Method for manufacturing mold

Abstract

Provided is a method for manufacturing a mold capable of coping with a plurality of types and small batches. In the cutting step, the upper and lower sand molds are each cut to form a mold fitting surface, and the upper and lower sand molds are each cut with the mold fitting surfaces as a reference to form cavities (C1, C2). In the mold-closing step, at least three points (PU1-3) that are not positioned on the same straight line in the mold-closing surface of the lower sand mold placed on the placement surface are measured, and the Z coordinates of each point are identified. In addition, at least three points (PL1 to PL3) that are not positioned on the same straight line are measured on the mold-fitting surface of the upper sand mold held by the holding robot arm, and the Z coordinates of each point are identified. Afterwards, mold closing is performed in a manner that the mold closing surfaces (SmU, SmL) of the upper and lower sand molds are kept parallel.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a casting mold, and more specifically, to a method for manufacturing a casting mold comprising kneading molding sand and a binder, filling the mixture into a sand box, pressurizing the mixture so that the mixture solidifies in the sand box to produce a sand block, and performing a cutting step and a mold assembly step to produce a sand mold. Background Art

[0002] Regarding the manufacturing method of the above-mentioned casting mold, Patent Document 1 is known for the cutting process, and Patent Document 2 is known for the mold closing process. In the former, the molding mold and cutting of the sand block are combined to shorten the cutting process. In the latter, the reference model blocks 24 to 27 are used for the molding mold, and the reference models 28 to 31 are formed on the sand mold, and the sand mold is closed based on the reference model.

[0003] However, in order to meet the needs of small-batch production of multiple varieties of castings, any existing technology is insufficient. In the former, the sand block molding mold cannot cope with multiple varieties, and in the latter, the final size of the sand block molding is adjusted as a prerequisite. In small batches, the dimensional error caused by the curing conditions cannot guarantee the accuracy of the reference model.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-131901

[0007] Patent Document 2: Japanese Patent Application No. 2019-536636 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In view of the above-mentioned conventional actual situation, an object of the present invention is to provide a method for manufacturing casting molds capable of handling a large variety of small batches.

[0010] Means for solving problems

[0011] In order to achieve the above-mentioned purpose, the characteristic structure of the manufacturing method of the casting mold of the present invention is that the molding sand and the binder are mixed and filled into the sand box and pressurized so that they are solidified in the sand box to make a sand block, and the sand mold is manufactured through a cutting process and a mold closing process, wherein it comprises: a processing head, which is operated by a robot and performs cutting processing on the sand block to cut out upper and lower sand molds; and a holding robot arm, which is operated by a robot and holds the upper sand mold so that the mold closing surfaces forming the mold cavity in the upper and lower sand molds are matched with each other, and the Z axis of the specified Z coordinate is oriented in the up and down direction, and the processing head is in the In the cutting process, the upper and lower sand molds are respectively cut to form the joining surfaces, and the upper and lower sand molds are respectively cut to form the mold cavity based on the joining surfaces. In the closing process, at least three points that are not located on the same straight line are measured on the joining surface of the lower sand mold placed on the loading surface, and the Z coordinate of each point is identified. In addition, at least three points that are not located on the same straight line are measured on the joining surface of the upper sand mold held by the holding robot arm, and the Z coordinate of each point is identified. Then, the holding robot arm is used to close the upper and lower sand molds while keeping the joining surfaces of the upper and lower sand molds in parallel.

[0012] According to this structure, the processing head cuts and forms the joint surfaces on the upper and lower sand molds in the cutting process, and cuts and forms the mold cavity on the upper and lower sand molds based on the joint surfaces, so that even if the finished size of the sand block after solidification is different, the mold cavity can be accurately formed. In addition, in the mold closing process, at least three points that are not located on the same straight line are measured on the joint surface of the lower sand mold placed on the loading surface, and the Z coordinates of each point are identified, and at least three points that are not located on the same straight line are measured on the joint surface of the upper sand mold held by the holding robot arm, and the Z coordinates of each point are identified, and then, the holding robot arm is used to close the upper and lower sand molds in a posture that the joint surfaces are kept parallel, so that the upper and lower sand molds can be accurately closed regardless of the posture of the lower sand mold. The molding mold of the sand block can be used in different castings, and different sand molds can be manufactured only by cutting, so it can cope with small batches of multiple varieties.

