Laser Surface Texturing of Cutting Tools for Improving the Machining of Ti6Al4V: A Review

Abstract

The machining of titanium alloys, particularly Ti6Al4V, presents a significant challenge in manufacturing engineering. Its high strength, low thermal conductivity and high chemical reactivity make Ti6Al4V a hard-to-machine material. However, the machining process is critical for aerospace and biomedical industries. The rapid wear and short lifetime of cutting tools are the main limitations in Ti6Al4V machining, leading to a large increase in manufacturing costs and compromising the surface quality of machined components. Faced with this problem, the texturing of cutting tools, especially through laser-based techniques, has gained considerable attention in the last decade due to improvement of the tribological properties of textured surfaces. Laser Surface Texturing (LST) has emerged as a promising technique to improve the tribological performance of cutting tools by enabling the creation of precise surface structures. Building on prior research, this review provides a comprehensive overview of the most recent research on this topic, summarizing key findings and outcomes from various investigations.

1. Introduction

In recent years, the use of titanium alloys has increased in aerospace, marine and medical industries. Their high stiffness-to-mass ratio, high toughness at elevated temperatures, exceptional corrosion resistance and excellent biocompatibility make these superalloys excellent for several applications [1,2,3,4,5].

However, their low thermal conductivity and their ability to maintain strength at elevated temperatures lead to high temperatures, elevated cutting forces and rapid tool wear during machining [5]. These factors restrict productivity, increase operational costs and compromise the surface integrity of machined parts [6]. One of the possible solutions is the use of lubricants, but sustainability is increasingly important in a society prioritizing rational resource use and environmental protection. Therefore, green machining trends usually support lubricant reduction, as they have significant impact on the environment and economic costs. Numerous studies have been conducted to enhance the lifespan and cutting performance of tools. It has been found that tools coated with a durable ceramic layer can reduce tool wear and improve cutting performance [7]. Cryogenic treatment of cutting tools has also proven to be an effective method for enhancing cutting performance [8]. Additionally, the application of cutting fluids during the machining process has been shown to have a beneficial impact on tool life and cutting efficiency [9]. However, cutting performance still falls short of meeting the requirements for mass production, and costs remain high. Within the field of tribology, the concept of microtexturing has been introduced [10].

The research and development of cutting tools have evolved significantly over recent decades. Advances in cutting-tool design and manufacturing have been essential to meet the ever-growing demands of advanced manufacturing within modern industry, with Laser Surface Texturing (LST) emerging as a particularly promising solution.

Surface texturing refers to a set of techniques used to apply defined patterns to a surface, with the goal of enhancing its functional properties or introducing new ones by altering its topography [11,12]. Today, this technique is extensively employed to enhance the mechanical and tribological properties of materials, providing improvements in fatigue resistance, corrosion resistance and wear resistance, among others [11]. Industrial applications of these modified surfaces have undergone remarkable growth in recent years. In fact, they cover various fields, including the biomedical sector [13], the development of anti-icing materials [14] and the creation of corrosion-resistant surfaces [15]. Tanvir Ahmmed et al. [16] reviewed the use of direct femtosecond laser micromachining to fabricate micro-/nanostructures on metals. Li et al. [17] summarized the advances on surface nanostructuring technologies using femtosecond lasers, while Wang et al. [18] discussed in depth the applications of laser-induced periodic surface structure (LIPSS) in organic and inorganic materials. For instance, Kumar et al. [19] discussed how Laser Surface Texturing (LST) is used in dental and orthopaedic implants to improve different properties like friction, wettability and adherence. Jia et al. [20] effectively extended the service life of gears by enhacing lubricant storage and surface lipophilicity. Gear steels (20CrMnTi) were tested after LST parallel and perpendicular microgrooves were made on their surfaces. Droplet diffusion increased by 1.27 times, the friction coefficient decreased and the wear depth was reduced by 33.53% in the textured samples. In the aerospace sector, studies are currently exploring the application of copper–nickel–indium (CuNiIn) anti-wear coatings, commonly used on turbine blades, to laser-pulsed textured surfaces [21]. Currently, these surfaces are treated using shot blasting. In other research, Rezayat et al. [22] investigated the effect of nanosecond Laser Surface Texturing on microstructure and mechanical properties of AISI 301LN. This study also raised the possibility of practical applications of nanosecond Laser Surface Texturing for real-world industrial applications of AISI 301LN.

Looking to achieve friction reduction, Salguero et al. [23] found a linear impact of the energy density on the surface quality, whereas the scanning speed influences the homogeneity of the sample. Nevertheless, the microhardness was reduced by up to 33% on the textured area of AISI 630 steel. In another study, Salguero et al. [24] described the influence of microstructural modifications and oxidation processes on Ti6Al4V. They also highlighted that the tribological performance of textured surfaces strongly depends on the parameters used in laser patterning.

Comparing different pattern geometries, Long et al. [25] studied the influence of depth patterns on the operational performance of textured rolling bearings under severe lubrication conditions. The authors analyzed concave, decreasing, increasing, convex and horizontal variations. The convex pattern stood out for providing comprehensive and favorable tribological and vibration properties. Narayana et al. [26] explored the dry and lubricated tribological properties of LST Ti6Al4V, comparing cyclic, square and triangular textures. The results obtained showed a significant reduction in COF (coefficient of friction) and wear rate, specifically on circular textures in every lubricant used (PAO-4 and PAO- 4 + 1% wt MoS₂), due to the high oleophobility of the textured surface. Similarly, Shabir et al. [27] studied three distinct configurations of microtextures, namely, co-axial circles, hexagons and lines, with varying spacing. The results proved that co-axial circles with lower spacing were the most efficient in enhancing the tribological performance.

Baby et al. [28] compared mechanical indentation and microdrilling as texturing methods, analyzing the effects of the texture generation method, texture spacing and temperature on friction and wear behaviour. Some of the spacings negatively affected the tribological performance, reinforcing the importance of identifying the appropriate design. Following this research line, Gaikwad et al. [29] evaluated the effect of dimple density under lubrication. Wear behaviour was strongly influenced by the dimple density, while the friction coefficient presented stable results for intermediate dimple densities until the dimples wore away.

