Cutting performance of a tool with continuous lubrication of atomized cutting fluid at the tool-chip interface

To improve the tool lubrication performance and reduce the use of cutting fluid as much as possible, a new type of tool with continuous lubrication on the tool-chip contact interface has been fabricated. The atomized cutting fluid can be directly delivered to the tool-chip contact interface through the inner microchannel. Experiments were conducted on the new lubrication method, dry cutting, and traditional MQL cutting of 45 steel. The three-dimensional cutting forces and the cutting temperatures were measured. The wear surface of the rake face was analyzed through SEM micromorphology and EDS element detection. The results showed that the main cutting force of the tool with continuous lubrication at the tool-chip interface decreased by 14.5% and 5.9% compared with the conventional tools of dry cutting and MQL cutting. Moreover, the friction coefficient decreased by 14.2% and 9.8%, the length of the tool-chip contact interface decreased by 35.4% and 19.1%, and the amount of cutting fluid was only 1/10 of that in MQL cutting. The new lubrication method had better cutting fluid penetration and lubrication film formation performance than the traditional MQL method on the tool-chip interface. Furthermore, the surface wear of the new lubrication method was significantly reduced, and the main wear form of the new lubrication method was adhesive wear.


Introduction
During the machining process, the temperature in the vicinity of the tool-chip contact interface significantly increases because of low heat conductivity and high chemical reactivity [1,2]. Therefore, severe friction at the tool-chip interface will increase the tool surface wear and reduce tool life without any lubrication measures in the cutting process. Studies have found that wear can be reduced by introducing cutting fluids between the tool and the chip [3]. However, the lubrication of the cutting fluid is weakened due to its difficulty penetrating the cutter-chip interface. To improve the cutting performance and service life of tools, many different strategies and research on reducing the friction and wear of the cutting tool have been implemented by scientists. The following contents are studied: the lubrication performance of soft coatings [4][5][6][7], research on MQL/MQCL [8][9][10], research on nano-MQL/EMQL technology [11,12], research on tools with micro-textures [13,14], lubrication technology for high-pressure cooling [15][16][17], and research on cryogenic cooling [18][19][20].
Scholars lubricated the cutting tool by preparing a lowshear strength self-lubricating coating on the front cutting surface instead of the cutting fluid. Xing et al. [4] examined the cutting performance and wearing characteristics of tools with WS2/Zr soft coatings and uncoated tools through cutting tests on hardened steel. The results showed that the coated tools significantly improved the lubricity at the toolchip interface compared with the uncoated tool. Although coated tools have ecological and economic advantages, the negatives of insufficient cooling are also obvious [21]. Usually, the thermal stress inside the material can cause cracks on the coating surface because of the high temperature, which will accelerate the wear and peeling of the coating. Therefore, not only can the soft coat not extend the tool life, but it is difficult to guarantee the machining quality during the cutting process due to its random deciduous features.
Ge et al. [13] studied the micro-texture effect with different groove widths for wet cutting. In conclusion, the microtextured tool with a groove width of 50 µm had the best performance among all tested tools. However, the amount of cutting fluid used is much greater than that used in MQL cutting, and high-pressure coolant-assisted turning has the same disadvantage. For example, Mia et al. [22] performed a cause-effect analysis of high-pressure coolant-assisted turning of Tie6Ale4V alloy and summarized the improvements of machinability by high-pressure coolant. Da Silva et al. [23] claimed that the highest tool life can be attained through the highest cooling pressure (20.3 MPa) and the lowest cutting speed. Although the cooling and lubricating of the cutting fluid between the tool-chip interface can be improved by the micro-texture on the rake face and high pressure, it is inevitable to use much cutting fluid at the cutting zone.
