Cooling method, cooling device, machining method, and machining device

Abstract

To provide a cooling method which enables a mixture of dry ice particles and an oil solution to be jetted to a processed portion easily and uniformly, also enables reduction of deterioration of a processing tool, and is used for machining, and to provide a cooling device, a machining method, and a machining device.SOLUTION: A method for cooling a processed portion of a workpiece to be machined or a processing tool, includes a mixture jetting step in which a mixture of dry ice particles and an oil solution is jetted from a single jet nozzle 15 to the processed portion or the processing tool during machining.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cooling method, a cooling device, a machining method, and a machining device used in machining. [Background technology]

[0002] During machining, particularly cutting, the part to be machined is overheated by cutting with a cutting tool, which causes deterioration of the cutting tool and a decrease in the machining accuracy of the part to be machined. Therefore, it is important to cool the part to be machined and the cutting tool. One cooling method uses cutting oil, but this has problems with oxidation of the cutting tool and residual cutting oil on the cutting tool and the part to be machined. In recent years, in order to solve these problems, a cooling method using dry ice particles without using cutting oil has been adopted.

[0003] Patent Document 1 discloses that dry ice gas and a mist containing a small amount of oil are sprayed onto the machining area to cool the machining area and cutting tools. The dry ice gas provides a cooling effect, while the mist containing a small amount of oil provides a lubricating effect. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-110619 A Summary of the Invention [Problem to be solved by the invention]

[0005] The cooling device disclosed in Patent Document 1 includes a nozzle that blows out dry ice gas and a nozzle that blows out a small amount of oil mist. However, the use of two nozzles makes the device structure complicated. In addition, the dry ice gas and the oil are mixed after each fluid is sprayed from the nozzles of the two nozzles, so the mixture is non-uniform and the synergistic effect of mixing the two fluids is low. In addition, the non-uniform mixture also causes the deterioration of the processing tool to be accelerated.

[0006] The present invention has been made in consideration of the above-mentioned situation, and aims to provide a cooling method, cooling device, machining method, and machining device for use in machining, which can easily and uniformly spray a mixture of dry ice particles and oil onto the machining area and reduce deterioration of the machining tool. [Means for solving the problem]

[0007] A cooling method according to a first aspect of the present invention comprises: 1. A method for cooling a workpiece or a tool to be machined, comprising the steps of: The method includes a mixture injection step of injecting a mixture of dry ice particles and oil from a single injection nozzle toward the machining site or the machining tool during machining.

[0008] The method further includes a dry ice spraying step of spraying dry ice particles from the spray nozzle toward the processing site or the processing tool. This may also be the case.

[0009] A machining method according to a second aspect of the present invention comprises: A machining step of machining a workpiece; and a cooling step of cooling the processed portion of the workpiece or the processing tool by the cooling method.

[0010] A cooling device according to a third aspect of the present invention comprises: A cooling device for cooling a processing portion or a processing tool of a workpiece during machining, An injection nozzle that injects a cooling medium onto the processing site or the processing tool; A liquefied carbon dioxide gas supply unit that supplies liquefied carbon dioxide gas to the injection nozzle; An oil supply unit that supplies an oil to the injection nozzle, The spray nozzle adiabatically expands the liquefied carbon dioxide gas inside to generate dry ice particles, and sprays the cooling medium containing a mixture of the dry ice particles and the oil onto the processing area or the processing tool.

[0011] The dry ice particle ejection nozzle may further include a gas ejection unit that ejects a gas to the ejection nozzle. The oil supplied from the oil supply unit is supplied through a jet gas supply path from the supply source of the jet gas supply unit to the jet nozzle. This may also be the case.

[0012] The oil agent is atomized by a lubricator disposed in the injection gas supply path and supplied to the injection gas supply path. This may also be the case.

[0013] A heater for heating the ejection gas is provided in the ejection gas supply path, The oil agent is supplied downstream of the heater. This may also be the case.

[0014] Further provided is a switching unit that switches whether the oil agent supplied by the oil agent supply unit is supplied to the injection nozzle or not. This may also be the case.

