Transport method using unmanned transport machine, method for manufacturing ceramic sintered body, and method for manufacturing ceramic degreased body

Abstract

A transport method according to an embodiment uses an unmanned transport machine capable of carrying a transport container in which a transport object is disposed, the method comprising a moving step for moving the unmanned transport machine from a start point position to an end point position along a transport route by a laser guidance system, which determines the current position and direction of the unmanned transport machine by capturing reflected light from three or more reflection plates irradiated with laser from the unmanned transport machine. In the transport method, at least one of the start point position and the end point position is disposed on the side of a heat treatment furnace.

Description

Conveying method using an unmanned conveying machine, manufacturing method of ceramic sintered body, and manufacturing method of ceramic degreased body

[0001] The embodiments described below generally relate to a transport method using an automated transport vehicle, a method for manufacturing a ceramic sintered body, and a method for manufacturing a ceramic degreased body.

[0002] Ceramic sintered bodies are used in a variety of fields, including substrates for semiconductor devices and wear-resistant components. To obtain a ceramic sintered body, a ceramic powder serving as a base material is mixed with a sintering aid powder to form a ceramic green body, which is then degreased and sintered. For example, Japanese Patent No. 6293772 (Patent Document 1) discloses a silicon nitride substrate. In Patent Document 1, the degreasing step is performed at 500 to 800°C, and the sintering step is performed at 1800 to 1950°C. The degreasing step is performed by loading the ceramic green body into a degreasing furnace. The sintering step is performed by loading the degreased ceramic body into a sintering furnace.

[0003] Conventionally, the work of placing ceramic green bodies in and removing them from heat treatment (debinding and sintering) furnaces was done manually. Each heat treatment process exposes workers to a high-temperature environment. After heat treatment, it takes time for the temperature inside the heat treatment furnace to return to room temperature, so workers had to wait a long time to remove the ceramic sintered body from the heat treatment furnace. Furthermore, if the temperature inside the heat treatment furnace did not return to room temperature, it was not possible to place the next ceramic green body in the heat treatment furnace after removing the ceramic sintered body from the heat treatment furnace.

[0004] In recent years, the use of an automated guided vehicle to transport a product to a heat treatment furnace and store the product in the heat treatment furnace has been considered. For example, Japanese Patent Laid-Open Publication No. 2012-68886 (Patent Document 2) discloses a transport and storage process using an automated guided vehicle. In Patent Document 2, the position of the automated guided vehicle is detected by a magnetic guide outside the heat treatment furnace and by laser detection inside the heat treatment furnace.

[0005] Japanese Patent No. 6293772 Japanese Patent Application Laid-Open No. 2012-68886

[0006] In the conventional transport method using an automated guided vehicle, the magnetic guide is a method in which a magnetic tape is attached to the floor to determine the transport route. Repeated transport causes the magnetic tape to peel off. Furthermore, while the conventional transport method using an automated guided vehicle is efficient because it does not require waiting for the temperature inside the heat treatment furnace to drop after use, it does not use laser detection outside the heat treatment furnace, so the laser detection technology cannot be fully utilized in a wide area such as inside a building.

[0007] The problem to be solved by the present invention is to provide a transport method using an unmanned transport vehicle, a method for manufacturing a ceramic sintered body, and a method for manufacturing a ceramic degreased body, which can transport objects efficiently and effectively even in a large area such as inside a building.

[0008] A transport method using an automated guided vehicle capable of carrying a transport container containing an object to be transported, according to an embodiment, includes a moving step of moving the automated guided vehicle from a start position to an end position along a transport route using a laser guidance system that captures reflected light from three or more reflectors irradiated with a laser from the automated guided vehicle to determine the current position and orientation of the automated guided vehicle. In the transport method, at least one of the start position and the end position is located near a heat treatment furnace.

[0009] 1 is a diagram showing an overview of a moving step in a transfer method using an automated guided vehicle according to an embodiment. A top view showing a first example of an arrangement within a building to explain a transfer method using an automated guided vehicle according to an embodiment. A top view showing a second example of an arrangement within a building to explain a transfer method using an automated guided vehicle according to an embodiment. A top view showing an overview of a storing step and a removing step in a transfer method using an automated guided vehicle according to an embodiment. A top view showing an overview of a storing step and a removing step in a transfer method using an automated guided vehicle according to an embodiment. A top view showing an example of an arrangement position of three or more reflecting plates in a transfer method using an automated guided vehicle according to an embodiment. A top view showing an example of a distance between three or more reflecting plates in a transfer method using an automated guided vehicle according to an embodiment. A flowchart including a transfer method using an automated guided vehicle according to an embodiment. A flowchart including a transfer method using an automated guided vehicle according to an embodiment. An external perspective view showing an example of a ceramic substrate made of a ceramic sintered body manufactured by the method for manufacturing a ceramic sintered body according to an embodiment. An external view showing an example of a ceramic ball made of a ceramic sintered body manufactured by the method for manufacturing a ceramic sintered body according to an embodiment. Embodiment

[0010] A transport method using an automated guided vehicle capable of carrying a transport container containing an object to be transported, according to an embodiment, includes a moving step of moving the automated guided vehicle from a start position to an end position along a transport route using a laser guidance system that captures reflected light from three or more reflectors irradiated with a laser from the automated guided vehicle to determine the current position and orientation of the automated guided vehicle. In the transport method, at least one of the start position and the end position is located near a heat treatment furnace.