While surface texturing has been applied in other fields, its use on cutting tools began gaining traction in the early 2000s, when studies demonstrated the benefits of introducing micro- and nanotextures on cutting-tool surfaces [30]. The main key factors that enable surface texturing to improve titanium machining include enhanced lubrication, as the textures serve as reservoirs for cutting fluids in contact areas; the ability to capture debris generated during machining; and a reduction in the contact area between the cutting tool and the chip, which improves chip flow and size control.

These effects lead to several notable advantages, such as reduced cutting-tool wear, lower friction coefficients, decreased cutting forces and lower temperatures during the machining process [30,31,32]. Similarly, the possibility of using conventional tools for highly demanding applications using minimal amounts of cutting fluids can be achieved. This has a significant impact in terms of cost savings, efficient resource management, carbon footprint, improved process sustainability and increased cutting-tool functionality, leading to increased performance from all possible perspectives.

Nevertheless, a considerable amount of research has been conducted to establish optimal texture designs specifically for cutting tools. Understanding the phenomena that govern the interactions between contact surfaces with functional topographies is essential for enhancing the performance of Ti6Al4V machining processes from the perspective of cutting tools.

Therefore, this review discuses the current state of the art of LST for cutting tools in titanium machining, analyzing the main technologies used and the effects of laser parameters, texture geometry and positioning on machining performance.

2. Fundamentals of Laser Surface Texturing

Surface texturing on cutting tools can be performed through different technologies. Each of them creates geometrical characteristics (shapes, dimensions, and the density and form of surface distributions) [12,32,33]. Figure 1 summarizes the technologies, clasified by the type of energy used during the texturing process. According to the literature, the most widely used technique for texturing cutting tools is Laser Surface Texturing (LST).

LST uses a laser for texturing. The laser operates by directing focused laser beams onto a material surface, creating micro- and nanoscale patterns. The laser’s intensity and pulse duration are precisely controlled to achieve the desired textures, enhancing surface properties such as friction, wear resistance and adhesion, thereby improving the cutting-tool material’s overall performance [34]. This eco-friendly technology imparts specific properties to the material, making it suitable for highly demanding technological applications [35].

In LST, the angle and method of laser projection influence the precision and finish of the texture. Three main LST techniques can be distinguished in this technology to create microindentations and alter the surface topography:

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LST by laser interference: Two or more overlapping laser beams are used. The interference of these beams produces a periodic intensity distribution, which ablates the surface, forming textures that enhance tribological properties, reduce friction and improve wear resistance [36].

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LST by laser shock: High-intensity laser pulses generate shock waves on a material’s surface. These shock waves enhance properties like hardness, fatigue strength and wear resistance. This method is particularly effective for improving the durability of materials used in demanding applications, as it increases surface compressive stresses [37].

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LST by direct ablation: Short, high-intensity laser pulses are used to remove material from a surface in a controlled manner. This ablation process evaporates or sublimates tiny surface areas, allowing for custom-designed textures that can enhance properties such as friction reduction, wear resistance and hydrophobicity [31,35].

These techniques can be used to improve the machining of titanium alloys, with ablation being the most widely applied method. This texturing technique provides control, precision and efficiency, and, unlike other methods, results in minimal contamination of the substrate surface.

During ablation, the material is removed through laser-energy absorption, where high-energy pulses rapidly melt and vaporize the material. To achieve the ablation phenomenon, the ablation threshold of the material must be exceeded. For a higher ablation rate, higher energy intensities are required. Thus, two phenomena appear: soft ablation (Coulomb explosion), where energy intensities are close to the ablation threshold, and strong ablation (thermal vaporization), where energy intensities significantly exceed the threshold. Soft ablation results in smoother surfaces with limited depth per pulse, while strong ablation provides a higher material removal rate but leaves a rougher surface [38,39,40]. Figure 2 shows the scheme configuration of LST by direct ablation.

Direct laser ablation equipment is classified by beam type, either pulsed or continuous. For pulsed beams, the pulse duration can vary: long (milliseconds), short (microseconds and nanoseconds) or ultrashort (picoseconds and femtoseconds). Pulse duration influences the texture characteristics of the material. The main limitations of this process include heat-affected zones (HAZs), such as cracks and pores; however, these can be minimized by using ultrashort pulses in the picosecond or femtosecond range [11,31,41].

The main differences in beam duration lie in whether the process is photothermal or photochemical. In the photothermal process, which occurs with short-pulse lasers (nanosecond to microsecond durations), the material absorbs laser energy, causing a rapid temperature increase that melts the material. In contrast, the photochemical process takes place with ultrashort-pulse lasers (picosecond and femtosecond durations). Here, photon absorption induces reactions that exceed the atomic bond energy, breaking bonds and removing material without thermal damage.

In these processes, notable differences in material behavior can be observed between long and short pulse durations, once the laser has impinged (see Figure 3). For pulses lasting from nanoseconds to microseconds, effects such as thermal damage, heat-affected zones, material buildup, spattering, debris and cracking are commonly detected. Sometimes, the debris is part of the vaporized material that has solidified in the areas where the laser has impacted. Energy density, along with a low number of pulses, is a parameter that significantly influences this phenomenon [24], allowing removal processes without thermal impact on the surface. Metallurgically, in typical tool materials for titanium machining, such as WC-Co, selective removal is based on the lower melting point of the cobalt phase (1768 K), which acts as a binder and is vaporized, reducing the stability of the WC grains (3243 K) and leading to their removal [42]. For example, when a nanosecond laser is employed to texture WC-Co, the thermal effects during the laser ablation process include melting, evaporation and phase explosion, which serve as the primary material-removal mechanisms. These effects influence the texture geometry by increasing the accumulation of molten material on both sides of the groove. Additionally, thermal stress induces surface cracking at the edges and bottom of the groove, with preferential removal of the Co binder due to its lower melting point. The ablated surface is also characterized by scratches caused by particles generated during the phase explosion. Furthermore, surface oxidation occurs during laser ablation, with the main oxidation products being WO₃, CoWO₄, Co₃O₄ and CoO [43]. These effects are significant limiting factors for the application of this type of laser in the texturing of tool materials, which will be subjected to high temperatures and stresses during machining processes.