[0013] In the above features, it is preferred that the XY coordinates in the horizontal direction are defined by the XY axis orthogonal to the Z axis, the processing head cuts and forms at least two horizontal positioning surfaces oriented at the intersection angle of the XY axis near the mold-joining surfaces of the upper and lower sand molds in the cutting process, the XY coordinates of the horizontal positioning surfaces of the upper and lower sand molds are identified in the mold-joining process, and the horizontal positions of the upper and lower sand molds are aligned and the molds are joined using the holding robot arm. According to this feature, the horizontal positioning surfaces are cut without cutting other horizontal surfaces, and accurate horizontal positioning can be performed while limiting the amount of sand cutting to a minimum.

[0014] Preferably, at least one of the at least two transverse positioning surfaces is disposed at two or more separated positions (one transverse positioning surface is cut at two or more positions to separate the transverse positioning surfaces). By disposing at least one of the transverse positioning surfaces at two or more separated positions, the inclination of the side of the transverse positioning surface can be detected, and the transverse mold fitting becomes more accurate.

[0015] Preferably, the sand blocks constituting the upper and lower sand molds are convex polygons in a plan view, and the lateral positioning surface is formed at the corners of the convex polygons.

[0016] Preferably, the convex polygon is rectangular, and the lateral positioning surface has different cutting lengths at adjacent corners and opposite corners of the rectangle, and is formed to have the same cutting length in the upper and lower sand molds. According to this structure, when the upper and lower sand molds are in different rotational positions during mold closing, it can be immediately found by visual inspection, image recognition, etc., especially when the lateral positioning surfaces are formed at all corners of the sand mold.

[0017] Preferably, in addition to the two transverse positioning surfaces, at least two other transverse positioning surfaces processed by the robot and all non-parallel to each other are provided near the mold-joining surfaces of the upper and lower sand molds, and the mold-joining is confirmed by identifying the XY coordinates of two points on the other transverse positioning surfaces of the upper and lower sand molds. In this way, the accuracy of the mold-joining and the cutting error can be confirmed.

[0018] Preferably, when the robot performs cutting, the upper side of the sand block is the constituent surface of the cavity, and a vertical wall portion is provided on the side surface near the lower surface of the sand block, so that the positioning piece abuts against the vertical wall portion as a reference for the horizontal coordinate of the robot's cutting. According to this structure, the sand block can be more accurately tilted and aligned with the coordinates, thereby reducing the amount of cutting. That is, if the sand block is tilted relative to the coordinates, the amount of cutting needs to be increased in order to ensure accuracy, but in the present invention, this necessity is reduced.

[0019] Preferably, the holding robot arm is provided with a coordinate measurement sensor, and after the lower sand mold is placed on the placing surface on which the lower sand mold is placed, the coordinate measurement sensor is used to identify the coordinates of the lower sand mold placed on the placing surface, and another coordinate measurement sensor is provided at a portion connected to the placing surface on which the lower sand mold is placed, and the coordinates of the upper sand mold in the holding state of the upper sand mold held by the holding robot arm are identified by the other coordinate measurement sensor. According to this structure, the above-mentioned coordinates are measured in a state where the lower sand mold is placed on the placing surface, and the above-mentioned coordinates are measured in a state where the upper sand mold is held by the holding robot arm, and in a state where the positional relationship between the two is understood, the molds can be closed while limiting the variable factors to a minimum, so that the molds can be closed accurately.

[0020] Effects of the Invention

[0021] According to the characteristic structure of the method for manufacturing a casting mold according to the present invention, a method for manufacturing a casting mold capable of coping with multiple varieties and small batches through reasonable cutting and mold assembly can be provided. In addition, according to other characteristic structures of the present invention, the amount of sand mold cutting is limited to a minimum, and the processing can be rationalized to further promote the coping with multiple varieties and small batches.

[0022] Other objects, structures, and effects of the present invention will become more apparent from the following detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an explanatory diagram showing an overview of the entire process.

[0024] Figure 2 The figures show the molding process, (a) is a longitudinal sectional view after the molding die is separated, (b) is a longitudinal sectional view during the molding process, and (c) is a top view of the state after the molding die is removed.

[0025] Figure 3 The figure shows a cutting machine that performs a cutting process, wherein (a) is a side view and (b) is a top view of a base.