[0011] An outline of a transport method using an automated guided vehicle according to an embodiment is shown in Figure 1. In the figure, reference numeral 1 denotes the automated guided vehicle, reference numeral 2 denotes a transport route, reference numeral 3 denotes a heat treatment furnace, and reference numeral 4 denotes a waiting area. The transport route 2 includes a first transport route 21 to a fifth transport route 25. The heat treatment furnace 3 includes at least one of a degreasing furnace 31 and a sintering furnace 32. The waiting area 4 includes a first waiting area (waiting area before degreasing) 41, a second waiting area (waiting area after degreasing and before sintering) 42, and a third waiting area (waiting area after sintering) 43.

[0012] FIG. 1A shows a first mode in which the automated guided vehicle 1 moves from position P1 corresponding to the first waiting area 41 along the first transport route 21 to position Q1 on the side of the degreasing furnace 31. In this case, position P1 is the starting position, and position Q1 is the end position. The first mode shown in FIG. 1A corresponds to the movement process ST2 shown in FIG. 8 , which will be described later. Note that although the first transport route 21 is shown as a straight line, it may be a curved line, multiple straight lines connected at a corner, or a combination thereof, depending on the arrangement of the waiting area 4 and the heat treatment furnace 3 within the building. Furthermore, the "side" of the degreasing furnace 31 refers to the periphery of the degreasing furnace 31, i.e., the vicinity of the opening of the degreasing furnace 31.

[0013] 1(B) shows a second mode in which the automated guided vehicle 1 moves from position Q1 on the degreasing furnace 31 side along the second transport route 22 to position P2 corresponding to a second waiting area 42 that is not on the degreasing furnace 31 side. In this case, position Q1 is the starting point position, and position P2 is the ending point position. The second mode shown in FIG. 1(B) corresponds to the moving step ST7 shown in FIG. 8, which will be described later. Note that although the first transport route 21 is shown as multiple straight lines connected at corners, it may be a curved line, a straight line, or a combination thereof, depending on the arrangement of the waiting area 4 and the heat treatment furnace 3 within the building.

[0014] 1(C) shows a third mode in which the automated guided vehicle 1 moves from position P2 corresponding to the second waiting area 42 along the third transport route 23 to position Q2 on the side of the sintering furnace 32. In this case, position P2 is the starting position, and position Q2 is the end position. The third mode shown in FIG. 1(C) corresponds to the movement process ST8 shown in FIG. 8, which will be described later. Note that although the third transport route 23 is shown as a straight line, it may be a curved line, multiple straight lines connected at a corner, or a combination thereof, depending on the arrangement of the waiting area 4 and the heat treatment furnace 3 within the building. Furthermore, the "side" of the sintering furnace 32 refers to the periphery of the sintering furnace 32, i.e., the vicinity of the opening of the sintering furnace 32.

[0015] FIG. 1(D) shows a fourth mode in which the automated guided vehicle 1 moves from position Q2 on the degreasing furnace 31 side to position Q2 on the sintering furnace 32 side along the fourth transport route 24. In this case, position Q1 is the starting position, and position Q2 is the end position. The fourth mode shown in FIG. 1(D) corresponds to the moving step ST9 shown in FIG. 8 (described later). Note that although the fourth transport route 24 is shown as multiple straight lines connected at corners, it may be a curved line, a straight line, or a combination thereof depending on the arrangement of the waiting area 4 and the heat treatment furnace 3 within the building. Furthermore, the fourth transport route 24 from one furnace side to another furnace side is not limited to a route from the degreasing furnace to the sintering furnace. For example, it may be a route from the sintering furnace 32 side where the first sintering is performed to the sintering furnace 32 side where the second sintering is performed.

[0016] 1(E) shows a fifth mode in which the automated guided vehicle 1 is moved from position Q2 on the sintering furnace 32 side along the fifth transport route 25 to position P3 corresponding to the third waiting area 43 that is not on the sintering furnace 32 side. In this case, position Q2 is the starting point position, and position P3 is the end point position. The fifth mode shown in FIG. 1(E) corresponds to the moving process ST13 shown in FIG. 9, which will be described later. Note that although the fifth transport route 25 is shown as multiple straight lines connected at corners, it may be a curved line, a straight line, or a combination thereof, depending on the arrangement of the waiting area 4 and the heat treatment furnace 3 in the building.

[0017] 2 and 3 show examples of layouts within a building to explain a transfer method using an automated guided vehicle 1 according to an embodiment. In the figures, reference numeral 1 denotes the automated guided vehicle, reference numeral 2 denotes a transfer route, reference numeral 3 denotes a heat treatment furnace, reference numeral 5 denotes a reflector, and reference numeral W denotes a wall of the building. The reflectors 5 are disposed on the walls W or pillars of the building, and three or more reflectors are provided for one route (first reflector 51, second reflector 52, ...). FIG. 2 shows a case where the transfer route is a straight line, while FIG. 3 shows a case where the transfer route is a plurality of straight lines connected at corners.

