Industrial marking durability: ensuring permanent marking and reliable traceability over time

The nature of the material is one of the most critical factors influencing marking durability, as it directly determines how the material reacts to dot peen marking, scribing, or laser marking.

Hardness, metallurgical structure, thermal conductivity, surface condition, and the presence of surface treatments all influence achievable depth, contrast quality, and the resistance of permanent marking over time.

These characteristics determine the ability to achieve a durable marking that maintains readability after each stage of the manufacturing process and throughout the entire service life of the part.

• On steels, it is generally possible to achieve a deep and durable marking, as the material supports plastic deformation well in dot peen or scribing processes, and also enables stable laser engraving suitable for permanent marking and industrial traceability applications.

• On heat-treated or hardened steels, higher hardness can limit mechanical penetration and may require increased impact force or laser energy to ensure sufficient depth and marking durability aligned with traceability requirements.

• Stainless steels behave differently, especially in laser marking, where process settings directly affect contrast, readability, and marking durability.

Contrast strongly depends on the selected marking mode: thermal annealing marking produces clear coloration without material removal but is more sensitive to abrasion, whereas engraving or ablation provides better mechanical resistance at the cost of a more pronounced surface modification.

• Aluminium, due to its low hardness and high thermal conductivity, requires more precise parameter tuning to ensure marking durability.
  In mechanical marking, the material deforms easily, but depth remains limited if the applied force is insufficient to ensure a permanent mark.
  In laser marking, rapid heat dissipation can reduce engraving efficiency, requiring adjustments in power, speed, and number of passes to achieve a durable and long-lasting mark suitable for traceability requirements.

• Cast iron has a more heterogeneous structure but is well suited to deep mechanical marking, especially dot peen, as the material absorbs localized deformation effectively.
  It often enables a robust and durable marking, even on rough or uneven surfaces, making it a typical case where long-term marking retention and traceability take priority over appearance.

• Engineering plastics require a different approach, as marking behavior depends on polymer composition, fillers, pigments, and thermal sensitivity.
  In laser marking, some plastics mark by contrast, others by ablation or chemical change, and results can vary significantly depending on formulation, requiring process adaptation to ensure a durable and readable marking aligned with traceability requirements.
  Incorrect settings may result in shallow marking, surface deformation, or loss of readability over time, compromising marking durability and traceability reliability.

The presence of surface treatments must also be considered.

Painting, anodizing, galvanizing, phosphating, heat treatment, or coatings can alter material behavior and require adjustments to marking technology or marking depth to maintain sufficient readability after each manufacturing step and ensure long-term marking durability.

The depth of industrial marking is one of the most critical parameters for ensuring the durability of permanent marking over time.

It directly determines the ability of the marking to remain readable despite mechanical stresses, manufacturing operations, and operating conditions the part will be exposed to throughout its lifecycle, particularly in industrial traceability applications.

A shallow marking may show good contrast immediately after application but can quickly lose readability after handling, machining, painting, heat treatment, cleaning, or abrasion.

In the context of industrial traceability and DPM marking (Direct Part Marking), this loss of depth can lead to degradation of code geometry, reduced contrast, and reading difficulties for machine vision systems, ultimately compromising marking durability over time.

Conversely, a sufficiently deep engraved mark remains identifiable even when the surface of the part deteriorates.

When the material is worn, polished, or partially covered by a treatment, the marking geometry remains embedded in the material volume, allowing characters or codes to stay readable throughout the product’s lifetime and ensuring permanent marking durability.

The actual achieved depth depends on several mechanical and energy-related factors linked to the marking technology used and the material characteristics, all of which directly influence marking durability and long-term stability.

• In dot peen marking, depth is determined by impact force, striking frequency, stylus diameter, and material hardness.
  Insufficient impact produces a light mark that may be visible in the short term but can quickly lose definition after friction or handling, reducing marking durability.
  Conversely, properly adjusted settings create sufficient plastic deformation to ensure strong permanent marking performance, even on parts exposed to significant mechanical stress or harsh operating conditions.

• In scribing, depth depends on carbide tip pressure, guide rigidity, and part fixturing stability.
  Insufficient force produces a shallow line prone to wear, while properly controlled force creates a continuous groove with strong abrasion resistance and improved marking durability, while maintaining consistent geometry compatible with traceability requirements.

• In laser marking, depth results from the energy delivered into the material, which depends on power, frequency, scan speed, number of passes, and the interaction mode between the beam and the surface.
  A laser annealing mark changes surface colour without material removal and is more sensitive to abrasion, whereas ablation or engraving achieves greater penetration and therefore improved long-term marking durability.
  Settings must be adapted to the material, as thermal conductivity, hardness, and surface structure significantly affect achieved depth and marking stability in industrial traceability applications.

In DPM marking applications, where automated reading determines industrial traceability, insufficient depth is one of the most common causes of readability loss.

Even slight surface wear can distort code geometry or reduce contrast, making reading unstable or impossible for machine vision systems.

To ensure durable industrial marking, depth must therefore be defined not only based on the immediate visual result, but also by considering post-marking operations, in-service mechanical stresses, and the expected service life of the part, in order to guarantee reliable long-term traceability.

The durability of industrial marking does not depend solely on the technology used, but also on the actual settings of the marking machine.

Even with a solution suited to the material and application, incorrect parameter settings can produce a marking that is too shallow, inconsistent, or insufficiently stable to withstand production and service conditions, compromising marking durability.

