JP2018187765A - Dry ice powder jet cooling method and cooling device - Google Patents

Abstract

An object of the present invention is to provide an unprecedented cooling method and cooling device for cooling a processing part when processing a workpiece, and further, friction between the workpiece and a processing tool, and laser light. Simultaneously suppresses processing heat (primary generated heat) due to concentration of energy, etc., and reaction heat (secondary generated heat) due to oxidative combustion reaction of workpieces, processing tools, chips, etc. A cooling method and a cooling device that can perform the above are provided. In cooling a processing part when processing a workpiece, by using dry ice powder, primary generated heat and secondary generated heat can be suppressed at the same time. [Selection] Figure 1

Description

  The present invention relates to a cooling method and a cooling device for a processing part when processing a workpiece.

  In general, a technique for cooling a cutting portion in metal cutting is important from the viewpoint of suppressing deterioration of a cutting tool and improving processing accuracy. Conventionally, the cooling means used in cutting is a wet method (wet cutting) in which cooling is performed by supplying a cutting fluid to the cutting part, and cooling by injecting a low-temperature gas into the cutting part in an air atmosphere. There is a dry method (dry cutting) to perform.

  Since wet cutting uses a cutting fluid to obtain a lubricating effect, a cooling effect, and a cleaning effect, cooling can be performed while suppressing generation of processing heat. However, in addition to the need to remove the cutting fluid adhering to the surface after processing, oxidation of the cutting tool is unavoidable, environmental pollution occurs when processing the cutting fluid, processing costs are high, etc. There's a problem.

  On the other hand, in dry cutting, the above problems do not occur because no cutting fluid is used. However, dry cutting cannot produce a lubrication effect and has low cooling efficiency, and therefore generates very high processing heat compared to wet cutting. Therefore, there is a problem that the economic burden is large because cutting burns and cutting cracks are likely to occur on the processed surface and the cutting tool is rapidly deteriorated.

Therefore, proposals have been made for techniques for improving the cooling method in dry cutting (Patent Documents 1 and 2).
In Patent Document 1, “Cooling air of dry air of −1 ° C. or less is supplied to a processing point, and particulate oil composed of a non-polluting oil such as vegetable oil is directly applied to the processing point or via a processing jig. A technique of “a cold air machining method characterized in that grinding of a grinding wheel or cutting of a cutting tool is performed indirectly while supplying the point” is described. Thus, it is possible to improve a cooling efficiency rather than the conventional dry cutting by injecting particulate oil with a low-temperature dry air to a cutting part.

  Patent Document 2 describes a technique of “a dry grinding method characterized by using an inert gas as a dry grinding atmosphere of a workpiece”. In this way, in dry cutting, it is possible to suppress heat generation due to oxidation combustion reaction of chips by forming the ambient atmosphere of the work material with an inert gas.

JP-A-10-86036 Japanese Patent Laid-Open No. 7-60621

  By the way, in the heat generation process in the processing, the processing heat (primary generated heat) due to friction between the workpiece and the processing tool or the concentration of energy such as laser light, the processing material and processing. There is reaction heat (secondary generated heat) due to oxidation combustion reaction of tools, chips and the like.

  In the cooling method described in Patent Document 1, the primary purpose is to suppress the primary generated heat that is the processing heat, and it does not suppress the secondary generated heat due to oxidation of the workpiece or the like. In addition, since the particulate oil agent is used, it is necessary to remove the oil agent adhering to the surface of the workpiece after processing.

  On the other hand, the cooling method described in Patent Document 2 is mainly intended to suppress the secondary generated heat due to the oxidative combustion reaction of the workpiece or the like, and does not suppress the primary generated heat of the processing heat itself. . Moreover, in order to make the periphery of the processing part an inert atmosphere, it is necessary to form an airtight space by covering the periphery of the processing part with a member.

  In view of such circumstances, the present invention has an object to provide an unprecedented cooling method and cooling device for cooling a processing portion when processing a workpiece, and further, primary generated heat and second It is an object of the present invention to provide a cooling method and a cooling device that can simultaneously suppress the next generated heat.

  In order to solve the above-mentioned problems, a cooling method according to the present invention is a cooling method for a processing part when processing a workpiece, and is characterized by injecting dry ice powder to the processing part.

According to the present invention, the primary generated heat and the secondary generated heat can be suppressed at the same time by spraying the dry ice powder onto the processed portion of the workpiece and cooling it.
Further, since the dry ice powder is vaporized immediately after cooling, it does not adhere to the processed surface and there is no need to clean the processed surface.

In a preferred aspect of the present invention, the processing is cutting processing.
Thus, the lifetime of a cutting tool can be extended by performing a cutting process, cooling a cutting part with dry ice powder.

In a preferred embodiment of the present invention, the material of the cutting tool used for the cutting is ceramic.
Thus, by applying the cooling method according to the present invention to processing with a ceramic cutting tool, cutting can be performed at a higher speed compared to the conventional cutting using the same tool.

