Processing apparatus and processing method

Abstract

The present invention provides a machining apparatus that can improve the lifespan of tools used in machining. The machining apparatus (100) comprises a friction-applying device (3) and a supply device (4). The friction-applying device (3) applies friction to the machining fluid (PF) to change the zeta potential of the machining fluid (PF), increasing the absolute value of the zeta potential of the machining fluid (PF) after friction is applied compared to the absolute value of the zeta potential of the machining fluid (PF) before friction is applied. The supply device (4) supplies the machining fluid (PF), to which friction has been applied by the friction-applying device (3), to the machining point (P0), which is the contact point between the workpiece (W) and the tool (1) during machining.

Description

[Technical Field]

[0001] This disclosure relates to a processing apparatus and a processing method. More specifically, this disclosure relates to a processing apparatus and a processing method for performing processes such as subtractive deformation or cold plastic deformation on a workpiece. [Background technology]

[0002] Methods are known for performing subtractive deformation or cold plastic deformation on a workpiece. These processes yield parts such as intermediate or final components. For example, if the workpiece is a metal material, then the component produced by the process is also a metal material.

[0003] There are three main types of material removal processes: (1) cutting, (2) grinding, and (3) polishing.

[0004] Cutting processes use cutting tools, pressing the cutting edge of the tool against the workpiece to cut it. Examples of cutting processes include threading, milling, turning, and drilling. Grinding processes use grinding wheels, pressing a high-speed rotating grinding wheel against the workpiece to grind it. Examples of grinding processes include surface grinding, cylindrical grinding, and internal grinding. Polishing processes use grinding wheels, bringing the grinding wheel into contact with the workpiece to polish it and finish the surface of the workpiece smoothly. Examples of polishing processes include grinding with abrasive wheels, polishing with abrasive cloth and paper, lapping, tape polishing, buffing, and barrel polishing.

[0005] Cold plastic deformation can be broadly classified into (1) wire drawing, (2) cold drawing, (3) cold extrusion, and (4) cold rolling. The workpieces subjected to cold plastic deformation are metal materials.

[0006] Wire drawing is a process in which a metal material is passed through a die and then drawn out of the die to produce a metal wire. In wire drawing, the die is the tool. The metal wire produced by wire drawing may have a diameter of less than 1 mm, and wire drawing is suitable for producing such extremely fine metal wires. Cold drawing is a process in which a metal material is passed through a die and then drawn out of the die to produce a metal material. In cold drawing, the die is the tool. Metal materials produced by cold drawing include, for example, metal rods or metal tubes.

[0007] Cold extrusion is a method of manufacturing metal materials by using a stem to push the metal material through a die. In cold extrusion, the die acts as the tool. Examples of metal materials manufactured by cold extrusion include metal profiles. Cold rolling is a method of manufacturing metal materials by using work rolls to roll the metal material. In cold rolling, the work rolls act as the tool. Examples of metal materials manufactured by cold rolling include metal sheets, metal wires, metal rods, or metal tubes.

[0008] In these removal or cold plastic deformation processes, the tool comes into contact with the workpiece during the process. Therefore, it is necessary to ensure lubrication between the tool and the workpiece. In particular, the tool wears down or deteriorates due to contact with the workpiece. Consequently, in removal or cold plastic deformation processes, it is required to suppress tool wear and deterioration and improve tool life.

[0009] Regarding material removal processes, for example, Japanese Patent Publication No. 2007-331088 (Patent Document 1) describes a machining apparatus. This machining apparatus sprays a cutting fluid containing microbubbles onto the cutting tool and the workpiece to perform the cutting process. Patent Document 1 states that this reduces tool wear. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2007-331088 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, the technology described in Patent Document 1 does not necessarily significantly improve tool life.

[0012] The purpose of this disclosure is to provide a machining apparatus and a machining method that can improve the lifespan of tools used in machining. [Means for solving the problem]

[0013] The processing apparatus according to this disclosure comprises a friction-applying device and a supply device. The friction-applying device applies friction to the processing fluid, changing the zeta potential of the processing fluid, and increasing the absolute value of the zeta potential of the processing fluid after friction is applied compared to the absolute value of the zeta potential of the processing fluid before friction is applied. The supply device supplies the processing fluid to which friction has been applied by the friction-applying device to the processing point, which is the contact point between the workpiece and the tool during processing.

[0014] The processing method according to this disclosure comprises a friction application step and a processing step. The friction application step applies friction to the processing fluid to change the zeta potential of the processing fluid, increasing the absolute value of the zeta potential of the processing fluid after friction is applied compared to the absolute value of the zeta potential of the processing fluid before friction is applied. The processing step performs material removal or cold plastic deformation while supplying the friction-applied processing fluid to the processing point, which is the contact point between the workpiece and the tool. [Effects of the Invention]

[0015] According to this disclosure, the lifespan of tools used in machining can be improved. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram showing an example of a processing apparatus in the first embodiment. [Figure 2] Figure 2 shows the configuration of a friction-generating device equipped with a friction structure. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. [Figure 4] FIG. 4 is a schematic view showing an example of a processing apparatus in the second embodiment. [Figure 5] FIG. 5 is a schematic view showing an example of a processing apparatus in the third embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

[0017] In this specification, in the case of removal machining or cold plastic working, the portion of the tool that is in contact with the workpiece and the portion of the workpiece that is in contact with the tool may be referred to as a machining point. That is, the machining point is the contact point between the workpiece and the tool. Removal machining or cold plastic working may be simply referred to as machining.

[0018] In machining (removal machining or cold plastic working), the tool comes into contact with the workpiece and wears. Also, in removal machining, machining chips, that is, cuttings or swarf, are generated at the machining point of the workpiece. When the machining chips do not separate from the workpiece and adhere to the tool, the portion of the tool where the machining chips adhere is likely to wear. Tool wear reduces the tool life. If machining is continued using an overly worn tool, the dimensional accuracy of parts such as intermediate parts or final parts manufactured by the machining also deteriorates.

[0019] In order to improve the tool life, it is necessary to improve the lubricity between the tool and the workpiece. For this purpose, it is sufficient if a machining fluid (coolant) effectively intervenes at the machining point between the tool and the workpiece. Therefore, the inventors of the present invention have intensively studied a method by which the machining fluid can effectively intervene at the machining point. As a result, the inventors of the present invention have found the following.

[0020] In machining a workpiece using a tool (removal or cold plastic deformation), the machining point of the workpiece tends to become positively charged. If the machining fluid supplied to the machining point is negatively charged, a portion of the fluid will adhere to the machining point of the workpiece, improving the lubrication provided by the fluid. In the case of removal, the machining chips generated at the machining point tend to become positively charged. If the machining fluid supplied to the machining point and flowing down from it is negatively charged, a portion of the machining chips will adhere to the fluid and be discharged from the workpiece together with the fluid. In this case, the performance of removing machining chips also improves.

[0021] To obtain a negatively charged machining fluid, the absolute value of the zeta potential of the machining fluid should be increased. This is because the zeta potential is a negative potential. By applying friction to the machining fluid, the zeta potential of the machining fluid changes, and the absolute value of the zeta potential of the machining fluid after friction is applied can be increased compared to the absolute value of the zeta potential of the machining fluid before friction is applied. In this specification, a machining fluid in which the absolute value of the zeta potential has increased due to the application of friction and which has become negatively charged may be referred to as a "zeta potential machining fluid."