[0015] A machining apparatus according to a fourth aspect of the present invention comprises: A processing unit that machines a workpiece; The cooling device; A control unit that controls the switching unit, The control unit controls the switching unit in accordance with the machining process, and switches between spraying dry ice particles from the spray nozzle and spraying a mixture of dry ice particles and oil. Effect of the Invention

[0016] According to the present invention, it is possible to provide a cooling method, a cooling device, a machining method, and a machining device for use in machining, which can easily and uniformly spray a mixture of dry ice particles and oil onto the machining area and reduce deterioration of the machining tool. [Brief description of the drawings]

[0017] [Figure 1] 1 is an external view of a cutting device according to an embodiment of the present invention; [Diagram 2] 1 is a conceptual diagram of a cutting device according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view of a main portion of a jet unit of the cooling device according to the embodiment of the present invention. [Figure 4] FIG. 2 is a schematic piping diagram of a spray unit of the cooling device according to the embodiment of the present invention. [Diagram 5] 3 is a side cross-sectional view of an injection nozzle of an injection unit of a cooling device according to an embodiment of the present invention. FIG. [Figure 6] FIG. 2 is a front view of a control unit of the cooling device according to the embodiment of the present invention. [Figure 7] FIG. 2 is a diagram showing the appearance of an end mill and a workpiece to be cut used in the examples. [Figure 8] Graphs showing the results of the examples, where (a) is a graph showing the relationship between the cooling method and the processing length, and (b) is a graph showing the relationship between the processing length of the wet cooling method and the processing length of other cooling methods when the processing length of the wet cooling method is set to 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Embodiment) Hereinafter, an embodiment of a cutting device equipped with a cooling device that executes the cooling method according to the present invention will be described with reference to the drawings. The embodiment described below is for illustrative purposes only and does not limit the scope of the present invention. Therefore, a person skilled in the art can adopt an embodiment in which each or all of these elements are replaced with an equivalent, and such an embodiment is also included in the scope of the present invention. In addition, in the present invention, "cutting" refers to cutting the surface of a workpiece by a processing means such as cutting or laser processing, and also includes cutting by cutting.

[0019] (Structure of cutting device) An outline of a cutting machine equipped with a cooling device according to one embodiment of the present invention will be described with reference to Figs. 1 and 2. The cooling device may be built into the cutting machine, or may be attached as a separate unit to the outside of an existing cutting machine. Fig. 1 shows an example in which a cooling device is attached to the outer wall of a cutting machine, and Fig. 2 shows a case in which a cooling device is built into the cutting machine. In the following description of Figs. 1 and 2, the same elements will be denoted by the same reference numerals.

[0020] The cutting device M includes a cutting tool M2 which is a processing tool for cutting a cutting target M1 which is a workpiece, an injection nozzle 15 which injects a cooling medium, a nozzle position control means M4 which controls the nozzle position of the injection nozzle 15, and a stage M5 on which the cutting target M1 is placed. The cutting device M may be a machining center, a milling machine, a lathe, a grinding machine, or other cutting device. In addition, the cutting device M may be applied to a mechanical processing device such as a beam processing device which performs processing by irradiating a workpiece with an energetic beam such as laser light or electrons.

[0021] The cutting tool M2 is a tool that cuts the workpiece M1, and may be a drill, a reamer, a tap, an end mill, a side cutter, a turning tool, a grindstone, etc. In this embodiment, an end mill is attached to a rotating main shaft M2A, and the workpiece M1 is cut while the end mill is rotated.

[0022] The jet nozzle 15 is disposed near the cutting tool M2 and jets a cooling medium containing a mixture of dry ice particles and oil toward the workpiece M1. The jet nozzle 15 may be configured to jet a cooling gas or cutting oil instead of the mixture of dry ice particles and oil. The structure of the jet nozzle 15 will be described later.

[0023] The control panel M3 can at least control the spraying parameters of the dry ice particles (e.g., the size of the dry ice particles) and the supply parameters of the oil (e.g., the amount of oil supplied). As shown in Fig. 2, the control panel M3 is used when the cooling device is built into the cutting device M, and is controlled by the control unit 2 shown in Fig. 1 when the cooling device is retrofitted to the cutting device M. The control panel M3 and the control unit 2 include a processor that executes programs and a RAM (Random Access Memory) that stores programs, etc., and control the cutting device M and the cooling device by executing the programs with the processor.

[0024] The nozzle position control means M4 is configured to be able to move the injection nozzle 15 and the flow pipe 14 connected to the injection nozzle 15, and can control at least one of the injection direction and injection position of the injection nozzle 15 with respect to the workpiece M1 to be cut. The nozzle position control means M4 may be configured to manually change the direction and position of the nozzle using a manual operation. Furthermore, the nozzle position control means M4 may automatically control the nozzle position. For example, the nozzle position control means M4 may be provided with a position adjustment function that receives position information of the processing portion of the workpiece M1 to be cut inputted to the cutting device M, and adjusts the position of the injection nozzle 15 based on the position information, thereby automatically controlling the position of the injection nozzle 15.