[0018] The automated guided vehicle 1 is set with transport route data corresponding to the transport route 2. The transport route 2 can be set arbitrarily. The transport route 2 is set as a route from a waiting area 4, where an object to be transported by the automated guided vehicle 1 waits before being transported, to the side of the heat treatment furnace 3 (FIGS. 1A and 1C), or as a route from the side of the heat treatment furnace 3 to the waiting area 4 (FIGS. 1B and 1E), or as a route from one heat treatment furnace 3 to another heat treatment furnace 3 (FIG. 1D). The transport route 2 may also be set as a route from one waiting area 4 to another waiting area 4.

[0019] The automated guided vehicle 1 can carry a transport container B containing an object to be transported, and can move by itself to transport the transport container B. The automated guided vehicle 1 includes an automated guided vehicle (AGV) 11 without a forklift, and an automated guided forklift (AGF) 12 with a forklift. Fig. 4 shows a configuration in which the automated guided vehicle 11 is used as the automated guided vehicle 1, and Fig. 5 shows a configuration in which the automated guided forklift 12 is used as the automated guided vehicle 1.

[0020] As shown in FIG. 4A , a transport container B loaded on an automated guided vehicle 11 located near the heat treatment furnace 3 is lifted by a forklift 10 located near the automated guided vehicle 11 before heat treatment (as shown in FIG. 4A ) and stored in the heat treatment furnace 3 (as shown in FIG. 4B , corresponding to storage steps ST3 and ST10 in FIG. 8 , which will be described later). After heat treatment, the transport container B stored in the heat treatment furnace 3 is removed by the forklift 10 located near the automated guided vehicle 11 (as shown in FIG. 4B , corresponding to removal step ST5 in FIG. 8 and removal step ST12 in FIG. 9 , which will be described later) and loaded onto the automated guided vehicle 11 (as shown in FIG. 4A ). Positions Q1 and Q2 are positions that do not interfere with the movement of the forklift 10. If there are multiple heat treatment furnaces 3, multiple transport routes 2 can be established. Examples of the heat treatment furnace 3 include a degreasing furnace 31, a sintering furnace 32, and a drying device.

[0021] As shown in FIG. 5A, the automated transport forklift 12 carrying the transport container B moves to the side of the heat treatment furnace 3 (shown in FIG. 5A). The transport container B loaded on the automated transport forklift 12 located near the heat treatment furnace 3 is then stored in the heat treatment furnace 3 before heat treatment (shown in FIG. 5B, corresponding to storing steps ST3 and ST10 in FIG. 8, which will be described later). After heat treatment, the transport container B stored in the heat treatment furnace 3 is removed by the automated transport forklift 12 located near the automated transport vehicle 11 (shown in FIG. 5B, corresponding to removing step ST5 in FIG. 8 and removing step ST12 in FIG. 9, which will be described later). The automated transport forklift 12 then moves to the waiting area 4 (shown in FIG. 5A). Positions Q1 and Q2 are located directly in front of the opening of the heat treatment furnace 3.

[0022] The current position and orientation of the automated guided vehicle 1 on the transport route 2 are determined by a laser guidance system that captures the light reflected from reflectors 5 when a laser from the automated guided vehicle 1 is shone on it. The laser guidance system shines a pulsed laser beam on the surrounding reflectors 5 and measures the time it takes for the reflected light to return, thereby determining the distance to an object and the direction in which the automated guided vehicle 1 is facing. Layout information for the reflectors 5 is input into the system in advance, and the current position information of the automated guided vehicle 1 can be calculated by triangulation. The automated guided vehicle 1 is equipped with a laser scanner U. The laser scanner U has the function of emitting a laser and the function of detecting the laser reflected from the reflectors 5. Note that the laser emission function and the laser detection function may be separate devices.

[0023] The unmanned transport vehicle 1 detects its position using three or more reflectors 5. This is because a laser beam emitted from a laser scanner U mounted on the unmanned transport vehicle 1 is reflected by the reflectors 5, and the reflected laser beam is read by the laser scanner U to detect the position. Using three or more reflectors 5 means that three or more reflected laser beams are detected, thereby improving the accuracy of position detection.

[0024] The reflectors 5 are arranged around the transport route 2. Three or more reflectors 5 are arranged for one transport route 2. The reflectors 5 are preferably arranged at positions that are different in one or more of the following: front, rear, left, right, or height on the transport route 2. For example, three or more reflectors 5 may be arranged so as to sandwich the traveling unmanned transport vehicle 1 from the front and rear. Another example is a method of arranging three or more reflectors 5 so as to sandwich the unmanned transport vehicle 1 from the left and right. Another example is a method of arranging three or more reflectors 5 at different heights on the front, rear, left, and right of the unmanned transport vehicle 1. Furthermore, the three or more reflectors 5 arranged on the front, rear, left, and right of the unmanned transport vehicle 1 may be arranged symmetrically or asymmetrically with respect to a vertical plane including the transport route 2.

[0025] The three or more reflectors 5 being provided at positions that are different in at least one of the front, rear, left, right, and height of the transport route 2 means that, when viewed from the center of the automated transport vehicle 1, the three or more reflectors 5 are arranged asymmetrically with respect to a vertical plane that includes the transport route 2. By arranging the reflectors 5 asymmetrically, it becomes easier to perform three-dimensional position detection. Furthermore, in the case of an asymmetrical arrangement, there is no need to arrange the three or more reflectors 5 regularly, which increases the degree of freedom, and therefore it is possible to effectively utilize the available space within the building.

