Methods for manufacturing casting molds

Abstract

A method for manufacturing molds capable of handling small batches of various types is provided. In the cutting process, mating surfaces are formed by cutting the upper and lower sand molds respectively, and cavities (C1, C2) are formed in the upper and lower sand molds respectively using these mating surfaces as references. In the mold assembly process, at least three points (PU1-3) not collinear on the mating surface of the lower sand mold placed on the mounting surface are measured, and the Z-coordinates of each point are identified. Additionally, at least three points (PL1-3) not collinear on the mating surface of the upper sand mold held by a robotic arm are measured to identify the Z-coordinates of each point. Then, the upper and lower sand molds are assembled while maintaining parallel mating surfaces (SmU, SmL).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a casting mold. More specifically, it relates to a method for manufacturing a casting mold in which molding sand is mixed with a binder and filled into a sand box, pressurized to solidify within the sand box, and removed from the sand box to form a sand block, and a sand mold is manufactured by a cutting process and a mold assembly process. Background Technology

[0002] Regarding the aforementioned method for manufacturing the casting mold, Patent Document 1 is known regarding the cutting process, and Patent Document 2 is known regarding the mold assembly process. In the former, the forming mold of the combined sand blocks and the cutting process shorten the cutting process. In the latter, reference model blocks 24-27 are used for forming the mold, and reference models 28-31 are formed on the sand mold. The sand mold is then assembled based on the reference models.

[0003] However, no existing technology is sufficient to meet the demand for multi-variety, small-batch manufacturing of castings. In the former case, the molding die for sand blocks cannot handle multiple varieties; in the latter case, with the premise of adjusting the finished size of the sand blocks, the dimensional errors associated with the curing conditions cannot guarantee the accuracy of the reference model in small-batch production.

[0004] Existing technical documents

[0005] Patent documents

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

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

[0008] The problem that the invention aims to solve

[0009] In view of the past situation, the purpose of the present invention is to provide a manufacturing method for molds that can handle multiple varieties and small batches.

[0010] Methods for solving problems

[0011] To achieve the above objectives, the characteristic structure of the mold manufacturing method of the present invention is as follows: molding sand and binder are mixed and filled into a sand box, pressurized to solidify within the sand box, and removed from the sand box to form a sand block. A sand mold is then manufactured through a cutting process and a mold assembly process. The method includes: a machining head operated by a robot to cut the sand block, forming upper and lower sand molds; a holding robotic arm operated by a robot to hold the upper sand mold, causing the cavities forming in the upper and lower sand molds to align; and a coordinate measuring sensor that contacts at least the upper sand mold held by the holding robotic arm to detect coordinates. The sides of the sand mold have an inclination that approaches the opposing surfaces as they approach the aligning surfaces. The holding robotic arm... The holding surface also has the same slope as the side surface of the sand mold, and the Z-axis of the Z-coordinate is oriented in the up-down direction. In the cutting process, the machining head cuts to form a mating surface on the upper and lower sand molds respectively, and forms the cavity on the upper and lower sand molds respectively with the mating surface as a reference. In the mating process, at least three points not located on the same straight line are measured on the mating surface of the lower sand mold placed on the mounting surface, and the Z-coordinate of each point is identified. In addition, at least three points not located on the same straight line are measured on the mating surface of the upper sand mold held by the holding surface of the holding robot arm abutting against the side surface, and the Z-coordinate of each point is identified. Then, the mating is performed by the holding robot arm in an attitude that keeps the mating surfaces of the upper and lower sand molds parallel.

[0012] According to this structure, the machining head cuts to form mating surfaces on the upper and lower sand molds during the cutting process, and then cuts to form cavities on the upper and lower sand molds using these mating surfaces as references. Therefore, even if the finished dimensions of the solidified sand blocks are different, cavities can be accurately formed. Furthermore, during the mold-closing process, at least three points not on the same straight line are measured on the mating surface of the lower sand mold placed on the mounting surface, and the Z-coordinates of each point are identified. Similarly, at least three points not on the same straight line are measured on the mating surface of the upper sand mold held by the gripping robotic arm, with the gripping surface abutting against the side, and the Z-coordinates of each point are identified. Then, the mold is closed using the gripping robotic arm, keeping the mating surfaces of the upper and lower sand molds parallel. Therefore, regardless of the orientation of the lower sand mold, the upper and lower sand molds can be accurately closed. The sand block forming mold can be used in different casting molds, and different sand molds can be manufactured simply by cutting, thus enabling the production of multiple varieties in small batches.

