Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/64—Burning or sintering processes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B17/00—Furnaces of a kind not covered by any of groups F27B1/00 - F27B15/00
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/80—Apparatus for specific applications

Definitions

• Some aspects of the present invention relate to a manufacturing apparatus for producing solids such as metals and ceramics from a precursor such as a workpiece, and a method for producing solids such as metals and ceramics.
• Metal parts used in daily necessities, home appliances, machine tools, etc. are manufactured by further processing ingots and metal steel billets obtained by smelting ores, smelting intermediates, industrial waste containing metals, scrap, and incineration ash from urban waste.
• ceramic parts used in daily necessities, home appliances, machine tools, etc. are manufactured through a process in which crushed raw materials are shaped and fired, followed by processing. Both the manufacturing process for metal parts and the manufacturing process for ceramic parts include at least some steps that require high temperatures, and since it can take a lot of energy or time to reach a high temperature, there is a demand for improving the efficiency of the manufacturing process.
• One of the objectives of some aspects of the present invention is to provide a manufacturing apparatus and a manufacturing method capable of efficiently producing solids, particularly solids of inorganic substances such as metals and ceramics.
• the solid manufacturing apparatus is a solid manufacturing apparatus for manufacturing a solid from a workpiece, and includes a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a first base disposed inside the housing and capable of contacting at least a portion of the workpiece while protruding at least into the housing.
• the solid manufacturing apparatus may include a cooling unit for cooling at least one of the housing and the first base.
• the first substrate in the above-mentioned solid manufacturing apparatus can typically be, for example, at least one of the pressurizing unit 20 and the heat insulating member 80 and microwave absorbing member 90 attached to the pressurizing unit 20 in the solid manufacturing apparatus shown in FIG. 1 according to some embodiments of the present invention described below, or the stage 50 and pedestal 135 in the solid manufacturing apparatus also shown in FIG. 1, but is not limited to these.
• the workpiece in the above-mentioned solid manufacturing apparatus may typically be, for example, the workpiece 130 in the solid manufacturing apparatus shown in FIG. 1 according to some embodiments of the present invention described below, but is not limited thereto.
• the cooling section in the above solid manufacturing apparatus can typically be, for example, cooling section 1 in the solid manufacturing apparatus shown in FIG. 1 according to some embodiments of the present invention described below, but is not limited thereto.
• the cooling unit include a cooling device equipped with an air jet that sends air or cooled air to at least one of the housing and the first base, a liquid-cooling type cooling device that has a cooling tube that contacts the housing or the first base or is provided inside the housing or the first base and passes a cooling liquid such as water or alcohol through the cooling tube, and passes the cooled liquid through the cooling tube, and an electronic cooling mechanism that contacts the outside of the housing or the first base or has a Peltier cooling element or the like that is provided inside the housing or the first base.
• a cooling device equipped with an air jet that sends air or cooled air to at least one of the housing and the first base
• a liquid-cooling type cooling device that has a cooling tube that contacts the housing or the first base or is provided inside the housing or the first base and passes a cooling liquid such as water or alcohol through the cooling tube, and passes the cooled liquid through the cooling tube
• an electronic cooling mechanism that contacts the outside of the housing or the first base or has a Peltier cooling element or the like that is provided inside
• At least one of the housing and the first substrate has a cooling section, and therefore, for example, when microwaves or millimeter waves are emitted into the housing or the workpiece becomes hot, the following effects are achieved. (1) It is possible to suppress leakage of microwaves or millimeter waves emitted into the housing due to changes in dimensions of the housing and the first base caused by thermal deformation or expansion due to high temperatures.
• the first base When emitting microwaves or millimeter waves into a housing, in a case where the first base is moved from a predetermined position to come into contact with at least a part or all of the workpiece to apply pressure, etc., the first base is prevented from coming into contact with other members or components due to thermal expansion, etc., when being moved, thereby reducing the risk of malfunction. (3) Even if the workpiece requires a high process temperature, a temperature equal to or higher than the heat-resistant temperature of the housing or the first base can be applied to the workpiece.
• the solid manufacturing apparatus may further include a second substrate. It is preferable that the first substrate and the second substrate are configured so that the distance between the first substrate and the second substrate can be changed.
• the cooling section is configured to cool the first substrate, and that the first substrate is configured to apply pressure to the workpiece.
• any of the above solid manufacturing apparatuses may further include a third substrate.
• the third substrate is preferably configured to be disposed between at least one of the workpiece and the first substrate and an emission port for emitting microwaves or millimeter waves from the electromagnetic wave emission device into the housing during at least a portion of the period during which the electromagnetic wave emission device emits microwaves or millimeter waves into the housing.
• the third substrate may typically be, for example, the enclosure 40 in the solid manufacturing apparatus shown in FIG. 1 according to some embodiments of the present invention described below, but is not limited to this.
• the third substrate with an appropriate microwave or millimeter wave shielding function, it is possible to control the temperature of the workpiece or the first substrate so that it does not exceed a desired temperature.
• the third substrate with an appropriate microwave or millimeter wave shielding function, it is possible to appropriately adjust the balance between the heat conduction from other members to the workpiece and the direct heating of the workpiece.
• the temperature of the workpiece can be increased to a temperature required for processing the workpiece.
• processing auxiliary material another material (hereinafter “processing auxiliary material”) can be placed in the gap or space.
• the processing auxiliary material is preferably arranged so as to cover at least a portion of the workpiece.
• the processing auxiliary material is, for example, a molded object having a plate shape, a concave shape, a convex shape, or the like, and the shape of the molded object may be matched to the space or gap formed between the third substrate and the first substrate or workpiece.
• the shape of the workpiece, third substrate, or first substrate may be matched to the shape of the molded object.
• Processing aids other than molded products can be, for example, granular, powdery or liquid processing aids.
• the processing auxiliary material is preferably a material that increases in temperature by absorbing microwaves or millimeter waves and transmits the increased temperature to the workpiece.
• microwaves or millimeter waves are emitted into the housing, and in the process of processing the workpiece until the workpiece is sintered or melted, the temperatures of the processing auxiliary material and the workpiece are reversed at a boundary temperature, and the temperature of the workpiece becomes higher than the temperature of the processing auxiliary material after the boundary temperature.
• the microwaves or millimeter waves may be adjusted so that the temperature of the processing aid material and the temperature of the workpiece are reversed at the boundary temperature during the process of processing the workpiece until the workpiece is sintered or melted.
• the processing aid material can be heated using the electric field component of the microwaves at the start of processing the workpiece, and then heating can be switched to using the magnetic field component of the microwaves, so that the temperature of the processing aid material and the workpiece are reversed during the temperature change until the workpiece is sintered or melted.
• the magnetic field component of the microwave is used when processing of the workpiece begins, and the electric field component of the microwave is used midway through, so that the temperature of the processing aid can be raised from a state in which the temperature of the processing aid is initially higher than that of the workpiece to a state in which the temperature of the workpiece is higher than that of the processing aid, during the time it takes for the workpiece to reach the processing temperature after processing begins.
• the processing aid can be, for example, promoter 400, which will be described later, but is not limited to this.
• the processing aid can be, for example, a material similar to promoter 400, which will be described later, but is not limited to this.
• At least one of the housing, the first base, and the second base is equipped with a cooling unit.
• a third substrate which is a member or a plurality of powders or a plurality of particles, is disposed surrounding at least a portion of the workpiece during at least a portion of the period during which microwaves or millimeter waves are emitted into the housing.
• the component, the plurality of powders, or the plurality of particles is preferably, for example, the processing aid described above.
• the first substrate is preferably configured to apply pressure to the workpiece.