[0026] Figure 4 The figure shows a mold-closing device for performing a mold-closing process, wherein (a) is a top view and (b) is a front view.

[0027] Figure 5 express Figure 4 Near the holding robot arm, (a) is the front view, and (b) is the top view.

[0028] Figure 6 It is a three-dimensional picture of the sand mold.

[0029] Figure 7 This is the front view of the sand mold.

[0030] Figure 8 It is an unfolded top view of the sand mold with the Y-axis as the axis of symmetry.

[0031] Fig. 9 The figures show the matching process of the coordinates of the upper sand mold and the lower sand mold, (a) shows the state before the coordinate matching, and (b) shows the state after the coordinate matching. DETAILED DESCRIPTION

[0032] Next, the present invention will be described in further detail with reference to the drawings as appropriate.

[0033] like Figure 1 As shown, the manufacturing method of the sand mold of the present invention (the whole manufacturing process ST001) comprises: a molding process ST100, in which the molding sand and the binder are mixed and filled into a sand box and pressurized so as to solidify in the mold box to make a sand block; a cutting process ST200, in which the sand block is cut to form a sand mold; and a mold assembling process ST300, in which the cut upper and lower sand molds are assembled. As the processing equipment 100, a Figure 2 The molding device 110 shown, Figure 3 The cutting device 120 shown, Figure 4 , 5 The mold combining device 130 is shown. Regarding the robot 101 of the device 100, the cutting robot 121 is used in the cutting device 120, and the mold combining robot 131 is used in the mold combining device 130, but it is also possible to use a common robot and replace only the processing head and the holding robot arm as accessories.

[0034] The lower sand mold forming step ST110, the lower sand mold cutting step ST210 and the lower sand mold cleaning step ST310 are performed successively. Similarly, after the upper sand mold forming step ST130, the upper sand mold cutting step ST230 and the upper sand mold cleaning step ST330 are performed successively, the upper and lower sand mold combining step ST350 is performed. Figure 6 to Figure 9 The sand mold is first described, and the sand mold that is cut and formed into a mold is described, and then the manufacturing process is described in sequence. In addition, in the case of batch processing, the upper and lower sand molds can be formed and cut in large quantities and stored in one place, and the upper and lower sand molds can be cleaned and molded at any time as needed.

[0035] Figure 6 to Figure 9 The sand mold M shown includes an upper sand mold MU and a lower sand mold ML. The joining surface Sm of the upper and lower sand molds is the upper sand mold joining surface SmU and the lower sand mold joining surface SmL in the upper and lower sand molds. In this figure, the XYZ axes and their origin O intersecting each other at 90 degrees are shown, but the directions of the axes are Figure 2 to Figure 5The Z axis represents the up and down direction, which is basically the vertical direction, but not limited to this. In addition, the XY axis represents the lateral direction, which is basically horizontal, but not limited to this. A cavity C is formed in the upper and lower sand molds, and the upper cavity C1 and the lower cavity C2 are combined to form the cavity C. A gate W1 and a runner (dropping) W3 are formed in the upper sand mold, which are connected to the runner W2 to supply molten metal to the cavity C further forward.

[0036] In each sand mold, a vertical wall Sv rises from the bottom surface Sb, and a gently inclined side surface Ss continues toward the mold joint surface Sm. The vertical wall Sv is used for lateral positioning during cutting described later. The gently inclined slope Ss is given a draft angle for easily removing the sand mold from the forming mold, and is designed to be used for holding by the holding robot arm described later and to prevent the lateral positioning surface from protruding to the side and being damaged. These basic structures are also the same in the sand block.

[0037] As for the mold joining surface, the upper sand mold joint surface SmU and the lower sand mold joint surface SmL are respectively set on the upper and lower sand molds. By using the upper sand mold joint surface SmU and the lower sand mold joint surface SmL, the Z-axis positions of at least three points PU1~PU3 and PL1~PL3 that are not located on the same straight line can be grasped, thereby making it possible to keep these upper sand mold joint surfaces SmU and lower sand mold joint surfaces SmL parallel to each other for jointing. By setting these three points PU1~PU3 and PL1~PL3 near the corners of the upper sand mold and the lower sand mold, respectively, interference with the mold cavity C can be prevented, and by making the distance between each point farther, the inclination of each of the upper sand mold joint surface SmU and the lower sand mold joint surface SmL can be more accurately calculated.