In contrast, with ultrashort lasers, heat-affected zones are significantly reduced or even absent [40].

Nowadays, picosecond and femtosecond laser micromachining has emerged as a vital tool for precision manufacturing, fabricating microstructures with nanometer (nm) tolerances [45]. However, femtosecond lasers, while highly precise and effective for creating detailed surface textures, are characterized by significant energy demands. These arise from the complex mechanisms needed to produce ultrashort, high-intensity pulses, including advanced amplification systems like chirped-pulse amplification. Additionally, supporting infrastructure, such as cooling units, power supplies and control systems, adds to their overall energy consumption, contributing to higher carbon emissions. The energy intensity of these systems is driven by their high repetition rates and the substantial power required for their operation, especially in industrial and large-scale applications. This makes femtosecond laser systems less environmentally sustainable unless measures are taken to offset their energy usage. Studies on energy-efficient laser operation and alternative cooling technologies offer potential solutions to mitigate their environmental impact [46].

In LST processes, the characterization of the textures generated on substrates can be effectively monitored by adjusting the laser parameters. The texturing process is significantly influenced by several parameters, including wavelength, pulse duration, laser power, pulse rate, number of passes, fluence (J/cm²) and spot size, among others [35,39]. The main LST processing parameters in the development of textures are illustrated in Figure 4.

These technologies enable the machining of hard metals, ceramics and plastics, as well as the formation of various nano- and microtextures to enhance the functionality and properties of surfaces in a wide range of products [47]. In the case of femtosecond lasers, the pulse duration is on the order of 10⁻¹⁵ s, and they exhibit an exceptionally high maximum peak power ranging from 10¹³ to 10¹⁴ W/cm² [48]. The high pulse frequencies, combined with an extremely short time on the surface, prevent heat from being significantly transmitted to the substrate, avoiding problems associated with longer pulse durations. For this reason, lasers of this type are also referred to as “cold lasers”.

This review focuses on the study of textured tools to improve the machining of the Ti6Al4V alloy. However, textured cutting tools have also been widely investigated for machining materials like aluminum, steel and plastics. Laser texturing has proven effective in reducing cutting forces, enhancing wear resistance and minimizing chip adhesion in materials such as aluminum alloys and steels. For example, microgroove or “volcano” textures improve lubrication and reduce friction at the tool–chip interface, especially under wet or dry cutting conditions, with notable benefits in aluminum 6061 [49].

Other studies, such as the one carried out by Baumann et al. [50], have worked with 6061 aluminum as the material to be machined. In the latter study, Direct Laser Interference Patterning (DLIP) was employed to create periodic line-like structures with spatial periods of 2.0 μm and 5.5 μm on the rake and flank faces of cemented tungsten carbide cutting inserts. By adjusting the number of laser pulses, structure depths of up to 1.75 μm were achieved. Turning experiments on Al 6061 T6 components were conducted under lubricated conditions using both textured and untreated tools to evaluate their tribological behavior and performance. The turning experiments demonstrated that cutting tools textured using DLIP enhanced the resulting surface finish, reducing surface roughness by 31% compared to non-textured tools. Additionally, these tools reduced main cutting forces by up to 13.5%, feed forces by 28%, passive forces by 14% and the coefficient of friction by 28%. Additionally, the textured tools were able to produce chips that were 14% thinner, attributed to reduced friction and enhanced lubrication at the tool–chip interface. This improvement also contributed to a decrease in energy consumption.

Plastics are another material that can be machined with this texturizing technology. Research on textured cutting tools for machining plastics is relatively limited compared to that on metals like aluminum and steel, but significant progress has been made in recent years. Microtexturing techniques, such as Laser Surface Texturing (LST), have been applied to enhance tool performance in plastic machining. These textured-tool methods focus on reducing friction, improving lubrication and controlling heat generation, all of which are crucial when working with thermally sensitive materials like plastics.

Continuing with the same technique of DLIP, Teicher et al. [51] presented the structuring of tungsten carbide with varying cobalt contents. By interfering two laser beams, periodic line-like patterns with a spatial period of 5.5 μm were created. The depth of the structures reached a maximum of 2.2 μm through careful control of the processing parameters. Additionally, contact angle measurements were conducted to assess the wettability of the structured samples with selected cooling lubricants, showing a hydrophilic behavior with a 10° decrease in the contact angle. The tungsten carbide samples were synthesized as circular blanks with a diameter of 20 mm and a thickness of 5 mm. The primary goal was to create a surface pattern that would enhance the tool’s wear characteristics. Consequently, structured periodic surface patterns were developed. As its main objectives, the study involved structuring tungsten carbide materials with varying cobalt concentrations. A linear surface pattern with a spatial period of 5.5 μm was created, achieving a maximum depth of up to 2.2 μm.

Therefore, LST by ablation is a suitable technique for modifying cutting-tool surfaces, since it can create intricate surface geometries on a variety of materials, including hard and ultrahard composites [39]. It is important to note that each material has a specific ablation threshold, which varies based on its physical and chemical properties, as well as its microstructure and any defects present.

Studies indicate that Laser Surface Texturing using short pulses is frequently applied in cutting tools. Nevertheless, this technique can lead to the formation of heat-affected zones and a recast layer. While the process might demand significant time for texturing larger areas, it proves to be an effective and practical solution for small cutting-tool surfaces [52].

3. Recent Studies on LST in Cutting-Tool Texturing for Titanium Machining

Laser Surface Texturing is a technology that has demonstrated significant improvements in the machining of titanium alloys, particularly with a focus on the Ti6Al4V alloy. One of the main challenges observed in the machining of Ti6Al4V is adhesion on the rake face. Adhesion between the titanium and the tool during machining processes can adversely affect the tool’s consistency, leading to wear on the tool flank and, consequently, reducing the tool life and impacting the mechanics of the machined parts.