Marking parameters directly influence achieved depth, contrast quality, code geometric precision, and the ability of the marking to remain readable over time.

In industrial traceability and DPM marking applications, mastering machine settings is essential to ensure permanent marking and reliable readability, even after handling, surface treatment, or exposure to mechanical stress.

• In dot peen marking, durability depends mainly on impact force, striking frequency, stylus diameter, dot density, and fixture rigidity.
  Insufficient force can produce a visible but shallow mark that quickly loses definition after abrasion or handling, reducing marking durability.
  Conversely, excessive force may cause excessive deformation of the part or distortion of code geometry, which can negatively affect readability, especially for DataMatrix codes and DPM applications.

• In scribing, the main parameters are stylus pressure, travel speed, working angle, and the mechanical stability of the machine–part setup.

Insufficient force produces a shallow line that is prone to wear, while properly tuned settings generate a continuous groove with strong abrasion resistance and improved marking durability, while maintaining consistent geometry aligned with traceability requirements.

• In laser marking, settings are even more critical.
  Power, pulse frequency, scan speed, number of passes, focusing, and spot size directly influence the energy delivered into the material, and therefore depth, stability, and marking durability.
  A laser mark that is too fast or underpowered may show good initial contrast but quickly lose readability after painting, heat treatment, or abrasion.
  Conversely, properly optimised settings produce a more stable engraving, suitable for permanent marking, DPM marking, and long-term traceability requirements.

Cycle time constraints must also be considered.

Excessively high marking speeds can reduce depth and marking quality, and therefore durability, while overly slow settings may reduce productivity without significantly improving marking performance if other parameters are not properly optimised.

The durability of industrial marking cannot be defined solely by the result achieved at the time of marking.

Real operating conditions of the part must always be considered, as they directly determine the ability of the marking to remain readable throughout the product lifecycle and to ensure reliable traceability over time.

In many cases, a marked part is later exposed to mechanical, thermal, or chemical stresses that can alter the surface.

A marking that is too shallow may then lose contrast, have its geometry degraded, or become difficult to read, even if it was perfectly visible immediately after the marking process.

Impacts, vibrations, and repeated friction, along with handling, assembly, or transportation, can gradually wear the surface of the part.

In these conditions, a shallow marking may partially fade, whereas a recessed marking preserves its geometry within the material and provides better marking durability, even after abrasion.

Manufacturing process constraints must also be anticipated.

These post-marking operations can significantly impact marking durability, particularly during the following steps:

• machining,
• shot blasting,
• sandblasting,
• painting,
• anodising,
• heat treatment,
• welding,
• chemical cleaning.

These steps can modify surface condition, reduce contrast, or partially cover the marking.
If depth is insufficient or if the technology is not appropriate, readability may be compromised, which becomes a major issue in industrial traceability and permanent marking applications.

The chemical environment is also an important factor.

Exposure to oils, solvents, fuels, cleaning agents, or corrosive atmospheres can degrade a shallow marking, especially when it relies solely on surface contrast.

In these situations, a deeper marking or more pronounced laser engraving helps maintain a stable identification over time and ensures marking durability in industrial traceability applications.

Thermal constraints must also be considered.

Some parts are exposed to high temperatures during production or use, for example during heat treatments, paint curing, or operation in hot environments.

Material expansion, oxidation, or surface changes can reduce readability of insufficiently deep or overly superficial markings, which can compromise marking durability in traceability applications.

In DPM marking applications, where the code must be read by automated vision systems, durability is not limited to visual presence.

Geometry, contrast, and depth must remain sufficiently stable to ensure reliable reading despite wear, surface treatments, or stresses applied to the part, ensuring long-lasting industrial traceability.

The durability of industrial marking also depends on the type of information to be marked on the part.

The level of requirement is not the same depending on whether it is simple alphanumeric text, a serial number, a logo, or a DataMatrix code used in DPM marking for automated traceability.

A text marking generally remains readable even if contrast slightly decreases or if the surface undergoes moderate wear.

In contrast, a 2D code intended for machine vision reading imposes much stricter requirements in terms of geometry, depth, and long-term stability.

Even slight degradation of relief or contrast can make reading difficult or impossible, even if the marking is still visible to the naked eye.

In industrial traceability applications, DataMatrix codes or QR codes must maintain precise geometry to be correctly interpreted by cameras and automated readers.

Reading quality depends notably on module consistency, marking depth, contrast uniformity, and the absence of deformation caused by wear or surface treatments.

A marking that is too shallow, irregular, or insufficiently contrasted may be compliant at the time of marking but become unreadable after handling, painting, shot blasting, or exposure to mechanical stress.

In such cases, vision systems may generate reading errors, production rejects, or traceability failures, which can have significant impacts on quality, logistics, or regulatory compliance.

The choice of marking technology and penetration level must therefore be defined based on the type of code to be produced.

A marking intended for simple visual identification does not require the same depth level as a permanent DPM marking that must remain readable throughout the entire product lifecycle.

In sectors where traceability is critical, such as automotive, aerospace, energy, or medical, the marking must maintain sufficient quality to be read automatically after multiple manufacturing, transport, or usage stages.

Mastering depth, contrast, and code geometry therefore becomes essential to ensure durable and permanent marking that complies with industrial traceability requirements.