removing surface material for light reflection; engraving, which involves material removal for deeper marks; foaming, generating bubbles under plastic surfaces; and chemical alteration of pigments.
Common laser technologies include fiber lasers (1064 nm wavelength) for metals, CO₂ lasers (9000–11,000nm wavelength) for organic materials, and UV lasers for heat-sensitive substrates.
Applications span serial numbers, QR codes, medical device labeling, and aerospace part identification.
Compatible materials include metals, plastics, ceramics, glass, and rubber.
Laser marking ensures traceability, supports automation, and eliminates consumable reliance, enhancing operational efficiency across industries.
Laser marking uses a concentrated beam of light to permanently alter material surfaces. The process involves transferring heat energy to induce changes like oxidation, melting, or vaporisation, depending on the material and the laser’s energy level. This non-contact method is precise and maintains the material’s integrity.
The system comprises three key components:
The beam generation process in laser marking involves the following sequence of stages.
This sequence results in a coherent, high-energy laser beam capable of creating precise, permanent marks on various materials. Adjusting parameters at each stage allows customization to suit different materials and marking requirements.
When laser light interacts with material surfaces, it induces physical and chemical changes through energy absorption and heat transfer, influenced by material properties and laser parameters.
Heat conduction plays a key role, with metals dissipating heat quickly due to high thermal conductivity, while ceramics and polymers localise heat more effectively.
The material response includes surface melting, vaporisation, chemical modifications, and physical changes in crystal structures. Temperature gradients are also generated.
Metals exhibit high reflectivity at room temperature. Aluminium reflects around 92% of visible light. This high reflectivity requires higher laser power for effective marking. As the metal’s temperature rises, its absorptivity also increases; for instance, the absorptivity of copper at a 10.6 μm wavelength can rise from 0.015 at 20 °C. As the temperature increases, absorptivity rises due to surface oxidation and other factors.
For instance, at 500 °C, absorptivity can reach around 0.30, and at 1000 °C, it may approach 0.50. Laser marking can also induce oxidation layers on metal surfaces – a property that is exploited for colour laser marking through controlled oxide layer formation.
Polymers undergo bond breaking, release hydrogen and oxygen during carbonisation, form gas bubbles during foaming, and exhibit colour changes through chemical reactions. Thermal effects depend on pulse duration, with shorter pulses minimising heat-affected zones and longer pulses causing larger zones, while material thickness and geometry influence heat dissipation and flow. Surface modifications include micro and nanoscale changes, pattern formation through beam interference, and periodic surface structures.
Stainless steel and iron are good at absorbing laser energy and are ideal for laser marking. Fibre lasers, in particular, are highly effective for marking these metals, for both annealing (creating colour changes without material removal) and engraving (removing material for deeper marks).
Aluminium is a commonly marked material, though its high thermal conductivity requires higher laser power. At lower power settings, laser marking creates white contrasts, while increased power produces darker, more defined marks. Fibre and pulsed lasers are typically used for marking aluminium.
Soft metals like gold and silver require careful adjustment of laser parameters to prevent distortion or overheating during marking. Copper and brass, which have high thermal conductivity, often require shorter laser pulses to manage heat buildup. Nickel-plated surfaces, commonly used in electronics and decorative applications, respond well to hybrid lasers that combine different wavelengths for optimal absorption.
Metal Name | Thermal Conductivity (W/m·K) | Laser Wavelength (nm) | Typical Type of Laser Used for Marking |
|---|---|---|---|
Stainless Steel | 16.2 | 1064 | Fibre Laser |
Aluminium | 205 | 1064 | Fibre or Pulsed Laser |
Copper | 398 | 532 | Green Laser (532 nm) or Fibre Laser |
Gold | 318 | 1064 | Fibre Laser or Nd:YAG Laser
|
Silver | 429 | 1064 | Fibre Laser or Nd:YAG Laser
|
Brass | ~109 | 532 | Green Laser or Fibre Laser |
Nickel (Plated) | 90 | 1064 | Hybrid Laser
|
PVC, ABS, and polycarbonate are highly suitable for laser marking. Changes in their molecular structure during marking cause permanent colour changes or engraving. Laser marking on these materials typically involves bond breaking or surface carbonisation to produce legible and durable marks.
Materials like glass-filled epoxy (used in circuit boards) and polyimide (used in flexible printed circuits) exhibit strong marking results under tailored laser settings. PET (polyethylene terephthalate), widely used in packaging, is best marked with CO₂ lasers because it absorbs infrared wavelengths.
Ceramics and glass require careful power and frequency adjustment for precise marking without cracking. CO₂ and UV lasers are commonly used to etch or engrave these materials, often for applications like labelling medical instruments or decorative glass.
Rubber, particularly black rubber, absorbs laser energy effectively and provides excellent contrast. Laser power and speed must be finely tuned to avoid excessive depth or uneven edges, ensuring clean and consistent marks.
Dark-coloured or matte-finish surfaces absorb laser light more efficiently, which enhances marking quality. Reflective or polished surfaces, on the other hand, reflect more laser energy, requiring higher power settings to achieve the desired depth and clarity. The surface finish also affects mark readability; rough surfaces may scatter the laser beam, causing inconsistencies, while smooth surfaces allow for clearer and more uniform marks
Thermal conductivity significantly impacts laser marking. High-conductivity materials like metals dissipate heat rapidly, requiring power adjustments for effective marking. Materials with low thermal conductivity, such as plastics and ceramics, localise heat, making them easier to control during marking. While material hardness has minimal effect on marking, thicker materials may need increased power to achieve the desired depth and clarity.