[0038] The lateral posture and position of the upper and lower sand molds when closing the mold are controlled and corrected by the lateral positioning surfaces. The X-axis lateral positioning surfaces SUWX1 and SLNX2 used to control the displacement in the X-axis direction are surfaces along the Y-axis. Similarly, the Y-axis lateral positioning surfaces SUWY1 and SLNY2 used to control the displacement in the X-axis direction are surfaces along the X-axis. In addition, Figure 6 to Figure 9 The width of each lateral positioning surface toward the left side of the paper is wider than that of the lateral positioning surface on the right side. For example, the left side is 55 mm and the right side is 35 mm, but it is not limited to this. Therefore, the former is marked with wide lateral positioning surfaces SUW and SLW, and the third character is marked with W, while the latter is marked with narrow lateral positioning surfaces SUN and SLN, and the third character is marked with N.

[0039] The width and narrowness of the lateral positioning surface are formed in a matching manner in the upper and lower sand molds so as not to make a mistake in the orientation of the upper and lower sand molds. Figure 8In the figure, the left side is a wide positioning surface, the right side is a narrow positioning surface, and the wide and narrow surfaces are opposite at the diagonal. This configuration makes it possible to immediately know the error through the positioning surface when the upper and lower sand molds overlap in the wrong direction. The judgment can be made by visual inspection or automatic recognition based on image recognition.

[0040] The above markings form X-axis lateral positioning surfaces SUWX1 and SLNX2, and Y-axis lateral positioning surfaces SUWY1 and SLNY2. In addition, as an example, the markings are such that the first X-axis lateral positioning surface SUWX1 is wider at the top and the second Y-axis lateral positioning surface SLNY2 is narrower at the bottom.

[0041] Next, the contents of each process and the manufacturing equipment used therein will be described in order.

[0042] First, if Figure 2 As shown, the molding equipment 110 used in the molding process ST100 includes a molding die 111, a compression plate 112, a lower plate 113, an injection device for molding sand (not shown), and a compression device capable of vibration. The molding die 111 is used in the upper block BU and the lower block BL, and only the positioning pin 113b of the lower plate 113 is set to be shared, and the gate die 113a is only set as the gate die for the upper block BU. By sharing the mold as much as possible in the upper block BU and the lower block BL, the molding error is reduced. In addition, by providing the gate die 113a, the cutting amount of the sand mold is reduced, and the reverse cutting for cutting the gate from the back side can be omitted, thereby reducing the man-hours for sand mold manufacturing.

[0043] like Figure 3 As shown, the cutting equipment 120 used in the cutting process ST200 includes a cutting robot 121, a base floor 124, a mounting surface 125, and a positioning piece 126. The cutting robot 121 has a multi-jointed arm 121b on a base table 121a connected to the base floor 124 and the mounting surface 125, and can freely move a processing head 122 in the XYZ direction, and the processing head 122 rotates a tool 123 such as a cutting tool.

[0044] The origin O of the coordinate axis is set according to the positioning piece 126 of the mounting surface 125. In the figure, for easy understanding, the origin O is determined on the mounting surface 125 at the intersection of the extension line of the X-axis positioning piece 126X for positioning in the X-axis direction along the Y-axis and the extension line of the Y-axis positioning piece 126Y for positioning in the Y-axis direction along the X-axis. The vertical wall portion Sv of each sand mold rises from the bottom surface Sb, and the sand block is laterally positioned relative to the origin O by making the positioning piece 126 and the pressing piece 127 abut against each other, so as to limit the cutting amount to a minimum. Specifically, the vertical wall portion Sv is fixed and supported by both an X-axis positioning piece 126X and two Y-axis positioning pieces 126Y, and the X-axis pressing piece 127X and the Y-axis pressing piece 127Y are brought close to and abutted against the vertical wall portions Sv on the opposite sides of each other, thereby limiting the inclination relative to the XY direction.