[0022] Therefore, by using a zeta potential machining fluid and supplying it to the workpiece and tool during machining, the machining fluid effectively intervenes at the machining point between the tool and the workpiece, increasing the lubrication between the tool and the workpiece. As a result, tool life can be improved. In particular, if friction is applied to the machining fluid while circulating it, negative zeta potential accumulates in the machining fluid, further increasing lubrication.

[0023] The processing apparatus and processing method according to the embodiments of this disclosure have been completed based on the above findings.

[0024] The machining apparatus according to this embodiment comprises a friction-applying device and a supply device. The friction-applying device applies friction to the machining fluid, changing the zeta potential of the machining fluid, and increasing the absolute value of the zeta potential of the machining fluid after friction is applied compared to the absolute value of the zeta potential of the machining fluid before friction is applied. The supply device supplies the machining fluid to which friction has been applied by the friction-applying device to the machining point, which is the contact point between the workpiece and the tool during machining (first configuration).

[0025] In the first configuration of the machining apparatus, the absolute value of the zeta potential of the machining fluid is increased by the friction-imparting device. During machining (removal machining or cold plastic deformation), the machining fluid to which friction has been applied, i.e., the machining fluid with an increased absolute value of zeta potential, is supplied to the workpiece and the tool by the supply device. In other words, zeta potential machining fluid is supplied to the machining point. The zeta potential machining fluid supplied to the machining point is negatively charged. On the other hand, the machining point of the workpiece is positively charged. Therefore, a portion of the zeta potential machining fluid is adsorbed to the machining point of the workpiece, and the machining fluid effectively intervenes at the machining point between the tool and the workpiece. As a result, the lubricity between the tool and the workpiece is increased. Therefore, tool life can be improved with the first configuration of the machining apparatus.

[0026] The processing apparatus described above preferably further comprises a tank, a circulation pipe, and a pump. The tank stores the processing fluid. The circulation pipe has an inlet end and an outlet end, each of which opens to the processing fluid in the tank. The pump is provided in the circulation pipe and draws the processing fluid from the tank into the circulation pipe from the inlet end, and circulates the processing fluid in the circulation pipe toward the outlet end. In this case, the friction-applying device is provided in the circulation pipe, and the supply device is connected to the tank (second configuration).

[0027] In the second configuration of the machining apparatus, a circulation pipe is provided to a tank that stores the machining fluid, and both the inlet and outlet ends of the circulation pipe are open to the machining fluid in the tank. A pump is installed in this circulation pipe. A friction-applying device is also installed in the circulation pipe. In this case, the operation of the pump causes the machining fluid to circulate between the tank and the circulation pipe. Therefore, the machining fluid in the tank flows continuously through the friction-applying device in the circulation pipe. As a result, the absolute value of the zeta potential in the machining fluid in the tank is effectively increased, and negative zeta potential accumulates. That is, the absolute value of the zeta potential stabilizes at a high level. During machining, zeta potential machining fluid with a stable absolute value of zeta potential at a high level in the tank is supplied from the tank to the machining point by the supply device. Therefore, the adsorption of the zeta potential machining fluid to the machining point of the workpiece is constantly obtained, and as a result, the lubrication between the tool and the workpiece is constantly increased.

[0028] In the processing apparatus relating to the second configuration, preferably, the flow rate L(m³) of the processing fluid in the circulating piping 3 The volume V(m³) of the processing fluid in the tank is equal to the volume of the processing fluid in the tank ( / min). 3 The relationship between ( ) satisfies equation (1) (third construction). 5 <L / V×100<60 (1)

[0029] In equation (1), "L / V × 100" represents the ratio (%) of the machining fluid returning to the tank from the circulation piping per minute to the machining fluid in the tank. That is, "L / V × 100" represents the ratio (%) of the zeta potential machining fluid supplied to the tank per minute through the friction-applying device to the machining fluid in the tank. Hereinafter, "L / V × 100" may be referred to as the "circulation flow index".

[0030] In the third configuration of the processing apparatus, equation (1) is satisfied. That is, the circulation flow index (L / V × 100) is greater than 5 and less than 60. In short, the circulation flow index is limited, and the absolute value of the zeta potential of the zeta potential processing fluid supplied to the tank by circulation is at a moderately high level.

[0031] In the processing apparatus according to the third configuration, preferably, the supply flow rate U(m) of the processing fluid supplied to the processing point by the supply device 3 The flow rate L(m³) of the processing fluid in the circulating piping is 3 The relationship with / min) satisfies equation (2) (fourth configuration). 10

[0032] In equation (2), "U / L × 100" represents the ratio (%) of the flow rate of the machining fluid supplied from the tank to the machining point to the flow rate of the machining fluid returning from the circulation piping to the tank. That is, "U / L × 100" represents the ratio (%) of the discharge flow rate of the zeta potential machining fluid discharged from the tank to the machining point to the flow rate of the zeta potential machining fluid supplied to the tank through the friction-applying device. Hereinafter, "U / L × 100" may be referred to as the "discharge flow rate index".

[0033] In the fourth configuration of the processing apparatus, equation (2) is satisfied. That is, the discharge flow rate index (U / L × 100) is greater than 10 and less than 100. In short, the discharge flow rate index is limited, and the amount of zeta potential processing fluid accumulated in the tank is appropriate.

[0034] A processing apparatus relating to any one of the second to fourth configurations is preferably further equipped with a recovery device that collects the used processing fluid used in processing and returns it to a tank (fifth configuration).

[0035] When a zeta potential machining fluid is used for machining, the absolute value of its potential (zeta potential) decreases. Therefore, in the used machining fluid, the zeta potential returns to the potential it was at before the friction treatment was applied. In the machining apparatus of the fifth configuration, the used machining fluid is returned to the tank by a recovery device. Thus, the machining fluid can be effectively recycled.

[0036] ​In a processing apparatus relating to any one of the first to fifth configurations, the friction-applying device may include a friction structure that applies friction to the processing fluid. In this case, the friction structure includes a passage having a central axis and a plurality of friction parts provided within the passage that rub against the processing fluid flowing through the internal space of the passage. In the friction structure, if the lateral area of ​​the passage is A and the total surface area of ​​the plurality of friction parts is A1, then the ratio of the total surface area A1 to the lateral area A, "A1 / A", satisfies equation (3) (sixth configuration). A1 / A>3.0 (3)

[0037] According to the sixth configuration of the processing apparatus, the friction-applying device is equipped with a friction structure, which applies friction to the processing fluid and increases the absolute value of the zeta potential. If equation (3) is satisfied in the friction structure, it becomes possible to increase the absolute value of the zeta potential more effectively.

[0038] In the processing apparatus according to the sixth configuration, the length H of the passage is preferably twice or more the outer diameter D of the passage (seventh configuration). In the friction structure, by making the length H of the passage twice or more the outer diameter D of the passage, it becomes possible to increase the absolute value of the zeta potential more effectively.