As a representative of an environmentally friendly machining system, Khanna et al. [20] studied liquid carbon dioxide (LCO2), traditional MQL, and EMQL, in combination with ultrasonic-assisted turning; these are used to reduce tool wear in the machining of Inconel 718. Compared with traditional MQL and EMQL, the synergistic effect of LCO2 and EMQL has better cutting performance and lubrication effects. Islam et al. [24] made use of a rotary applicator for the internal supply of cryogenic liquid nitrogen and reported lower tool wear than conventional cutting and dry cutting. Krolczyk et al. [9] studied the influence of the application of MQCL and dry machining on the surface roughness parameters of the workpiece through cutting tests. The results showed that the MQCL method has a better cutting performance than dry machining. Gupta et al. [10] found that the cutting performance and energy consumption of dual jet MQL technology are better than those of dry and traditional MQL cutting, and the tool wear is the lowest. Compared with conventional MQL lubrication, the advantages of dual jet MQL technology are outstanding because it can further reduce the temperature of the cutting area, and the cutting fluid can easily penetrate the flank surface of cutting tools to reduce wear and friction. With the use of the MQL/MQCL/ EMQL and cryogenic cooling methods, the atomized cutting fluid can penetrate the cutter-chip interface compared with wet cutting, and the lubrication performance of the cutting fluid has been greatly improved. However, it is sprayed directly into the air to cool and lubricate the cutting area, which will harm the environment and the health of people because a large amount of oil mist particles will become suspended in the air [25,26].
In this paper, a new cutting tool with continuous lubrication of atomized cutting fluid in the tool-chip interface was proposed. The new lubrication method can directly supply the atomized cutting fluid into the tool-chip contact interface to cool and lubricate the tools. Compared with previous studies [27,28], the lubrication method of this paper has a better diffusion performance on the cutting surface because it atomizes the cutting fluid into droplets. Meanwhile, this lubrication method is different from both the method of pouring cutting fluid and the MQL/EMQL/nano-MQL technique in that the lubrication of the cutting fluid is weakened between the tool and the chip due to its difficulty in penetrating into the cutter-chip interface. In addition, cryogenic cooling can cool the cutting tool but has insufficient lubrication performance. In addition, the atomized cutting fluid can be continuously supplied to the tool-chip interface, which will have better cutting stability during the cutting process than the soft coating tools.

Experiment
According to the wear law of tools in the cutting process, a microchannel was manufactured on the appropriate position of the cutting tool rake face. The microchannel can contact the tool rake face with the large oil hole to supply the atomized cutting fluid to the tool-chip contact surface.

Design of the cutting tool
Cemented carbide YW1 was selected as the cutting tool material for this study. The composition, physical, and mechanical properties of this tool material are listed in Table 1 [27]. A large hole was processed through EDM and fabricated on the bottom of the cutting tool. A microchannel with a diameter of approximately 300μm was processed through EDM and fabricated in the proper position at the tool-chip interface of the rake face to connect the large hole inside. A tool holder with an inner channel was prepared. The inner channel connects with the large hole on the bottom of the cutting tool. A schematic of the cutting tool and the tool holder is shown in Fig. 1.

Construction of the atomizing system
The equipment used for building the atomizing system includes an air pump, an oil mist apparatus, pipelines, a special tool holder, a piezometer, an overflow valve, and a pentrough, as shown in Fig. 2a. The principle of this atomizing system is that the cutting fluid in the oil mist apparatus is atomized by the compressed air from the air pump, and the oil mist passes through the pipelines and enters the special holder. Then, the oil mist passes through the channel inside the holder into the cutting tool and is sprayed by the microchannel inside the tool. Figure 2c shows the operational principle of the oil mist apparatus in which the compressed air enters the equipment through Air import. A part of the compressed air enters the space of the cutting fluid, and then the cutting fluid will be pressed into the top of the apparatus through the channel under the action of compression. The cutting fluid will leave the top through Export a, which will rendezvous with the air of Import b, and then the cutting fluid of Export a will be atomized through high-speed air to become liquid droplets. According to the following Darcy-Weisbach formula [29]: where V is the air flow rate of the pipeline at the outlet, D is the pipeline hydraulic radius, H L is the differential pressure, g is the acceleration of gravity, F is the friction coefficient, and L is the length of the pipeline. We know from Darcy-Weisbach formula that the air velocity of the system outlet is proportional to its hydraulic radius. Therefore, the velocity of airflow at the microchannel outlet is very slow, and the velocity of airflow at Import b in Fig. 2c is very slow. Therefore, the cutting fluid at Export a in Fig. 2c cannot be atomized into droplets, and the atomized cutting fluid cannot be sprayed at the microchannel outlet.
Fortunately, the problem can be solved by adding a very large outlet with a diameter of 2 mm inside the tool holder, as shown in Fig. 2b. The outlet of this atomizing system was expanded through this method so that the velocity of airflow inside the system was accelerated. The cutting fluid in the oil mist apparatus can be atomized successfully, and then the oil mist can be sprayed at the microchannel outlet through this atomized system.