[0013] Preferably, among the above features, the machining head has XY coordinates defined laterally by an XY axis orthogonal to the Z-axis. During the cutting process, the machining head cuts near the mating surface of the upper and lower sand molds to form at least two lateral positioning surfaces oriented at an angle to each other along the XY axis. During the mating process, the XY coordinates of each of the lateral positioning surfaces of the upper and lower sand molds are identified, and the mating is performed using the holding robotic arm to ensure the lateral positions of the upper and lower sand molds are aligned. According to this feature, cutting the lateral positioning surfaces without cutting other lateral surfaces allows for accurate lateral positioning while minimizing the amount of sand removed.

[0014] Preferably, at least one of the at least two lateral positioning surfaces is positioned at two or more spaced locations (by cutting a lateral positioning surface at two or more locations to separate the lateral positioning surfaces). By positioning at least one of the lateral positioning surfaces at two or more spaced locations, the inclination of the edge of the lateral positioning surface can be detected, and the lateral fitting becomes more accurate.

[0015] Preferably, the sand blocks constituting the upper and lower sand molds are convex polygons when viewed from above, and the lateral positioning surface is formed at the corner of the convex polygon.

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

[0017] Preferably, in addition to the two lateral positioning surfaces, there are at least two other lateral positioning surfaces near the mating surface of the upper and lower sand molds, each machined by the robot and not parallel to each other. The mating is confirmed by identifying the XY coordinates of two points on each of the other lateral positioning surfaces of the upper and lower sand molds. This allows for the confirmation of the accuracy of the mating and cutting errors.

[0018] Preferably, during the robot's cutting process, the upper side of the abrasive block forms the cavity surface, and the side near the lower surface of the abrasive block has a vertical wall portion, with the positioning plate abutting against this vertical wall portion, serving as a reference for the robot's horizontal coordinates during cutting. This structure allows the abrasive block to more accurately reduce its tilt and align with the coordinates, thus reducing the amount of cutting. That is, if the abrasive block were to be tilted relative to the coordinates, an increased amount of cutting would be necessary to ensure accuracy; however, in this invention, this necessity is reduced.

[0019] Preferably, the holding robotic arm is equipped with a coordinate measuring sensor that measures coordinates by contacting the detection element. After the lower sand mold is placed on the mounting surface, the coordinate measuring sensor identifies the coordinates of the lower sand mold placed on the mounting surface. Other coordinate measuring sensors are installed at locations connected to the mounting surface where the lower sand mold is placed. For the upper sand mold held by the holding robotic arm, these other coordinate measuring sensors identify the coordinates of the upper sand mold in its holding state. According to this structure, the coordinates are measured when the lower sand mold is placed on the mounting surface, and when the upper sand mold is held by the holding robotic arm. By understanding the positional relationship between the two, molding can be performed while minimizing variations, thus enabling accurate molding.

[0020] Invention Effects

[0021] Based on the characteristic structure of the mold manufacturing method of the present invention, a method for manufacturing molds of multiple varieties in small batches can be provided, which can handle the production of molds in small batches through reasonable cutting and mold assembly. Furthermore, according to other characteristic structures of the present invention, the amount of cutting in the sand mold is limited to a minimum, and through the rationalization of processing, the handling of multiple varieties in small batches can be further improved.

[0022] Other objects, structures, and effects of the invention will become clearer from the following description of embodiments of the invention. Attached Figure Description

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

[0024] Figure 2 The diagrams 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 cutting equipment for performing the cutting operation is shown, (a) is a side view, and (b) is a top view of the platform.

[0026] Figure 4 The image shows the molding equipment used in the molding process. (a) is a top view, and (b) is a front view.

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

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

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

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

[0031] Figure 9 The diagrams show the process of matching the coordinates of the upper and lower sand molds. (a) shows the state before coordinate matching, and (b) shows the state after coordinate matching. Detailed Implementation

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

[0033] like Figure 1 As shown, the sand mold manufacturing method of the present invention (total manufacturing process ST001) includes: a molding process ST100, in which molding sand and binder are mixed and filled into a sand box and pressurized to solidify within the mold box to produce a sand block; a cutting process ST200, in which the sand block is cut to form a sand mold; and a mold assembly process ST300, in which the upper and lower sand molds are assembled. As the processing equipment 100, a method using... Figure 2 The molding equipment 110 shown Figure 3 The cutting equipment 120 shown Figure 4 , 5 The molding equipment 130 is shown. Regarding the robot 101 of the equipment 100, a cutting robot 121 is used in the cutting equipment 120 and a molding robot 131 is used in the molding equipment 130. However, a common robot can also be used, with only the processing head and the holding robotic arm being replaced as accessories.