In a preferred embodiment of the present invention, the processing is beam processing.
Thus, the cooling method according to the present invention is suitable when the processing means is beam processing.

In a preferred embodiment of the present invention, the workpiece is a metal.
Thus, the cooling method according to the present invention is suitable when the workpiece is a metal.

In a preferred embodiment of the present invention, the metal is selected from cemented carbide, super heat resistant alloy, heat resistant alloy, stainless steel, aluminum alloy, carbon steel, copper, and tungsten.
Thus, the cooling method according to the present invention is suitable when the metal to be processed is a difficult-to-process metal material or a non-ferrous metal material.

In a preferred embodiment of the present invention, the workpiece is a resin.
Thus, the cooling method according to the present invention is suitable when the workpiece is a resin.

In a preferred embodiment of the present invention, the resin is a fiber reinforced plastic selected from carbon fiber reinforced plastic or glass fiber reinforced plastic.
Thus, the cooling method according to the present invention is suitable when the resin to be processed is a difficult-to-process material.

In a preferred embodiment of the present invention, the dry ice has an average particle size of 500 μm or less.
By spraying the dry ice powder having such a particle size, the processed part can be efficiently cooled.

In a preferred embodiment of the present invention, the dry ice powder is produced by adiabatic expansion of liquefied carbon dioxide gas.
Thus, by producing | generating dry ice powder, the dry ice powder whose average particle diameter is 500 micrometers or less can be injected easily.

In a preferred embodiment of the present invention, the mass flow rate of the liquefied carbon dioxide gas is 50 to 250 g / min.
By injecting dry ice powder generated at a mass flow rate of liquefied carbon dioxide in such a range, the processed part can be efficiently cooled.

According to a preferred embodiment of the present invention, there is provided a processing method for processing a workpiece, wherein the processing is performed while spraying dry ice powder onto a processing portion.
As described above, by performing the processing, the primary generated heat and the secondary generated heat generated from the workpiece as described above can be suppressed at the same time, and the generated heat is greatly suppressed to perform the processing. can do.

In a preferred embodiment of the present invention, an apparatus for cooling a processing part when processing a workpiece, the liquefied carbon dioxide cooling means for adiabatic expansion of liquefied carbon dioxide supplied from a liquefied carbon dioxide supply source, An injection nozzle for injecting dry ice powder generated by the liquefied carbon dioxide cooling means and an injection gas supply means for supplying an injection gas for injecting the dry ice powder are provided.
By using such a dry ice jet cooling device, it is possible to obtain a dry ice particle size that is optimal for cooling the workpiece.

In a preferred embodiment of the present invention, the spray nozzle is directed to a processing point for processing the workpiece.
By setting it as such a structure, a workpiece can be cooled efficiently.

In a preferred embodiment of the present invention, an injection unit having the liquefied carbon dioxide cooling means, the injection nozzle, and the injection gas supply means, an injection gas flow rate control means for adjusting a flow rate of the injection gas, and a flow rate of the liquefied carbon dioxide gas And a control unit having a liquefied carbon dioxide flow rate control means for adjusting the flow rate, wherein the injection unit and the control unit can be installed at different locations.
In this way, by allowing the injection unit and the control unit to be arranged separately, it can be easily applied to existing devices.

In a preferred embodiment of the present invention, a plurality of the injection nozzles are provided.
In this way, by providing multiple injection nozzles, when the workpiece has a large diameter, when the workpiece has a wide processing range, when the processing depth is deep, or when the processing pattern is complex Even so, the processed portion can be effectively cooled.

In a preferred embodiment of the present invention, a processing apparatus for processing a workpiece includes a processing tool for processing the workpiece and an injection nozzle for injecting dry ice powder, and the processing tool performs processing. The spray nozzle is directed to the processing portion.
Thus, by applying the cooling means using dry ice powder to the processing apparatus, it is possible to provide a processing apparatus capable of suppressing deterioration of the processing tool.

In a preferred aspect of the present invention, the apparatus further comprises nozzle position control means capable of controlling at least one of an injection direction and an injection position of the injection nozzle with respect to the workpiece.
In this way, by providing nozzle position control means that can control the injection direction and injection position of the injection nozzle, the position control of the injection nozzle can be handled according to the size, shape, material, processing conditions, cooling conditions, etc. of the workpiece. It is possible to achieve highly accurate control.

In a preferred embodiment of the present invention, the nozzle position control means receives position information of the processing portion input to the processing apparatus and injects dry ice powder toward a processing point where the workpiece is processed. It is characterized by having a position adjusting function for adjusting the position.
By adopting such a configuration, it is not necessary to manually adjust the position of the injection nozzle, and the dry ice powder can be injected safely and accurately toward the processing portion.