[0039] In the processing apparatus relating to the sixth or seventh configuration, if S is the cross-sectional area at the entrance of the passage, and S1 is the minimum cross-sectional area perpendicular to the central axis within the internal space of the passage, then the ratio of the minimum cross-sectional area S1 to the cross-sectional area S, "S1 / S", satisfies equation (4) (eighth configuration). S1 / S > 1 / 10 (4)

[0040] In the eighth configuration of the processing apparatus, equation (4) is satisfied in the friction structure. In this case, the minimum cross-sectional area S1 of the passage is appropriately larger than the cross-sectional area S of the passage entrance. Therefore, the processing fluid flows smoothly through the passage. As a result, clogging of the processing fluid can be suppressed by the friction-applying device.

[0041] In a processing apparatus relating to any one of the first to eighth configurations, preferably, the friction-applying device increases the absolute value of the zeta potential of the processing fluid after friction is applied relative to the absolute value of the zeta potential of the processing fluid before friction is applied, and generates fine bubbles in the processing fluid (ninth configuration).

[0042] In this specification, a fine bubble refers to a microbubble with an average diameter of less than 100.00 μm, as defined in JIS B 8741-1:2019. A microbubble refers to a microbubble with an average diameter of 1.00 μm or more and less than 100.00 μm, and an ultrafine bubble refers to a microbubble with an average diameter of 0.01 μm or more and less than 1.00 μm. The average diameter of a fine bubble refers to the median diameter D50.

[0043] In the ninth configuration of the processing apparatus, fine bubbles are introduced into the processing fluid by a friction-inducing device. Because fine bubbles carry a high zeta potential, they are suitable for effectively increasing the absolute value of the zeta potential.

[0044] In the processing apparatus according to the ninth configuration, preferably, the average diameter of the fine bubbles is 0.05 μm or more and 30.00 μm or less (tenth configuration).

[0045] In a processing apparatus relating to the ninth or tenth configuration, in a typical example, the friction-applying device does not include an air supply mechanism for introducing gas from the outside into the processing fluid (eleventh configuration).

[0046] In a processing apparatus relating to any one of the configurations from the 1st to the 11th, the friction-applying device increases the absolute value of the zeta potential of the processing fluid after friction is applied by 10% or more compared to the absolute value of the zeta potential of the processing fluid before friction is applied (configuration 12).

[0047] The machining method according to this embodiment comprises a friction application step and a machining step. The friction application step applies friction to the machining fluid to change the zeta potential of the machining fluid, increasing the absolute value of the zeta potential of the machining fluid after friction is applied compared to the absolute value of the zeta potential of the machining fluid before friction is applied. The machining step performs material removal or cold plastic deformation while supplying the friction-applied machining fluid to the machining point, which is the contact point between the workpiece and the tool (13th configuration).

[0048] In the 13th configuration of the machining method, the absolute value of the zeta potential of the machining fluid increases through a friction-inducing step. Then, during the machining process, the friction-inducing machining fluid, i.e., the machining fluid with an increased absolute value of zeta potential, is supplied to the machining point while machining (removal machining or cold plastic deformation) is performed by the tool. At this time, the zeta potential machining fluid supplied to the machining point becomes negatively charged, while the machining point of the workpiece tends to become positively charged. Therefore, a portion of the zeta potential machining fluid is adsorbed to the machining point of the workpiece, and the zeta potential machining fluid effectively intervenes at the machining point between the tool and the workpiece. As a result, the lubricity between the tool and the workpiece is increased. Therefore, the 13th configuration of the machining method can improve tool life. As a result, it becomes possible to manufacture parts with high dimensional accuracy over a long period of time.

[0049] The processing method according to the 13th configuration preferably further includes a storage step in which the processing fluid is stored in a tank before the processing step. In this case, the friction application step can be repeatedly performed on the processing fluid stored in the tank before the processing step (14th configuration).

[0050] In the 14th configuration of the machining method, a friction-applying process is repeatedly performed on the machining fluid stored in the tank before the machining process. This effectively increases the absolute value of the zeta potential in the machining fluid in the tank, and a negative zeta potential accumulates. In other words, the absolute value of the zeta potential stabilizes at a high level. During machining, the zeta potential machining fluid, which has a stable absolute value of zeta potential at a high level in the tank, is supplied from the tank to the machining point. Therefore, the adsorption of the zeta potential machining fluid to the machining point of the workpiece is consistently obtained, and as a result, the lubrication between the tool and the workpiece is consistently increased.

[0051] In the processing method relating to the 13th or 14th configuration, the friction application step increases the absolute value of the zeta potential of the processing fluid after friction is applied by 10% or more compared to the absolute value of the zeta potential of the processing fluid before friction is applied (15th configuration).

[0052] The processing apparatus and processing method according to this embodiment will be described below with reference to the drawings. In each drawing, the same or equivalent components are denoted by the same reference numerals, and redundant explanations will not be repeated.

[0053] [First Embodiment] In this embodiment, the processing apparatus can be applied to the processing method. The processing method comprises a friction application step and a processing step. The friction application step uses a friction application device to increase the absolute value of the zeta potential of the processing fluid. The processing step involves bringing a tool into contact with the workpiece to perform material removal or cold plastic deformation. In the processing step, processing (material removal or cold plastic deformation) is performed while supplying the processing fluid, whose absolute value of the zeta potential has been increased, to the processing point (workpiece and tool).

[0054] As described above, material removal processes can be broadly divided into (1) cutting, (2) grinding, and (3) polishing. Cold plastic working processes can be broadly divided into (1) wire drawing, (2) cold drawing, (3) cold extrusion, and (4) cold rolling. In this embodiment, material removal processes will be taken up, and as an example, cutting will be used to explain the processing apparatus and method, but the same methods can be applied to grinding and polishing.

[0055] [About the processing equipment] Figure 1 is a schematic diagram showing an example of the processing apparatus of this embodiment. Referring to Figure 1, the processing apparatus 100 is a material removal processing apparatus and comprises a tool 1, a fixing jig 2 for fixing the workpiece W, a friction applying device 3, and a supply device 4. The processing apparatus 100 further comprises a tank 5, a circulation pipe 6, and a pump 7.

[0056] Tool 1 is a removal tool for removing material from the workpiece W. If the removal process is cutting, tool 1 is, for example, a cutting tool such as a turning tool, milling cutter, end mill, or drill. If the removal process is grinding, tool 1 is, for example, a grinding tool such as a grinding wheel or brush. If tool 1 is a polishing tool, the polishing tool is, for example, a grinder, sander, or polisher. Fixing jig 2 fixes the workpiece W. Fixing jig 2 is, for example, a chuck. If the removal process is turning, fixing jig 2 fixes the workpiece W so that it can rotate around its axis.

[0057] The material of the workpiece W is not particularly limited. For example, the material of the workpiece W is metal. In this case, the workpiece W is a metallic material. The material of the workpiece W may also be ceramics, glass, or CFRP (carbon fiber reinforced plastic), etc.

[0058] The friction-imparting device 3 increases the absolute value of the zeta potential of the processing fluid PF.

[0059] In this embodiment, the processing fluid PF is stored in tank 5. Tank 5 is a container capable of storing the processing fluid PF.

[0060] The machining fluid PF is a water-soluble machining fluid (coolant). The machining fluid PF may also be a water-insoluble machining fluid. A water-soluble machining fluid is, for example, one selected from the group consisting of emulsion type, soluble type, and solution type. A water-insoluble machining fluid is, for example, a cutting oil. The machining fluid PF may also be water (tap water or industrial water).