• pressure may be applied to the workpiece using the first base during at least a portion of the period during which microwaves or millimeter waves are emitted inside the housing. This allows pressure to be applied, for example, when the workpiece is sintered or melted, making it possible to manufacture a solid having a denser structure from the workpiece.
• the workpiece is an aggregate of powder or particulate matter
• applying pressure to the aggregate using the first base reduces the tendency of the aggregate to crumble or keeps the shape nearly constant. This improves the reproducibility of the positional relationship between the workpiece and the processing aid and the degree of contact when the processing aid is placed in contact with at least a portion of the workpiece or when the processing aid is placed so as to cover at least a portion of the workpiece, etc., making it easier to ensure the reproducibility of the properties, shape, or performance of the solid obtained from the workpiece.
• the third substrate includes a first portion having a first transmittance for microwaves or millimeter waves, and a second portion having a second transmittance for microwaves or millimeter waves, and it is preferable that the first transmittance and the second transmittance are different.
• the first transmittance is higher than the second transmittance, and that the distance between the first portion and the workpiece is smaller than the distance between the second portion and the workpiece during at least a portion of the period during which microwaves or millimeter waves are emitted into the housing.
• microwaves or millimeter waves can be concentrated on the workpiece to be processed when heating the workpiece. Also, for example, during at least a portion of the period during which microwaves or millimeter waves are emitted into the housing, it is possible to prevent the second substrate or the first substrate from becoming excessively hot. This makes it possible to prevent malfunction of the mechanical mechanism due to thermal deformation or thermal expansion of the second substrate or the first substrate when, for example, the second substrate or the first substrate is moved within the housing using a mechanical mechanism.
• the first substrate has a first portion and a second portion, and it is preferable that the first portion absorbs microwaves or millimeter waves more than the second portion.
• the first substrate is heated, and the workpiece is also heated by the heat.
• a third portion is provided between the first portion and the second portion, and the thermal conductivity of the third portion is lower than the thermal conductivity of at least one of the first portion and the second portion.
• the third portion is provided between the first portion and the second portion, and has a thermal conductivity lower than that of the second portion, thereby suppressing heat conduction from the first portion to the second portion.
• the third portion suppresses the conduction of heat from the first portion to the second portion, thereby suppressing thermal deformation and thermal expansion of the second portion and reducing the risk of obstruction to the movement of the second portion.
• the first portion of the first substrate is configured to be in contact with at least a portion of the workpiece during at least a portion of the period during which the electromagnetic wave emitting device emits microwaves or millimeter waves into the housing.
• the first portion of the first base absorbs microwaves or millimeter waves, and the heat generated can be transferred to the workpiece, improving the efficiency of processing the workpiece.
• Some aspects of the solid manufacturing apparatus of the present invention are solid manufacturing apparatus that manufacture a solid from a workpiece, and are equipped with a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, a stage arranged within the housing on which the workpiece that is the raw material for the solid is placed, and a solid receiving section that receives the solid when it is transferred from inside the housing to outside the housing, and are configured so that the solid is formed on the stage.
• the solids become hot after they are manufactured, but the hot solids can be safely removed from the housing.
• the solids transferred to the solid receiving section are cooled there, allowing for safe operation of the device.
• the stage is configured to move so that the solid can be delivered to the solid receiving section.
• the stage is configured to move in a direction in which the solid approaches the solid receiving section from inside the housing so that the solid can be delivered to the solid receiving section.
• This configuration makes it easy to remove the solids produced by the solid manufacturing device from the housing.
• the solid receiving section has a first space inside and is configured with a frame member surrounding the first space, and the stage is configured to be movable inside the frame member.
• the frame member is attached below the housing.
• the housing has a protrusion protruding from a first surface inside the housing toward the first surface and a second surface opposite the first surface, and has a second space inside the protrusion, and is configured so that the stage is movable in the second space.
• the protrusion can be, for example, an enclosure 40 of the solid manufacturing apparatus according to some embodiments of the present invention, which will be described later, but is not limited to this.
• the solid receiving section is connected to the housing directly or via another member, and is configured to be able to receive the solid by moving the stage through the first space.
• the solid receiving portion and the protruding portion are configured so that the first space and the second space can be connected directly or via at least one member having a space therein.
• the first space and the second space are configured to be connected directly or via at least one member having a space therein.
• the solid receiving portion is configured to be movable in a direction along the first surface or in a direction intersecting the first surface.
• Some aspects of the present invention relate to a method for producing a solid from a workpiece, the method comprising a first step and a second step, in which the workpiece and a first member are placed inside a housing during at least a part of the first step, the workpiece is sintered or melted during at least a part of the second step, the period during which the second step is carried out includes at least a first period and a second period, microwaves or millimeter waves are emitted inside the housing during both the first period and the second period, at least a part of the workpiece is in contact with the first member during the first period, and the temperature of the first member is higher than the temperature of the workpiece, and in the second period, the temperature of the first member is lower than the temperature of the workpiece.
• the heat conduction from the first member to the workpiece is relatively reduced in the second period compared to the first period, the workpiece absorbs microwaves or millimeter waves in a self-propelled manner, and the workpiece quickly reaches a temperature at which it absorbs microwaves or millimeter waves, making it possible to sinter or melt the workpiece efficiently overall.
• the workpiece reaches a temperature at which the workpiece sinters or melts during at least a portion of the second period.
• the workpiece is in contact with the second member during at least a portion of the first period.
• examples of the manner in which microwaves or millimeter waves are emitted inside the housing when the first member is in contact with at least a portion of the workpiece and the second member is in contact with at least a portion of the workpiece include, but are not limited to, the case in which microwaves or millimeter waves are emitted when the microwave absorbing member 90 and the promoter 400 are in contact with the workpiece 130 as shown in FIG. 11 described later.
• the first member is preferably a molded product, a particle aggregate, or a powder aggregate.
• molded products include a plate, dish, or doughnut shape, and can be appropriately selected according to the shape of the workpiece. If the particle aggregate or powder aggregate does not have a stable shape as an aggregate, it can assume a shape according to the shape of the workpiece. For example, if the first member is given a thermal conductivity function to the workpiece, it can efficiently transfer heat to the workpiece.
• the first member includes a first material and a second material, and that the microwave absorption efficiency of the first material is greater than the microwave absorption efficiency of the second material.
• the microwave absorption of the first member may become large, making it difficult for the workpiece to absorb microwaves in a self-propelled manner.
• the melting point of the second material is higher than the melting point of the first material. This makes it possible to impart heat resistance to the first member, for example.
• the insulating properties of the second material are greater than the insulating properties of the first material. This makes it preferable, for example, to impart insulating properties to the first member.
• the workpiece is preferably a powder aggregate or a molded body of a powder aggregate.
• the second member preferably includes a third material and a fourth material, and the microwave absorption efficiency of the third material is greater than the microwave absorption efficiency of the fourth material.
• the first member may be, for example, at least one of the microwave absorbing member 90 and the promoter 400 in this embodiment according to some aspects of the present invention, but is not limited thereto.
• the member (hereinafter, "process member”) used in the process using electromagnetic waves such as microwaves or millimeter waves according to some aspects of the present invention preferably contains a microwave absorbing material that absorbs microwaves.
• the process member includes a first member and a second member.
• the process member is also called a promoter.
• the microwave absorbing material includes, for example, a carbon-containing material.
• carbon-containing materials include carbon black, amorphous carbon, graphite, silicon carbide, carbon resin, and metal carbide.
• examples of the microwave absorbing material include metal particles, metal nitrides, metal oxides, and metal borides. A mixture of at least two of the materials exemplified above may be used.
• the process member preferably further includes a heat insulating material.
• the heat insulating material include, for example, metal oxides and semi-metal oxides.