This issue can be mitigated by microtexturing the tool, which reduces the contact area and allows lubricant to be deposited in the recesses of the textures, improving the tribological properties of the tool life.

Currently, milling processes for titanium machining are relatively well-established. However, there remains a significant need to enhance process stability in operations such as turning and drilling. Niketh et al. [53] studied the effectiveness of microtextures in reducing the sliding friction at the contact surfaces and their application in drill tools for the sustainable machining of Ti-6Al-4V. Drilling experiments were performed on Ti-6Al-4V work material by drilling a through-hole of 10 mm depth using non-textured, flute-textured and margin-textured tools. From the cutting forces recorded during machining, it was observed that even at the higher cutting speed of 60 m/min and feed of 0.07 mm/rev, the margin-textured tool performed better than all other tool types, achieving a net reduction of 10.68% in thrust force and 12.33% in torque compared to the non-textured tools. Studies on chip morphology revealed that tools with flute texturing experience reduced chip clogging, indicating a significant decrease in chip evacuation force. Experimental findings confirm that microtexturing drill tools is an effective method for lowering energy losses by minimizing frictional forces during operation.

Several studies have highlighted the impact of textured cutting tools on machinability and tool performance. For instance, Pradhan et al. [54] investigated a novel design of a cutting insert textured with graphene for machining Ti Gr-2. Their ANOVA results demonstrated a significant influence of the textured insert on surface roughness [54]. Similarly, Zhou et al. [55] explored Laser Surface Texturing (LST) of coated tools for machining Ti6Al4V. Their findings showed that the main cutting force was reduced by up to 11.6% compared to non-textured tools. Additionally, the application of textures enhanced the friction state at the tool–chip contact interface, as evidenced by a reduction in the friction coefficient. They also identified the physical mechanisms behind the improved cutting performance and reduced tool wear [55].

In related work, Mishra et al. [56] reported that cutting forces decreased by 10%, with significant reductions in the apparent coefficient of friction (64%) and flank wear (65%) at progressive wear stages [56]. Sun et al. [6] demonstrated that incorporating textures reduced the tool–chip friction coefficient by 14% while it improved the surface roughness of the workpiece by 29% [6]. Furthermore, Wu et al. [57] observed substantial improvements in tool wear and texture morphology. Their results revealed that untextured tools exhibited a crater area of 760.512 μm² on the rake face accompanied by debris adhesion. In contrast, textured tools displayed a reduced crater area of 496.440 μm² with no debris adhesion, corresponding to a cutting-edge wear reduction of 34.7% [57].

This section highlights various studies aimed at achieving better tribological properties, thereby increasing tool life. An explanatory table (

Table 1. Summary of most recents studies on Laser Surface Texturing of cutting tools.

Authors	Tool Material	Studied Process	Ti Alloy	Laser Parameters	Texture Geometry	Cooling
Wan et al., 2024 [58]	WC	Turning	Ti6Al4V	St = 2, 3, 4, 5 N Lp = 40, 42.5, 45, 47.5 W Ss = 1200, 1300, 1400, 1500 mm/s	Dimples	Dry
Narayana et al., 2024 [26]	WC-Co	Tribology study	Ti6Al4V	Ss = 200 mm/s Lp = 8 W f = 23 kHz LBd = 20 μm	Triangular, square and circular	Dry and lubricated (PAO-4 and MoS2)
Ajay Kumar et al., 2024 [59]	AISI H13	Turning	Ti6Al4V	Not described	Dimples and grooves (hybrid textures)	Dry
Vázquez et al., 2022 [60]	WC-Co	Tribology study	Not defined	Ss = 50, 100, 150 mm/s Ed = 5.89/11.79/17.68/35.37	Grooves	Lubricated (Acculube LB5000)
Mishra et al., 2019 [56]	PVD-coated (AlTiN and AlCrN) WC-Co	Sliding and turning	Ti6Al4V	Wl = 1064 nm Spot size = 2 mm	Microholes	Dry
Salguero et al., 2022 [24]	WC-Co	Tribology study	Ti6Al4V	f = 20, 50, 80 kHz Ed = 17.68/7.07/4.42 J/cm2 Wl = 1070 nm	Grooves	Lubricated
Palanivel et al., 2024 [61]	PCD	Turning	Ti6Al4V	Not described	Concentric circular pattern, square pattern, cross pattern and diagonal pattern	Dry
Zhou et al., 2019 [62]	PCD	Turning	Ti6Al4V	St = 8 f = 25 kHz Ss = 200 mm/s	Grooves	Lubricated
Fouathiya et al., 2021 [63]	WC-Co	Turning	Ti6Al4V; Ti-555	Ss = 3.3 m/s f = 100 kHz 120 fs	Parallel, perpendicular, cross and tank grooves	Lubricated
Yang et al., 2024 [64]	Hybrid textured tool (HTT)	Milling	Titanium	Lp = 40 W Ss = 50, 100, 150 mm/s	Dimples	Not described
Zhang et al., 2020 [65]	WC-Co	Tribology study	Ti6Al4V	Ss = 100 mm/s f = 20 kHz; 10 ns, 200	Line and sinusoidal grooves	Dry
Sun et al., 2021 [6]	WC-Co	Turning	Ti6Al4V	Ss = 100 μm/s; 120 ns; f = 1 kHz	Grooves	Lubricated
Pradhan et al., 2022 [54]	CVD	Turning	Ti Gr-2	f = 10 kHz; 100 fs Lp = 500 mW	Grooves	Lubricated
Zhou et al., 2022 [55]	Cemented carbide tool	Turning	Ti6Al4V	Lp = 60 W Wl = 1080 nm St = 1	Dimples	Lubricated

(Scanning time: St, Laser power: Lp, Scanning speed: Ss, Frequency: f, Laser beam diameter: LBd, Energy density: Ed, Wavelength: Wl.).

) is presented to summarize the most recent studies on Laser Surface Texturing of cutting tools’ rake faces for the manchining of Ti alloys, categorized by the type of machining operation evaluated, texture geometry, material being machined, texture orientation, LST machining parameters and cutting conditions (lubricated or dry).