[0061] Preferably, the processing fluid PF is an emulsion-type water-soluble processing fluid. The emulsion-type water-soluble processing fluid contains, for example, water and a surfactant. The surfactant may be any well-known one. The surfactant is, for example, one or more selected from the group consisting of nonionic surfactants, anionic surfactants, amphoteric surfactants, and cationic surfactants. The water-soluble processing fluid may also contain other components besides water and surfactants. Other components may include, for example, extreme pressure additives, rust inhibitors, preservatives, friction reducers, etc.

[0062] The circulation pipe 6 is provided for the processing fluid PF in the tank 5 and has an inlet end 61 and an outlet end 62. Each of the inlet end 61 and the outlet end 62 opens to the processing fluid PF in the tank 5. Specifically, as shown in Figure 1, the circulation pipe 6 is fixed to the side wall of the tank 5, and the inlet end 61 and the outlet end 62 are spaced apart from each other and open to the processing fluid PF in the tank 5. In this case, the inlet end of the circulation pipe 6, including the inlet end 61, may penetrate the side wall of the tank 5, and the inlet end 61 may be located in the processing fluid PF. Similarly, the outlet end of the circulation pipe 6, including the outlet end 62, may penetrate the side wall of the tank 5, and the inlet end 61 may be located in the processing fluid PF. However, the circulation pipe 6 may not be fixed to the side wall of the tank 5, and the inlet end and outlet end of the circulation pipe 6 may be immersed in the processing fluid PF from above the tank 5.

[0063] Pump 7 is installed in the circulation piping 6. It is the power source for circulating the processing fluid PF in the circulation piping 6. When pump 7 is operated, the processing fluid PF in tank 5 is drawn into the circulation piping 6 from the inlet end 61, and the processing fluid PF in the circulation piping 6 flows toward the outlet end 62 and is discharged into tank 5 from the outlet end 62. In this way, the processing fluid PF circulates between tank 5 and circulation piping 6.

[0064] The friction-applying device 3 is installed in the circulation piping 6. Specifically, in the circulation piping 6, the friction-applying device 3 is installed downstream of the pump 7. Therefore, when the pump 7 is operated, the processing fluid PF in the tank 5 flows continuously through the friction-applying device 3 in the circulation piping 6.

[0065] The supply device 4 comprises a drive source 41, piping 42, and a nozzle 43. One end of the piping 42 is immersed in the processing fluid PF stored in the tank 5. The other end of the piping 42 is connected to the nozzle 43. The drive source 41 supplies the processing fluid PF from the tank 5 to the nozzle 43 via the piping 42. The drive source 41 is, for example, a pump.

[0066] During the removal process, the nozzle 43 sprays the processing fluid PF and supplies the sprayed processing fluid PF to the workpiece W and the tool 1. Specifically, the nozzle 43 flows the processing fluid PF over the part of the tool 1 that is in contact with the workpiece W, and / or over the part of the workpiece W that is in contact with the tool 1. In other words, when the removal process is being performed, the nozzle 43 flows and supplies the processing fluid PF to the processing point P0.

[0067] The processing apparatus 100 may further include a recovery device 8. The recovery device 8 recovers the used processing fluid PF used in processing and returns it to the tank 5. Specifically, the recovery device 8 includes a recovery pan 81 and a recovery pipe 82. The recovery pan 81 functions as a receptacle for collecting the processing fluid PF discharged from the nozzle 43, flowing over the processing point P0, and falling down. The recovery pipe 82 is positioned between the recovery pan 81 and the tank 5, connecting the recovery pan 81 and the tank 5. The recovery pipe 82 discharges the processing fluid PF stored in the recovery pan 81 to the tank 5. The recovery device 8 allows the processing fluid PF to be circulated and reused. Note that the processing apparatus 100 does not necessarily have to include the recovery device 8.

[0068] [About friction-generating devices] The friction-imparting device 3 increases the absolute value of the zeta potential of the processing fluid PF. Specifically, the friction-imparting device 3 applies friction to the processing fluid PF, changing the zeta potential of the processing fluid PF, and increases the absolute value of the zeta potential of the processing fluid PF after friction is applied compared to the absolute value of the zeta potential of the processing fluid before friction is applied. To achieve this function, the friction-imparting device 3 is equipped with a friction structure.

[0069] Figures 2 and 3 show the configuration of a friction-applying device 3 equipped with a friction structure. Figure 2 shows a longitudinal cross-sectional view of the friction-applying device 3, and Figure 3 shows a cross-section along line III-III in Figure 2. Referring to Figures 2 and 3, the friction structure in the friction-applying device 3 comprises a passage 31 having a central axis CL and a plurality of friction parts 32. The passage 31 is formed, for example, in the internal space of a cylindrical body 30. The processing fluid PF flows through this passage 31 in one direction.

[0070] Multiple friction parts 32 are provided within the passage 31 and rub against the processing fluid PF flowing through the internal space of the passage 31. The multiple friction parts 32 are provided, for example, on the inner circumferential surface of the cylindrical body 30. The multiple friction parts 32 are provided in multiple stages along the central axis CL. Each friction part 32 is, for example, plate-shaped and inclined with respect to the central axis CL. However, each friction part 32 does not have to be inclined with respect to the central axis CL. Also, the shape of each friction part 32 may be other shapes besides plate-shaped.

[0071] As the processing fluid PF flows through the passage 31, the processing fluid PF flows along the surface of the friction part 32 and rubs against the friction part 32. At this time, friction is applied to the processing fluid PF. The application of friction to the processing fluid PF increases the absolute value of the zeta potential of the processing fluid PF. Thus, in the case of the friction-applying device 3 equipped with a friction structure, friction is applied to the processing fluid PF. This changes the zeta potential of the processing fluid PF. As a result, the absolute value of the zeta potential of the processing fluid PF after friction is applied can be increased compared to the absolute value of the zeta potential of the processing fluid before friction is applied.

[0072] The friction-applying device 3, which has a friction structure, preferably has the following configuration. Let A be the lateral area of ​​the passage 31. The lateral area A means the lateral area of ​​the passage 31 when there are no multiple friction parts 32 present. In the example of this embodiment, the lateral area A is the area of ​​the inner circumferential surface of the cylindrical body 30 that forms the passage 31. Let A1 be the total surface area of ​​the multiple friction parts 32. The total surface area A1 of the friction parts 32 means the total surface area of ​​the friction parts 32 that are exposed in the internal space of the passage 31. In this case, the ratio of the total surface area A1 to the lateral area A, "A1 / A", satisfies equation (3). A1 / A>3.0 (3)

[0073] If equation (3) is satisfied in the friction structure, the region where friction occurs with respect to the processing fluid PF present in the passage 31 by all the friction parts 32 is sufficiently large. Therefore, it is possible to more effectively increase the absolute value of the zeta potential. The lower limit of "A1 / A" is preferably 5.0. The upper limit of "A1 / A" is not particularly limited, but is preferably 30.0, for example.