According to the present invention, it is possible to provide an unprecedented cooling method and cooling device for cooling a processing part when processing a workpiece, and further, it is possible to provide primary generated heat and secondary generated heat. A cooling method and a cooling device that can be simultaneously suppressed can be provided.
By applying this cooling method and cooling device, it is possible to extend the working tool life and prevent contamination of the workpiece.

It is a perspective view of the cutting device which applied the cooling device concerning Embodiment 1 of the present invention. It is a perspective view of the injection unit of the cooling device concerning Embodiment 1 of the present invention. It is a schematic block diagram of the injection unit of the cooling device which concerns on Embodiment 1 of this invention. It is a sectional side view of the injection nozzle of the injection unit of the cooling device concerning Embodiment 1 of the present invention. It is a front view of the control unit of the cooling device concerning Embodiment 1 of the present invention. It is a schematic block diagram of the injection unit of the cooling device which concerns on Embodiment 2 of this invention. It is a front view of the cutting device incorporating the cooling device which concerns on Embodiment 3 of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
First, prior to the cooling method of the present invention, a cooling device suitably used in the present cooling method will be described with reference to FIGS.

  The “cutting” in the present invention refers to cutting the surface of a workpiece by a cutting means such as cutting or laser processing, and includes cutting by cutting.

<Cooling device according to Embodiment 1>
Hereinafter, the cooling apparatus of Embodiment 1 of this invention is demonstrated in detail with reference to FIGS.
The cooling device according to the first embodiment of the present invention includes an injection unit 1 that injects dry ice powder, 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. I have. As shown in FIG. 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 the cutting portion M1 of the cutting apparatus M.

  As shown in FIGS. 2 and 3, the injection unit 1 has a box-shaped casing 1A, and in this casing 1A, a liquefied carbon dioxide supply line 11, an injection gas supply line 12, a flow pipe 13, The injection nozzle 14 is accommodated. This injection unit 1 generates dry ice powder by adiabatic expansion of liquefied carbon dioxide supplied from a liquefied carbon dioxide supply source, receives a signal from the control unit 2, and cuts dry ice powder together with the injection gas. It is comprised so that it can inject toward the part M1.

  The liquefied carbon dioxide supply line 11 includes a liquefied carbon dioxide inlet 111, a gas filter 112 that removes impurities in the liquefied carbon dioxide, an electromagnetic valve 113 that is a valve opening / closing means for circulating the liquefied carbon dioxide, And a needle valve 114 which is a throttle means.

  The liquefied carbon dioxide inlet 111 is connected to a high-pressure gas container (gas cylinder) or a low-temperature liquefied gas storage tank that is a liquefied carbon dioxide supply source T, and pressurized liquefied carbon dioxide is supplied from there.

  The needle valve 114 is provided so that the flow rate of the liquefied carbon dioxide gas can be adjusted. In general, in order to generate dry ice powder from liquefied carbon dioxide gas, a liquefied carbon dioxide gas is expanded and cooled by providing a throttle part (orifice) and an expansion space to generate dry ice powder. Also in this embodiment, the needle valve 114 may function as a throttle portion that can expand and cool the liquefied carbon dioxide gas. In that case, the degree of adiabatic expansion of the liquefied carbon dioxide gas, that is, the amount of dry ice powder produced can be adjusted as appropriate by adjusting the needle valve 114.

  The injection gas supply line 12 includes an injection gas inlet 121, an electromagnetic valve 122 that is a valve opening / closing means for circulating the injection gas, a pressure indicator 123 that displays the injection pressure of the injection gas, and a heating means for the injection gas. A spot heater 124, a gas filter 125 that removes impurities in the injection gas, and a relief valve 126 that releases an abnormal pressure of the injection gas are provided.

  The injection gas inlet 121 is connected to the injection gas supply source G. As the injection gas supply source G, in addition to nitrogen gas, carbon dioxide gas, argon gas, compressed air, or the like may be used. These gases may be used by being pressurized and filled in a high-pressure gas container (gas cylinder), and in the case of air, the gas may be pressurized and supplied by a compressor.

The spot heater 124 includes a thermometer 124 a and a temperature controller 124 b, both of which are connected to the control unit 2 via the cable 3.
When the pressure indicator 123 of the injection unit 1 shows an abnormally high value, the relief valve 126 releases the relief valve 126 so that the inside of the injection unit 1 communicates with the outside, and an abnormal internal pressure is generated. Can escape to the outside.

  The flow pipe 13 includes a liquefied carbon dioxide flow pipe 13a and a jet gas flow pipe 13b. The inside of the flow pipe 13 has a double-pipe structure in which a liquefied carbon dioxide flow pipe 13a is inserted into a jet gas flow pipe 13b through which the jet gas flows. A liquefied carbon dioxide supply line 11 is connected to the upstream side of the liquefied carbon dioxide circulation pipe 13a, and an injection gas supply line 12 is connected to the upstream side of the injection gas circulation pipe 13b. A spray nozzle 14 is connected to the nozzle.