[0045] As the order of cutting, after cutting the lower sand mold ML, when the upper sand mold MU is cut, in the subsequent mold closing process, the mold closing is directly entered after cleaning the upper sand mold MU, so it is advantageous in terms of omitting the process, but the cutting order is not limited to this. Regarding the cutting of each part, it is preferred that the mold closing surfaces SmU and SmL are first cut from each sand block BU and BL, and then the lateral positioning surfaces SU and SL, the cavity C and the runner W2 are cut. This is because by cutting based on the mold closing surfaces SmU and SmL, the entire cavity C, the runners W2 and W3, etc. can be accurately formed, and the lateral positioning becomes reliable.

[0046] like Figure 4 , Figure 5 As shown, the mold combining equipment 130 used in the lower sand mold cleaning process ST310, the upper sand mold cleaning process ST330 and the upper and lower sand mold combining process ST350 includes: a mold combining robot 131, an air cleaning compartment 133, a base ground 134, a loading surface 135, a first coordinate measurement sensor 136 and a second coordinate measurement sensor 137.

[0047] The mold-forming robot 131 is provided with a gripping robot arm 132 at the end of an arm 131b on a base 131a that allows the end to move freely in three dimensions. The gripping robot arm 132 can grip the sand mold M between a pair of opposing gripping surfaces 132a by bringing a pair of gripping pieces closer and further apart. Unlike the vertical wall portion Sv, the side surface Ss of the sand mold M has an inclination that approaches the opposing surfaces as it approaches the bonding surface Sm. The gripping surface 132a also has the same inclination, and in particular, the gripping surface 132a is made such that the bonding surface Sm of the upper sand mold MU is directed downward. Figure 5 By contacting with the side surface Ss in this way, it is possible to prevent the upper sand mold MU from being displaced relative to the lower side.

[0048] The air cleaning booth 133 cleans the cutting chips such as sand particles attached to the sand mold M, and cleans the cutting chips by blowing away the cutting chips with airflow from an air nozzle 133 b having a plurality of air holes provided below the air cleaning chamber 133 a .

[0049] A mold combining robot 131 and a loading surface 135 are provided on the base ground 134. Furthermore, a first coordinate measurement sensor 136 is provided on the holding robot arm 132, and a second coordinate measurement sensor (other coordinate measurement sensor) 137 is provided on the base ground 134. The first and second coordinate measurement sensors 136 and 137 respectively grasp the spatial coordinates of the contacted object through the XYZ coordinate axes using detection parts 136a and 137a. The coordinate positions of the sand mold M on the loading surface 135 are grasped by the first coordinate measurement sensor 136 of the holding robot arm 132, and the coordinate positions of the sand mold M held by the holding robot arm 132 are grasped by the second coordinate measurement sensor 137 on the base ground 134.

[0050] In this equipment, after the lower sand mold cleaning step ST310 and the upper sand mold cleaning step ST330, the above-mentioned coordinate grasping is performed in each of these steps, and the upper and lower sand mold closing step ST350 is performed based on the results. The upper sand mold cleaning step ST330 is the same as the lower sand mold cleaning step ST310, but only the different parts are described below.

[0051] In the lower sand mold cleaning process ST310, first, the lower sand mold ML that has completed the cutting process is placed on any one of the first loading surface 135a to the third loading surface 135c in the loading surface 135 in a manner that the mold surface Sm faces upward. Then, the positions of the plurality of lateral positioning surfaces SL are measured using the detection member 136a of the first coordinate measurement sensor 136, and the lower sand mold ML is held by the holding robot 132, and the lower sand mold ML is reversely rotated around the reversal axis parallel to the X-axis, and enters the air cleaning chamber 133a of the air cleaning compartment 133, and the air nozzle 133b is used to blow air flow from the lower side to the mold cavity C side for cleaning.

[0052] After that, the mold surface Sm is placed upward on any one of the first to third loading surfaces 135a to 135c of the loading surface 135 around the inversion axis again. Then, the positions of the mold surface Sm and the lateral positioning surface SL are measured by the detection piece 136a of the first coordinate measurement sensor 136 of the holding robot 132 as described later, and the mold is faced to the mold.

[0053] In the upper sand mold cleaning process ST330, the processes up to the cleaning are the same, but are different in the following aspects. With the mold surface Sm facing downward, the upper sand mold MU held by the holding robot 132 is brought close to the detection member 137a of the second coordinate measurement sensor 137 on the base ground 134, and the positions of the mold surface Sm and the lateral positioning SL are measured as described later, and the mold is faced to the mold.