[0074] Furthermore, the length H of the passage 31 is at least twice the outer diameter D of the passage 31. The length H of the passage 31 refers to the dimension in the direction along the central axis CL from the inlet 31i to the outlet 31o of the passage 31. In this embodiment, the outer diameter D of the passage 31 refers to the inner diameter of the cylindrical body 30 that forms the passage 31. In the friction structure, if the length H of the passage 31 is at least twice the outer diameter D of the passage 31, the processing fluid PF flows through the relatively elongated passage 31, generating sufficient friction in the processing fluid PF. This makes it possible to increase the absolute value of the zeta potential more effectively. Preferably, the length H of the passage 31 is at least four times the outer diameter D of the passage 31. Also preferably, the length H of the passage 31 is 20 times or less the outer diameter D of the passage 31.

[0075] Furthermore, in the internal space of the passage 31, let S be the cross-sectional area of ​​the entrance 31i of the passage 31 among the cross-sectional areas perpendicular to the central axis CL. Let S1 be the minimum cross-sectional area among the cross-sectional areas perpendicular to the central axis CL. Cross-sectional areas S and S1 are the cross-sectional areas of the space. More specifically, the minimum cross-sectional area S1 is the total area of ​​the voids of the surface with the smallest void area among all surfaces perpendicular to the central axis CL. In this case, the ratio of the minimum cross-sectional area S1 to the cross-sectional area S, "S1 / S", satisfies equation (4). S1 / S > 1 / 10 (4)

[0076] If equation (4) is satisfied in the friction structure, then the minimum cross-sectional area S1 of the passage 31 is appropriately larger than the cross-sectional area S of the inlet 31i of the passage 31. In this case, the portion of the passage 31 with the minimum cross-sectional area S1 is not too narrow. Therefore, the processing fluid PF flows smoothly through the passage 31. As a result, clogging of the processing fluid PF can be suppressed by the friction device 3. The lower limit of "S1 / S" is preferably 1 / 7. The upper limit of "S1 / S" is not particularly limited, but for example, 1 / 2 is preferred.

[0077] The friction-imparting device 3 only needs to be able to impart friction to the processing fluid PF, and its structure may be any structure other than the friction structure described above.

[0078] [Regarding processing methods] The processing method of this embodiment will now be described with reference to Figure 1. As described above, the processing method comprises a friction application step and a processing step.

[0079] First, prepare the workpiece W. Specifically, the workpiece W is a material made of metal. If the workpiece W is a metal material, its material may be, for example, carbon steel, alloy steel, Fe-based alloy, Ni-based alloy, Ti-based alloy, Al-based alloy, etc. Here, "X-based alloy" means that the metal element X is contained in 50% or more by mass. Examples of Fe-based alloys are machine structural steel, stainless steel, etc. Fix the prepared workpiece W to the fixing jig 2 of the removal processing device.

[0080] In the friction application process, the friction application device 3 is used to increase the absolute value of the zeta potential of the processing fluid. Specifically, the pump 7 is activated. As a result, the processing fluid PF in the tank 5 is drawn into the circulation pipe 6 from the inlet end 61, and the processing fluid PF in the circulation pipe 6 flows toward the outlet end 62.

[0081] The machining fluid PF flowing through the circulation pipe 6 passes through the friction-applying device 3 and is discharged into the tank 5 from the outlet end 62 of the circulation pipe 6. When the machining fluid PF passes through the friction-applying device 3, friction is applied to the machining fluid PF. This changes the zeta potential of the machining fluid PF. As a result, the absolute value of the zeta potential of the machining fluid PF after friction is applied increases compared to the absolute value of the zeta potential of the machining fluid before friction is applied.

[0082] Consequently, the absolute value of the zeta potential increases, and negatively charged machining fluid PF (zeta potential machining fluid PF) is continuously discharged into tank 5. In this way, the machining fluid PF in tank 5 is replaced by zeta potential machining fluid PF, and zeta potential machining fluid PF accumulates in tank 5.

[0083] The absolute value of the zeta potential of the zeta potential machining fluid PF accumulated in tank 5 is 10% or more higher than the absolute value of the zeta potential of the machining fluid PF before friction treatment, without passing through the friction device 3. That is, the absolute value of the zeta potential of the machining fluid PF (zeta potential machining fluid PF) after friction is applied by the friction device 3 is 10% or more higher than the absolute value of the zeta potential of the machining fluid PF before friction is applied (untreated machining fluid PF). Preferably, the absolute value of the zeta potential of the zeta potential machining fluid PF is 15% or more higher than the absolute value of the zeta potential of the untreated machining fluid PF. In short, the rate of increase of the absolute value of the zeta potential of the zeta potential machining fluid PF relative to the absolute value of the zeta potential of the untreated machining fluid PF is 10% or more, preferably 15% or more. The higher the rate of increase, the better, but it is preferably 400% or less, and more preferably 200% or less.

[0084] The zeta potential of each processing fluid PF is measured by the following method.

[0085] Regarding the method for measuring the zeta potential of zeta potential processing fluid PF, 1 L (liter) of zeta potential processing fluid PF flowing in the vicinity of the outlet end 62 of the circulation pipe 6 is collected. For the purpose of collecting such zeta potential processing fluid PF, a liquid outlet is provided in the circulation pipe 6 near the outlet end 62. The zeta potential of the collected zeta potential processing fluid PF is measured. As the device for measuring the zeta potential, a Malvern Zetasizer Nano ZS (electrophoretic zeta potential measuring device) and a capillary cell (disposable zeta potential measuring cell) can be used. Using this zeta potential measuring device, a portion of the collected processing fluid PF can be introduced into the capillary cell and its zeta potential measured.

[0086] Regarding the method for measuring the zeta potential of untreated processing fluid PF, in the first method, a sample of the processing fluid PF stored in tank 5 before friction treatment is taken in advance. Then, the zeta potential of the collected untreated processing fluid PF can be measured using the zeta potential measuring device described above. In the second method, a sample is taken from the processing fluid PF before it is supplied to tank 5. In this case, the zeta potential of the sample can be measured using the zeta potential measuring device described above, and this zeta potential is treated as the standard zeta potential of untreated processing fluid PF. If either the first or second method is adopted, the other method can be omitted.

[0087] In the machining process, tool 1 is brought into contact with the workpiece W to perform material removal. Through this material removal process, an intermediate or final part is manufactured. If the workpiece W is, for example, a metal material, the manufactured part will be a metal material. If the material removal process is cutting, cutting tool 1 is brought into contact with the workpiece W to perform cutting. If the material removal process is grinding, grinding tool 1 is brought into contact with the workpiece W to perform grinding. If the material removal process is polishing, polishing tool 1 is brought into contact with the workpiece W to perform polishing.

[0088] During the removal process, the Zeta Potential Cutting Fluid PF is sprayed from the nozzle 43 and supplied to the cutting point P0. This allows the removal process to be carried out while supplying the Zeta Potential Cutting Fluid PF to the cutting point P0. During the removal process, cutting debris is generated at the cutting point P0 of the workpiece W. The generated cutting debris is adsorbed by the Zeta Potential Cutting Fluid PF and discharged from the part together with the Zeta Potential Cutting Fluid PF.