Although diamond or CBN (cubic boron nitride) tools are also used, most previous studies focused on the texture of cemented tungsten carbide (WC-Co) cutting tools.

WC-Co is a metallic composite material from the hard-metal family. The types used for metal-cutting applications consist of more than 80% WC in the hard phase and they have the great advantage of having good thermal stability of mechanical properties at high temperatures (approximately 1270 K) and resistance to high thermal shocks [66,67,68,69]. Their microstructures are classified in the ISO 4499-2:2021 standard [70] based on grain size.

WC-Co is produced by sintering tungsten carbide (WC) and cobalt (Co) powders. The boiling point of the binder (Co) is approximately 3200 K, which is very close to the melting temperature of WC (around 3000 K). When irradiated with a laser, the binder is ablated due to its low ablation threshold, making the WC grains increasingly unstable and more susceptible to subsequent ablation. Thus, the removal of Co facilitates the removal of WC [42,71,72].

Consequently, it is essential to optimize the laser parameters for the cutting-tool material to achieve the desired surface modification without compromising the integrity of the tool.

4. Laser Surface Texturing for Titanium Machining

Recent research on laser texturing of cutting tools for titanium machining indicates that laser power, scanning speed, number of passes and texture geometry/orientation are the most influential parameters for achieving optimal results [73].

Generally, as has been shown through the synthesis of previous investigations, pulse power and pulse rate are the parameters that govern the amount of energy supplied by the laser in each pulse. Therefore, two main parameters can be considered as the more influential factors with respect to the laser ablation process.

4.1. Effect of Laser Power

Similar to other materials, laser parameters have an impact on the width and depth of the textures created [74]. However, their effect depends on the ablated material.

Regarding laser power, according to the research developed by Yang et al. [75], after carrying out a study of wettability in femtosecond WC-Co, it was detected that as the power increased, the width of the microgeometries also increased until they stabilized at 167 μm. In addition, it was detected that irregular protrusions were also generated with these parameters, due to the resolidification of the molten material.

Sun et al. [76] used a nanosecond laser to process the microhole texture on a tool to carry out an orthogonal microcutting test on a titanium alloy. The study found that the influence of laser power on the recast layer was greater than the pulse rate, determining that laser power is one of the most important parameters to study in this technology, with better results achieved at 15 W.

Wu et al. [57] also reached conclusions very close to those mentioned above. By keeping constant some parameters, such as the number of passes and the laser pulse energy and frequency, and modifying the laser power value, it was observed that the laser energy was higher than the ablation threshold, thus producing higher material removal rates.

Wan et al. [58] worked with differents laser power values to texture cemented carbide tools for dry-cutting titanium. As the main conclusion, through the experimental verification and comparative analysis of the experimental results, the order of the influence of the laser parameters on the cutting force is scan speed > laser power > scan times. The effect of laser parameters on cutting temperature is different. The effect of scan speed is weak, but there is no significant difference between scan time and laser power.

For instance, Rodriguez-Garcia et al. [33] investigated the effects of varying laser power and frequency on WC-Co substrates, focusing on how these parameters impact on width, wall inclination and surface roughness. The results showed a proportional linear increase in depth with higher power and frequency; however, at specific frequency values, depth showed a stabilized behavior, suggesting that a maximum depth is reached where beam focusing diminishes, lowering material removal capacity at 1250 kHz. Laser power emerged as the most influential parameter, consistently showing linear depth increases across all frequency settings, with accuracies above 95%. Additionally, low pulse frequencies created material buildup above the initial surface level, forming grooves along edges and promoting texture regrowth across the irradiated area. This regrowth is likely due to high pulse energy densities, which cause melting and material expulsion that subsequently accumulates on the surface. The study also noted that at higher power and frequency settings, burns appeared on irradiated surfaces, suggesting that aggressive parameter settings can result in thermal damage. Another observation made by the research group was that with the use of more aggressive parameters in these two variables (power and frequency), burns are produced in the irradiated parts. The results on groove width indicate that the laser texturing process maintained stability across both tests. In linear tests, groove width increased notably with higher power, remaining consistent across all frequency settings, confirming power as the primary parameter influencing groove width. This increase may also relate to surface focusing inaccuracies or energy accumulation.

It can be observed that higher laser power tends to increase the depth and width of the marks due to the greater energy available to melt or vaporize the material. However, exceeding the material’s absorption threshold may result in irregularities or inconsistencies in the texture. Therefore, careful selection of this parameter is crucial to ensure optimal outcomes.

In summary, pulse energy density emerges as a critical factor in laser–WC-Co interactions, as it enables control over material removal rates and texture morphology. The femtosecond laser demonstrated high efficiency in material removal at higher frequencies, while lower frequencies facilitated heat transfer phenomena more common with longer-pulse lasers. This technology effectively enables the creation of high-precision microgeometries.

4.2. Effect of the Number of Passes

Wu et al. [57], maintaining a constant sweep speed, a pulse energy of 10 μJ and a frequency of 40 kHz, observed that a single pass did not generate a groove, and very fuzzy edges were obtained. This was corrected as the number of passes increased and microcracks and sharp edges were obtained (see Figure 5).

Yang et al. [75] observed that as the number of passes increased, surface protrusions decreased, leading to the conclusion that both the number of passes and power significantly impact surface finish. Further analysis by Zhang et al. [65] examined pass counts ranging from 1 to 50 in increments of five, showing that greater number of passes resulted in increased microtexture depths.

On the other hand, in the work of Wan et al. [58], dimple textures were applied to tool surfaces for texturing tools, modifying the laser power values (40, 42.5, 45 and 47.5 W), the pass speed (1200, 1300, 1400 and 1500 mm/s) and the number of passes (2, 3, 4 and 5). In addition, changes in microstructural properties and tool-wear morphology were analyzed, and it was determined that this type of texture geometry significantly reduces the cutting heat for turning processes.