  As shown in FIG. 4, the injection nozzle 14 includes an outer tube 141, an inner tube 142, and a mixing unit 143, an injection port 141 a at the end of the outer tube 141, and an end of the inner tube 142. A liquefied carbon dioxide supply port 142a is provided, and the mixing unit 143 is provided between the injection port 141a and the liquefied carbon dioxide supply port 142a. The injection port 141a is directed to the cutting point of the workpiece, and is configured to be able to inject dry ice powder to the cutting point.

The mixing unit 143 functions as a cooling unit that adiabatically expands the liquefied carbon dioxide gas by forming a space. Therefore, dry ice powder can be produced by expanding the liquefied carbon dioxide gas supplied from the liquefied carbon dioxide gas supply port 142a. The generated dry ice powder is mixed with the injection gas and injected from the injection port 141a.
Although not shown, a space for freely expanding the liquefied carbon dioxide and a throttle (orifice) may be provided in the middle of the injection nozzle 14, the flow pipe 13, and the liquefied carbon dioxide supply line 11.

  2 and 3 show an example in which one liquefied carbon dioxide supply line 11, one injection gas supply line 12, one flow pipe 13, and one injection nozzle 14 are provided. The number is not limited to one, and a plurality may be provided according to a necessary situation.

  As shown in FIG. 5, the control unit 2 includes a spot heater controller 21, a buzzer 22, a control button 23 of the liquefied carbon dioxide electromagnetic valve 113, and an injection gas electromagnetic valve 122 on the front surface of the casing 2 </ b> A. A control button 24, a buzzer stop button 25, a setting reset button 26, a main power supply 28, and an emergency stop button 29 are provided. The control unit 2 is connected to the injection unit 1 via the cable 3 and is configured to send a control signal to the injection unit 1.

According to this embodiment, the injection unit 1 provided with members necessary for generating dry ice powder and the control unit 2 for controlling the injection unit 1 are separately provided.
That is, the injection unit 1 includes a casing 1A, the control unit 2 includes a casing 2A, each component of the injection unit 1 is accommodated in the casing 1A, and each component of the control unit 2 is accommodated in the casing 2A. Yes.
By doing in this way, since the position of the injection unit 1 can be determined freely, it is possible to adapt and equip it with the cutting device M of various specifications. Examples of the cutting device M include a machining center, a milling machine, a lathe, and a grinding machine.
In addition, the present invention may be applied to a beam processing apparatus that performs processing by irradiating a workpiece with a beam having energy such as laser light or electrons.

  Moreover, according to this embodiment, by providing a plurality of the liquefied carbon dioxide supply line 11, the injection gas supply line 12, the flow pipe 13, and the injection nozzle 14, the dry ice powder is injected from multiple directions onto the workpiece. can do. For this reason, even when the workpiece has a large diameter, the processing range is wide, the processing depth is deep, or the processing pattern is complicated, multiple nozzles are arranged at different locations. By spraying the dry ice powder from the direction, the cutting portion can be effectively cooled.

  Note that the lengths of the flow pipe 13, the injection nozzle 14, the cable 3, and the like in the present embodiment can be changed as appropriate in accordance with the size and configuration of the applicable cutting device M.

<Cooling device according to Embodiment 2>
Hereinafter, the cooling device of Embodiment 2 of this invention is demonstrated in detail with reference to FIG. The cooling device according to the second embodiment is characterized in that the spot heater 124 attached to the injection unit 1 of the previous embodiment is eliminated, and the casing 1A is downsized. In the same embodiment, components that are basically the same as those of the previous embodiment are denoted by the same reference numerals, and description thereof is simplified.

  When the injection unit 4 (see FIG. 6) according to the second embodiment is compared with the injection unit 1 (see FIG. 3) of the previous embodiment, the injection unit 4 according to the present embodiment is connected to the injection gas supply line 12. The spot heater 124 that is a heating means for the injection gas is not provided, and the injection gas heating means 5 is provided on the upstream side of the injection gas inlet 121 connected to the injection gas supply source G. Is different.

  The injection gas heating means 5 is provided between the injection gas supply source G and the injection gas inlet 121 and includes a thermometer 5a and a temperature controller 5b so that the control unit 2 can adjust the temperature. . As the spray gas heating means 5, a conventional heating means may be used, and examples thereof include induction heating, dielectric heating, resistance heating and the like. Therefore, a pipe having a heating mechanism is preferably used as a pipe connecting the injection gas supply source G and the injection gas introduction port 121.

  According to this embodiment, by removing the spot heater 124 from the injection unit 1, the casing 4A of the injection unit 4 can be significantly reduced in size. Therefore, the injection unit 4 according to this embodiment can be installed closer to the cutting portion M1 than the injection unit 1 of the previous embodiment, and further, the injection unit 4 is installed inside the cutting apparatus M. It becomes possible. Thus, regardless of the type and size of the cutting device M, the injection unit 4 can be installed in the vicinity of the cutting portion M1, and the length of the flow pipe 13 can be made constant.