[0089] In this machining method, the absolute value of the zeta potential of the machining fluid PF increases through the friction-inducing process. During the machining process, the zeta potential machining fluid PF is supplied to the workpiece W and the tool 1 while the tool 1 performs the removal process. At this time, the zeta potential machining fluid PF supplied to the workpiece W and the tool 1 is negatively charged. On the other hand, the machining point P0 of the workpiece W is positively charged. Therefore, a portion of the zeta potential machining fluid PF is adsorbed to the machining point P0 of the workpiece W, and the machining fluid FP effectively intervenes at the machining point P0 between the tool 1 and the workpiece W. As a result, the lubrication between the tool 1 and the workpiece W is increased. Consequently, the life of the tool 1 can be improved during the removal process. As a result, it becomes possible to manufacture parts with high dimensional accuracy over a long period of time.

[0090] Furthermore, in this embodiment, a circulation pipe 6 is provided to the tank 5 that stores the machining fluid PF, and the inlet end 61 and outlet end 62 of the circulation pipe 6 each open to the machining fluid PF in the tank 5. A pump 7 is provided in this circulation pipe 6. A friction-applying device 3 is also provided in the circulation pipe 6. In this case, the operation of the pump 7 causes the machining fluid PF in the tank 5 to flow continuously through the friction-applying device 3 in the circulation pipe 6. As a result, the absolute value of the zeta potential in the machining fluid PF in the tank 5 is effectively increased, and negative zeta potential accumulates. That is, the absolute value of the zeta potential stabilizes at a high level. During machining, the zeta potential machining fluid PF, which has a stable absolute value of zeta potential at a high level in the tank 5, is supplied from the tank 5 to the machining point P0 by the supply device 4. Therefore, the adsorption of the zeta potential machining fluid PF to the machining point P0 of the workpiece W is constantly obtained, and as a result, the lubricity between the tool 1 and the workpiece W is constantly increased.

[0091] In this embodiment, a recovery device 8 is provided to recover the used processing fluid PF used in processing and return it to the tank 5. When the zeta potential processing fluid PF is used for processing, the absolute value of its potential (zeta potential) decreases. Therefore, in the used processing fluid PF, the zeta potential returns to the potential it was at before the friction treatment was applied. Thus, the processing fluid PF can be effectively recycled.

[0092] [Preferred conditions] The following describes preferred conditions in this embodiment.

[0093] <Flow rate L(m) of processing fluid PF in circulation piping 6 3 / min)> The flow rate L is equal to the volume V(m³) of the processing fluid PF in tank 5. 3 It is preferable that the relationship between ) satisfies equation (1). 5 <L / V×100<60 (1)

[0094] The flow rate L is, for example, the flow rate of the processing fluid PF at the outlet end of the circulation piping 6, including the outlet end 62. The flow rate L can be measured by a known flow meter, such as an ultrasonic flow meter.

[0095] In equation (1), as described above, "L / V × 100" is the circulation flow index. If the circulation flow index is too small, the amount of zeta potential processing fluid PF supplied to tank 5 by circulation will be insufficient. On the other hand, if the circulation flow index is too large, the amount of zeta potential processing fluid PF supplied to tank 5 by circulation will be excessive.

[0096] According to equation (1), the circulation flow index (L / V × 100) is greater than 5 and less than 60. In short, the circulation flow index is limited, and the absolute value of the zeta potential of the zeta potential processing fluid PF supplied to tank 5 by circulation is at a moderately high level. In equation (1), the lower limit of the circulation flow index (L / V × 100) is preferably 10, more preferably 30. The upper limit of the circulation flow index (L / V × 100) is preferably 50.

[0097] <Flow rate U(m) of processing fluid PF supplied by supply device 4> 3 / min)> The supply flow rate U is the flow rate L(m³) of the processing fluid PF in the circulation pipe 6. 3 It is preferable that the relationship with / min) satisfies equation (2). 10

[0098] ​The supply flow rate U is the flow rate of the processing fluid PF supplied to the workpiece W and tool 1 by the supply device 4. The supply flow rate U can be calculated by measuring the volume of processing fluid PF sprayed from the nozzle 43 per unit time.

[0099] In equation (2), as described above, "U / L × 100" is the discharge flow rate index. If the discharge flow rate index is too small, the amount of zeta potential processing fluid PF accumulated in tank 5 will be excessive. On the other hand, if the discharge flow rate index is too large, the amount of zeta potential processing fluid PF accumulated in tank 5 will be insufficient.

[0100] According to equation (2), the discharge flow rate index (U / L × 100) is greater than 10 and less than 100. In short, the discharge flow rate index is limited, and the amount of zeta potential processing fluid PF accumulated in tank 5 is appropriate. In equation (2), the lower limit of the discharge flow rate index (U / L × 100) is preferably 20. The upper limit of the discharge flow rate index (U / L × 100) is preferably 80.

[0101] [An example of the operation of the processing device 100 in the processing method] <Example of operation 1> In the friction application process, the pump 7 is operated to circulate the processing fluid PF to the friction application device 3. This adjusts the zeta potential of the processing fluid PF in the tank 5 to an appropriate potential. After adjustment, the pump 7 is kept running while the machining process is carried out using the adjusted zeta potential processing fluid PF. In other words, the friction application process and the machining process proceed simultaneously. At this time, the used processing fluid PF used in machining is collected in the tank 5. If the processing fluid PF decreases due to evaporation or scattering, new processing fluid PF is replenished in the tank 5. This keeps the volume V of the processing fluid PF in the tank 5 constant.

[0102] <Example of operation 2> In operation example 2, the used processing fluid PF is not recovered into tank 5. In this case, the amount of processing fluid PF in tank 5 decreases as processing progresses. Therefore, the pump 7 controls the flow rate L of the processing fluid PF in the circulation piping 6. Furthermore, new processing fluid PF is replenished in tank 5, and the volume V of the processing fluid PF in tank 5 is kept constant.

[0103] [Second Embodiment] Figure 4 is a schematic diagram showing an example of the processing apparatus 100A in the second embodiment. The processing apparatus 100A differs from the processing apparatus 100 of the first embodiment in that it is used for cold plastic deformation of the workpiece WA. In this case, the material of the workpiece WA is metal.

[0104] Referring to Figure 4, the processing apparatus 100A is a cold plastic working apparatus. Specifically, the processing apparatus 100A is a wire drawing apparatus. The processing apparatus 100A comprises a tool 1A, a drawing device 9, and a friction applying device 3.

[0105] Tool 1A is a plastic working tool for drawing a workpiece WA. The workpiece WA is a metal wire. Tool 1A is a die. In this embodiment, tool 1A will also be referred to as die 1A in the following description.

[0106] Die 1A has a through hole in the center. Die 1A may have a well-known configuration. The through hole of die 1A includes, for example, an approach and reduction section, a bearing section, and a back relief section, in order from the inlet side to the outlet side of die 1A. The inner diameter of the approach and reduction section decreases from the inlet side to the outlet side of die 1A. The approach and reduction section introduces the workpiece WA, which is a metal wire, into die 1A and reduces the diameter of the workpiece WA. The inner diameter of the bearing section is constant. The inner diameter of the bearing section corresponds to the die diameter. The bearing section restrains the workpiece WA and keeps the outer diameter of the workpiece WA constant. The inner diameter of the back relief section increases from the inlet side to the outlet side of die 1A. The back relief section prevents damage to die 1A from the reduced diameter of the workpiece.