Cutting test
To investigate the lubricating and cooling performances of the new lubrication method, the experiments of the dry cutting, the MQL cutting, and the cutting of the new lubrication method have been conducted. According to the different lubricating methods, the tool of the three group experiments was named Dry-T, MQL-T, and New-T.
Cutting tests were carried out on a CA6140 lathe equipped with the tool holder having the following geometry: rake angle of o = 0 o , clearance angle of o = 11 o , inclination angle of s = 0 o , and side cutting edge angle of r = 75 o . Cutting tools were used with the new lubricating cutting tool and conventional tools. Conventional tools were used for both the Dry-T cutting and the MQL-T cutting. The new lubrication cutting tool was used for the New-T cutting. Micro-emulsified water-soluble cutting fluid for semi-refined cutting was used in this experiment, and the composition of the cutting fluid is listed in Table 2 (the cutting fluid was produced by the LOSH company from China). The flow of the cutting fluid was 1.2 L/h, and the pressure of the atomizing system was 4 bar in the MQL-T cutting process. The flow of the cutting fluid was 0.12 L/h, and the pressure of the atomizing system was 4 bar in the New-T cutting process. Cutting forces were obtained with a piezoelectric quartz dynamometer (type JR-YDCL-III05B, made in China) linked via change amplifiers to a chart recorder. The cutting temperatures were attained with a FLUKE 66 handheld infrared thermometer. The worn regions of the cutting tools were examined using a scanning electron microscope (SEM). The workpiece materials are 45 steel.
All cutting tests were implemented with the following parameters: cutting depth of a p = 0.3mm , feed rate of f = 0.1mm∕r , cutting speed of v = 130m∕min , and cutting length of L = 400 m. Cutting schematic diagrams of the above three groups of tests is shown in Fig. 3. The images of the New-T lubrication and the MQL-T lubrication atomizing cutting fluid supply modes during operations with no cutting are shown in Fig. 4. Figure 5 shows the changes in the three-dimensional cutting forces with the cutting distance. At the beginning of cutting, the three-dimensional cutting forces of the New-T tool were the lowest, and the cutting forces of the MQL-T tool were slightly less than those of the Dry-T tool. The three-dimensional cutting forces of the MQL-T tool and the New-T tool were comparatively stable with the cutting distance. Especially for the New-T tool, the three-dimensional cutting forces were more stable than those of the MQL-T tool. The results of Fig. 5 indicate that atomized cutting fluid can make the cutting process more stable and reduce the cutting forces. Because the atomized cutting fluid is supplied directly to the toolchip interface through the microchannel to achieve continuous lubrication at the tool-chip interface, the New-T tool can achieve a more stable cutting process than the MQL-T tool. Figure 6 shows the three-dimensional cutting forces of the three lubrication methods under stable cutting conditions. The cutting forces of the New-T cutting were the lowest, while the cutting forces of the Dry-T cutting were the largest. The New-T cutting force Fx decreased by 26.7% and 14.3%, Fy decreased by 20.5% and 10.9%, and Fz decreased by 14.5% and 5.9% compared with the Dry-T and the MQL-T. The atomized cutting fluid can be supplied to the tool-chip interface directly, reducing the area of the tool-chip contact interface to decrease the friction of the rake face. Thus, the three components of the cutting forces of the New-T cutting have decreased compared with the MQL-T cutting, which indicates that the lubrication performance of the new lubrication method is better than the conventional MQL cutting.  Figure 7 shows the changes in the cutting temperatures with the different types of lubrication. The cutting temperatures were 259.3℃, 129.9℃, and 155℃ in the cutting areas of the Dry-T tool, the MQL-T tool, and the New-T tool, respectively. During the cutting process, there were three main heat sources in the cutting zone: the rake face frictional heat source, the shear plane heat source, and the flank face frictional heat source; moreover, the rake face frictional heat source was dominant for the cutting tool temperature rise [30]. Khanna et al. [31] considered that the cutting fluid has difficulty playing a role in the tool-chip interface, and Airao et al. [32] claimed that the cutting fluid particles can penetrate the tool-chip interface when the tool rake face is separated from the chip due to vibration, removing the heat and lowering the tool wear. However, the reduction effect of cooling and lubricating is extremely unstable because the cutting fluid flows into the tool-chip interface through vibration. Thus, as shown in Fig. 8(a), the heat dissipation of the traditional MQL technique usually utilizes heat exchange by spraying an amount of atomized cutting fluid to the cutting zone: chip surface, shear plane heat source, and flank face frictional heat source. Due to the cooling of the cutting fluid, the temperature was reduced compared to the Dry-T cutting. As shown in Fig. 8b, the new lubrication method supplied the atomized cutting fluid directly to the tool-chip interface, and the tool was cooled through the evaporation and heat absorption of cutting fluid droplets. When the water in the cutting fluid droplets evaporates due to heat absorption, the cutting fluid components will adhere to the wear surface, which will reduce the tool-chip contact area. Then, the friction coefficient of the surface wear is reduced. Therefore, the cutting heat of the New-T tool generated by friction was