[0026] It is preferable that three of the three or more reflectors 5 be arranged so that they can surround the unmanned transport vehicle 1 (laser scanner U) traveling on the transport route 2 in a triangle. By surrounding the unmanned transport vehicle 1 in a triangle, the accuracy of detecting the position of the unmanned transport vehicle 1 is improved. In addition, the accuracy of detecting obstacles is also improved. From this point of view, it is preferable that the number of three or more reflectors 5 is four or more.

[0027] If the radius of the automated guided vehicle 1 (laser scanner U) moving along the transport route 2 is R, it is preferable that two or more of the three or more reflectors 5 be located within 25 meters of the radius R. FIG. 6 shows an example of an arrangement in which two reflectors 5 are located within 25 meters of the radius R. In the figure, symbols U1 to U4 indicate the positions of the automated guided vehicle 1, symbols P1 to P3 indicate positions corresponding to the waiting area 4, symbols Q1 and Q2 indicate positions near the heat treatment furnace 3, symbol 2 indicates the transport route, symbol 5 indicates a reflector, and symbols 51 to 54 indicate individual reflectors among the reflectors 5. Furthermore, symbols 61 to 64 indicate circles with a radius R at positions U1 to U4 of the automated guided vehicle 1. Providing two or more reflectors 5 within 25 meters of the radius R from the automated guided vehicle 1 moving along the transport route 2 means that, as shown in FIG. 6, no matter which of positions U1 to U4 the automated guided vehicle 1 is located on the transport route 2, there are two or more reflectors 5 within 25 meters of the radius R. By having two or more reflectors 5 within a radius R of 25 m, the accuracy of detecting the position of the unmanned transport vehicle 1 is improved.

[0028] The shortest distance from the automated guided vehicle 1 (laser scanner U) moving along the transport route 2 to each of the three or more reflectors 5 is not particularly limited, but is preferably 2 m or more. A shortest distance of less than 2 m does not adversely affect the detection accuracy of the automated guided vehicle 1, but may adversely affect the degree of freedom of the transport route 2. For this reason, it is preferable that the reflectors 5 be located at a shortest distance from the automated guided vehicle 1 moving along the transport route 2 within a range of 2 m to 25 m, and even more preferably 5 m to 22 m. The height at which the reflectors 5 are arranged is preferably within a range of 0.5 m to 5 m. The upper limit on the number of reflectors 5 per 25 m of transport distance is not particularly limited, but it is preferable that there be 10 or fewer reflectors per 25 m of transport distance.

[0029] Furthermore, it is preferable that the difference in the distance between the two nearest reflectors 5 (hereinafter referred to as the "nearest distance"), using each reflector 5 as a reference, is within 10 m. A conceptual diagram of the nearest distance is shown in Figure 7. In the figure, reference numeral 1 denotes the unmanned transport vehicle, reference numeral 2 denotes the transport route, reference numeral 5 denotes a reflector, reference numerals 51 to 55 denote the first to fifth reflectors, respectively, and reference numeral 7 denotes the nearest distance using the first reflector 51 as a reference.

[0030] The two closest reflectors 5 refer to two reflectors 5 whose centers are located at a short distance from the center of an arbitrary reflector 5. The arbitrary reflector 5 is defined as the first reflector 51. The two reflectors 5 located at a short distance from the first reflector 51 are defined as the second reflector 52 and the third reflector 53. When the first reflector 51 is used as a reference, the two reflectors 5 located at a short distance are the second reflector 52 and the third reflector 53. The shortest distance 7 between the first reflector 51 and the second reflector 52 is the first shortest distance 71. Furthermore, the distance between the first reflector 51 and the third reflector 53 is the second shortest distance 72. A difference in the shortest distances of 10 m or less means that the following formula (1) is satisfied. |First shortest distance - second shortest distance|≦10 m ... (1)

[0031] 7, the closest distance 7 will be described using the first reflector 51 as an example. The two closest reflectors 5 relative to the first reflector 51 are the second reflector 52 and the third reflector 53. The distance between the first reflector 51 and the second reflector 52 is the first closest distance 71, and the distance between the first reflector 51 and the third reflector 53 is the second closest distance 72.

[0032] 7, a case where the fourth reflector 54 is used as a reference will be described. In this case, the distance between the fourth reflector 54 and the third reflector 53 is the first closest distance, and the distance between the fourth reflector 54 and the fifth reflector 55 is the second closest distance. Even when the fourth reflector 54 is used as a reference, it is preferable that the above formula (1) be satisfied.

[0033] Even when four or more reflectors 5 are used, it is preferable that the difference between the two nearest distances based on each reflector 5 be within 10 m. This can improve the position detection accuracy of the automated guided vehicle 1.