[0034] The lower sand mold forming process ST110, the lower sand mold cutting process ST210, and the lower sand mold cleaning process ST310 are performed sequentially. Similarly, after the upper sand mold forming process ST130, the upper sand mold cutting process ST230, and the upper sand mold cleaning process ST330 are performed sequentially, the upper and lower sand mold assembly process ST350 is performed. Figures 6-9 It is a sand mold. First, the sand mold formed and assembled by cutting will be explained, and then the manufacturing process will be explained in turn. In addition, in the case of batch processing, the upper and lower sand molds can be formed, cut and stored in a single location, and the upper and lower sand molds can be cleaned and assembled as needed.

[0035] Figures 6-9 The sand mold M shown includes an upper sand mold MU and a lower sand mold ML. Regarding the mating surface Sm where the upper and lower sand molds combine, these are respectively the upper sand mold mating surface SmU and the lower sand mold mating surface SmL in the upper and lower sand molds. The figure shows the XYZ axes that intersect each other at 90 degrees and their origin O, but the directions of the axes are... Figures 2-5The basic structure is the same. The Z-axis represents the vertical direction, which is basically vertical, but not limited to this. Additionally, the XY-axis represents the horizontal direction, which is basically horizontal, but not limited to this. Cavities C are formed in both the upper and lower sand molds; the upper cavity C1 and the lower cavity C2 are combined to form cavity C. A gate W1 and a runner (gutter) W3 are formed in the upper sand mold, continuing from the runner W2, supplying molten metal to the cavity C further forward.

[0036] In each sand mold, the vertical wall Sv rises from the bottom surface Sb, and the gently sloping side surface Ss continues towards the mating surface Sm. The vertical wall Sv is used for lateral positioning during cutting, as described later. The gently sloping surface Ss is given a draft angle for easy removal of the sand mold from the forming die, and is designed for gripping by the holding robotic arm, as described later, and to prevent the lateral positioning surface from protruding to the side and causing damage. These basic structures are the same in the sand block.

[0037] Regarding the mating surfaces, the upper sand mold mating surface SmU and the lower sand mold mating surface SmL are respectively set on the upper and lower sand molds. Using these upper sand mold mating surfaces SmU and SmL, the Z-axis positions of at least three points PU1-PU3 and PL1-PL3 that are not on the same straight line can be determined. This allows the upper sand mold mating surfaces SmU and SmL to be kept parallel to each other during mating. By setting these three points PU1-PU3 and PL1-PL3 near the corners of the upper and lower sand molds respectively, interference with the cavity C can be prevented. Furthermore, by increasing the distance between each point, the inclination of each upper sand mold mating surface SmU and lower sand mold mating surface SmL can be determined more accurately.

[0038] The lateral orientation and position of the upper and lower sand molds during assembly are controlled and corrected using lateral positioning surfaces. The X-axis lateral positioning surfaces SUWX1 and SLNX2, used to control displacement in the X-axis direction, are along the Y-axis. Similarly, the Y-axis lateral positioning surfaces SUWY1 and SLNY2, used to control displacement in the X-axis direction, are along the X-axis. Additionally, Figures 6-9 The width of each lateral positioning surface facing the left side of the paper is wider than the width of the lateral positioning surface facing the right side. For example, the left side is 55 mm and the right side is 35 mm, but this is not the only possibility. 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 to ensure proper alignment of the upper and lower sand molds and to match them within the molds. Figure 8In the center, the left side has a wide positioning surface, and the right side has a narrow positioning surface. Furthermore, the wide and narrow surfaces are arranged diagonally opposite each other. This configuration creates a structure where the error can be immediately detected by the positioning surfaces when the upper and lower sand molds are misaligned. The determination can be made visually or through automatic identification based on image recognition.

[0040] Based on the above markings, they become X-axis lateral positioning surfaces SUWX1 and SLNX2, and Y-axis lateral positioning surfaces SUWY1 and SLNY2. Alternatively, as an example, they are marked as a first X-axis lateral positioning surface SUWX1 with a wider top and a second Y-axis lateral positioning surface SLNY2 with a narrower bottom.