[0025] (Cooling device structure) 1, the cooling device 10 includes an injection unit 1 that injects a cooling medium, and a control unit 2 that is connected to the injection unit 1 via a cable 3 and controls the operation of the injection unit 1. The injection unit 1 and the control unit 2 can be arranged separately, and the injection unit 1 is installed in the vicinity of an object M1 to be cut by a cutting device M.

[0026] 3 and 4, the jet unit 1 has a box-shaped casing 1A, and this casing 1A houses a liquefied carbon dioxide gas supply line 11, a jet gas supply line 12, an oil agent supply line 13, and a circulation pipe 14. The jet unit 1 receives a signal from the control unit 2, and generates dry ice particles by adiabatic expansion of liquefied carbon dioxide gas supplied from a liquefied carbon dioxide gas supply source T, and jets a mixed cooling medium of the dry ice particles, the oil agent supplied from the oil agent supply line 13, and the jet gas supplied from the jet gas supply line 12 from the jet nozzle 15 toward the cutting object M1.

[0027] The liquefied carbon dioxide supply line 11 (liquefied carbon dioxide supply section) comprises a liquefied carbon dioxide inlet 111, a gas filter 112 for removing impurities from the liquefied carbon dioxide, an electromagnetic valve 113 which is a valve opening and closing means for circulating the liquefied carbon dioxide, and a needle valve 114 which is a throttling means for the liquefied carbon dioxide, and is arranged in this order from upstream to downstream.

[0028] The liquefied carbon dioxide gas inlet 111 is connected to a liquefied carbon dioxide gas supply source T, such as a high-pressure gas container (gas cylinder) or a low-temperature liquefied gas storage tank, from which pressurized liquefied carbon dioxide gas is supplied to the liquefied carbon dioxide gas inlet 111.

[0029] Needle valve 114 adjusts the flow rate of the liquefied carbon dioxide gas. Generally, to generate dry ice particles from liquefied carbon dioxide gas, a throttle section (orifice) or an expansion space is provided to expand and cool the liquefied carbon dioxide gas to generate dry ice particles. In this embodiment, needle valve 114 may also function as a throttle section that can expand and cool the liquefied carbon dioxide gas. In that case, by adjusting needle valve 114, the degree of adiabatic expansion of the liquefied carbon dioxide gas, i.e., the amount of dry ice particles generated, can be appropriately adjusted.

[0030] The ejection gas supply line 12 (ejection gas supply section) is equipped with an ejection gas inlet 121, an electromagnetic valve 122 which is a valve opening and closing means for circulating the ejection gas, a pressure indicator 123 which displays the ejection pressure of the ejection gas, a spot heater 124 which is a heating means for the ejection gas, a gas filter 125 which removes impurities in the ejection gas, and a relief valve 126 which releases abnormal pressure of the ejection gas, and are arranged in this order from upstream to downstream.

[0031] The jet gas inlet 121 is connected to a jet gas supply source G. Gases used in this jet gas supply source G include nitrogen gas, carbon dioxide gas, argon gas, compressed air, etc. These gases may be filled under pressure in a high-pressure gas container (gas cylinder), and air may be pressurized and supplied by a compressor.

[0032] The spot heater 124 includes a thermometer 124a and a temperature controller 124b, both of which are connected to the control unit 2 via a cable 3. The spot heater 124 is disposed in the path of the ejection gas supply line 12, and heats the ejection gas to 50 to 60°C.

[0033] When the pressure indicator 123 of the injection unit 1 indicates an abnormally high value, the relief valve 126 opens to connect the inside of the injection unit 1 to the outside, thereby allowing the abnormal internal pressure to escape to the outside.

[0034] The oil agent supply line 13 (oil agent supply section) comprises an electromagnetic valve 131 which is an opening and closing means for a valve that circulates the injection gas, a regulator 132 which adjusts the pressure of the injection gas, and a lubricator 133 which injects the oil agent into the oil agent supply line 13, and these are arranged in this order from upstream to downstream. The oil agent supply line 13 may be housed inside the casing 1A of the injection unit 1, or may be later attached to the outside of the casing 1A.