Friction coefficient and length of the tool-chip contact interface
According to the value of the three-way cutting forces, the average friction coefficient of the rake face, friction angle, and shear angle can be calculated based on the following formulas [28]: where is average friction coefficient at the rake face, is the friction angle, is the shear angle, and o is the rake angle. Figure 9 illustrates the average friction coefficient at the rake face of different lubrication types. It can be seen from the figure that the average friction coefficient of the Dry-T cutting was the largest, the MQL-T cutting decreased by 4.9% compared with the Dry-T cutting, and the New-T cutting decreased by 14.2% and 9.8% compared with the Dry-T cutting and MQL-T cutting. This is mainly associated with the amount of cutting fluid entering the tool-chip interface. In the process of the Dry-T cutting, there was no cutting fluid entering the tool-chip interface to form a lubrication film in the worn area for cooling and lubricating, and then the chips contacted the tool substance directly. Thus, the friction coefficient was the largest. Many scholars have proven that the capillary plays an important role in the process of using cutting fluid for the cutting lubrication, and the cutting fluid can be pumped into the tool-chip interface to cool and lubricate tools through the capillary [33,34]. Meanwhile, the capillary axis is perpendicular to the main cutting edge and randomly distributed on the tool-chip contact interface with the flow of the cutting chip [35]. Furthermore, capillaries run throughout the whole toolchip contact interface in the cutting process [36]. As shown in Fig. 10a, during the MQL-T cutting process, the flowing chips mainly had bulk contact with the tool rake face and were followed by elastic contact just before leaving the contact with the tool, and elastic contact allows slight penetration of the cutting fluid only over a small region of the edge of the toolchip contact interface through capillary action. As shown in Fig. 10b, during the New-T cutting, some capillaries passing through the outlet were truncated due to the microchannel outlet on the rake face, which not only shortened the distance between the atomized cutting fluid and the main cutting edge but also increased the efficiency of the pump of the capillaries and promoted the diffusion of atomized cutting fluid in the worn area of the rake face. The above analysis can be proven by Figs. 14 and 15. The substrate supports the load, and the lubricating film dominates friction when the cutting fluid flowing into the interface is sufficient; the lubricating film will cover all worn surfaces [37,38]. Therefore, the friction coefficients of the MQL-T and the New-T cutting were lower than those of the Dry-T cutting. The friction coefficient of the New-T cutting was the lowest because the New-T tool had a larger area covered by the lubricating film, and the zone of the tool-chip contact interface was decreased.
The friction angle and shear angle of different lubrication methods can be calculated through Formulas (2) The formula for the total length of the tool-chip contact is as follows [39,40]: where L f is the total length of the tool-chip contact interface, a is the undeformed chip thickness, a 1 is the real chip thickness, and is the chip thickness coefficient.
Meanwhile, the total length of the tool-chip contact contains the length of the tool-chip contact of the adhesive area and the length of the tool-chip contact of the slide area, which can be calculated by the following formulas [41]: These parameters were obtained through calculations according to the above Formulas (8), (9), and (10). As shown in Fig. 11, the tool-chip contact length of the Dry-T cutting was the longest, the MQL-T cutting decreased by 20.1% compared with the Dry-T cutting, and the New-T cutting decreased by 35.4% and 19.1% compared with the Dry-T cutting and MQL-T cutting. Meanwhile, the toolchip contact length of the adhesive area and the slide area of the MQL-T cutting and the New-T cutting had a marked decline compared with that of the Dry-T cutting. The three kinds of tool-chip contact lengths of the New-T cutting were the shortest. The atomized cutting fluid was directly  transmitted to the tool-chip contact interface. Thus, the cutting fluid can continuously supply and form a stable lubrication film during the cutting process, and then part of the adhesive area on the rake face will transform the slide area. Meanwhile, the chip can leave the rake face in advance due to the presence of a lubrication film with a low shear strength reducing the cutting force so that the whole length of tool-chip contact will be reduced.