[0034] Furthermore, it is preferable that the automated guided vehicle 1 is provided with an obstacle sensor that detects obstacles (including people). The transport route 2 can be set to any desired path. Furthermore, multiple sintering furnaces 32 or degreasing furnaces 31 may be placed, and the transport destination may be changed each time. A person or object may be placed on the transport route 2 as an obstacle. By providing an obstacle sensor on the automated guided vehicle 1, the travel of the automated guided vehicle 1 can be temporarily stopped. This makes it possible to avoid the risk of the automated guided vehicle 1 colliding with an obstacle. Furthermore, the automated guided vehicle 1 may be allowed to travel again after the obstacle has disappeared. By including such a program when setting transport route data, safety can also be ensured.

[0035] The technology of an autonomous control system can be adopted in the transportation method using the automated guided vehicle according to the embodiment. The autonomous control system utilizes SLAM (Simultaneous Localization and Mapping) to grasp the current position of the automated guided vehicle 1 and the situation around it, and can make a "decision" as to what action the automated guided vehicle 1 should take. Then, by executing that decision as an actual "operation," the automated guided vehicle moves from the start position to the end position while avoiding obstacles.

[0036] Furthermore, the transported objects arranged in the transport container B transported by the automatic transport vehicle 1 are preferably any one of ceramic molded bodies, degreased ceramic bodies, and sintered ceramic bodies.

[0037] The method for manufacturing a ceramic sintered body according to the embodiment will be described with reference to Fig. 8 and Fig. 9. Hereinafter, the case of Fig. 4 (where the automated guided vehicle 1 is an automated guided vehicle 11) will be described as an example, out of Figs. 4 and 5.

[0038] The method for manufacturing a ceramic sintered body according to the embodiment includes a transporting step F1, F2, or F3. The transporting step F1 may include a pre-degreasing transporting step ST2 and a storing step ST3. The transporting step F2 may include at least one of transporting steps ST7 to ST9 and at least one of a removing step ST5 and a storing step ST10. The transporting step F3 may include a post-sintering transporting step ST13 and a removing step ST12.

[0039] First, in the molding / vehicle loading step ST1, ceramic powder is molded to obtain a ceramic molded body, and the transport container B containing the ceramic molded body is loaded onto the automatic guided vehicle 11. Examples of the ceramic powder include a single ceramic powder that serves as a base material, or a mixed powder obtained by mixing the ceramic powder that serves as a base material with a sintering aid. The ceramic powder that serves as a base material is preferably one selected from silicon nitride, aluminum nitride, aluminum oxide, and zirconium oxide. The base material refers to the material that is most abundant.

[0040] The ceramic molded body is formed by molding ceramic powder. Furthermore, when producing the ceramic molded body, a binder or a solvent is added as necessary. Any molding method can be used. Examples of molding methods include doctor blade molding, injection molding, slip casting, metal molding, rolling granulation, and cold isostatic pressing (CIP). These molding methods may also be combined.

[0041] The ceramic molded body loaded onto the vehicle in the molding / loading process ST1 is subjected to a degreasing process as necessary. When the degreasing process is performed, the pre-degreasing transfer process ST2 moves the automated guided vehicle 11 (shown in FIG. 4) carrying the transport container B containing the ceramic molded body from the first waiting area 41 along the transport route 21 to the degreasing furnace 31 (shown in FIG. 1(A)). Next, in the storage process ST3, a forklift 10 (shown in FIG. 4) lifts the transport container B loaded onto the automated guided vehicle 11 and stores the transport container B in the degreasing furnace 31. Next, in the degreasing process ST4, the ceramic molded body placed in the transport container B in the degreasing furnace 31 is degreased.

[0042] The degreasing step ST4 is a step for removing binders and solvents from the ceramic compact. The degreasing step ST4 is preferably performed at a temperature in the range of 400°C to 800°C. The degreasing step ST4 is also preferably performed in the air or in an inert atmosphere. Examples of inert atmospheres include a nitrogen atmosphere and an argon atmosphere. By performing the degreasing step, a degreased body can be obtained. The furnace used in the degreasing step ST4 is called a degreasing furnace 31 (an example of a heat treatment furnace 3).

[0043] When degreasing is performed, in a removal step ST5, the forklift 10 removes the transport container B from the degreasing furnace 31 and loads the transport container B onto the automated guided vehicle 11. Next, when moving to the second waiting area 42 (YES in step ST6), in a post-degreasing movement step ST7, the automated guided vehicle 11 carrying the transport container B containing the ceramic degreased body is moved from the degreasing furnace 31 along the transport route 22 to the second waiting area 42 (shown in FIG. 1(B)).

[0044] Next, the ceramic green body or the ceramic degreased body is subjected to a sintering process. In a pre-sintering transfer step ST8, the automated guided vehicle 11 carrying the transfer container B containing the ceramic degreased body is moved from the second waiting area 42 along the transfer route 23 to the sintering furnace 32 side (shown in FIG. 1(C)). Alternatively, if the automated guided vehicle 11 is not moved to the second waiting area 42 (NO in step ST6), the automated guided vehicle 11 carrying the transfer container B containing the ceramic degreased body is moved from the degreasing furnace 31 along the transfer route 24 to the sintering furnace 32 side (shown in FIG. 1(D)) in a post-degreasing / pre-sintering transfer step ST9.

[0045] Next, in a storing step ST10, the forklift 10 lifts the transport container B loaded on the automatic guided vehicle 11 and stores the transport container B in the sintering furnace 32. Next, in a sintering step ST11 shown in Fig. 9, the degreased ceramic body (or the ceramic compact if no degreasing treatment is performed) placed in the transport container B in the degreasing furnace 31 is sintered.