• the metal and semi-metal oxides include, for example, aluminum oxide ( Al2O3 ), silicon oxide ( SiO2 ), magnesium oxide (MgO), zirconium oxide ( ZrO2 ), and titanium oxide ( TiO2 ).
• Al2O3 aluminum oxide
• SiO2 silicon oxide
• MgO magnesium oxide
• ZrO2 zirconium oxide
• TiO2 titanium oxide
• the melting point of aluminum oxide ( Al2O3 ) is 2072°C.
• the melting point of silicon oxide ( SiO2 ) is 1710°C.
• the melting point of magnesium oxide (MgO) is 2852 ° C.
• the heat insulating material may be a compound or a mixture of these .
• the process component may include a high melting point material having a higher melting point than the microwave absorbing material.
• the high melting point material may be, for example, carbon and a reducing material that reduces the silicon carbide workpiece.
• the mass ratio of the microwave absorbing material and the heat insulating material in the process member is preferably selected so that the process member absorbs relatively more microwaves than the workpiece 130 in at least a portion of the temperature range below the temperature range where the microwave absorption efficiency of the workpiece increases, and the workpiece absorbs relatively more microwaves than the process member in at least a portion of the temperature range above the temperature range where the microwave absorption efficiency of the workpiece increases.
• the mass ratio of the microwave absorbing material and the heat insulating material in the process member so that the temperature of the process member is relatively higher than the temperature of the workpiece in at least a portion of the temperature range up to the sintering or melting temperature of the workpiece, and so that the temperature of the workpiece is relatively higher than the process member in at least a portion of the temperature range after the sintering or melting temperature of the workpiece is reached.
• the mass ratio of the microwave absorbing material to the insulating material in a typical process member is preferably 1:1, or the mass ratio of the insulating material is greater than the mass ratio of the microwave absorbing material.
• the mass ratio of the microwave absorbing material in the process member is 1 mass% or more, 2 mass% or more, or 5 mass% or more, and 70 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 20 mass% or less, or 10 mass% or less, but may be selected appropriately depending on the desired processing conditions.
• microwave absorbing in “microwave absorbing material” and “insulating” in “insulating material” do not necessarily mean absolute microwave absorbing and insulating properties, respectively.
• microwave absorbing properties of a microwave absorbing material are higher than the microwave absorbing properties of an insulating material.
• insulating properties of an insulating material are higher than the insulating properties of a microwave absorbing material.
• a method for producing a solid is a method for producing a solid from a workpiece, comprising a first step and a second step, in which the workpiece and a first member are arranged inside a housing during at least a part of the first step, and the workpiece is sintered or melted during at least a part of the second step, the second step is carried out in a first temperature range in which the temperature of the workpiece or the first member is greater than a first temperature and less than a second temperature, and in a second temperature range in which the temperature of the workpiece or the first member is greater than a third temperature and less than a fourth temperature, microwaves or millimeter waves are emitted inside the housing in the first temperature range and the second temperature range, the microwave absorption efficiency of the first member in the first temperature range is greater than the microwave absorption efficiency of the workpiece, and the microwave absorption efficiency of the workpiece in the second temperature range is greater than the microwave absorption efficiency of the first member.
• the second step preferably includes a first substep and a second substep, the first substep being carried out in a first temperature range, the second substep being carried out in a second temperature range, and the first substep being carried out before carrying out the second substep.
• the above-mentioned method for manufacturing a solid allows, for example, the workpiece to quickly reach a temperature at which it can absorb microwaves or millimeter waves, and then the workpiece itself absorbs the microwaves, making it possible to sinter or melt the workpiece efficiently overall.
• the third temperature is higher than the second temperature.
• the second temperature range includes a sintering temperature at which the workpiece is sintered or a melting temperature at which the workpiece is melted.
• the first temperature, the second temperature, the third temperature, and the fourth temperature are preferably the temperatures of the workpiece and the first member.
• the method for manufacturing a metal product includes a first step and a second step, in which the raw material of the metal product and a first member are arranged inside a housing during at least a part of the first step, the raw material is sintered or melted during at least a part of the second step, the period during which the second step is carried out includes at least a first period and a second period, microwaves or millimeter waves are emitted inside the housing during both the first period and the second period, during the first period, at least a part of the raw material is in contact with the first member, and the temperature of the first member is higher than the temperature of the raw material, during the second period, the temperature of the first member is lower than the temperature of the raw material, and during at least a part of the second period, the raw material reaches a temperature at which the workpiece is sintered or melted.
• the metal product is, for example, a metal solid.
• a method for producing a solid is a method for producing a solid from a workpiece, comprising a first step of arranging the workpiece and a first member inside a housing, and a second step of sintering or melting the workpiece with at least a portion of the workpiece in contact with the first member, the period during which the second step is performed includes at least a first period and a second period, microwaves or millimeter waves are emitted inside the housing during both the first period and the second period, the temperature of the first member is higher than the temperature of the workpiece during the first period, and the temperature of the first member is lower than the temperature of the workpiece during the second period.
• the heat conduction from the first member to the workpiece is relatively reduced in the second period compared to the first period, the workpiece absorbs microwaves or millimeter waves spontaneously, and the workpiece quickly reaches a temperature at which it absorbs microwaves or millimeter waves, making it possible to sinter or melt the workpiece efficiently overall.
• the workpiece reaches a temperature at which the workpiece sinters or melts.
• Some aspects of the present invention provide a solid manufacturing apparatus for manufacturing a solid from a workpiece, and the solid manufacturing apparatus includes a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a first base body disposed inside the housing and capable of contacting at least a portion of the workpiece while protruding at least into the housing.
• a configuration that enables temperature measurement at multiple locations on the solid manufacturing apparatus, particularly multiple locations inside the housing is preferable.
• the temperature may be measured at multiple locations on the inner wall of the housing and multiple locations on the first substrate.
• the configuration may be such that the temperature is measured at multiple locations on the second substrate.
• a thermometer may be provided for each of at least two of the interior of the housing, the first substrate, and the second substrate.
• the temperature measured at multiple locations it is preferable to adjust at least one of the time for which microwaves or millimeter waves are emitted inside the housing and the intensity of the microwaves or millimeter waves so that the difference falls within a predetermined range.
• the solid manufacturing apparatus is a solid manufacturing apparatus for manufacturing a solid from a workpiece, and includes a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a first base body disposed inside the housing and capable of contacting at least a portion of the workpiece while protruding at least into the housing, at least a portion of the housing being composed of multiple layers.
• At least one of the multiple layers is made of a metal material, and it is even more preferable that at least two of the multiple layers are made of a metal material. It is preferable that at least one of the multiple layers is made of a heat insulating material.
• the solid manufacturing apparatus is a solid manufacturing apparatus for manufacturing a solid from a workpiece, and includes a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a first base disposed inside the housing and capable of contacting at least a portion of the workpiece while at least protruding into the housing, and includes a plurality of electromagnetic wave emitting devices for emitting microwaves or millimeter waves. This makes it difficult for the microwaves or millimeter waves to become out of phase with each other inside the housing, for example, and reduces the risk of sparks due to hotspot generation.
• the multiple generators are configured so that the phases of the microwaves or millimeter waves emitted do not match.
• the anisotropy of the cross-sectional shape of the waveguide corresponding to the microwave generation of one of the multiple microwave generators may be made different from the anisotropy of the cross-sectional shape of the waveguide corresponding to the other microwave generators of the multiple microwave generators.
• the frequency of the microwaves or millimeter waves may be changed over time. Details will be described in the section explaining the solid manufacturing apparatus according to some aspects of the present invention.
• the solid manufacturing apparatus is a solid manufacturing apparatus for manufacturing a solid from a workpiece, and includes a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a first base body disposed inside the housing and capable of contacting at least a portion of the workpiece while protruding at least into the housing, and may further include a function of applying pressure to or shaping the workpiece.