As the main conclusion, the best parameters were found to be 1500 mm/s, 42.5 W laser power and four passes. Similar trends were observed in the research work of Sasi et al. [77], where dimple textures were obtained on the rake face (see Figure 6).

There have been several investigations, such as the one carried out by Ye et al. [78], in which different laser beam trajectories were tested with the aim of verifying which laser processing techniques are suitable. In the latter work, two different scanning strategies were employed, from which two different morphologies were obtained. The first study was carried out with a frequency of 100 kHz, 90 μJ and 1 mm/s in a single pass, while the second study employed a frequency of 100 kHz and a pulse energy of 30 μJ, kept the same speed, and extended the number of passes to five. In the first study, a slit with a Gaussian geometry was obtained. In contrast, in the second study, a groove with a flat bottom was obtained, leading to better results for texture generation since the possibility of diffusion to the surrounding areas was reduced.

Roushan et al. [79] developed this study on the surface of a tungsten carbide substrate. Indeed, as the creep value increased, the volume of molten material increased, generating resolidified debris around the groove. In turn, this debris accumulated at the edges of the groove was reduced as the number of pulses decreased from 5 pulses/spot (Figure 7).

4.3. Effect of Other Laser Processing Parameters

Some additional parameters also show significant influence in the development of textures. Several research studies have shown that scanning speed affects the size and morphology of textures. Returning once more to the research conducted by Wu et al. [57], this parameter was also evaluated, using scanning speeds of 0.3, 0.7, 1.5 and 2 mm/s; keeping as fixed variables the laser pulse energy at 10 μJ and the frequency at 40 kHz; and using a single pass. The results obtained confirmed that at lower scanning speeds the energy deposited in the unit area was quite high. This resulted in a liquid phase that could not be ejected in time and was deposited in the slot. On the other hand, at high speeds, the overlap of the laser spots was too low, thus reducing the number of pulses deposited in the unit area. This resulted in shallow textures. In this case, not the scanning speed but the number of pulses was examined and how it influences the creation of linear textures.

4.4. Effect of Texture Orientation and Geometry

Tool performance is highly afected by the positioning of the texture, its orientation and geometry. On the other hand, LST enables the application of various designs, patterns and textures on surfaces to achieve specific tribological properties. Figure 8 illustrates different variants of surface textures. As previously mentioned, numerous studies indicate that texture characteristics, including shape, size, density, orientation and distribution, significantly influence the functionality of these surfaces [12,35].

On the one hand, the positioning of textures on cutting tools is critical for optimal performance. Typically, textures created via LST are applied on the clearance and rake faces of cutting tools. The literature widely supports that applying textures on the rake face decreases the contact area between the tool and the chip, which in turn reduces cutting forces, friction coefficients and machining temperatures [80]. One of the first teams to corroborate this was Wu et al. [81]. They investigated dry turning of Ti6Al4V with textures on tools’ flank and rake faces. Their study found that cutting forces and temperatures were reduced when using self-lubricating textured tools compared to conventional tools, with the lowest values achieved when textures were applied on the rake face.

The influence of textures on the machining process has been studied by several authors, covering simple geometries to complex ones. Palanivel et al. [61] investigated the influence of textured patterns on polycrystalline diamond (PCD) tool inserts during the dry turning of Ti-6Al-4V. Four different patterns were applied to the rake face: concentric circular, square, cross and diagonal patterns. Among these, the diagonal pattern exhibited the best performance due to its larger surface area, which enhanced heat dissipation and debris trapping and reduced contact length. This led to improved machinability, reduced cutting force and a better surface finish while minimizing tool wear. The textured patterns decreased nose and crater wear, with enhanced wear resistance attributed to improved anti-adhesion properties and effective heat transfer. Some tools presented a built-up edge (BUE) on the rake face at lower cutting speeds (as shown in Figure 9). Additionally, the textured tools reduced curl diameter and chip thickness, with a less pronounced serration pattern on the chip surface, resulting from reduced contact length and an increased shear angle.

Chen et al. [82] applied a bionic microtexture (BMT) on a tool (shown in Figure 10) to facilitate directional cutting-fluid transport, thereby improving cooling and lubrication conditions in the cutting zone of titanium for biomedical applications. The BMT, designed with a rear rim angle of 45°, demonstrated optimal fluid transport capacity and eddy generation. This textured surface achieved a high directional fluid flow rate of 3.7 m/s and a reduced shear force and produced a defect-free morphology with a nanometer-scale roughness of just 13 nm. Additionally, the BMT tool reduced flank wear by 84%. The hydrophilicity enhanced by femtosecond laser processing resulted in a 41% reduction in the contact angle.

In other research, Arulkirubakaran et al. [83] modified the orientation of microgroove-like textures on carbide cutting tools for machining Ti6Al4V. Textures were arranged in cross patterns, perpendicularly and parallel to the chip direction. Tools with textures oriented perpendicularly to the chip direction showed a significant reduction in frictional wear, highlighting texture orientation as a key factor in enhancing tool performance.

In a review, Özel et al. [52] mentioned this point. In this case, it was determined that grooves on the rake faces of cutting tools are most effective when aligned parallel to the cutting edge rather than in the direction of chip flow. This alignment plays a crucial role in managing chip movement and mitigating tool wear. Additionally, there is strong evidence suggesting that grooves oriented perpendicularly to the cutting edge on the flank face can enhance the delivery of cutting fluid to the tool–workpiece contact zone, improving lubrication and cooling efficiency.

The same conclusion was reached by Machado et al. [84] in their review work. From a tribological perspective, grooves oriented perpendicularly to the chip flow (aligned parallel to the main cutting edge) are most effective in rough machining operations, enhancing material removal efficiency. Conversely, for finishing operations, linear grooves are less effective, likely due to their reduced capacity to channel material flow over the textured surface. Generally, grooves parallel to the main cutting edge contribute to improved lubricant penetration at the cutting interface, offering significant advantages when used in combination with cooling techniques such as flood cooling, MQL and cryogenic systems.