[0046] The sintering step ST11 is preferably performed at a temperature in the range of 1500°C to 2000°C. Any method can be used in the sintering step ST11. Examples of sintering methods include atmospheric sintering, pressure sintering, hot isostatic pressing (HIP), and reactive sintering. These methods may also be combined. Examples of the sintering atmosphere include air, an inert atmosphere, and a reducing atmosphere. Examples of inert atmospheres include a nitrogen atmosphere and an argon atmosphere. Examples of reducing atmospheres include a carbon-containing atmosphere and a hydrogen-containing atmosphere. The furnace used in the sintering step ST11 is called a sintering furnace 32 (an example of a heat treatment furnace 3).

[0047] Next, in a removal process ST12, the forklift 10 removes the transport container B from the sintering furnace 32 and loads the transport container B onto the automated guided vehicle 11. Next, in a post-sintering transfer process ST13, the automated guided vehicle 11 carrying the transport container B containing the ceramic sintered body is moved from the sintering furnace 32 along the transfer route 25 to the third waiting area 43 (shown in FIG. 1(E)).

[0048] In the degreasing step ST4, if a plurality of ceramic green bodies are placed in the transport container B, a plurality of ceramic degreased bodies can be obtained. Furthermore, in the sintering step ST11, if a plurality of ceramic degreased bodies are placed in the transport container B, a plurality of ceramic sintered bodies can be obtained. The sintering step ST11 can also be performed twice. In this case, after sintering in the sintering furnace 32 where the first sintering step ST11 is performed, the automated guided vehicle 11 is moved from that sintering furnace 32 to the sintering furnace 32 where the second sintering step ST11 is performed. This allows for the production of a ceramic sintered body (a ceramic sintered body subjected to the second sintering step). Placing a plurality of ceramic green bodies, ceramic degreased bodies, or ceramic sintered bodies in the transport container B can improve mass productivity.

[0049] It is preferable to place a plurality of ceramic green bodies, degreased ceramic bodies, or sintered ceramic bodies in the transfer container B and perform two or more heat treatment steps (degreasing step ST4 and sintering step ST11) while the bodies are still in the same transfer container B. This eliminates the need to transfer the objects to the transfer container B. Naturally, this may be done as needed.

[0050] The ceramic green body, degreased ceramic body, or sintered ceramic body may have any shape. Various shapes can be used, such as a plate, a disk, a column, a sphere, a rod, or a concave-convex shape. In the pick-up and polishing step ST14, the ceramic sintered body is picked up from the transfer container B and polished to produce a ceramic substrate or a ceramic ball made of the ceramic sintered body.

[0051] 10 and 11 show examples of the configuration of a ceramic sintered body manufactured by the method for manufacturing a ceramic sintered body according to this embodiment. Reference numeral 8 in FIG. 9 denotes a ceramic substrate made of a ceramic sintered body, and reference numeral 9 in FIG. 11 denotes a ceramic ball made of a ceramic sintered body. The ceramic substrate 8 is obtained by polishing the surface of a plate-shaped ceramic sintered body and can be used as a substrate for a semiconductor device. The ceramic ball 9 is obtained by polishing the surface of a spherical ceramic sintered body and can be used as a bearing ball or a grinding machine media. Another example is a ceramic ball having a band-shaped portion on the circumference of a sphere. A ceramic ball having a band-shaped portion is sometimes called a bare ball. A bare ball refers to a ceramic ball (including a ceramic ball having a band-shaped portion) before polishing.

[0052] The transfer container B is preferably made of a highly heat-resistant material. Examples of highly heat-resistant transfer containers B include those made of carbon and boron nitride. A highly heat-resistant transfer container B can be used without problems in the degreasing step ST4 and the sintering step ST11.

[0053] The above-described transport method using the automated transport vehicle 1 can improve the transport accuracy of the transport container B and efficiently transport the transport container B. Furthermore, in order to obtain a ceramic sintered body, the sintering step ST11 is required, but the degreasing step ST4 is optional.

[0054] The debinding step ST4 and the sintering step ST11 are performed in a high-temperature environment. It takes time for the temperature inside the heat treatment furnace 3 and the debound ceramic or sintered ceramic body after heat treatment to cool to room temperature. By using the automated guided vehicle 1, the transfer steps ST2, ST7 to ST9, and ST13 of the transport container B, the storage steps ST3 and ST10, and the removal steps ST5 and ST12 can be performed before the temperature cools to room temperature. This not only improves the efficiency of the transport work but also ensures the safety of the workers.

[0055] Furthermore, the transport method using the automated transport device 1 according to the embodiment can be used in a method for manufacturing a ceramic sintered body or a method for manufacturing a ceramic degreased body.

[0056] The method for manufacturing a ceramic sintered body according to the embodiment may include a storing step ST10 to a post-sintering transfer step ST13. Of these, it is preferable to use a transport method using an automated transport vehicle 1 in at least one of the storing step ST10, the removing step ST12, and the post-sintering transfer step ST13.