[0035] Any type of cutting oil can be used as long as it is used in cutting processes. Use water-soluble cutting oils that are a mixture of water and oil, such as emulsions, solubles, and solutions, or water-insoluble cutting oils that are used without diluting with water. Using oils reduces cutting resistance and has a lubricating and cooling effect during processing.

[0036] The solenoid valve 131 functions as a switching valve (switching unit) that switches whether or not the jet gas supplied from the jet gas supply source G is supplied to the oil supply line 13. The jet gas supplied from the jet gas supply source G is divided at the branch point 16 into the jet gas supply line 12 and the oil supply line 13 and supplied to each line. The solenoid valve 131 is switched according to the machining process of the cutting device M. When the solenoid valve 131 is open, a cooling medium containing a mixture of dry ice particles and oil is sprayed from the spray nozzle 15, and when the solenoid valve 131 is closed, a cooling medium containing only dry ice particles is sprayed from the spray nozzle 15. The solenoid valve 131 may be automatically switched by the control panel M3 or the control unit 2, or may be manually switched.

[0037] The regulator 132 reduces the pressure of the injection gas supplied via the solenoid valve 131 to provide an appropriate amount of gas.

[0038] The lubricator 133 is disposed downstream of the regulator 132 and supplies a mist of oil to the injection gas supply line 12. The lubricator 133 atomizes the oil using the atomizing principle, and the atomized oil is supplied to the injection gas supply line by the flow of pressurized injection gas. The lubricator 133 may be any of a full-flow lubricator, an automatic variable throttle lubricator, or a selective lubricator.

[0039] 3 and 4, the flow pipe 14 includes a liquefied carbon dioxide gas flow pipe 14a and a jet gas flow pipe 14b. The flow pipe 14 has a double pipe structure in which the liquefied carbon dioxide gas flow pipe 14a is inserted into the jet gas flow pipe 14b through which the jet gas flows. The liquefied carbon dioxide gas supply line 11 is connected to the upstream side of the liquefied carbon dioxide gas flow pipe 14a, and the jet gas supply line 12 is connected to the upstream side of the jet gas flow pipe 14b, and the jet nozzle 15 is connected to the downstream side of both.

[0040] 5, the injection nozzle 15 includes an outer pipe 151, an inner pipe 152, and a mixer 153. An injection port 151a is provided at the downstream end of the outer pipe 151, and a liquefied carbon dioxide gas supply port 152a is provided at the downstream end of the inner pipe 152. The mixer 153 is disposed between the injection port 151a and the liquefied carbon dioxide gas supply port 152a. The injection port 151a is directed toward the cutting portion of the workpiece M1, and injects the cooling medium onto the workpiece M1.

[0041] The mixing section 153 functions as a cooling means for adiabatically expanding the liquefied carbon dioxide gas by forming a space therein. Therefore, the liquefied carbon dioxide gas supplied from the liquefied carbon dioxide gas supply port 152a is expanded, thereby generating dry ice particles. The generated dry ice particles are mixed with the propellant gas and oil agent, and are sprayed from the spray port 151a. Although not shown, a space or a throttle section (orifice) for allowing the liquefied carbon dioxide gas to freely expand may be provided in the spray nozzle 15, the flow pipe 14, or the liquefied carbon dioxide gas supply line 11.

[0042] Figures 3 and 4 show an example in which one each of a liquefied carbon dioxide gas supply line 11, a jet gas supply line 12, an oil agent supply line 13, a circulation pipe 14, and a jet nozzle 15 is provided, but the number of each of these is not limited to one, and multiple may be provided depending on the situation as required.

[0043] The control unit 2 controls the operation of the cutting device M. For example, the control unit 2 controls the movement of the cutting tool M2 according to a designed machining process, the position of the injection nozzle of the cooling device 10, the cooling pattern (described later), and the like. As shown in FIG. 6, the control unit 2 includes a spot heater control unit 21, a buzzer 22, a liquefied carbon dioxide gas switching button 23 for switching the liquefied carbon dioxide gas solenoid valve 113 between on and off, an injection gas switching button 24 for switching the injection gas solenoid valve 122 between on and off, a buzzer stop button 25, a setting reset button 26, a main power supply 28, an emergency stop button 29, and an oil agent switching button 30 for switching the oil agent solenoid valve 131, on the front side of the casing 2A. The control unit 2 is connected to the injection unit 1 via a cable 3, and sends a control signal to the injection unit 1.