  Moreover, according to this embodiment, the injection unit 4 can be installed in the vicinity of the cutting part M1, and the flow pipe 13 can be formed short. Therefore, it is possible to stably supply dry ice powder having a preferable particle diameter by reducing the probability of generation of particles in the flow pipe 13.

  Moreover, according to this embodiment, since the heat source for heating the injection gas is arranged outside the injection unit 4, the inside of the injection unit 4 can be prevented from being inadvertently heated. Therefore, the risk of malfunction and malfunction due to heat can be reduced.

<Cooling device according to Embodiment 3>
Hereinafter, the cooling apparatus of Embodiment 3 of this invention is demonstrated in detail with reference to FIG. The cooling device according to the third embodiment is provided integrally with the cutting device M. In the same embodiment, components that are basically the same as those of the previous embodiment are denoted by the same reference numerals, and description thereof is simplified.

  The cooling device according to the third embodiment is provided inside the cutting device M as a cooling mechanism for cooling the cutting portion M1 of the cutting device M. The cutting device M includes a machining center, a milling machine, a lathe, and a grinding machine. And other cutting devices. FIG. 7 is an example of a cutting device M equipped with the cooling device according to the present embodiment. The cutting device M includes an injection nozzle 14 that injects dry ice powder according to the present invention in addition to the cutting tool M2, and A control panel M3 for controlling the spray parameters of the dry ice powder and nozzle position control means M4 are further provided.

  The injection nozzle 14 is provided around the cutting tool M2, and is configured to be able to inject dry ice powder toward the cutting portion M1 that cuts the workpiece. Moreover, you may comprise from this injection nozzle 14 so that not only dry ice powder but the gas for cooling and cutting fluid can be injected.

  The control panel M3 is configured to control at least cutting parameters and dry ice powder injection parameters. That is, the control panel M3 has the function of the control unit 2 according to the previous embodiment.

The nozzle position control means M4 is configured to be able to position the injection nozzle 14 and the flow pipe 13, and can control at least one of the injection direction and the injection position of the injection nozzle 14 with respect to the workpiece. The nozzle position control means M4 may be configured to control the direction and position of the nozzles manually.
Further, the nozzle position control means M4 is provided with a position adjusting function for receiving the position information of the cutting portion input to the cutting device and adjusting the sprayed dry ice powder toward the cutting point. Alternatively, the nozzle position may be automatically controlled.

According to this embodiment, the cutting device M which can suppress deterioration of the cutting tool M2 can be provided by providing the cooling device which concerns on this invention in the cutting device M integrally.
Moreover, the control system of the cutting device M and the cooling device can be arranged at the same position, and the operability of the device can be improved.

  According to this embodiment, by providing the nozzle position control means M4 that can control the injection direction and the injection position of the injection nozzle 14, the control of the injection nozzle 14 is controlled by the size, shape, material, and cutting conditions of the workpiece. In addition, high-precision control corresponding to the cooling conditions and the like can be achieved.

  According to the present embodiment, since the nozzle position control means M4 has a configuration that can automatically control the nozzle position, it is not necessary to manually adjust the position of the injection nozzle. It is not necessary to adjust the position, and the dry ice powder can be sprayed toward the cutting point safely and accurately.

<Cooling method according to the present invention>
The cooling method which concerns on this invention cools a process part by injecting the dry ice powder produced | generated with the above cooling devices to the cutting process part M1.

The dry ice powder of the cooling method according to the present invention is desirably sprayed locally toward the cutting point, and a preferable range of the spray width indicating the irradiation width of the dry ice powder is 20 mm or less, and a more preferable range Is 12 mm or less.
The preferable range of the spray distance indicating the distance between the spray nozzle 14 and the workpiece to achieve the above-described spray width is 50 to 100 mm, and the spray angle indicating the spread angle of the dry ice powder sprayed from the spray nozzle 14 is preferable. The range is 5 degrees or less. Moreover, although it is desirable that the range of the incident angle of the dry ice powder to the workpiece is 30 to 60 degrees, it can be set according to the shape of the workpiece, and is selected in the range of 10 to 170 degrees. be able to.

The preferable range of the average particle diameter of the sprayed dry ice powder is 500 μm or less, the more preferable range is 100 μm or less, and the more preferable range is 5 to 30 μm. By cooling with dry ice powder having an average particle diameter in such a range, dry ice can be effectively vaporized in the vicinity of the cut portion M1.
The average particle diameter here means a particle diameter at an integrated value of 50% in a particle size distribution obtained by a laser interference imaging method or an image imaging method. This laser interference imaging method is a method of obtaining an interference fringe image by irradiating a particle with laser light and observing scattered light from the particle other than the focal position, and obtaining a particle size from the number of interference fringes.