[0054] Regarding the mold surface Sm, Figure 7 , Figure 8 As shown, in the upper closing mold surface SmU, the Z coordinates of at least three points PU1 to PU3 that are not located on the same straight line are identified. Similarly, in the lower closing mold surface SmL, the Z coordinates of at least three points PL1 to PL3 that are not located on the same straight line are identified. Even if different lateral positions are selected, the result is, for example, as described below. Fig. 9 As shown, the posture of the upper side MU is adjusted by the mold combining robot 131 so that the inclination of the lower mold combining surface SmL is parallel to the inclination of the upper mold combining surface SmU, so that the two mold combining surfaces SmU and SmL are close to each other and joined.

[0055] Regarding the lateral positioning surfaces SU and SL, Figure 7 , Figure 8 As shown, two Y-axis lateral positioning surfaces SUWY1, SUWY2, SLWY1, SLWY2 and one X-axis lateral positioning surface SUNX1, SLNX1 are measured in the upper and lower sand molds MU and ML, respectively. Then, the posture of the upper sand mold MU is adjusted by the mold combining robot 131 so that the positions of the positioning surfaces of the upper sand mold MU are consistent with the positions of the positioning surfaces of the lower sand mold ML, and then the two combined mold surfaces SmU and SmL are brought close to and joined.

[0056] If only the lateral position is to be aligned, the X-axis and Y-axis lateral positioning surfaces can be located at one location each in the upper and lower sand molds MU and ML. However, by measuring two Y-axis lateral positioning surfaces SUWY1, SUWY2, SLWY1, and SLWY2 at separate locations, the inclination around the axis parallel to the Z axis can be corrected.

[0057] Regarding the matching of the coordinates of the combined type, Figure 7 , Figure 8 The measurement of the lateral positioning surface SLWX1, SLWY1, SLWY2 of the lower sand mold ML and the three points PL1 to PL3 on the lower mold surface SmL is performed with respect to the XYZ coordinate axis indicated by the single-point dashed line of the mold closing device 130, and the measurement is performed by Fig. 9 The position and posture of the X1, Y1, and Z1 coordinate axes specified by the side surface of the lower sand mold ML and the mold surface SmL shown in (a). Similarly, for the XYZ coordinate axes shown by the single-point chain line, the position and posture of the X1, Y1, and Z1 coordinate axes specified by the mold surface SmL are measured. Fig. 9The positions and postures of the Xu, Yu, and Zu coordinate axes specified by the side surface of the upper sand mold MU and the closing surface SmU shown in (a) (-Z is a vector indicating the negative direction of Z, and -Zl is a vector indicating the negative direction of Zl, which are essentially the same).

[0058] Afterwards, the position and posture of the holding arm 132 of the molding robot 131 are adjusted, and the posture is adjusted in a way that the Xl, Yl, Zl coordinate axes are consistent with the Xu, Yu, Zu coordinate axes and brought close to each other, thereby completing the coordinate matching and enabling accurate molding.

[0059] In addition, as a lateral coordinate check, after the mold is closed, if Figure 7 , Figure 8 As shown, in both the upper and lower sand molds MU and ML, one Y-axis lateral positioning surface SUNY2 and one X-axis lateral positioning surface SUNX2 and SLNX2 are measured respectively. By making these coordinates consistent with each other, the accuracy of the mold can be checked.

[0060] After the above-mentioned mold closing step, the mold M is sent to a known pouring step. The casting is poured from the gate W1 side to complete the casting.

[0061] Finally, other embodiments of the present invention are described. The present invention is not limited to the above and following embodiments, and can be changed as long as it does not deviate from the gist of the present invention. In addition, in the following description, the same reference numerals are used for the same components as those in the above embodiments.

[0062] The XYZ axes do not have to be arranged to intersect each other at 90 degrees, but if they are arranged to intersect each other at 90 degrees, it is easier to grasp the coordinates. If the intersection angle of the lateral positioning surface is the same as the intersection angle of the XY axes, positioning can be performed by grasping the coordinates of the single axis direction of the X or Y axis.