• the solid manufacturing apparatus may be configured to apply pressure to or shape the workpiece inside the housing.
• the timing for applying pressure to or shaping the workpiece may be at least a part of the period during which microwaves or millimeter waves are emitted inside the housing, or may be after the workpiece has been sintered or melted to obtain a solid.
• Some aspects of the present invention provide a solid manufacturing apparatus for manufacturing a solid from a workpiece, the solid manufacturing apparatus comprising a housing, an electromagnetic wave emitting device for emitting microwaves or millimeter waves into the housing, and a moving device for moving the workpiece into the housing.
• the moving device moves the workpiece, for example, using at least a portion of a moving path from outside the housing to inside the housing.
• the apparatus is configured to move the workpiece in a first direction from a point where the workpiece is input to reach the first point, and then move the workpiece in a direction intersecting the first direction to reach a second point.
• the first direction is a direction along the bottom of the housing, and it is preferable that the second direction is a direction intersecting the bottom.
• the member is used for sintering or melting a workpiece, and the microwave absorption efficiency of the member is higher than that of the workpiece when the workpiece or member is in a first temperature range above a first temperature and below a second temperature, and the microwave absorption efficiency of the workpiece is higher than that of the member when the workpiece or member is in a second temperature range above a third temperature and below a fourth temperature, and the member is used for sintering or melting the workpiece with at least a portion of the workpiece in contact with the member, and the third temperature is higher than the second temperature.
• process members can, for example, efficiently raise the temperature of the workpiece to a temperature range where microwaves can be easily absorbed, and thus can have the effect of promoting the sintering or melting of the workpiece.
• the above-mentioned components may be in the form of powder or molded products.
• the process member preferably contains a microwave absorbing material that absorbs microwaves. This allows the process member to, for example, play a role in conducting heat to the workpiece at least in the initial stage of starting microwave processing of the workpiece.
• the microwave absorbing material includes, for example, a carbon-containing material. Examples of carbon-containing materials include carbon black, amorphous carbon, graphite, silicon carbide, carbon resin, and metal carbides. Examples of microwave absorbing materials include metal particles, metal nitrides, metal oxides, and metal borides. A mixture of at least two of the materials listed above may also be used.
• the process member preferably further includes a heat insulating material.
• the heat insulating material include, for example, metal oxides and semi-metal oxides.
• the metal and semi-metal oxides include, for example, aluminum oxide ( Al2O3 ), silicon oxide ( SiO2 ), magnesium oxide (MgO), zirconium oxide ( ZrO2 ), and titanium oxide ( TiO2 ).
• Al2O3 aluminum oxide
• SiO2 silicon oxide
• MgO magnesium oxide
• ZrO2 zirconium oxide
• TiO2 titanium oxide
• the melting point of aluminum oxide ( Al2O3 ) is 2072°C.
• the melting point of silicon oxide ( SiO2 ) is 1710°C.
• the melting point of magnesium oxide (MgO) is 2852 ° C.
• the heat insulating material may be a compound or a mixture of these .
• the process component may include a high melting point material having a higher melting point than the microwave absorbing material.
• the high melting point material may be, for example, carbon and a reducing material that reduces the silicon carbide workpiece.
• the mass ratio of the microwave absorbing material and the heat insulating material in the process member is preferably selected so that the process member absorbs relatively more microwaves than the workpiece 130 in at least a portion of the temperature range below the temperature range where the microwave absorption efficiency of the workpiece increases, and the workpiece absorbs relatively more microwaves than the process member in at least a portion of the temperature range above the temperature range where the microwave absorption efficiency of the workpiece increases.
• the mass ratio of the microwave absorbing material and the heat insulating material in the process member so that the temperature of the process member is relatively higher than the temperature of the workpiece in at least a portion of the temperature range up to the sintering or melting temperature of the workpiece, and so that the temperature of the workpiece is relatively higher than the temperature of the process member in at least a portion of the temperature range after the sintering or melting temperature of the workpiece is reached.
• the mass ratio of the microwave absorbing material to the insulating material in a typical process member is preferably 1:1, or the mass ratio of the insulating material is greater than the mass ratio of the microwave absorbing material.
• the mass ratio of the microwave absorbing material in the process member is 1 mass% or more, 2 mass% or more, or 5 mass% or more, and 70 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 20 mass% or less, or 10 mass% or less, but may be selected appropriately depending on the desired processing conditions.
• microwave absorbing in “microwave absorbing material” and “thermal insulating” in “thermal insulating material” does not necessarily mean absolute microwave absorbing and insulating properties, respectively.
• microwave absorbing properties of a microwave absorbing material are higher than the microwave absorbing properties of an insulating material.
• insulating properties of an insulating material are higher than the insulating properties of a microwave absorbing material.
• FIG. 1 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 2 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 3 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 4 is a schematic diagram of a solid state manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 5 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 6 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 7 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 1 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 2 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 8 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 9 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 10 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 11 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 12 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 13 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 14 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 14 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 15 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 16 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 17 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• FIG. 18 is a schematic diagram of a solid manufacturing apparatus according to an embodiment of some aspects of the present invention.
• This section describes a typical basic configuration of a solid manufacturing apparatus in some embodiments of the present invention.
• the solid manufacturing apparatus includes a microwave heating chamber, which includes a housing 10, a cooling unit 1 for cooling the housing 10, a blower 15, a position sensor 16, a thermometer 19a, a thermometer 19b, a pressurizing unit 20, gas supply units 21-23 for supplying multiple types of gas, a microwave generator 30 for emitting microwaves inside the housing 10, and a stage 50 for placing the workpiece 130.
• a microwave heating chamber which includes a housing 10, a cooling unit 1 for cooling the housing 10, a blower 15, a position sensor 16, a thermometer 19a, a thermometer 19b, a pressurizing unit 20, gas supply units 21-23 for supplying multiple types of gas, a microwave generator 30 for emitting microwaves inside the housing 10, and a stage 50 for placing the workpiece 130.
• the solid manufacturing apparatus further includes a transport unit 300 for moving the workpiece 130 to the stage 50, a transport table 250 for transporting the workpiece 130 to the stage 50, a solid receiving unit 100 for receiving the solid obtained after processing the workpiece 130, a shaft 120 for moving the solid receiving unit 100 on the support table 51, a shaft connection unit 110 for connecting the solid receiving unit 100 and the shaft 120, a shaft drive unit 125 for driving the shaft 120, a load receiving unit 60 for receiving a load applied to the support table 51, and a base unit 55 for supporting the stage 50 and the load receiving unit 60.
• the solid manufacturing apparatus includes a raw material supply stage 200. Before the workpiece 130 is moved from outside the housing 10 toward the stage 50 inside the housing 10, the workpiece 130 is placed on the raw material supply stage 200.
• the raw material supply stage 200 can be made of the same material as the stage 50, which will be described later.
• the transport platform 250 can be used, for example, to move the workpiece 130 from the raw material supply stage 200 outside the housing 10 in the direction of the stage 50 inside the housing 10 by the transport unit 300.
• a space be provided between the transport platform 250 in the solid manufacturing apparatus and the part that forms the bottom of the housing 10. This allows the workpiece 130 and the transport part 300 to move through the space toward the stage 50.
• the solid manufacturing apparatus may be provided with a stopper 11 that protrudes from the bottom of the housing 10, which is the surface portion facing the pressure unit 20, in the opposite direction to the pressure unit 20, i.e., to the outside of the housing 10.
• the stopper 11 is configured, for example, so that when the transport unit 300 moves the workpiece 130 above the stage 50, the transport unit 300 does not reach above the shaft 120.