Laser marking techniques vary based on material type, desired mark depth, and application requirements. Each method offers unique advantages and is suited for specific industries and purposes.
Laser engraving removes material to create a deep, permanent groove, typically between 0.001 mm and 0.1 mm, depending on the material. For applications requiring durability, such as automotive components or industrial tools, engravings can reach depths of up to 5 mm. This process is achieved by a focused laser beam heating and vaporising the material. Laser engraving is ideal for metals, plastics, and wood.
Laser cutting removes entire sections of material by vaporising it along a defined path. The precision of laser cutting produces kerf widths as narrow as 0.1 mm, enabling intricate designs and clean edges. Smooth edges eliminate the need for post-processing, making this technique ideal for manufacturing, aerospace, and electronics.
Laser etching removes a small amount of material, altering the surface to create a high-contrast mark. The laser heats the material, causing expansion that results in a textured surface. Typical etching depths are less than 0.01 mm, making the process fast and efficient. This method is commonly used to mark barcodes, serial numbers, and logos on metals, plastics, and ceramics.
Material Type | Typical Etch Depth (mm) | Laser Type Used | Applications |
|---|---|---|---|
Stainless Steel | 0.01-0.5 | Fiber Laser | Automotive parts, Medical devices |
Aluminum | 0.025-0.5 | Fiber Laser | Industrial components, Consumer electronics |
Plastics | 0.0025-0.125 | CO2/Fiber Laser | Electronic housings, Consumer goods |
Precious Metals | 0.01-0.03 | Green/Fiber Laser | Jewelry, Luxury items |
Carbon Steel | 0.01-0.5 | Fiber Laser | Machine parts, Tools |
Copper/Brass | 0.01-0.3 | Green/Fiber Laser | Electrical components, Decorative items |
Titanium | 0.01-0.5 | Fiber Laser | Aerospace parts, Medical implants |
Ceramics | 0.01-0.2 | CO2 Laser | Electronic substrates, Industrial components |
Glass | 0.01-0.1 | CO2/UV Laser | Display panels, Optical components |
Carbide | 0.01-0.3 | Fiber Laser | Cutting tools, Wear components |
Laser annealing heats metal surfaces to create dark, oxidation-based marks without removing material. The marks penetrate 20 to 30 µm and are corrosion-resistant, ensuring stability in harsh environments. This technique is widely used in medical instruments, automotive parts, and tools requiring permanent, high-contrast marks.
Foaming creates raised, frothy marks on plastic surfaces by using a laser to generate gas bubbles within the material. This process alters the material’s light reflection, resulting in bright, visible marks. Foaming is primarily used in consumer goods for branding and labelling.
Carbon migration involves using a laser to heat metals, causing carbon to concentrate at the surface. This process alters the material’s properties to produce dark, durable marks. Common applications include marking steel alloys, medical tools, and industrial equipment.
Colour marking uses precise laser settings to induce oxidation or structural changes on certain materials, producing coloured effects. This technique is often employed in decorative branding, luxury goods, and customised designs.
Each laser marking technique has distinct capabilities tailored to specific materials and applications, making it essential to choose the appropriate method for the desired outcome.
Material | Colour Range | Laser Wavelength | Applications |
|---|---|---|---|
Stainless Steel | Gold, blue, red, green, etc. | 1064 nm
| Automotive, electronics, medical equipment, jewelry |
Titanium | Blue, Yellow, Green, Violet, Brown, Black | 355 nm | Medical, Aerospace, Automotive
|
Plastic | High contrast markings, various colors including white, black, gray | 532 nm, 355 nm | Automotive, Electronics, Medical, Consumer Goods, Jewelry
|
Copper | Various colors depending on oxidation; black, white, and other shades | 1064 nm | Jewelry, Automotive parts, Electronics, Construction |
Brass | Full spectrum including blues, grays, pinks, and black | 1064 nm | Jewelry, musical instruments, electrical components, awards, signage
|
Laser marking is a key technology that has helped many companies improve their processes by delivering precise, durable, and tamper-proof markings. This section will look at how laser marking has specifically benefited two companies, boosting their efficiency and ensuring compliance.
Tahbilk Winery, a family-owned business in Victoria, faced difficulties with its traditional ink-based system for marking wine bottles. Issues like smudging and fading were common, which affected both the quality of the markings and product traceability.
To solve this, Tahbilk Winery implemented fiber laser marking technology into their production process. This led to several significant improvements:
DMG MORI, a leader in automotive manufacturing, needed a reliable way to mark 3D-printed aluminum parts used in their production. They integrated fiber laser marking systems to ensure better traceability across their automated processes.
Here’s how laser marking helped:
Laser marking is a precise, non-contact method that creates permanent markings on materials like metals, plastics, and ceramics. Using advanced laser systems, it enables engraving, etching, annealing, and more with high accuracy. Trusted suppliers like Triton Store provide the cutting-edge equipment businesses need to achieve superior results.
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