[0057] The method for manufacturing a ceramic degreased body according to the embodiment may include a storing step ST3 to a post-degreasing / pre-sintering transfer step ST9. Of these, it is preferable to use a transport method using an automated transport vehicle 1 in at least one of the storing step ST3, the removing step ST5, the post-degreasing transfer step ST7, the pre-sintering transfer step ST8, and the post-degreasing / pre-sintering transfer step ST9.

[0058] As mentioned above, the degreasing step ST4 and the sintering step ST11 are performed in a high-temperature environment. Therefore, using the automated guided vehicle 1 for transportation is effective not only in terms of efficiency but also in terms of safety. Furthermore, by using the automated guided vehicle 1 as an automated guided vehicle forklift 12, not only the moving steps ST2, ST7 to ST9, and ST13 but also the storing steps ST3, ST10 and the removing steps ST5, ST12 can be automated. Since no operator intervention is required, problems such as dropping the transport container B do not occur. This prevents damage to the ceramic molded body, the degreased ceramic body, and the sintered ceramic body. This also improves the yield of the degreased ceramic body and the sintered ceramic body. Furthermore, the storing steps ST3, ST10 and the removing steps ST5, ST12 can be performed even when the furnace temperature is 50°C or higher. Since there is no need to wait for the furnace to cool to room temperature, not only safety but also time efficiency is improved. Furthermore, the transport method using the automated guided vehicle 1 according to the embodiment can also be used to transport a laminated body composed of a ceramic substrate, a brazing material layer, and a metal plate. A laminated body in which a ceramic substrate, a brazing material layer, and a metal plate are laminated is formed into a bonded body by thermal bonding.

[0059] (Examples) (Examples 1 to 6, Comparative Example 1) In the transport methods according to the Examples and the Comparative Example, an unmanned transport forklift 12 (shown in FIG. 5) equipped with a forklift was prepared as the unmanned transport device 1. In the transport methods according to the Examples, the unmanned transport forklift 12 was equipped with an obstacle sensor. On the other hand, in the transport method according to the Comparative Example, the unmanned transport forklift 12 was not equipped with an obstacle sensor. A ceramic molded body or a ceramic degreased body was placed as the transported object in a transport container B mounted on the unmanned transport forklift 12. Table 1 shows the presence or absence of obstacle sensors and the transport route 2, and Tables 1 and 2 show the number and arrangement of reflectors 5 per transport route 2.

[0060] In the examples, three or more reflectors 5 were arranged asymmetrically with respect to a vertical plane including the transport route 2. Furthermore, as shown in Table 2, in Examples 1 to 5, three of the three or more reflectors 5 were arranged to surround the unmanned transport forklift 12 on the transport route 2 in a triangle, while in Example 6, reflectors 5 were provided only on the opposite side of the transport route 2. Furthermore, Examples 4 to 6 shown in Table 1 each include two transport routes 2 ([1] and [2]). In Table 2, the total number of reflectors 5 in Examples 4 to 6 indicates the total number on the two transport routes 2 and the individual number on each of the two transport routes 2. For example, in Table 2, the total number of reflectors 5 in Example 4 is 12, the individual number of reflectors 5 on transport route 2 [1] is 6, and the individual number of reflectors 5 on transport route 2 [2] is 6.

[0061]

[0062]

[0063] In the examples and comparative examples, transport route data was set for the automated transport forklift 12. In test 1, for each example and comparative example, the automated transport forklift 12 was run 10 times along the transport route 2 shown in Table 1 to check for the presence or absence of position detection errors, i.e., the presence or absence of transport errors, for the automated transport forklift 12. In examples 4 to 6, the automated transport forklift 12 was run 10 times, with the transport route 2 [1] and the transport route 2 [2] being treated as a pair. In test 2, for each example and comparative example, an obstacle was placed on the transport route 2, and the automated transport forklift 12 was run 10 times along the transport route 2 to check the number of times it was able to stop without hitting the obstacle (number of normal stops / number of runs). In examples 4 to 6, obstacles were placed on both the transport route 2 [1] and the transport route 2 [2], and the automated transport forklift 12 was run 10 times. In test 2, the obstacles were placed in different locations for each of the 10 runs. After the automatic guided forklift 12 was stopped and the obstacle was removed from the transport route 2, the automatic guided forklift 12 was made to travel again based on the transport route data. The results of tests 1 and 2 are shown in Table 3.

[0064]

[0065] As can be seen from the results of Test 1 in Table 3, no transport errors occurred with the transport methods according to the examples. Also, as can be seen from the results of Test 2 in Table 3, with the transport methods according to Examples 1 to 5, even if there was an obstacle on the transport route 2, the unmanned transport forklift 12 was able to stop without hitting the obstacle at all. In particular, in Examples 4 and 5, there were two transport routes 2 and the distance was long, but even so, no transport errors occurred.

[0066] Furthermore, when the reflectors 5 are arranged so as not to surround the unmanned transport forklift 12 in a triangle, as in Example 6, there were three reflectors 5 per transport route 2 (in Example 6, two transport routes 2 were included, so the total number of reflectors 5 was six), and there was one collision with an obstacle. It was found that the accuracy of position detection using the reflectors 5 varies depending on the location of the obstacle. For this reason, it is preferable to arrange the reflectors 5 so as to surround the unmanned transport forklift 12 in a triangle. Furthermore, the number of reflectors 5 per transport route 2 may be three or more, but it is preferable to have four or more as in Examples 1 to 5.