• the housing 10 is preferably made up of multiple layers, for example, as shown in FIG. 18.
• the solid manufacturing apparatus according to this embodiment is composed of three layers, layer 10a, layer 10b, and layer 10c, from the inside of the housing.
• Various alloys or pure metals can be used as the material for layers 10a and 10c.
• steel, stainless steel, aluminum, etc. can be used, but metals that are more likely to flow current induced by microwaves are more likely to concentrate microwave energy on the workpiece 130. Therefore, metals or alloys such as iron with an electrical conductivity of 17.5% or more in IACS% (volume resistivity of annealed standard soft copper) are preferred.
• IACS% volume resistivity of annealed standard soft copper
• metals or alloys such as aluminum with an IACS% of 55% or more are preferred.
• metals or alloys such as copper with an IACS% of 75% or more are preferred.
• the material of layer 10a and the material of layer 10c may be different, but for the material of layer 10a located inside the housing 10, i.e., inside the microwave heating chamber, it is preferable to use a material with a higher electrical conductivity than the material of layer 10c on the outside, for example, if there are restrictions on manufacturing costs, dimensional accuracy, strength, etc.
• the material of layer 10b is preferably a heat insulating material.
• the heat resistant temperature of the heat insulating material is preferably 400°C or higher, and more preferably 500°C or higher.
• the material is preferably glass fiber or ceramic fiber. Examples include Miorex (registered trademark), Losnaboard (registered trademark), glass epoxy, Besthermo, BLA-GLA (registered trademark), Calhon, and Hemisal (registered trademark).
• the stage 50 on which the workpiece 130 is placed can be made of, for example, a metal such as stainless steel or aluminum, or a ceramic such as aluminum oxide or aluminum nitride.
• a pedestal 135 may be provided on the stage 50, and the workpiece 130 may be placed on the pedestal 135.
• an opening may be provided on the bottom surface of the housing 10, and the stage 50 may pass through the opening in the housing 10 and move in and out of the housing 10.
• the position sensor 16 detects the position of the workpiece 130 placed on the stage 50.
• the stage 50 moves toward the pressure unit 20 until the position sensor 16 detects the workpiece 130.
• a non-contact type position sensor is preferably used as the position sensor 16 used in the solid manufacturing apparatus according to this embodiment.
• the reason for using a non-contact type position sensor in this manner is, for example, that the temperature inside the housing 10 may become high, or that it may be difficult to secure space inside the housing 10 because many parts are placed inside the housing 10, such as the pressure unit 20 and the enclosure 40 described below.
• non-contact type position sensor for example, a linear transducer type using electromagnetic induction or magnetostriction, a linear encoder type that obtains an electrical output according to the position, or an optical sensor type that measures length using light such as laser light can be used.
• the type of position sensor to be used can be selected appropriately according to the desired length measurement accuracy and the layout inside the housing 10, but since the solid manufacturing apparatus according to this embodiment requires length measurement accuracy, an optical sensor type that has a relatively high length measurement accuracy is used among non-contact type position sensors.
• the pressure applying unit 20 applies pressure to the workpiece 130 placed on the stage 50.
• the pressure applying unit 20 can be fitted with, for example, a microwave absorbing member 90 that has greater microwave absorption capacity than the pressure applying unit 20 and generates heat by absorbing microwaves.
• a microwave absorbing member 90 that has greater microwave absorption capacity than the pressure applying unit 20 and generates heat by absorbing microwaves.
• the pressurizing unit 20 may apply pressure to the solid 140 obtained by processing such as sintering or melting. In this case, it is preferable to apply pressure when the solid 140 has heat and before it is cooled to a predetermined temperature, and when the temperature is higher than the predetermined temperature.
• the pressure applied is, for example, 1 MPa or more, 100 MPa or more, or 200 MPa or more, and 2000 MPa or less, 1900 MPa or less, or 1800 MPa or less. By applying pressure, the obtained solid 140 can be made even denser.
• the heat insulating member 80 provided in the pressure applying unit 20 preferably has a function of suppressing heat conduction to the pressure applying unit 20 even when the workpiece 130, the microwave absorbing member 90, or the inside of the housing 10 becomes hot. It is preferable to use a material for the heat insulating member 80 whose thermal conductivity is lower than that of the microwave absorbing member 90.
• the material for the heat insulating member 80 is preferably an inorganic material containing, for example, 50% or more of aluminum oxide or silicon oxide. It may also contain a silicate such as calcium silicate.
• the microwave absorbing member 90 provided in the pressure unit 20 comes into contact with the workpiece 130, for example, when the pressure unit 20 applies pressure to the workpiece 130.
• the material of the microwave absorbing member 90 is preferably selected so that, for example, in a first temperature range in which the workpiece 130 or the microwave absorbing member 90 is at or above a first temperature and at or below a second temperature, the microwave absorption efficiency of the microwave absorbing member 90 is higher than that of the workpiece 130, and in a second temperature range in which the workpiece 130 or the microwave absorbing member 90 is at or above a third temperature and at or below a fourth temperature, the microwave absorption efficiency of the workpiece 130 is higher than that of the microwave absorbing member 90. It is preferable that the second temperature is lower than the third temperature.
• the material of the microwave absorbing member 90 for example, a material containing a wide gap semiconductor such as silicon carbide, an oxygen-containing anion salt such as zinc oxide or lead zirconate titanate, conductive particles such as graphite or titanium, or metal powder or metal particles is preferable. It is more preferable to mix the above-mentioned materials with a material having a lower microwave absorption rate than the above-mentioned materials, for example, an inorganic material such as alumina or silicon oxide, or cement, and use a molded product such as a plate obtained by appropriately sintering or baking the mixture. This makes it possible to impart higher mechanical strength to the microwave absorbing member 90, for example. Alternatively, it is possible to adjust the ratio of heat conduction from the microwave absorbing member 90 and direct heating of the workpiece 130 by microwaves during the heating process of the workpiece 130.
• the raw material for the microwave absorbing member 90 may be a molded or processed material or mixture similar to the promoter 400 described below.
• thermo insulation in “thermal insulating member” and “microwave absorption” in “microwave absorbing member” do not necessarily mean absolute thermal insulation and microwave absorption, respectively, but also include, for example, the meaning that, as a condition for manufacturing using the solid manufacturing apparatus of this embodiment, the thermal insulation of the thermal insulating member 80 is relatively higher than the thermal insulation of the microwave absorbing member 90. Also, as a condition for manufacturing using the solid manufacturing apparatus of this embodiment, it also includes the meaning that the microwave absorption efficiency of the microwave absorbing member 90 is relatively higher than the microwave absorption efficiency of the thermal insulating member 80.
• the solid manufacturing apparatus shown in FIG. 1 may include, for example, a plate jig 95 for attaching the microwave absorbing member 90 and the heat insulating member 80 to the pressure unit 20.
• the plate jig 95 may be configured to attach at least one of the microwave absorbing member 90 and the heat insulating member 80 to the pressure unit 20.
• the workpiece 130 may be processed using electromagnetic waves such as microwaves or millimeter waves with an adhesion prevention plate 410 placed between the workpiece 130 and the pressure unit 20.
• an adhesion prevention plate 410 placed between the workpiece 130 and the pressure unit 20.
• This makes it possible to prevent the workpiece 130 from adhering to the pressure unit 20.
• it is preferable to process the workpiece 130 with at least a part of the adhesion prevention plate 410 in contact with at least a part of the adhesion prevention plate 410.
• the material of the adhesion prevention plate 410 can be appropriately selected depending on the workpiece 130.
• the workpiece 130 is made of a metal material, for example, a carbon plate is preferable as the adhesion prevention plate 410.