The average friction coefficient of the rake face contains the average friction coefficient of the adhesive area and the average friction coefficient of the slide area, which can be calculated through Formula (10) and the following formula [41]: where 1 is the friction coefficient of the adhesive area. Figure 12 shows the change in the average friction coefficient of the adhesive area and the slide area. Compared with the Dry-T cutting, the friction coefficient of both the adhesive and the slide wear area of the MQL-T and New-T cutting decreased significantly. The friction coefficient of the adhesive area is affected by both the temperature and the length of the adhesive area. During MQL cutting, the atomized cutting fluid can cool the cutting zone, and a trace of the cutting fluid will penetrate into the tool-chip interface for cutting lubrication. Thus, the friction coefficient of the adhesive area decreases compared with Dry-T cutting. For the new lubrication method, although the performance of cooling of the traditional MQL was better, the new lubrication method had a lower lubrication coefficient because the presence of the microchannel on the rake face reduced the chip contact area and provided cutting fluid droplets continuously to the adhered area of the tool-chip interface, and then the length of the adhesive area was reduced, as shown in Fig. 11. Moreover, the friction coefficient of the slide area of the New-T cutting was lower than that of the MQL-T cutting because the length of the slide area was reduced due to the diffusive performance of the cutting fluid in the wear face of the New-T tool. Figure 13 shows the wear surface of the tool tip and the rake face under three lubrication conditions. It can be seen in Figs. 13a, b, and c that the volume of the built-up edge on the tool tip of the Dry-T cutting was the largest, followed by the MQL-T cutting, and the New-T cutting was the smallest. This situation is related to the cutting temperature and lubrication of the cutting fluid. Due to the action of cooling and lubricating the cutting fluid, the volume of the built-up edge on the tool tip of the MQL-T cutting and the New-T cutting was relatively minor. However, the size of the built-up edge on the tool tip of the New-T cutting was smaller than that of the MQL-T cutting because the cutting fluid of the New-T cutting more easily entered the regions of the main and auxiliary cutting edge and played a role in cooling and lubricating during the cutting process. Figure 13d shows that there were a large number of furrows, micropores, and adhesive materials at the worn area of the rake face of the Dry-T cutting. For MQL-T cutting, all three of these phenomena were reduced, as shown in Fig. 13e. Figure 13f shows that the furrows on the rake face of the New-T cutting almost disappeared, and the number of micropores and adhesive materials in the wear area also decreased significantly. Moreover, the furrows on the wear area are mainly caused by abrasive wear. In dry cutting, the chip contacts directly with the tool rake face because there is no cutting fluid to form a lubricating film. Therefore, the cutting heat generated by cutting cannot dissipate in time due to a lack of cutting liquid cooling, and the hardness of the rake face will decrease sharply at high temperatures. When the chip with hard points flowed through the rake face, many furrows were fabricated on the tool rake face. In MQL cutting, the hardness of the rake face was less affected by temperature because conventional MQL lubrication has a better cooling effect during the cutting process, and then the number of furrows was reduced. There is little difference between the cutting temperature of the New-T and the MQL-T, as shown in Fig. 7, while the New-T lubrication can supply the atomized cutting fluid to enter the tool-chip contact interface directly and further reduce the friction coefficient and contact area of the tool-chip interface. Thus, the furrows almost disappeared. The micropores and adhesive materials in the wear area were mainly caused Fig. 12 The average friction coefficient of the adhesive area and slide area of different types of lubrication by adhesive wear. In dry cutting, the atoms of the chip and the atoms of the tool were adhered together by the cutting condition of high temperature and high pressure. Because the shear strength of some adhesive points was lower than the tool strength, these adhesive points were torn from the chip and left on the tool rake face when the adhesive points suffered from a strong impact during cutting. While the shear strength of other adhesive points was higher than the tool strength, these adhesive points were torn from the tool and taken away by the flowing chip. Therefore, many micropores and adhesive materials appeared on the worn area of the rake face. The number of adhesive points on the wear area of the MQL-T tool was reduced compared with that of the Dry-T tool due to the impact of cooling and lubrication of the atomized cutting fluid. In New-T cutting, the number of adhesive points on the wear area was less than the tool of MQL-T. On the one hand, the microchannel outlet on the rake face reduced the contact area between the tool and the chip. On the other hand, the atomized cutting fluid can be supplied directly to the tool-chip interface, and the diffusion performance of the cutting fluid on the rake face was better than that of traditional MQL lubrication. The range of the lubrication film formation was larger than that of MQL-T lubrication. Therefore, the number of adhesive points on the wear area of the New-T tool was less than that of the MQL-T tool, so the number of micropores and adhesive materials was less than that of the MQL-T tool. Meanwhile, the lubrication effect of the New-T lubrication is better than that of the MQL-T lubrication.