[0044] In this embodiment, a jetting unit 1 that generates dry ice particles and a control unit 2 that controls the jetting unit 1 are separately arranged. That is, the jetting unit 1 includes a casing 1A, the control unit 2 includes a casing 2A, each component of the jetting unit 1 is housed in the casing 1A, and each component of the control unit 2 is housed in the casing 2A.

[0045] In this way, the position of the injection unit 1 can be freely determined, so that it can be adapted to and installed on cutting machines M of various specifications.

[0046] (Cooling method) In the cooling method according to the present embodiment, a mixture of dry ice particles and oil, generated in a cooling device 10, is sprayed onto an object M1 to be cut, thereby cooling a processing site and a cutting tool.

[0047] First, the main power supply 28 is turned on to operate the cooling device 10. Similarly, the main power supply (not shown) of the cutting device M is turned on to start the cutting operation.

[0048] Then, liquefied carbon dioxide is supplied from a liquefied carbon dioxide supply source T to a liquefied carbon dioxide inlet 111 of a liquefied carbon dioxide supply line 11. The supplied liquefied carbon dioxide passes through the liquefied carbon dioxide supply path 11, and reaches the injection nozzle 15 via a liquefied carbon dioxide flow pipe 14a of a flow pipe 14, which is a double supply pipe. The liquefied carbon dioxide that has reached the injection nozzle 15 passes through an inner pipe 152 of the injection nozzle 15, and adiabatically expands in a mixing section 143 to generate dry ice particles.

[0049] Meanwhile, the ejection gas is supplied from the ejection gas supply source G to the ejection gas inlet 121 of the ejection gas supply line 12. The supplied ejection gas branches into the ejection gas supply line 12 and the oil supply line 13 at the branch point 16. The ejection gas branched into the ejection gas supply line 12 reaches the flow pipe 14 via the solenoid valve 122, the spot heater 124, and the gas filter 125. The ejection gas that has arrived passes through the ejection gas flow pipe 14b of the flow pipe 14 and the outer pipe 151 of the ejection nozzle 15, is mixed with the dry ice particles generated in the mixer 153, and is ejected from the ejection nozzle 15 (mixture ejection process). The ejection pressure is about 350 Pa.

[0050] In addition, the injection gas branched to the oil agent supply line 13 at the branch point 16 reaches the lubricator 133 via the solenoid valve 131 and the regulator 132. The injection gas that reaches the lubricator 133 atomizes the oil agent in the lubricator 133, and the atomized oil agent is supplied to the injection gas supply line 12. The fine oil agent supplied to the injection gas supply line 12 is mixed with the injection gas, passes through the injection gas circulation pipe 14b of the circulation pipe 14 and the outer pipe 151 of the injection nozzle 15, is mixed with the dry ice particles generated in the mixer 153, and is injected from the injection nozzle 15.

[0051] The cooling medium, which is a mixture of dry ice, jet gas, and oil sprayed from the spray nozzle 15, reaches the processing site of the workpiece M1 where cutting by the cutting device M has started, and cools the processing site and the cutting tool. At that time, the dry ice particles are cooled to -80°C and sprayed, and collide with the workpiece together with the transporting jet gas. The jet gas is heated to 50-60°C by the spot heater 124, so that sudden condensation on the workpiece can be prevented.

[0052] The type of cooling medium can be changed by switching the solenoid valve 131. When the solenoid valve 131 is open, a mixture of dry ice, propellant gas, and oil is sprayed from the spray nozzle 15 as the cooling medium. When the solenoid valve 131 is open, a mixture of dry ice and propellant gas is sprayed from the spray nozzle 15 as the cooling medium. That is, when the solenoid valve 131 is open, the cooling device 10 executes a mixture spraying step of spraying a cooling medium containing a mixture of dry ice particles and oil from the spray nozzle 15, and when the solenoid valve 131 is closed, a dry ice spraying step of spraying a cooling medium containing only dry ice particles from the spray nozzle.

[0053] The cutting object M1 to be cooled includes difficult-to-machine metals such as cemented carbide, heat-resistant alloy, super heat-resistant alloy, stainless steel, aluminum alloy, and carbon steel, non-ferrous metals such as copper and tungsten, and resins such as carbon fiber reinforced plastic and glass fiber reinforced plastic.

[0054] In addition, the cooling method of this embodiment is suitable for use in cutting tools M2 made of materials such as diamond, cemented carbide, ceramic, and garnit e, and can extend the life of these cutting tools M2 and improve the cutting speed.