• the gas supply units 21 to 23 included in the solid manufacturing apparatus are configured to be able to supply a plurality of types of gases into the housing 10, and are preferably configured to supply gases during at least a portion of the time that the workpiece 130 is being processed, such as sintered or melted.
• the plurality of types of gases include inert gases such as neon (Ne), argon (Ar), and helium (He), neutral gases such as nitrogen (N 2 ), dry hydrogen (H 2 ), and ammonia (NH 3 ), and reducing gases such as hydrogen (H 2 ), carbon monoxide (CO), and hydrocarbon gases (CH 4 , C 3 H 8 , C 4 H 10, etc.).
• Oxidizing gases such as oxygen, ozone, nitrous oxide, nitric oxide, and nitrogen dioxide can also be used.
• the microwave generator 30 may be an oscillator using an electron tube such as a magnetron, klystron, gyrotron, or traveling wave tube, a solid-state oscillator that amplifies the natural vibration of a quartz crystal oscillator, or a semiconductor element made of a semiconductor material such as gallium nitride or gallium arsenide.
• Microwaves with a frequency of about 300 MHz to about 300 GHz are used, but preferably microwaves with a frequency in the range of 1 GHz to 10 GHz are used. It is further preferable to vary the microwave frequency. This makes it possible to suppress the occurrence of hot spots caused by the concentration of microwaves inside the housing 10.
• multiple microwave generators 30 may be provided for one microwave heating chamber. This makes it possible to reduce the degree of localization of microwaves inside the housing 10, for example.
• the generation of hot spots due to microwave concentration can be suppressed by making the direction of anisotropy of the cross-sectional shape of the waveguides 32 not coincident among the multiple waveguides 32.
• the waveguides 32 corresponding to each of the multiple microwave generators 30 have a rectangular cross-sectional shape, and it is preferable to configure the waveguides 32 so that the direction of the long side of the rectangular cross-sectional shape of one waveguide 32 intersects with the long side of the rectangular cross-sectional shape of the other waveguide 32.
• a window 31 and a waveguide 32 are arranged between the microwave generator 30 and the inside of the housing 10, starting from the side closest to the inside of the housing 10. Microwaves emitted from the microwave generator 30 are emitted from the window 31 into the inside of the housing 10 via the waveguide 32.
• An example of a material for the window 31 is quartz glass.
• the air blower 15 is, for example, an air curtain supply device, and generates an airflow along the main surface of the window 31 on the inside side of the housing 10, thereby preventing dust, powder, and debris from the workpiece 130, etc., generated inside the housing 10, from adhering to the window 31.
• the solid manufacturing apparatus may include an electromagnetic wave diffusion plate 12 provided inside the housing 10.
• the electromagnetic wave diffusion plate 12 can rotate to prevent microwaves from concentrating at a certain location inside the housing 10. It can also prevent, for example, temperature unevenness depending on the location of the workpiece 130 and the occurrence of sparks inside the housing 10.
• the microwave sensor 35 provided in the solid manufacturing apparatus according to this embodiment can measure at least one of the magnetic field strength, electric field strength, and high frequency strength. It is preferable that the microwave sensor 35 can simultaneously measure at least two of the magnetic field strength, electric field strength, and high frequency strength, and it is particularly preferable that the microwave sensor 35 can simultaneously measure all of the magnetic field strength, electric field strength, and high frequency strength.
• thermometer 19a and thermometer 19b can measure temperatures in the range of 500°C or higher.
• At least one of the multiple thermometers, i.e., thermometer 19a and thermometer 19b, is preferably equipped with a cooling device that cools the lens of the radiation thermometer. It is preferable to use an air blowing type cooling device.
• the temperature is preferably measured at multiple locations within the housing 10. This makes it possible, for example, to prevent temperature differences due to the position of the workpiece 130.
• the thermometers 19a and 19b are arranged at multiple locations in the pressure unit 20, i.e., one thermometer is arranged closer to the center of the pressure unit 20 or housing 10 than the other thermometer.
• the emission of microwaves into the housing 10 may be stopped for at least a portion of the period until the difference in temperature measured at multiple positions disappears, or for at least a portion of the period until the difference in temperature measured at multiple positions reaches a predetermined value.
• the microwave output may be set to a second output lower than the first output, which is the output of the microwaves when processing the workpiece 130, for at least a portion of the period until the difference in temperature measured at multiple positions disappears, or for at least a portion of the period until the difference in temperature measured at multiple positions reaches a predetermined value.
• At least a portion of the setting or execution of the processing conditions for the workpiece 130, such as the microwave output, based on the measurements from such a thermometer may be programmed and automated using a control device such as a computer.
• the cooling unit 1 is attached to the housing 10, but it can also be attached to the pressurizing unit 20 as shown in FIG. 10 or FIG. 13. Also, the cooling unit 1 can be attached to the stage 50 side as shown in FIG. 13 or FIG. 14.
• the cooling unit 1 can be attached to at least two of the housing 10, the pressurizing unit 20, and the stage 50.
• a typical example of the cooling unit 1 is a Peltier element, but a cooling unit that provides piping on the outside or inside of the housing 10, the pressurizing unit 20, or the stage 50 and circulates water, refrigerant, or air through the piping is particularly effective for large microwave heating chambers.
• the enclosure 40 provided in the solid manufacturing apparatus according to this embodiment is disposed within the housing 10 and surrounds the side of the workpiece 130 disposed on the stage 50. For example, as shown in FIG. 3, even if the workpiece 130 is deformed by applying pressure to the workpiece 130 via the heat insulating member 80 and the microwave absorbing member 90 by the pressure applying unit 20, the enclosure 40 can suppress the deformation of the workpiece 130 by confining the deformation of the workpiece 130 to the range of the enclosure 40 at most.
• the enclosure 40 is positioned in a second direction intersecting the first direction from the workpiece 130 to the pressurizing unit 20.
• the enclosure 40 is positioned around the workpiece 130 when the pressurizing unit 20 applies pressure to the workpiece 130 via the insulating member 80 and the microwave absorbing member 90 as shown in FIG. 3.
• the material of the enclosure 40 may be a pure metal, an alloy, or a non-metallic inorganic material.
• Pure metals include aluminum, copper, iron, and other pure metals. Alloys include stainless steel, nickel-chromium steel, chromium-molybdenum steel, manganese steel, manganese-chromium steel, chromium steel, carbon steel forgings, carbon-copper forgings, gray iron, spheroidal graphite cast iron, and blackheart malleable cast iron.
• Non-metallic inorganic materials include aluminum oxide, alumina porcelain, sintered beryllium oxide, sintered zirconium oxide, sintered mullite, hot-pressed silicon nitride, reactive sintered silicon nitride, fused quartz, hot-pressed titanium carbide, graphite, and other non-metallic materials.
• enclosures 41 and 42 made of multiple materials as shown in FIG. 10 may be used.
• the enclosure 42 is disposed on the side of the enclosure 41 facing the pressure unit 20.
• the material of the enclosure 41 may be a nonmetallic inorganic material
• the material of the enclosure 42 may be a material with high microwave absorption, such as the above-mentioned metal, alloy, or graphite.
• the function of heating the workpiece 130 by thermal conduction can be assigned to the enclosure 41, and the load-bearing function can be assigned to the enclosure 42.
• microwaves may be irradiated onto the workpiece 130 while at least a portion of the promoter 400 is in contact with the workpiece 130.
• the promoter 400 is preferably prepared so as to absorb relatively more microwaves in a temperature range lower than the temperature range where the microwave absorption efficiency of the workpiece 130 increases. This allows the promoter 400 to generate heat faster than the workpiece 130, shortening the time it takes for the workpiece 130 to reach a temperature range where the microwave absorption efficiency of the workpiece 130 is relatively higher than that of the promoter 400, and shortening the time required to process the workpiece 130. Furthermore, it is preferable to select a combination of the promoter 400 and the workpiece 130 so that the temperature of the workpiece 130 is higher than the temperature of the promoter 400 during at least a portion of the processing time during which the workpiece 130 is in the temperature range after it has reached the temperature at which it sinters or melts.