A preferred range for the mass flow rate of the liquefied carbon dioxide gas that produces dry ice powder is 50 to 250 g / min, and a more preferred range is 50 to 180 g / min.
In addition, the value of the mass flow rate here is a mass flow meter (metal tube type area flow meter) generally used when measuring a mass flow rate when using a siphon tube type liquefied carbon dioxide storage container (pressure about 6 MPa). Or a Coriolis type mass flow meter).

The cooling method of the present invention includes hard-working 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, carbon fiber reinforced plastic and glass. It is suitable when cutting resin such as fiber reinforced plastic.
Further, as the cutting tool M2 used in the cooling method of the present invention, it is suitable when diamond, cemented carbide, ceramic, sarnite or the like is used, which can contribute to extending the life of these, and further, cutting. Speed can be improved.

  According to the present invention, by using dry ice powder for cooling the cutting part M1, the cooling medium can efficiently reach the periphery of the cutting part M1. There are a lot of air convection generated by driving the cutting tool M2, chips of the workpiece, and the like around the cutting portion M1 that needs to be cooled. At this time, if the cooling medium is a gas, it is hindered by air convection, chips, etc., and a large amount of the cooling medium cannot reach the cooling location, resulting in poor efficiency. However, since dry ice powder is solid and has a larger specific gravity than gas, it is less affected by air convection, chips, etc., and can easily reach the cooling location.

  Moreover, according to this invention, it is possible to cool, without condensing the cutting part M1 by using dry ice powder for cooling of the cutting part M1. When the cooling medium is a gas such as a gas, there is a problem in that the surrounding air is carelessly cooled to condense the processing portion periphery M1 and the visibility of the processing portion periphery M1 is deteriorated. On the other hand, since the present invention uses dry ice powder to reach the processed part periphery M1 without inadvertently cooling the air, it is possible to improve visibility without causing condensation. .

  Moreover, according to this invention, by using dry ice powder for cooling of the cutting part M1, it can be set as inert atmosphere, without covering the cutting part M1 periphery with an apparatus etc. By vaporizing after the dry ice powder reaches the cooling location, only the periphery of the cut portion M1 can be made an inert atmosphere. Therefore, it is not necessary to surround the periphery of the cutting part M1 with a member.

  Moreover, according to this invention, it is not necessary to wash | clean the workpiece surface after a process by using dry ice powder for cooling of the cutting part M1. Since the dry ice powder that has reached the cutting portion M1 is vaporized immediately after contributing to cooling, no impurities remain on the surface of the workpiece. Therefore, there is no need for a step of removing the cutting fluid as with the surface of the workpiece after wet cutting. Moreover, it is not necessary to use a cutting oil material and is environmentally friendly.

  Further, according to the present invention, by using the dry ice powder for cooling the cutting part M1, the surface of the workpiece can be cleaned and cooled at the same time. For example, even if there are deposits on the surface of the workpiece, the deposits can be cooled rapidly by being sprayed with dry ice powder and peeled off slightly due to the effect of heat shrinkage. Then, the dry ice powder enters between the slightly separated deposit and the workpiece, and is rapidly vaporized to change the expansion of the volume, whereby the deposit can be completely peeled off and removed. Thus, since the deposit | attachment on the surface of a workpiece can be removed, it is not necessary to wash | clean the surface after cutting.

  Moreover, according to this invention, a primary generated heat and a secondary generated heat can be suppressed simultaneously by using dry ice powder for cooling of the cutting part M1. The dry ice powder, which is a cooling medium, reaches the cutting portion M1 and cools, thereby suppressing processing heat (primary generated heat) due to friction between the workpiece and the cutting tool M2. In addition, the dry ice powder is vaporized to form an inert atmosphere around the cutting portion M1, so that the reaction heat (secondary) due to the oxidative combustion reaction of the metal (chip, cutting tool M2, workpiece, etc.) (Heat generated) is suppressed. Thus, by applying dry ice powder as a cooling medium, primary generated heat and secondary generated heat can be simultaneously suppressed.

  Moreover, according to this invention, deterioration of the cutting tool M2 can be suppressed by using dry ice powder for cooling of the cutting part M1. A problem in the deterioration of the cutting tool M2 is the oxidation reaction of the metal, but the present invention suppresses the oxidation reaction of the cutting tool M2 by setting the periphery of the cutting portion to an inert atmosphere. In general, the higher the temperature, the faster the metal oxidation reaction proceeds. However, in the present invention, heat generation can be suppressed as described above. Therefore, it is possible to suppress the deterioration of the cutting tool M2.

  Moreover, according to this invention, a peripheral speed can be improved by using dry ice powder for cooling of the process part M1. In general, when the peripheral speed is increased, the temperature of the cutting portion increases, and the life of the cutting tool M2 is extremely shortened. However, by applying the cooling method of the present invention, the temperature rise at the cutting point can be suppressed, the peripheral speed can be improved, and the processing time can be greatly shortened.