Kumar et al. [59] developed hybrid textured tools (HTTs) by combining dimples and grooves and studied their performance. The experimental results revealed that HTT application during machining achieved a 47% reduction in cutting force, a 12% decrease in friction temperature, a 26% improvement in surface roughness (Ra) and a 30% reduction in flank wear (Vb) compared to non-textured tools. These outcomes indicate substantial improvements in machining performance and extended tool life.

Wu et al. [85] conducted a study using Finite Element Method (FEM) simulations to analyze the cutting performance of Ti-6Al-4V alloys with both microtextured and non-textured cutting tools. Their findings demonstrated several advantages of microtextured tools, including reductions in cutting temperature (5–25%), main cutting forces (2–10%), cutting resistance (5–20%) and actual tool–chip contact lengths (10%). Additionally, these tools facilitate chip breaking and exhibit more pronounced fluctuations in cutting resistance compared to non-textured tools. This study emphasizes the need for future research on surface texture designs to minimize secondary cutting across various materials. Recent advancements are focusing on integrating optimization techniques for structural design, aiming to enhance the performance and application prospects of microtextured cutting tools.

Using the same pattern (dimples), Jahaziel et al. [86] studied the influence of microtextured tools on machining parameters of Ti6Al4V under dry conditions. It was observed that cutting forces on textured tools were significantly lower compared to commercial tools. This reduction in cutting force using textured tools in comparison with commercial tools (without textures) varied from 4% to 38%. In machining experiments conducted at high cutting speeds, with lower feed rates and shallow depths of cut, the cutting forces measured were minimal for both textured and non-textured inserts. This was attributed to the thermal softening effect occurring throughout the workpiece, which reduces friction at the tool–chip interface [83]. However, tests performed at higher cutting speeds, higher feed rates and greater depths of cuts led to increased cutting forces due to the larger volume of material being sheared.

Mishra et al. [87] presented a study which developed experimental investigations towards an integrated coolant and cutting-tool-based strategies for sustainable machining of the Ti6Al4V alloy. Laser-textured cutting tools were used under vegetable oil-based MQL (Minimum Quantity Lubrication) and alumina-suspended DI water-based nMQL environments. The results were compared with those of plain and textured tools under dry conditions with the same machining parameters. A detailed experimental plan was executed to conduct the series of experiments considering machining parameters, texture parameters and machining environment collectively. The MQL and nMQL parameters were selected based on the spreadability of droplets at varying air pressures and flow rates. The results showed a reduction in cutting forces, apparent friction coefficient, contact length, tool wear and chip adhesion over the rake face with textured tools under the MQL environment. The conclusions obtained were that for dry cutting of titanium, aerodynamic lubrication in textured tools is ineffective due to severe chip adhesion and high friction. Also, the vacuum generated by the textured surface and the decreased capillary suction time facilitated the formation and rapid evaporation of microdroplets. This improves heat dissipation at the secondary interface through enhanced evaporative heat transfer. Furthermore, the textured surface significantly increases the spreadability of the MQL fluid, optimizing lubrication efficiency.

Pakula et al. [88] investigated the effects of laser texturing with a honeycomb-like pattern on cemented carbides and sialon ceramics and found that laser treatment modifies tool material structure and enhances tribological properties. As shown in Figure 11, the friction coefficient diagram indicates that laser texturing can significantly improve the durability of the cutting-tool edge. The study demonstrated that sequential laser texturing of the surface layer fragments the microstructure within the laser impact zone, creating uniformly shaped nanoripples arranged axially. These micro-/nanostructures reduce surface wear intensity, confirmed by “pin-on-disc” testing, with lubricant microreservoirs accumulating impurities during abrasion. The results show a decrease in both the width and depth of wear marks and a notable reduction in the friction coefficient. Overall, abrasion resistance testing supports that laser texturing may substantially enhance cutting-tool durability, making it a promising method for future industrial applications.

Siju et al. [89] studied the effect of four different microtextures (grooves, “TI-1”; a combination of grooves and dimples, “TI-2”; dimples, “TI-3”; and squares, “TI-4”) on the rake surfaces of cutting-tool inserts in hard turning of Ti-6Al-4V alloys. The research specifically addressed the effect of microtextures on tool–chip contact length and chip morphology. Further, the effects of texture geometries on parameters like the chip compression ratio and the shear angle were examined. As the main conclusions, a reduction in COF at 0.2 mm/rev feed was observed, and it was around 13% and 6% higher at 0.1 and 0.3 mm/rev for TI-2. In addition, compared to inserts with grooves alone (TI-1), incorporating dual textures in both the sticking and sliding regions significantly reduced the contact length. This design not only minimizes tool material loss on the rake surface—reducing abrasive wear—but also slows the accumulation of chip debris within the textures, prolonging their functional lifespan. Specifically, TI-2 textures demonstrated a more durable effect, as they filled with debris more slowly than TI-1. Additionally, TI-2 achieved a smaller tool–chip contact area than TI-3 and TI-4. For TI-2, the contact length reduction was approximately 36% compared to non-textured (NT) inserts.

Another study conducted by Fernández-Lucio et al. [90] proposed a groove-type laser-engraved chipbreaker design and a manufacturing methodology in a PCD tool, with experimental validation on turning a Ti6Al4V workpiece. The manufactured chipbreakers achieved titanium alloy chip fragmentation, allowing for easy chip removal from the cutting zone. A set of experiments involving various laser parameters were carried out to characterize the PCD depth and surface integrity and experimentally validate the chipbreaker designs in finishing cutting conditions. The optimum parameters for the engraving of PCD were found, obtaining satisfactory breakage of titanium chips. Chip length was always below 17.29 mm. As the main conclusions, the optimal laser parameters for processing polycrystalline diamond (PCD) used in cutting-tool inserts included a scanning speed of 400 mm/s and a pulse frequency of 50,000 Hz combined with a radial step size of 0.02 mm and a pulse duration of 250 ns. These settings resulted in an average surface roughness of 1.31 µm on the PCD substrate, with an average peak-to-valley height of 19.013 µm, making them highly suitable for fabricating chipbreakers. In terms of chipbreaker performance, grooves aligned parallel to the tool edge and overlapping groove patterns were effective in redirecting chips away from the workpiece reliably and consistently. However, out of the five strategies evaluated, only the overlapping groove configuration, termed “overlapped 0”, successfully achieved complete chip breakage.