[0067] Furthermore, because the unmanned transport device 1 is the unmanned transport forklift 12, it was possible to automatically perform the storing steps ST3 and ST10 of the transport container B into the degreasing furnace 31 or the sintering furnace 32, and the removing steps ST5 and ST12. The degreasing step ST4 and the sintering step ST11 were performed in a high-temperature environment, but it was possible to perform the storing steps ST3 and ST10 and the removing steps ST5 and ST12 without waiting for the temperature to drop to room temperature.

[0068] In contrast, in Comparative Example 1, when two reflectors 5 were used, a position detection error occurred in the unmanned transport forklift 12, resulting in a transport error. Also, in Comparative Example 1, the unmanned transport forklift 12 was not equipped with an obstacle sensor, so the position of the obstacle could not be detected and the unmanned transport forklift 12 collided with the obstacle and came to a stop.

[0069] According to at least one of the embodiments described above, even in a large area such as inside a building, the transported items can be transported efficiently and effectively without transport errors, without waiting for the heat treatment furnace 3 or the transported items to cool.

[0070] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other.

Claims

1. A transportation method using an unmanned transport vehicle capable of carrying a transport container containing an object to be transported, the transportation method comprising a transportation step of moving the unmanned transport vehicle from a start position to an end position along a transport route using a laser guidance system that captures reflected light from three or more reflectors onto which a laser from the unmanned transport vehicle is directed and determines the current position and orientation of the unmanned transport vehicle, and at least one of the start position and the end position is located on the side of a heat treatment furnace.

2. A transportation method using an unmanned transport vehicle as described in claim 1, characterized in that the three or more reflectors are installed at positions that change one or more of the following: front, back, left, right, and height of the unmanned transport vehicle.

3. A transportation method using an unmanned transport vehicle according to claim 1 or 2, characterized in that two or more reflectors are provided within a radius of 25 m from the unmanned transport vehicle moving along the transportation route.

4. A transportation method using an unmanned transport vehicle as set forth in claim 1 or claim 2, characterized in that the difference in distance between each of the three or more reflectors and the two nearest reflectors is within 10 m.

5. A transportation method using an automatic transport vehicle according to claim 3, characterized in that the difference in distance between each of the three or more reflectors and the two nearest reflectors is within 10 m.

6. A method of transporting using an unmanned transport vehicle according to claim 1 or 2, characterized in that the transported object is a transport container containing one of a ceramic molded body, a ceramic degreased body, and a ceramic sintered body.

7. A method of transporting using an unmanned transport vehicle according to claim 3, wherein the transported object is a transport container containing one of a ceramic molded body, a ceramic degreased body, and a ceramic sintered body.

8. A method of transporting using an unmanned transport vehicle according to claim 5, wherein the transported object is a transport container containing one of a ceramic molded body, a ceramic degreased body, and a ceramic sintered body.

9. A transportation method using an unmanned transport vehicle as described in claim 1 or claim 2, characterized in that the movement process includes a sensor provided on the unmanned transport vehicle that detects obstacles on the transportation route, thereby preventing the unmanned transport vehicle from colliding with the obstacle.

10. A transportation method using an unmanned transport vehicle as described in claim 3, characterized in that the movement process includes a sensor provided on the unmanned transport vehicle that detects obstacles on the transportation route, thereby preventing the unmanned transport vehicle from colliding with the obstacle.

11. A transport method using an unmanned transport vehicle as described in claim 1 or claim 2, characterized in that the transport process further includes a storage process of lifting the transport container loaded on the unmanned transport vehicle and storing it in the heat treatment furnace, or a removal process of removing the transport container stored in the heat treatment furnace.

12. A transport method using an unmanned transport vehicle as described in claim 3, characterized in that the transport process further includes a storage process of lifting the transport container loaded on the unmanned transport vehicle and storing it in the heat treatment furnace, or a removal process of removing the transport container stored in the heat treatment furnace.

13. A method for producing a ceramic sintered body, comprising: a conveying step according to claim 1; and a sintering step of sintering the conveyed ceramic compact or degreased ceramic body in a sintering furnace as the heat treatment furnace.

14. A method for producing a ceramic sintered body, comprising: a conveying step according to claim 3; and a sintering step of sintering the conveyed ceramic compact or degreased ceramic body in a sintering furnace as the heat treatment furnace.

15. A method for producing a ceramic sintered body, comprising: a conveying step according to claim 8; and a sintering step of sintering the conveyed ceramic compact or degreased ceramic body in a sintering furnace as the heat treatment furnace.

16. A method for producing a degreased ceramic body, comprising: a conveying step as set forth in claim 1; and a degreasing step of degreasing the ceramic molded body as the conveyed object in a degreasing furnace as the heat treatment furnace.

17. A method for producing a degreased ceramic body, comprising: a conveying step as set forth in claim 3; and a degreasing step of degreasing the ceramic molded body as the conveyed object in a degreasing furnace as the heat treatment furnace.

18. A method for producing a degreased ceramic body, comprising: a conveying step as set forth in claim 8; and a degreasing step of degreasing the ceramic molded body as the conveyed object in a degreasing furnace as the heat treatment furnace.

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