[0107] The drawing device 9 draws the workpiece WA from the die 1A. The drawing device 9 includes an unwinding device 91, a winding device 92, and a support reel 93. The unwinding device 91 unwinds the coiled workpiece WA. The winding device 92 draws the workpiece WA, which has been unwinded from the unwinding device 91 and passed through the die 1A, from the die 1A. The winding device 92 further winds the metal material produced by drawing from the die 1A into a coil. The support reel 93 is positioned on the entry and / or exit sides of the die 1A and supports the workpiece WA during the wire drawing process and the metal material produced by the wire drawing process. The drawing device 9 does not necessarily include the support reel 93.

[0108] The drawing device 9 is not limited to the above configuration. The drawing device 9 may have any configuration other than the above, as long as it is configured to draw the workpiece WA from the die 1A.

[0109] The friction-applying device 3 has the same configuration as in the first embodiment. However, in this embodiment, the nozzle 43A of the supply device 4 is positioned on the inlet side of the die 1A. During wire drawing, the nozzle 43A sprays the zeta potential cutting fluid PF and adheres the sprayed cutting fluid PF to the surface of the workpiece WA before it passes through the die 1A.

[0110] Even in the machining method of this embodiment, similar to the first embodiment, the zeta potential machining fluid FP is effectively interposed at the machining point P0 between the tool 1A and the workpiece WA, thereby increasing the lubricity between the tool (die) 1A and the workpiece WA. Therefore, the life of the tool 1A can be improved in cold plastic deformation.

[0111] [Third Embodiment] The processing apparatus used in the processing method of this embodiment, i.e., the cold plastic deformation apparatus, is not limited to the processing apparatus 100A shown in Figure 4. Figure 5 is a schematic diagram showing an example of the processing apparatus 100B in the third embodiment. The processing apparatus 100B differs from the processing apparatuses 100 and 100A of the first and second embodiments in that it is used for cold rolling of the workpiece WB. In this case, the material of the workpiece WB is metal.

[0112] Referring to Figure 5, the processing apparatus 100B is a cold rolling mill. The processing apparatus 100B includes a tool 1B and a friction-applying device 3.

[0113] Tool 1B is a plastic working tool for cold rolling a workpiece WB. The workpiece WB is a metal sheet. Tool 1B is a pair of work rolls. In this embodiment, tool 1B will also be referred to as work roll 1B in the following description.

[0114] Each of the pair of work rolls 1B is supported by a corresponding support roll 10. The friction-applying device 3 has the same configuration as in the first embodiment. However, in this embodiment, the nozzle 43B of the supply device 4 is positioned on the entry side of the pair of work rolls 1B. During cold rolling, the nozzle 43B sprays zeta potential cutting fluid PF between the work rolls 1B, causing the sprayed cutting fluid PF to adhere to the surface of the workpiece WB passing between the work rolls 1B.

[0115] The processing method of this embodiment also produces the same effects as the second embodiment described above.

[0116] Figure 5 shows a processing apparatus (cold rolling mill) 100B when the workpiece WB is a metal plate. However, in this embodiment, the workpiece WB may also be a metal wire, a metal rod, or a metal tube. In these cases, a caliber is formed on a pair of work rolls, and a hole is formed by the pair of work rolls. When the workpiece WB is a metal wire, a metal rod, or a metal tube, the cold rolling mill may include three or more work rolls. When the cold rolling mill includes three work rolls, each work roll is arranged at a 120° pitch around the central axis of the workpiece WB. In this case, a hole is formed by the three work rolls. When the cold rolling mill includes four work rolls, each work roll is arranged at a 90° pitch around the central axis of the workpiece WB. In this case, a hole is formed by the four work rolls. [Examples]

[0117] Hereinafter, the processing method according to the present disclosure will be described in more detail with reference to examples. However, the processing method according to the present disclosure is not limited to the following examples.

[0118] Using the processing apparatus shown in FIG. 1, removal processing was performed. Specifically, a hot forged product was prepared as the workpiece, and drilling and finish reaming were performed on this workpiece. The material of the workpiece was low Mn steel. The main elements contained in the workpiece were, in mass%, C: 0.31%, Si: 0.24%, Mn: 1.49%, and P: 0.019%. In the comparative example, the flow rate L of the processing fluid in the circulation pipe was set to zero, and an untreated processing fluid without performing a friction application process was prepared. In the example of the present invention, the flow rate L of the processing fluid in the circulation pipe was set to 0.043 (m 3 / min), and a zeta potential processing fluid obtained by subjecting the processing fluid of the comparative example to a friction application process was prepared. The volume V of the processing fluid in the tank was 1 (m 3 ).

[0119] At that time, in each of the example of the present invention and the comparative example, four types of processing fluids (processing fluid 1, processing fluid 2, processing fluid 3, and processing fluid 4) were used as the processing fluid. Processing fluid 1 was an emulsion-type water-soluble processing fluid containing 5% by volume of a processing fluid stock solution (product name: Sugicut CE14SZ) manufactured by Sugimura Chemical Industry Co., Ltd. Processing fluid 2 was a soluble-type water-soluble processing fluid containing 5% by volume of a processing fluid stock solution (product name: Simiron SCF500) manufactured by Daido Chemical Co., Ltd. Processing fluid 3 was an emulsion-type water-soluble processing fluid containing 5% by volume of a processing fluid stock solution (product name: Simiron EX173) manufactured by Daido Chemical Co., Ltd. Processing fluid 4 was an emulsion-type water-soluble processing fluid containing 5% by volume of a processing fluid stock solution (product name: Sugicut CE18FL) manufactured by Sugimura Chemical Industry Co., Ltd. Processing fluid 5 was a soluble-type water-soluble processing fluid containing 1% by volume of the same processing fluid stock solution as processing fluid 2.

[0120] In both the present invention example and the comparative example, the zeta potential of each prepared processing fluid 1, 2, 3, 4, and 5 was measured. For the processing fluid in the present invention example, the zeta potential before friction treatment corresponds to the zeta potential of the processing fluid in the comparative example. As the apparatus for measuring the zeta potential, the Malvern Zetasizer Nano ZS (electrophoretic zeta potential measuring apparatus) and capillary cell (disposable zeta potential measuring cell) described above were used. Each processing fluid was supplied to a tool, and the lifespan of the drill used for drilling and the lifespan of the reamer drill used for finishing reaming were investigated. The lifespan of each drill was defined as the total number of holes drilled at the point when the tool wore out and machining became impossible. Then, in order to evaluate the tool life, i.e., the lifespan of the drill, the rate of change in the lifespan in the present invention example compared to the lifespan in the comparative example was calculated. The results are shown in Table 1.

[0121] [Table 1]

[0122] In all of the machining fluids 1, 2, 3, 4, and 5, the absolute value of the zeta potential of the machining fluid of the present invention (zeta potential machining fluid) was higher than the absolute value of the zeta potential of the machining fluid of the comparative example (machining fluid before friction treatment). In particular, in machining fluids 1 to 4, the absolute value of the zeta potential of the machining fluid of the present invention was higher than the absolute value of the zeta potential of the machining fluid of the comparative example by 10% or more. In drilling operations, regardless of which of the machining fluids 1, 2, 3, 4, and 5 was used, the drill life of the present invention was improved compared to the drill life of the comparative example. Similarly, in finishing reaming operations, regardless of which machining fluid was used, the drill life of the present invention was improved compared to the drill life of the comparative example. In short, in both drilling and finishing reaming operations, using a zeta potential machining fluid as in the present invention improved tool life. In particular, in machining fluids 1 to 4, the increase rate of the absolute value of the zeta potential was 10% or more, indicating a significant improvement in tool life.