Wear mechanism
To compare the permeability of the cutting fluid at the tool-chip contact interface under the MQL-T and the New-T lubrication conditions, the EDS element analysis of the wear area of the two lubrication conditions was implemented. Figures 14 and 15 show the analysis results of the MQL-T and the New-T, respectively.
Most of the P and S elements that are the unique elements of the cutting fluid in Fig. 14 were located on the outside of the tool-chip contact interface of the rake face, and only a small part of the P and S elements were distributed in the vicinity of the main and auxiliary cutting edges. The result indicated that the cutting fluid has difficulty entering the too-chip contact interface to lubricate during the MQL cutting process. For the New-T tool, as shown in Fig. 15, the number of S and P elements in the vicinity of the main and auxiliary cutting edges were evidently increased and had a wider distribution range at the wear area than the MQL-T tool. This indicates that the tool-chip contact interface of the New-T tool was more conducive to the diffusion of cutting fluid and film formation due to the presence of the microchannel outlet.
The conditions of adhesive wear and oxidation wear in the MQL-T and the New-T cutting can be determined by comparing the amount of Fe and O elements on the rake face. Figure 14 shows that the Fe and O elements are more abundant in the area of severe wear on the rake face d The rake face of dry cutting. e The rake face of conventional MQL lubrication cutting. f The rake face of New-T lubrication cutting than in the same area of Fig. 15. This phenomenon proved that the degree of adhesive wear and oxidation wear of the New-T tool was less than that of the MQL-T. Severe oxidative wear will reduce the surface strength of tools, aggravate the tool wear in the cutting process, and reduce the life of the tool. These results indicate that the New-T cutting has better oxidation resistance than the MQL-T cutting. Thus, the tool service life will be extended by the New-T cutting.
It can be seen from Fig. 16a that there are some materials in the outlet of the microchannel. Figure 16b is the analysis result of the EDS element scanning on this material. These are the workpiece materials. Figure 17 is a schematic diagram of derivative cutting in the microchannel export. The chip generated by the derivative cutting will adhere to the outlet of the microchannel and fall into the inner microchannel. Therefore, derivative cutting will not only wear and destroy the microchannel export but  also adhere to the microchannel export due to the action of cold welding, blocking the outlet. Currently, the effective method of suppressing derivative cutting needs to be studied further.
The experiments indicated that the amount of the cutting fluid of the new type of lubrication is one-tenth that of conventional MQL lubrication, and the effect of the cutting lubrication is still better than that of conventional MQL lubrication. However, it is worth noting that the new lubrication method of this paper still has many deficiencies. First, the microchannel is difficult to fabricate because the diameter of the microchannel is very small, and machining accuracy is difficult to guarantee. For example, the lubrication effect of the new lubrication method will be diminished significantly if the exit of the microchannel cannot be processed in the wear area on the rake face. Second, the processing cost of the tool with microchannels is relatively high, and there is currently no mass production process.

Conclusions
A new cutting tool, which can directly provide the atomized cutting fluid to enter the tool-chip contact interface to continuously lubricate the wear area of the rake face, was fabricated. The main conclusions were organized as follows: 1. The New-T had better cutting lubrication performance.
The main cutting force, friction coefficient, wear, and oxidation of the New-T tool decreased significantly compared with the traditional tools of dry cutting and MQL  cutting, while the consumption of the cutting fluid was only 1/10 of the traditional MQL cutting. 2. The main lubricating mechanisms of the New-T were found that atomized cutting fluid can more easily enter into tool-chip interface through capillary action and more efficiently diffused in the worn area of the rake face than MQL. 3. The main form of wear of the New-T tool was adhesive wear. It was found that the New-T tool had better lubrication film-forming performance than traditional MQL lubrication, which can decreased adhesive wear.