[0063] Regarding the XYZ coordinate axes, if the coordinate transformation is appropriately performed by a known method to grasp the position, it is convenient to control the mold. For example, in the mold-closing process ST300, when the lower sand mold joint surface SmL is not parallel to the XY plane, the XY plane is transformed from the origin O with the lower sand mold joint surface SmL as the reference plane, so that the up and down axes are orthogonal to it for grasping. Thus, by measuring the up and down directions of the above three points, the upper sand mold joint surface SmL can be kept parallel to the lower sand mold joint surface SmL. Similarly, when the surface defined by the lower wide first and second Y-axis lateral positioning surfaces SLNY1 and SLNY2 is not parallel to the XZ plane, the X-axis and Y-axis coordinate transformations can be performed from the origin O with the surface defined by the lower wide first and second Y-axis lateral positioning surfaces SLNY1 and SLNY2 as the reference plane to grasp each lateral positioning surface.

[0064] The selection of the above-mentioned transverse joining surface is just an example, and the transverse joining surface of any corner may be selected.

[0065] The above-described embodiment uses a sand block that is substantially square in plan view, but the shape of the sand block can be appropriately changed to a rectangle, a polygon larger than a triangle, or the like.

[0066] The joining surface is one continuous surface in each of the upper and lower sand molds, but it can also be divided into two or more points. In the latter case, it is also possible to focus on one of the multiple joining surfaces and measure three points each time, but it is also possible to measure separately on the joining surface that separates the three points. As long as the matching joining surface parts are parallel in the upper and lower sand molds, it is sufficient. According to the above Fig. 9 According to the matching method, for the Z coordinates of at least three points PU1 to PU3 and PL1 to PL3 that are not located on the same straight line, it is not necessary to select the parts whose lateral positions in the upper and lower sand molds are the same coordinates. However, by selecting the parts whose lateral positions in the upper and lower sand molds are the same coordinates, if the ratio between the measured points on the Z coordinates of each part is known, it is easy to derive the inclination of the mold surface SmU and SmL, and the control parameters during mold closing are also simplified.

[0067] At least three points PU1-PU3 and PL1-PL3 that are not on the same straight line can also be measured at four or more points. As long as four or more points are measured to estimate the surface, the upper and lower mold surfaces can be estimated by mathematical and / or geometric methods such as removing points suspected of errors, and the upper and lower mold surfaces can be made close while keeping them parallel. Fig. 9 The coordinate matching method.

[0068] Possibility of Industrial Application

[0069] The present invention can be used as a method for manufacturing a casting mold, and can provide a casting mold that is particularly suitable for small-batch production of multiple varieties and has a small dimensional error.

[0070] Description of symbols

[0071] 100: processing equipment; 101: robot; 110: molding equipment; 111: molding die; 112: compression plate; 113: lower plate; 113a: gate mold; 113b: positioning pin; 120: cutting equipment; 121: cutting robot; 121a: base platform; 121b: arm; 122: machining head; 123: tool; 124: base floor; 125: loading surface; 126: positioning sheet; 126X: X-axis positioning sheet; 126Y: Y-axis positioning sheet; 127: pressing sheet; 127X: X-axis pressing sheet; 1 27Y: Y-axis pressing sheet; 130: combination equipment; 131: combination robot; 131a: base platform; 131b: arm; 132: holding robot arm; 132a: holding surface; 133: air cleaning compartment; 133a: air cleaning chamber; 133b: air nozzle; 134: base floor; 135: loading surface; 135a-c: first to third loading surfaces; 136: first coordinate measurement sensor; 136a: detection element; 137: second coordinate measurement sensor (other coordinate measurement sensors); 137a: detection element;

[0072] B: sand block; BU: upper block; BL: lower block; M: sand mold; MU: upper sand mold; ML: lower sand mold; SmU: upper sand mold joint surface; SmL: lower sand mold joint surface; O: XYZ origin (reference of spatial coordinates); Z axis (up and down axis); XY axis orthogonal to Z axis (lateral axis); C: mold cavity; C1: upper mold cavity; C2: lower mold cavity;

[0073] W1: gate; W2: runner; W3: runner (blank); SU, SL: lateral positioning surfaces; SU: upper lateral position joint surface; SL: lower lateral position joint surface; Ss: side surface; Sv: vertical wall; Sb: bottom surface;

[0074] SUW, SLW: wide lateral positioning surface; SUN, SLN: narrow lateral positioning surface; SUWX1, SLNX2: X-axis lateral positioning surface; SUWY1, SLNY2: Y-axis lateral positioning surface; SUWX1: (for example) the upper wide first X-axis lateral positioning surface; SLNY2: (for example) the lower narrow second Y-axis lateral positioning surface;

[0075] PU1~3, PL1~3: at least three points that are not located on the same straight line;

[0076] ST001: the entire manufacturing process; ST100: molding process; ST110: lower sand mold molding process; ST130: upper sand mold molding process; ST200: cutting process; ST210: lower sand mold cutting process; ST230: upper sand mold cutting process; ST300: mold closing process; ST310: lower sand mold cleaning process; ST330: upper sand mold cleaning process; ST350: upper and lower sand mold closing process.