• the promoter 400 is preferably selected such that, for example, in a first temperature range in which the workpiece 130 or the promoter 400 is at or above a first temperature and at or below a second temperature, the microwave absorption efficiency of the promoter 400 is higher than the microwave absorption efficiency of the workpiece 130, and in a second temperature range in which the workpiece 130 or the promoter 400 is at or above a third temperature and at or below a fourth temperature, the microwave absorption efficiency of the workpiece 130 is higher than the microwave absorption efficiency of the promoter 400. It is preferable that the second temperature is lower than the third temperature.
• the promoter 400 preferably contains, for example, a microwave absorbing material that absorbs microwaves. This allows the promoter 400 to play a role in conducting heat to the workpiece 130, for example, at least in the initial stage when microwave processing of the workpiece 130 begins.
• Microwave absorbing materials include, for example, carbon-containing materials.
• carbon-containing materials include carbon black, amorphous carbon, graphite, silicon carbide, carbon resins, and metal carbides.
• Other examples of microwave absorbing materials include metal particles, metal nitrides, metal oxides, and metal borides.
• the microwave absorbing material may be a mixture of at least two of the materials listed above.
• the promoter 400 preferably further includes a heat insulating material.
• the heat insulating material include, for example, metal oxides and semi-metal oxides.
• the metal and semi-metal oxides include, for example, aluminum oxide ( Al2O3 ), silicon oxide ( SiO2 ), magnesium oxide (MgO), zirconium oxide ( ZrO2 ), and titanium oxide ( TiO2 ).
• Al2O3 aluminum oxide
• SiO2 silicon oxide
• MgO magnesium oxide
• ZrO2 zirconium oxide
• TiO2 titanium oxide
• the melting point of aluminum oxide ( Al2O3 ) is 2072°C.
• the melting point of silicon oxide ( SiO2 ) is 1710°C.
• the melting point of magnesium oxide (MgO) is 2852 ° C.
• the heat insulating material may be a compound or a mixture of these .
• the promoter 400 may include a high melting point material having a higher melting point than the microwave absorbing material.
• the high melting point material may be, for example, carbon and a reducing material that reduces the silicon carbide workpiece 130.
• the mass ratio of the microwave absorbing material and the heat insulating material in the promoter 400 is preferably selected so that the promoter 400 absorbs relatively more microwaves than the workpiece 130 in at least a part of the temperature range lower than the temperature range where the microwave absorption efficiency of the workpiece 130 increases, and the workpiece 130 absorbs relatively more microwaves than the promoter 400 in at least a part of the temperature range higher than the temperature range where the microwave absorption efficiency of the workpiece 130 increases.
• the mass ratio of the microwave absorbing material and the heat insulating material in the promoter 400 is preferably set so that the temperature of the promoter 400 is relatively higher than the temperature of the workpiece 130 in at least a part of the temperature range up to the sintering or melting temperature of the workpiece 130, and the temperature of the workpiece 130 is relatively higher than the promoter 400 in at least a part of the temperature range after the sintering or melting temperature of the workpiece 130 is reached.
• the mass ratio of the microwave absorbing material to the insulating material in a typical promoter 400 is preferably 1:1, or the mass ratio of the insulating material is greater than the mass ratio of the microwave absorbing material.
• the mass ratio of the microwave absorbing material in the promoter 400 is 1% by mass or more, 2% by mass or more, or 5% by mass or more, and 70% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less, but may be selected appropriately depending on the desired processing conditions.
• microwave absorbing in “microwave absorbing material” and “thermal insulating” in “thermal insulating material” does not necessarily mean absolute microwave absorbing and insulating properties, respectively.
• microwave absorbing properties of a microwave absorbing material are higher than the microwave absorbing properties of an insulating material.
• insulating properties of an insulating material are higher than the insulating properties of a microwave absorbing material.
• the promoter 400 may also be disposed in a direction intersecting the direction from the workpiece 130 to the enclosure 41, i.e., in this embodiment, between the pressure unit 20 and the workpiece 130.
• the promoter 400 may be disposed at least either around the workpiece 130 or at a position opposite the workpiece 130 from the stage 50 on which the workpiece 130 is placed, and the workpiece 130 may be processed, but the processing may be performed with the promoter 400 disposed only between the workpiece 130 and the enclosure 41 or 42 as shown in FIG. 12.
• the load receiving part 60 used in the solid manufacturing apparatus shown in FIG. 1 is configured to include, for example, a shaft and a bearing.
• the load receiving part 60 may be configured to adjust the distance of the stage 50 relative to the pressure unit 20.
• the stage 50 moves the solid or solid combination 141 to the solid receiving part 100 as shown in FIG. 8.
• the solid receiving part 100 is located, for example, at the bottom of the housing 10 facing the pressure unit 20, on the outside opposite the pressure unit 20.
• the solid receiving part 100 has a function of receiving the solid combination 141, which is an object obtained through processing the workpiece 130 inside the housing 10.
• the solid receiving part 100 has, for example, a frame and has a space inside the frame.
• the stage 50 is movable in the space inside the frame of the solid receiving part 100.
• the solid receiving part 100 is configured, for example, so that the solid combination 141 moves together with the stage 50 in a direction away from the inside of the housing 10 to the outside, and stops the movement. In this stopped state, at least a part of the pedestal 135, which is disposed between the solid combination 141 and the support base 51, is in contact with at least a part of the support base 51.
• the support base 51 has an opening through which the stage 50 passes, and the pedestal 135 is large enough that it cannot pass through the opening.
• the shaft 120 connected via the shaft connection part 110 is driven by the shaft drive part 125, and the shaft 120 pushes the solid receiving part 100, so that as shown in FIG. 9, the solid receiving part 100 moves in a direction intersecting the direction in which the stage 50 moves between the inside of the housing 10 and the support base 51, and the solid combination 141 is removed from the solid manufacturing device by the subsequent operation.
• a typical example is a configuration in which the solid receiving unit 100 and the solid combination 141 are positioned at least temporarily below the housing 10 and the transport platform 250, as shown in FIG. 9.
• the raw material conveying direction in which the conveying unit 300 moves the workpiece 130 toward the stage 50, is configured to be aligned with the product conveying direction, in which the shaft driving unit can move the solid receiving unit 100 via the shaft 120.
• the raw material conveying direction and the product conveying direction may be configured to intersect, for example, typically to be substantially perpendicular.
• the workpiece 130 may be, for example, a metal material or a ceramic material, or a mixture of these materials or a composition in which additives have been added to these materials.
• the metal material or ceramic material may be one type or may contain two or more types, and may be appropriately selected depending on the target solid 140 to be obtained by processing the workpiece 130, such as sintering or melting, as shown in Figure 4.
• the metal material may include, for example, a single metal, or a metal compound such as an alloy of these.
• metal elements include iron (Fe), nickel (Ni), copper (Cu), gold (Au), silver (Ag), aluminum (Al), cobalt (Co), tungsten (W), titanium (Ti), chromium (Cr), molybdenum (Mo), beryllium (Be), magnesium (Mg), tin (Sn), cerium (Ce), lead (Pb), mercury (Hg), sodium (Na), bismuth (Bi), and gallium (Ga).
• the sintering temperature of iron (Fe) is, for example, 1200°C.
• the melting point of iron (Fe) is 1538°C.
• the sintering temperature of nickel (Ni) is, for example, 1200°C.
• the melting point of nickel (Ni) is 1495°C.