[0055] In this embodiment, a device that generates dry ice particles by expanding liquefied carbon dioxide gas is shown, but any device that generates dry ice particles that is generally used may be used. For example, a device that breaks dry ice pellets into small pieces and sprays them, or a device that cuts dry ice blocks and sprays them may be used.

[0056] Although the present invention has been described mainly in terms of cutting processing, it is applicable to all machining methods in which heat generated during processing affects the workpiece, including beam processing using laser light, electrons, ions, etc.

[0057] (Machining method using cooling) The machining process can be performed manually by an operator or automatically by a computer installed in the machining device. The machining method using the cooling method of the present embodiment will be described below.

[0058] When performing manual machining, for example, when performing milling using a milling machine, the operator starts machining (machining process), selects what cooling medium to use depending on the object to be machined, and switches the solenoid valve 113 and the solenoid valve 131. That is, by opening and closing the solenoid valve 131, it is possible to switch whether or not to include an oil agent in the cooling medium to be sprayed from the spray nozzle 15. Also, by opening and closing the solenoid valve 113, it is possible to switch whether or not dry ice particles generated from liquefied carbon dioxide are sprayed from the spray nozzle 1. Specifically, when the cooling device 10 is attached to the outside of the cutting device M, the solenoid valve 113 and the solenoid valve 131 are opened and closed by turning on and off the liquefied carbon dioxide gas switching button 23 and the oil agent switching button 30 shown in FIG. 6. When the cooling device 10 is built into the cutting device M, the valve opening and closing operations are performed by operating the corresponding buttons on the control panel M3 shown in FIG. 2. By combining the opening and closing of the solenoid valve 131 and the opening and closing of the solenoid valve 113, it is possible to spray a cooling medium according to the cutting process from the spray nozzle 15 (cooling process).

[0059] When machining is performed automatically, for example, when lathe machining is performed using an NC (Numerical Control) lathe, the NC lathe performs lathe machining according to a pre-installed program (machining process). The solenoid valves 113 and 131 are also switched according to a pre-installed program. A timer may be installed to switch the cooling medium ON / OFF according to time. Then, the desired cooling medium is sprayed from the spray nozzle 15 according to the program (cooling process).

[0060] By switching the type of cooling medium sprayed from the spray nozzle 15 by combining the opening and closing of the solenoid valve 113 and the solenoid valve 131, it is possible to apply this to various machining processes. For example, by opening the solenoid valve 113 and closing the solenoid valve 131, only dry ice is sprayed from the spray nozzle 15. This cooling medium can be applied when the workpiece is made of a material that deteriorates due to the influence of water, such as a titanium alloy, a carbon alloy, or a resin, or when oil cannot be used due to hygienic reasons.

[0061] Also, for example, by opening solenoid valve 113 and solenoid valve 131, dry ice and oil mist are sprayed from spray nozzle 15. This cooling medium contains oil to improve lubricity, so it is used when rough cutting difficult materials and can improve surface roughness.

[0062] (Example) The cutting process in which the cooling device 10 described in this embodiment was used in the machining experiment is a milling process, which is one of the removal machining methods, and is performed using an end mill. It is also used for rough machining in the machining steps of rough machining, semi-finishing machining, and finishing machining.

[0063] In this process, cutting was performed on stainless steel under the cutting conditions shown in Table 1. A comparison was made of the wear state of the cutting tool when using cutting oil used in wet cutting as the cutting coolant (Test 1), when using oil mist (Test 2), and when using oil mist and dry ice powder (Test 3).

[0064] As shown in FIG. 7, this processing example is side machining using an end mill. The end mill 70 has a peripheral blade 72 formed in a spiral shape at the bottom of a cylindrical body 71 and a bottom blade 73 formed at the bottom. The distance that one point on the circumference moves per unit time (1 minute) is called the cutting speed (V), the distance that moves in the advancing direction X per unit time (1 minute) is called the feed speed (F), the amount of cutting in the axial direction is called the axial cutting depth (ap), and the amount of cutting in the lateral direction is called the radial cutting depth (ae). In this processing example, the side machining of the workpiece SUS304 was performed using the end mill 70. In this processing example, machining was performed under the machining conditions shown in Table 1 below, and the results shown in Table 2 were obtained.