[0123] The embodiments of this disclosure have been described above. However, the embodiments described above are merely examples for implementing this disclosure. Therefore, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified as appropriate without departing from the spirit of the disclosure.

[0124] For example, the friction-applying device 3 may be located in the piping 42. That is, the circulation piping 6 may be omitted, and the friction-applying device 3 may be located in the supply device 4. However, it is preferable that the friction-applying device 3 is located in the circulation piping 6, as shown in Figure 1. If the friction-applying device 3 is located in the circulation piping 6, the absolute value of the zeta potential in the processing fluid PF in the tank 5 will increase effectively, and a negative zeta potential will accumulate. That is, the absolute value of the zeta potential will stabilize at a high level.

[0125] The friction-imparting device 3 may be configured to increase the absolute value of the zeta potential of the processing fluid PF and to generate fine bubbles. If the friction-imparting device 3 is configured to impart friction to the processing fluid PF, fine bubbles can be generated in the processing fluid PF. Fine bubbles are highly charged with zeta potential and are therefore suitable for effectively increasing the absolute value of the zeta potential.

[0126] In this case, preferably, the average diameter of the fine bubbles is 0.05 μm or more and 30.00 μm or less. In other words, the fine bubbles preferably include ultrafine bubbles with an average particle size of 0.05 μm or more and less than 1.00 μm, i.e., relatively large ultrafine bubbles. The fine bubbles also preferably include microbubbles with an average diameter of 1.00 μm or more and 30.00 μm or less, i.e., relatively small microbubbles.

[0127] In a typical example, the friction-generating device 3 does not have an air supply mechanism to introduce gas from an external source into the processing fluid PF. In this case, the friction-generating device 3 generates fine bubbles from dissolved oxygen in the processing fluid PF by applying friction to the fluid. In this case, the friction-generating device 3 does not take in gas (e.g., air) from an external source to generate fine bubbles. Therefore, a special air supply mechanism is unnecessary. However, the friction-generating device 3 may be equipped with an air supply mechanism. [Explanation of Symbols]

[0128] 100,100A,100B: Processing equipment 1,1A,1B:Tools 3: Friction-generating device 4: Feeding device 5: Tank 6: Circulation piping 7: Pump 8: Recovery device P0: Processing point W, WA, WB: Workpiece

Claims

1. A friction-applying device that applies friction to an emulsion-type water-soluble processing fluid to change the zeta potential of the processing fluid, and increases the absolute value of the zeta potential of the processing fluid after the application of friction with respect to the absolute value of the zeta potential of the processing fluid before the application of friction, The system includes a supply device that supplies the processing fluid, to which friction has been applied by the friction-applying device, to the processing point, which is the point of contact between the workpiece and the tool during processing. The friction-applying device comprises a friction structure that applies friction to the processing fluid, The friction structure includes a passage having a central axis, and a plurality of friction parts provided within the passage that rub against the processing fluid flowing through the internal space of the passage. The aforementioned passage is formed in the internal space of the cylindrical body. The friction portion is provided in multiple stages along the central axis on the inner circumferential surface of the cylindrical body. Each of the friction parts is plate-shaped and inclined with respect to the central axis. Processing equipment.

2. The processing apparatus according to claim 1, further, A tank for storing the processing fluid, A circulation pipe having an inlet end and an outlet end, each of which opens to the processing fluid in the tank, The circulation piping includes a pump that draws the processing liquid from the tank into the circulation piping from the inlet end and circulates the processing liquid in the circulation piping toward the outlet end, The friction-applying device is provided in the circulation piping, The supply device is connected to the tank. Processing equipment.

3. The processing apparatus according to claim 2, Flow rate L(m) of the processing fluid in the aforementioned circulation piping ３ The volume V(m³) of the processing fluid in the tank is equal to the volume V(m³) of the processing fluid in the tank. ３ In relation to ), the equation (1) is satisfied. Processing equipment. 5<L / V×100<60 (1)

4. The processing apparatus according to claim 3, The supply flow rate U(m) of the processing fluid supplied to the processing point by the supply device ３ / min) is the flow rate L (m) of the processing fluid in the circulation piping. ３ In relation to / min), equation (2) is satisfied. Processing equipment. 10<U / L×100<100 (2)

5. The processing apparatus according to claim 2, further, The system includes a recovery device that collects the used processing fluid used in the processing and returns it to the tank. Processing equipment.

6. A processing apparatus according to any one of claims 1 to 5, In the friction structure described above, if the lateral surface area of ​​the passage is A and the total surface area of ​​the plurality of friction parts is A1, then the ratio of the total surface area A1 to the lateral surface area A, "A1 / A", satisfies equation (3). Processing equipment. A1 / A>3.0 (3)

7. The processing apparatus according to claim 6, The length H of the passage is at least twice the outer diameter D of the passage. Processing equipment.

8. The processing apparatus according to claim 6, In the internal space of the passage, if S is the cross-sectional area of ​​the entrance to the passage among the cross-sectional areas perpendicular to the central axis, and S1 is the minimum cross-sectional area among the cross-sectional areas perpendicular to the central axis, then the ratio of the minimum cross-sectional area S1 to the cross-sectional area S, "S1 / S", satisfies equation (4). Processing equipment. S1 / S>1 / 10 (4)

9. A processing apparatus according to any one of claims 1 to 5, The friction-imparting device increases the absolute value of the zeta potential of the processing fluid after friction is applied, relative to the absolute value of the zeta potential of the processing fluid before friction is applied, and generates fine bubbles in the processing fluid. Processing equipment.

10. A processing apparatus according to claim 9, The average diameter of the fine bubbles is between 0.05 μm and 30.00 μm. Processing equipment.

11. A processing apparatus according to claim 9, The friction-applying device does not include an air supply mechanism for introducing gas from an external source into the processing fluid. Processing equipment.

12. A processing apparatus according to claim 1, The friction-applying device increases the absolute value of the zeta potential of the processing fluid after friction is applied by 10% or more compared to the absolute value of the zeta potential of the processing fluid before friction is applied. Processing equipment.

13. A friction application step comprising using the friction application device described in Claim 1 to apply friction to an emulsion-type water-soluble processing fluid to change the zeta potential of the processing fluid, thereby increasing the absolute value of the zeta potential of the processing fluid after the application of friction with respect to the absolute value of the zeta potential of the processing fluid before the application of friction, The process includes a step of performing a removal process or cold plastic deformation while supplying the processing fluid to which the friction has been applied to the processing point, which is the contact point between the workpiece and the tool. Processing method.

14. The processing method according to claim 13, further, The process includes a storage step in which the processing liquid is stored in a tank before the aforementioned processing step. Before the aforementioned processing step, the friction application step is repeatedly performed on the processing fluid stored in the tank. Processing method.

15. The processing method according to claim 13, The friction-applying step involves increasing the absolute value of the zeta potential of the processing fluid after the friction is applied by 10% or more compared to the absolute value of the zeta potential of the processing fluid before the friction is applied. Processing method.

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