• the sintering temperature of copper (Cu) is, for example, 800°C.
• the melting point of copper (Cu) is 1085°C.
• the sintering temperature of gold (Au) is, for example, 800°C.
• the melting point of gold (Au) is 1064°C.
• the sintering temperature of silver (Ag) is, for example, 750°C.
• the melting point of silver (Ag) is 962°C.
• the sintering temperature of aluminum (Al) is, for example, 500°C.
• the melting point of aluminum (Al) is 660°C.
• the sintering temperature of cobalt (Co) is, for example, 1100°C.
• the melting point of cobalt (Co) is 1455°C.
• the alloy may include alloys of multiple metal elements, alloys of metal elements and nonmetal elements, metal oxides, metal hydroxides, metal chlorides, metal carbides, metal borides, and metal sulfides, and may be appropriately selected depending on the desired solid 140.
• the elements constituting the alloy may include, for example, silicon (Si), manganese (Mn), chromium (Cr), nickel (Ni), carbon (C), boron (B), copper (Cu), aluminum (Al), titanium (Ti), niobium (Nb), vanadium (V), zinc (Zn), antimony (Sb), palladium (Pd), lanthanum (La), gold (Au), potassium (K), cadmium (Cd), indium (In), molybdenum (Mo), and sulfur (S).
• oxide ceramics or non-oxide ceramics can be used.
• the ceramic material include alumina (Al 2 O 3 ), zirconia (ZrO 2 ), barium titanate (BaTiO 3 ), barium oxide (BaO), titanium oxide (TiO 2 ), silicon oxide (SiO 2 ), zinc oxide (ZnO 2 ), neodymium oxide (Nd 2 O 3 ), lead zirconate titanate (PZT), silicon nitride (Si 3 N 4 ), silicon carbide (SiC), etc. These materials may be used alone or in combination of two or more.
• the workpiece 130 may be particles.
• the particle size of the workpiece 130 can be appropriately selected according to the desired solid 140.
• a molded product such as a compressed powder of the above-mentioned material or a similar product can be used. This can reduce the degree of deformation during processing, for example.
• a pressure of 1 MPa or more, 100 MPa or more, or 200 MPa or more, 2000 MPa or less, 1900 MPa or less, or 1800 MPa or less may be applied to an aggregate of material particles or powder.
• the resulting solid 140 tends to be dense.
• pressure application methods include uniaxial molding, cold isostatic pressing (CIP) molding, hot isostatic pressing (HIP) molding, and roller pressing.
• CIP cold isostatic pressing
• HIP hot isostatic pressing
• roller pressing roller pressing.
• various shapes such as a sheet or plate can be appropriately selected as the workpiece 130 depending on the desired solid 140.
• the microwave absorption efficiency of the workpiece 130 is relatively higher than the microwave absorption efficiency of the microwave absorbing member 90 in at least a certain temperature range.
• the control unit 1000 used in the solid manufacturing apparatus shown in FIG. 1 may be configured to control, for example, at least one of the cooling unit 1, electromagnetic wave diffusion plate 12, air blower 15, position sensor 16, thermometers 19a and 19b, pressurizing unit 20, gas supply units 21-23, microwave generator 30, stage 50, load receiving unit 60, shaft driving unit 125, raw material supply stage 200, and conveying unit 300. Also, for example, the control unit 1000 may be configured so that at least two of the above-mentioned devices can operate in conjunction with each other.
• control unit 1000 may control the microwave generator 30 to emit microwaves into the housing 10 when the temperature difference between multiple temperature measurement points such as thermometer 19a and thermometer 19b falls within a predetermined range.
• the control unit 1000 can also control the operation of moving at least one of the pressure unit 20 and the stage 50 from a state in which the pressure unit 20 and the stage 50 as shown in FIG. 1 are at a distance such that the workpiece 130 does not come into contact with the microwave absorbing member 90 attached to the pressure unit 20 to a state in which the pressure unit 20 and the stage 50 come closer to each other as shown in FIG. 3, so that the workpiece 130 and the microwave absorbing member 90 come into contact with each other.
• the control unit 1000 may control at least one of the stage 50 and the pressure unit 20 to control the pressure value applied to the workpiece 130 when the workpiece 130 and the microwave absorbing member 90 are in contact with each other, so that the pressure value is a predetermined value or within a predetermined range.
• the control unit 1000 may control at least a part of a series of operations, such as increasing the distance between the pressurizing unit 20 and the stage 50 as shown in FIG. 4 after a solid 140 has been obtained by sintering or melting through microwave irradiation inside the housing 10 as shown in FIG. 3, moving the workpiece 130 to be next subjected to microwave sintering on the conveying table 250 as shown in FIG. 5, and placing the next workpiece 130 above the solid 140 already obtained by microwave sintering as shown in FIG. 6.
• the control unit 1000 may be configured to control at least one of the pressure unit 20 and the stage 50 to control the pressure applied to the workpiece 130 or the distance between the pressure unit 20 and the stage 50 when microwaves are emitted into the inside of the housing 10 to process the workpiece 130, such as by melting or sintering, in a state in which a new workpiece 130 is placed on top of a solid 140 already obtained by processing the workpiece 130 with microwaves, as shown in FIG. 7.
• the control unit 1000 may move the stage 50 in the opposite direction to the pressure unit 20 so that at least a portion of the solid combined body 141 fits inside the solid receiving unit 100 as shown in FIG. 8, and may also control at least a portion of the operation of moving the solid receiving unit 100 via the shaft 120 by the shaft drive unit 125 in a direction intersecting the direction in which the pressure unit 20 is viewed from the stage 50 as shown in FIG. 9.
• the control unit 1000 exemplified above can be a computer, and it is preferable that at least a portion of the control by the control unit 1000 is stored as a program in the control unit 1000 and executed.
• a workpiece 800 that has not been subjected to pressure or molded can be used as the workpiece 130.
• the workpiece 800 can be, for example, an aggregate of powder that cannot maintain its shape.
• the conveying section 301 has a structure that allows the workpiece 800 to be placed thereon, as shown in FIG. 14.
• the conveying unit 301 may be moved to a position where the workpiece 800 faces the pressure unit 20 and the stage 50, and then the workpiece 800 may be slid from the location where the workpiece 800 was placed on the conveying unit 301 to be positioned above the stage 50, as shown in FIG. 16.
• the workpiece 800 may be placed between the pressure unit 20 and the stage 50, and pressure may be applied to the workpiece 800 to mold it or form a powder compact.
• the period during which pressure is applied to the workpiece 800 may be at least a part of the period during which microwaves or millimeter waves are emitted into the interior of the housing 10, or may be before the period during which microwaves or millimeter waves are emitted into the interior of the housing 10.
• Cooling section 10: Housing, 11: Stopper, 12: Electromagnetic wave diffusion plate, 15: Air blowing section, 16: Position sensor, 19a: Thermometer, 19b: Thermometer, 20: Pressurizing section, 21: Gas supply section, 22: Gas supply section, 23: Gas supply section, 30: Microwave generator, 31: Window, 32: Waveguide, 35: Microwave sensor, 40: Enclosure, 41: Microwave-transparent enclosure, 42: Microwave-absorbing enclosure, 50: Stage, 51: Support stand, 6 0: Load receiving part, 80: Thermal insulating member, 90: Microwave absorbing member, 95: Plate jig, 100: Solid receiving part, 110: Shaft connection part, 120: Shaft, 125: Shaft drive part, 130: Workpiece, 135: Base, 140: Solid (workpiece), 141: Solid joint, 200: Raw material supply stage, 250: Transport table, 300: Transport part, 400: Promoter, 410: Anti-adhesion plate, 800: Workpiece, 1000: Control

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