[0065] [Table 1]

[0066] [Table 2]

[0067] In the experimental results shown in Table 2, the life of the end mill 70 was determined by the machining distance at which the load on the spindle of the end mill 70 exceeded 40%. Figure 8 is a graph showing the experimental results listed in Table 2. Figure 8(a) shows the actual measured values ​​comparing the machining length at the end of the end mill's life for wet machining, machining with oil mist only, and machining with oil mist and dry ice, and Figure 8(b) shows the ratio of the machining length of the wet machining to the other machining lengths, assuming that the machining length of the wet machining is 1. As shown in Figure 8(b), the life of the end mill when machining with oil mist and dry ice is 1.9 times that of wet machining and 1.4 times that of oil mist machining, confirming that the life is longer.

[0068] As described above, according to this embodiment, by spraying a cooling medium containing a mixture of dry ice particles and oil onto the processing area or cutting tool, it is possible to simultaneously achieve the cooling effect of the dry ice particles and the lubricating effect of the oil.

[0069] According to this embodiment, a cooling medium containing a mixture of dry ice particles and oil can be sprayed using a single spray nozzle 15, which simplifies the device configuration.

[0070] According to this embodiment, by retrofitting the oil supply line 13 to the existing cooling device 10 that only sprays dry ice particles, it is possible to easily spray a cooling medium containing an oil onto the workpiece M1 to be cut.

[0071] According to this embodiment, the oil is supplied to the jet gas supply path (line) 12, so that the oil can be uniformly inserted into the jet gas.

[0072] According to this embodiment, since the oil agent is provided downstream of the spot heater 124, the oil agent is heated by the heat of the spot heater 124 and can be uniformly mixed into the ejected gas.

[0073] According to this embodiment, an electromagnetic valve 131 is provided for switching whether or not the injection gas supplied to the oil supply line 13 is allowed to enter, so that the cooling medium can be switched between dry ice particles only or a mixture of dry ice particles and oil depending on the process of the cutting device M.

[0074] According to this embodiment, the cooling medium injected from the injection nozzle 15 can be changed by selecting between opening and closing the solenoid valve 113 and opening and closing the solenoid valve 131. Therefore, with one cutting device, cooling operations according to various cutting processes can be efficiently performed without separately replacing the cooling device 10.

[0075] According to this embodiment, by using dry ice particles to cool the cutting target M1, it is possible to cool the cutting target without causing condensation on the cutting target M1. When the cooling medium is a gas such as a gas, the surrounding air is inadvertently cooled, causing condensation on the cutting target M1, which causes a problem of poor visibility around the cutting target M1. On the other hand, by using dry ice particles in this embodiment, the air reaches the periphery of the cutting target M1 without inadvertently cooling it, so that it is possible to improve visibility without causing condensation.

[0076] According to this embodiment, by using dry ice particles to cool the cutting target M1, it is possible to create an inert atmosphere around the cutting target M1 without covering the area around the cutting target M1 with a device, etc. That is, after the dry ice particles reach the cooling location, they evaporate, so that only the area around the cutting target M1 can be made into an inert atmosphere.

[0077] According to this embodiment, by using dry ice particles to cool the workpiece M1, it is not necessary to clean the surfaces of the workpiece M1 and the cutting tool M2 after processing. The dry ice particles that reach the cutting processing area vaporize immediately after contributing to cooling, so no impurities are left on the surfaces of the workpiece M1 and the cutting tool M2. In addition, the amount of oil mixed is small, so no oil remains and the lubricating effect is achieved.

[0078] According to this embodiment, the dry ice particles reach the cutting object M1 and cool it, suppressing the processing heat caused by friction between the cutting object M1 and the cutting tool M2. Also, the dry ice powder vaporizes to form an inert atmosphere around the cutting object M1, suppressing the reaction heat caused by the oxidation and combustion reaction of metals (chips, cutting tool M2, workpiece, etc.).

[0079] According to this embodiment, by using a mixture of dry ice particles and oil to cool the workpiece M1, deterioration of the cutting tool M2 can be suppressed. By cooling the periphery of the workpiece M1 under an inert atmosphere, oxidation reaction of the cutting tool M2 can be suppressed, and deterioration of the cutting tool M2 can be suppressed. In addition, since the oil is also contained, friction between the cutting tool M2 and the workpiece M1 can be suppressed, and deterioration of the cutting tool M2 can be suppressed.

[0080] According to this embodiment, by using a mixture of dry ice particles and oil to cool the workpiece M1, deterioration of the cutting tool M2 can be suppressed even when the workpiece is a difficult-to-machine metal material such as cemented carbide or ultra-heat-resistant alloy.