  Further, according to the present invention, by using dry ice powder for cooling the cutting portion M1, the cutting tool M2 is deteriorated even when the workpiece is a difficult-to-work metal material such as a hard metal or a super heat-resistant alloy. Can be suppressed.

In the present invention, an apparatus for generating dry ice powder by expanding liquefied carbon dioxide gas is shown. However, any apparatus that generates dry ice powder that is generally used may be used. For example, a device that finely pulverizes and injects dry ice pellets or a device that scrapes and injects block dry ice may be employed.
In addition, it has mainly shown cutting, but it can be applied to all processing methods in which heat during processing affects the workpiece. For example, in beam processing using laser light, electrons, ions, etc. Can adapt.

<Processing example 1>
Processing experiments were performed using the above-described <cooling device according to Embodiment 1>. The apparatus can eject dry ice powder having an average particle diameter of 5 to 20 μm by controlling the flow rate of the liquefied carbon dioxide gas. In this working example, the cemented carbide was cut under the cutting conditions shown in Table 1 and cooled by air blow (test 1), and when cooled by dry ice powder and jet gas ( In the test 2), the wear state of the cutting tool was compared. The results are shown in Table 2.
In addition, the average particle diameter of the dry ice powder used at this time was 5 to 30 μm, and the spray width of the dry ice powder on the workpiece was about 10 mm. At this time, the spray distance of the spray nozzle was 50 mm, the spray angle was 5 degrees or less, and the incident angle of the dry ice powder to the workpiece was about 45 degrees.

From the results in Table 2, the cutting tool was damaged when the processing distance reached 37.5 m in Test 1, whereas in Test 2, the cutting tool was reached even when the processing distance reached 37.5 m. It turns out that there was no damage. Furthermore, the wear state of the cutting tool at the processing distance of 37.5 m in Test 2 was almost the same as the wear state of the cutting tool at the processing distance of 25.0 m in Test 1. Therefore, under the conditions shown in Table 1, the tool with about 1.5 times the case of cooling using dry ice powder and injection gas (test 2) is compared with the case of cooling with air blow only (test 1). It is thought that it was a lifetime.
Moreover, in the test using dry ice powder and propellant gas, almost no condensation was observed around the processed part.

<Processing example 2>
Processing experiments were performed using the same apparatus as in Processing Example 1. In said processing example 1, the result that a tool life extends | stretches by cooling with dry ice powder and injection gas was shown. In this machining example, the cemented carbide was further cut under the cutting conditions shown in Table 3 and cooled by air blow (Test 3), and when cooled by dry ice powder and jet gas ( In tests 4 and 5), the cutting length until the cutting tool was damaged was measured and compared. The results are shown in Table 4.
In addition, the average particle diameter of the dry ice powder used at this time was 5 to 30 μm, and the spray width of the dry ice powder on the workpiece was about 10 mm. At this time, the spray distance of the spray nozzle was 50 mm, the spray angle was 5 degrees or less, and the incident angle of the dry ice powder to the workpiece was about 45 degrees.

From the results in Table 4, the cutting tool was damaged when the processing distance reached 11.75 m in Test 3, whereas in Test 4 and Test 5, the processing distances were 21.15 m and 28, respectively. It can be seen that the cutting tool was damaged when it reached 2 m. From this, the cutting length of the cutting process when cooling with dry ice powder and jet gas has a cutting length of more than twice that when cooling with air blow. all right. That is, it was confirmed that the life of the cutting tool was extended by cooling with dry ice powder and spray gas.
Further, in the test using the dry ice powder and the jet gas in this processing example, almost no condensation was observed around the processed portion.

<Processing example 3>
Using the same apparatus as in Processing Example 1, a processing experiment was performed in which the feed rate was greatly improved. In this machining example, the super heat-resistant alloy is cut by a ceramic end mill under the cutting conditions shown in Table 5, and the workpiece is cooled by dry ice powder and jet gas under the cooling conditions shown in Table 6. (Test 6).
In addition, the average particle diameter of the dry ice powder used at this time was 5 to 30 μm, and the spray width of the dry ice powder on the workpiece was about 10 mm. At this time, the spray distance of the spray nozzle was 50 mm, the spray angle was 5 degrees or less, and the incident angle of the dry ice powder to the workpiece was about 45 degrees.

  According to this test 6, as shown in Table 5, it has been found that cutting can be performed at a peripheral speed of 600 m / min, and further improved to about 800 m / min. Generally, when machining a difficult-to-process material such as a super heat-resistant alloy using a carbide end mill, unless the peripheral speed is about 30 m / min, the durability and accuracy of the cutting tool are required. Could not keep up. However, by applying the cooling method of the present invention, it is possible to dramatically improve the peripheral speed while maintaining the processing accuracy of the same level or more as before. From the above, it was found that by applying the cooling method of the present invention, the peripheral speed can be improved, and the cutting time can be significantly shortened.