Claims

1. A method for manufacturing a casting mold, comprising kneading molding sand and a binder, filling the mixture into a sand box, pressurizing the mixture so that the mixture solidifies in the sand box to produce a sand block, and manufacturing a sand mold through a cutting process and a mold assembly process, wherein: have: A processing head, which is operated by a robot, cuts the sand block to produce upper and lower sand molds; as well as The holding arm, which is operated by a robot, holds the upper sand mold so that the mold surfaces forming the mold cavity in the upper and lower sand molds are aligned with each other. The Z axis that specifies the Z coordinate is oriented in the up-down direction. In the cutting process, the processing head cuts and forms a mold joint surface on the upper and lower sand molds respectively, and cuts and forms the mold cavity on the upper and lower sand molds respectively with the mold joint surface as a reference. In the mold closing process, at least three points that are not located on the same straight line are measured on the mold closing surface of the lower sand mold placed on the loading surface, and the Z coordinate of each point is identified. Also, at least three points that are not located on the same straight line are measured on the mold closing surface of the upper sand mold held by the holding robot arm, and the Z coordinate of each point is identified. Then, the molds are closed using the holding robot arm in a manner that the mold closing surfaces of the upper and lower sand molds are kept in parallel.

2. The method for manufacturing a casting mold according to claim 1, wherein: The processing head has a lateral XY coordinate defined by an XY axis orthogonal to the Z axis. In the cutting process, the processing head cuts and forms at least two lateral positioning surfaces oriented to each other at an intersection angle of the XY axis near the joining surfaces of the upper and lower sand molds. In the joining process, the XY coordinates of each of the lateral positioning surfaces of the upper and lower sand molds are identified, and the lateral positions of the upper and lower sand molds are made consistent to perform the joining process using the holding robot arm.

3. The method for manufacturing a casting mold according to claim 2, wherein: At least one of the at least two lateral positioning surfaces is disposed at two or more spaced-apart positions.

4. The method for manufacturing a casting mold according to claim 3, wherein: The sand blocks constituting the upper and lower sand molds are convex polygons in a plan view, and the lateral positioning surfaces are formed at the corners of the convex polygons.

5. The method for manufacturing a casting mold according to claim 4, wherein: The convex polygon is in a rectangular shape, and the lateral positioning surface has different cutting lengths at adjacent corners and opposite corners of the rectangle, and is formed to have the same cutting length in the upper and lower sand molds.

6. The method for manufacturing a casting mold according to claim 2, wherein: In addition to the two lateral positioning surfaces, there are at least two other lateral positioning surfaces processed by the robot and all non-parallel to each other near the closing surfaces of the upper and lower sand molds. The closing is confirmed by identifying the XY coordinates of two points on the other lateral positioning surfaces of each of the upper and lower sand molds.

7. The method for manufacturing a casting mold according to claim 2, wherein: When the robot performs cutting processing, the upper side of the sand block is the constituent surface of the cavity, and the side surface near the lower surface of the sand block has a vertical wall portion, so that the positioning piece abuts against the vertical wall portion as a reference for the horizontal coordinate of the robot's cutting processing.

8. The method for manufacturing a casting mold according to any one of claims 1 to 7, wherein: The holding robot arm is provided with a coordinate measurement sensor. After the lower sand mold is placed on the loading surface for carrying the lower sand mold, the coordinate measurement sensor is used to identify the coordinates of the lower sand mold placed on the loading surface. Another coordinate measurement sensor is provided at a portion connected to the loading surface for carrying the lower sand mold. With respect to the upper sand mold held by the holding robot arm, the other coordinate measurement sensor is used to identify the coordinates of the upper sand mold in the holding state.

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