Finally, Vazquez et al. [60] investigated the effects of LST parameters on track size, roughness, microstructure, hardness and lubricant retention of textured surfaces. The findings highlight energy density as the key parameter influencing dimensional attributes and roughness. Specific channel morphologies increased lubricant expansion area by up to 50%, guiding it linearly. Low scanning speeds and high energy density also enhanced surface hardness by up to 20%. Laser-induced thermal effects modified the WC-Co microstructure, though the thermally affected zone remained minimal compared to other methods. Additionally, increased scanning speed led to shallower microgrooves, reducing burrs, while higher energy density improved wettability at a scanning speed of 150 mm/s.

5. Conclusions

Laser Surface Texturing (LST) presents a promising approach for optimizing the machining of titanium alloys, particularly Ti6Al4V. The application of LST to cutting tools enhances their performance by improving lubrication, reducing friction and facilitating chip management. These improvements are primarily attributed to the functional topographies created on the tool surfaces, which serve as reservoirs for cutting fluids and assist in debris removal during machining operations.

Moreover, the effectiveness of LST is significantly influenced by key parameters such as laser power, pulse duration and texture geometry. Optimizing these parameters is essential for achieving the desired enhancements in machining efficiency and tool longevity.

5.1. Sustainable LST Technics

The environmental benefits of LST further underscore its relevance in contemporary manufacturing practices. By reducing the reliance on conventional lubricants and coatings, LST contributes to more sustainable machining processes.

Although LST can reduce the need for additional processes, such as chemical treatments and coatings, which can be beneficial for sustainability, it would be important to quantify how the energy consumption of LST compares to other more traditional or alternative technologies (such as chemical and mechanical texturing). The sustainability of each technology is increasingly important. LST requires a significant amount of energy, but its ability to create textures without the use of chemicals or polluting processes could be considered an advantage compared to coating methods.

The energy intensity of femtosecond lasers and the infrastructure required for their operation contribute to a significant environmental footprint. Future works explore the following:

• Optimization strategies to reduce power consumption;
• Integration with renewable energy sources to power laser setups;
• The development of alternative green technologies with similar precision.

5.2. Future Opportunities and Challenges

Although future advancements in surface texturing techniques are justified, research would benefit from explicitly addressing key challenges such as the durability of textures, scalability for large cutting tools and hybrid approaches that integrate LST with coatings. Durability remains a critical issue, since surface textures are often exposed to extreme wear, high temperatures and chemical degradation during machining. Developing solutions to extend the lifespan of these textures, such as combining them with wear-resistant coatings or utilizing more robust materials, would be a significant step forward.

Scalability for larger tools poses another major challenge, as the time-intensive nature of laser processing limits its use in industrial-scale applications. Scalability in Laser Surface Texturing (LST) for larger tools is a recognized challenge due to limitations in precision, processing rates and system capabilities when scaling up to extensive surface areas. The primary issues revolve around maintaining texture uniformity and system synchronization while increasing the area or complexity of the textured surface. Future research could focus on optimizing laser systems for greater speed and precision or adopting hybrid methods—for instance, using mechanical pre-patterning followed by laser refinement to reduce processing time while preserving the benefits of texturing. It could also be interesting to study processing rates and system precision. As the area for texturing increases, the processing time grows significantly, particularly with traditional scanning strategies. High-frequency laser systems and advanced scanning techniques like polygon scanners and acousto-optic deflection can improve processing rates but introduce synchronization challenges between the laser and scanning system. This could be complemented with a study of geometric constraints. The scalability of LST also depends on the geometry of the tools. For complex geometries, the difficulty of maintaining precise textures across the surface increases. Scanning strategies optimized for flat or simple surfaces may not translate effectively to larger tools.

This problem is observed in complex geometries. Applying LST to free-form or curved surfaces is significantly more challenging than applying it to flat surfaces. Achieving consistent texture patterns requires advanced multi-axis systems, which increase the complexity and cost of the process.

Additionally, integrating LST with advanced coatings offers substantial potential for enhancing surface performance. Functionally graded coatings could work synergistically with textures to improve lubrication or resist corrosion, while selectively coating textured areas could balance cost and effectiveness. Such hybrid approaches require multidisciplinary collaboration and could expand the industrial applicability of LST.

By addressing these challenges, future studies could bridge the gap between experimental research and large-scale industrial implementation, promoting more sustainable and efficient machining technologies. In summary, Laser Surface Texturing emerges as an effective strategy to enhance the performance of cutting tools used in titanium machining, leading to increased efficiency, reduced wear and a lower environmental impact. In addition, it shows great potential for large-scale applicability.

Additionally, to emphasize economic considerations, the implementation cost of LST compared to other methods, such as tool coating or thermal treatments, is important for assessing economic feasibility. While LST may be more expensive in terms of equipment and energy, it can offer a better long-term cost–benefit ratio by extending tool life.

Future research should focus on refining texturing techniques and exploring the long-term effects of LST on tool life and machining outcomes.

Another challenge that the industry faces is the fact that high laser power and prolonged exposure can create a heat-affected zone in a substrate, altering its microstructure. This can lead to undesirable changes, such as reduced hardness, microcracking and residual stress formation, as well as vaporized material, which may solidify on the substrate surface, leading to roughness or irregularities. Excess energy input can also cause material to reflow, further complicating the desired textural uniformity. In addition to this, materials with low laser absorption rates may require higher power, increasing the risk of thermal degradation. Inhomogeneous substrates, such as WC-Co, are particularly vulnerable because cobalt (the binder phase) melts at a lower temperature than tungsten carbide, potentially weakening the overall structure. Future work could be focused on these challenges.

Overall, LST has great potential in the research field to revolutionize the cutting-tool industry, as well as for the generation of new technologies such as advanced coatings and nanostructures, as has been evaluated in this study.