Further, in this test 6, a ceramic end mill is used as a cutting tool. Conventionally, ceramic end mills have been rarely used because they are more brittle than carbide end mills and do not exhibit processing performance. However, by applying the cooling method of the present invention, the durability of the tool can be improved, and further, the feed rate can be made faster than the carbide end mill, and the cutting time can be greatly shortened.
Further, in the test using the dry ice powder and the jet gas in this processing example, almost no condensation was observed around the processed portion.

According to the present invention, dry ice powder is used as a cooling medium when cutting metal. As a result, an inert atmosphere is formed in the periphery of the cutting portion, and by suppressing the generation of heat and the oxidation of the cutting tool, the life of the cutting tool can be dramatically extended.
In particular, the tool life is more significantly extended when the mass flow rate is in the range of 50 to 180 g / min.
Furthermore, according to the present invention, no condensation occurs in the cut portion.

  In addition, according to the present invention, the peripheral speed at the time of cutting can be improved, and the cutting time can be greatly shortened. In particular, when the cooling method according to the present invention is applied to an end mill made of a ceramic material, the peripheral speed can be increased more remarkably.

  In addition, although this processing example showed the experimental result that the workpiece is a cemented carbide, it is difficult to process metal materials such as super heat resistant alloy, heat resistant alloy, stainless steel, aluminum alloy, and carbon steel, Naturally, it is possible to dramatically extend the life of cutting tools even with non-ferrous metals such as tungsten, and resins such as carbon fiber reinforced plastic and glass fiber reinforced plastic.

DESCRIPTION OF SYMBOLS 1 Injection unit 1A Casing 11 Liquefied carbon dioxide supply line 111 Liquefied carbon dioxide introduction port 112 Gas filter 113 Solenoid valve 114 Needle valve 12 Injection gas supply line 121 Injection gas introduction port 122 Solenoid valve 123 Pressure indicator 124 Spot heater 125 Gas filter 126 Relief valve 13 Distribution pipe 13a Liquefied carbon dioxide distribution pipe 13b Injection gas distribution pipe 14 Injection nozzle 141 Outer pipe 141a Injection port 142 Inner pipe 142a Liquefied carbon dioxide supply port 143 Mixing unit 2 Control unit 2A Casing 3 Cable 4 Injection unit 5 Injection gas Heating means G Injection gas supply source T Liquefied carbon dioxide supply source M Cutting device M1 Cutting part M2 Cutting tool M3 Control panel M4 Nozzle position control means M5 Stage

Claims (10)

A cooling device for cooling a processing part when processing a workpiece,
Liquefied carbon dioxide cooling means for adiabatically expanding the liquefied carbon dioxide gas supplied from the liquefied carbon dioxide gas supply means;
An injection nozzle for injecting dry ice powder generated by the liquefied carbon dioxide cooling means;
An injection gas supply means for supplying an injection gas for injecting the dry ice powder;
A dry ice powder injection type cooling apparatus, comprising: a heating means for heating the injection gas. An injection unit having the liquefied carbon dioxide cooling means and the injection nozzle;
2. The control unit according to claim 1, further comprising: a control unit including an injection gas flow rate control unit that adjusts a flow rate of the injection gas and a liquefied carbon dioxide flow rate control unit that adjusts the flow rate of the liquefied carbon dioxide gas. Dry ice powder injection type cooling device.   The dry ice powder injection cooling device according to claim 1 or 2, wherein the heating means is disposed between the injection unit and the liquefied carbon dioxide supply means.   The dry ice according to any one of claims 1 to 3, wherein the spray nozzle has a mixing unit that mixes the dry ice powder and the spray gas heated by the heating means. Powder injection type cooling device.   The dry ice powder jet cooling device according to any one of claims 1 to 4, wherein the dry ice powder has an average particle diameter of 5 to 30 µm. A processing device having a processing part for processing a workpiece,
Liquefied carbon dioxide cooling means for adiabatically expanding the liquefied carbon dioxide gas supplied from the liquefied carbon dioxide gas supply means;
An injection nozzle for injecting dry ice powder generated by the liquefied carbon dioxide cooling means;
An injection gas supply means for supplying an injection gas for injecting the dry ice powder;
And a heating device for heating the spray gas.   The processing apparatus according to claim 6, wherein the spray nozzle includes a mixing unit that mixes the dry ice powder and the spray gas heated by the heating unit.   The processing apparatus according to claim 6 or 7, further comprising nozzle position control means capable of controlling at least one of an injection direction and an injection position of the injection nozzle with respect to a workpiece.   The nozzle position control means receives a position information of the processing portion input to the processing apparatus, and has a position adjustment function for adjusting so as to inject dry ice powder toward a processing point for processing the workpiece. It has, The processing apparatus in any one of Claims 6-8 characterized by the above-mentioned. The processing apparatus according to claim 6, wherein an average particle size of the dry ice powder is 5 to 30 μm.