[0081] In this embodiment, the injection nozzle 15 has a double-pipe structure, in which liquefied carbon dioxide gas is passed through the inner pipe 152 and injection gas is passed through the outer pipe 151. The present invention is not limited to the double-pipe structure, and another outer pipe may be provided around the outer pipe 151, and dry air may be passed through to keep the dew point at -40°C or lower. The dry air forms an air shield that surrounds the outer periphery of the double-pipe structure. Condensation can be prevented by the dry air and the injection gas heated to 50 to 60°C.

[0082] In this embodiment, it has been described that the gas filter 125 is attached to the injection gas supply line 12 and the gas filter 112 is attached to the liquefied carbon dioxide gas supply line 11, but these gas filters may not be used depending on the cleanliness of the gas being supplied. [Industrial Applicability]

[0083] The present invention can be utilized in a cooling method, a machining method, a cooling device, and a machining device used in machining. [Explanation of symbols]

[0084] 1 Injection unit 1A Casing 2. Control unit 2A Casing 21 Spot heater control section 22 Buzzer 23 Liquid carbon dioxide gas switch button 24 Gas injection switch button 25 Buzzer stop button 26 Reset Button 28 Main power supply 29 Emergency stop button 30 Oil change button 3 Cable 10 Cooling device 11 Liquefied carbon dioxide gas supply line 111 Liquefied carbon dioxide gas inlet 112 Gas Filter 113 Solenoid valve 114 Needle valve 12 Propellant gas supply line 121 Injection gas inlet 122 Solenoid valve 123 Pressure Indicator 124 Spot heater 124a thermometer 124b Temperature Controller 125 Gas Filter 126 Relief valve 13 Oil supply line 131 Solenoid valve 132 Regulator 133 Lubricator 14 Flow pipe 14a Liquefied carbon dioxide gas distribution pipe 14b Injection gas flow pipe 15 Injection nozzle 151 Outer tube 151a Nozzle 152 Inner tube 152a Liquefied carbon dioxide gas supply port 153 Mixing section 16 Branching Point G. Propellant gas supply source T Liquefied carbon dioxide gas supply source M Cutting device M1 Cutting object M2 cutting tool M3 Control Board M4 Nozzle position control means M5 Stage

Claims

1. 1. A method for cooling a workpiece or a tool to be machined, comprising the steps of: A mixture injection step of injecting a mixture of dry ice particles and oil from a single injection nozzle toward the machining site or the machining tool during machining, Cooling method.

2. The method further includes a dry ice spraying step of spraying dry ice particles from the spray nozzle toward the processing site or the processing tool. The cooling method according to claim 1 .

3. A machining step of machining a workpiece; A cooling step of cooling the processed portion of the workpiece or the processing tool by the cooling method according to claim 1 or 2. Machining method.

4. A cooling device for cooling a processing portion or a processing tool of a workpiece during machining, An injection nozzle that injects a cooling medium onto the processing site or the processing tool; A liquefied carbon dioxide gas supply unit that supplies liquefied carbon dioxide gas to the injection nozzle; An oil supply unit that supplies an oil to the injection nozzle, The injection nozzle generates dry ice particles by adiabatic expansion of the liquefied carbon dioxide gas inside, and injects the cooling medium containing the mixture of the dry ice particles and the oil agent onto the processing site or the processing tool. Cooling device.

5. The dry ice particle ejection nozzle may further include a gas ejection unit that ejects a gas to the ejection nozzle. The oil supplied from the oil supply unit is supplied through a jet gas supply path from the supply source of the jet gas supply unit to the jet nozzle. The cooling device according to claim 4.

6. The oil agent is atomized by a lubricator disposed in the injection gas supply path and supplied to the injection gas supply path. The cooling device according to claim 5.

7. A heater for heating the ejection gas is provided in the ejection gas supply path, The oil agent is supplied downstream of the heater. The cooling device according to claim 5.

8. Further provided is a switching unit that switches whether the oil agent supplied by the oil agent supply unit is supplied to the injection nozzle or not. The cooling device according to claim 4.

9. A processing unit that machines a workpiece; A cooling device according to claim 8; A control unit that controls the switching unit, The control unit controls the switching unit in accordance with a machining process to switch between spraying dry ice particles from the spray nozzle and spraying a mixture of dry ice particles and oil. Machining equipment.

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