[0041] Next, the contents of each process and the manufacturing equipment used will be explained in turn.

[0042] First, such as Figure 2 As shown, the molding equipment 110 used in molding process ST100 includes a molding die 111, a compression plate 112, a lower plate 113, a sand injection device (not shown), and a vibration-enabled compression device. The molding die 111 is used in both the upper block BU and the lower block BL, while the lower plate 113 is shared only by the locating pin 113b, and the sprue die 113a is only provided for the upper block BU. By sharing the die as much as possible between the upper block BU and the lower block BL, molding errors are reduced. In addition, by providing the sprue die 113a, the amount of sand cutting is reduced, and reverse cutting for cutting the sprue from the back side is not required, thus reducing the time spent in 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 surface 124, a mounting surface 125, and a positioning plate 126. The cutting robot 121 has a multi-jointed arm 121b on a base platform 121a connected to the previous base surface 124 and mounting surface 125, which enables the machining head 122 to move freely in the XYZ directions, and the machining 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 on the mounting surface 125. In the figure, for ease of 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 (positioning along the Y-axis in the X-axis direction) and the extension line of the Y-axis positioning piece 126Y (positioning along the X-axis in the Y-axis direction). The vertical wall Sv of each sand mold stands upright from the bottom surface Sb. By abutting both the positioning piece 126 and the pressing piece 127, the sand block is laterally positioned relative to the origin O, and the cutting amount is limited to a minimum. Specifically, the vertical wall Sv is fixed and supported by one X-axis positioning piece 126X and two Y-axis positioning pieces 126Y. The X-axis pressing piece 127X and the Y-axis pressing piece 127Y are brought close together and abutted relative to their respective opposite vertical wall Sv, thereby limiting the tilt relative to the XY direction.

[0045] As for the cutting sequence, after cutting the lower sand mold ML, when cutting the upper sand mold MU, in the subsequent mold assembly process, after cleaning the upper sand mold MU, the mold assembly can proceed directly. Therefore, it is advantageous in terms of omitting steps, but the cutting sequence is not limited to this. Regarding the cutting of each part, it is preferable to first cut the mating surfaces SmU and SmL of each sand block BU and BL, and then cut the transverse positioning surfaces SU and SL, the cavity C, and the sprue W2, etc. This is because by cutting with the mating surfaces SmU and SmL as a reference, the entire cavity C, sprues W2 and W3, etc., can be accurately formed, and the transverse positioning becomes reliable.

[0046] like Figure 4 , Figure 5 As shown, the molding 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 molding process ST350 includes: a molding robot 131, an air cleaning compartment 133, a base ground 134, a mounting surface 135, a first coordinate measuring sensor 136, and a second coordinate measuring sensor 137.

[0047] The molding robot 131 has a gripping robotic arm 132 at the end of its arm 131b, which allows for free movement of its end in three dimensions, mounted on a base platform 131a. The gripping robotic arm 132 grips the sand mold M between a pair of opposing gripping surfaces 132a by bringing a pair of gripping plates closer together and separating them. 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 molding surface Sm. The gripping surfaces 132a also have the same inclination, particularly by positioning the upper sand mold MU with its molding surface Sm facing downwards. Figure 5 That way, when it comes into contact with the side Ss, it can prevent the upper sand-shaped MU from shifting relative to the lower position.

[0048] The air cleaning compartment 133 cleans the cutting chips such as sand particles attached to the sand mold M by blowing the cutting chips away through the airflow from the air nozzle 133b with multiple air holes provided below the air cleaning chamber 133a.

[0049] A molding robot 131 and a mounting surface 135 are provided on a base ground 134. Furthermore, a first coordinate measuring sensor 136 is provided on the holding robotic arm 132, and a second coordinate measuring sensor (or other coordinate measuring sensors) 137 is provided on the base ground 134. The first and second coordinate measuring sensors 136 and 137 respectively use detection elements 136a and 137a to determine the spatial coordinates of the contacting object via the XYZ coordinate axes. The sand mold M on the mounting surface 135 determines the coordinate positions of its surfaces Sm, SU, and SL through the first coordinate measuring sensor 136 of the holding robotic arm 132, and the sand mold M held by the holding robotic arm 132 determines the coordinate positions of its surfaces Sm, SU, and SL through the second coordinate measuring sensor 137 on the base ground 134.

[0050] In this equipment, after the lower sand mold cleaning process ST310 and the upper sand mold cleaning process ST330, the aforementioned coordinate control is performed in each of these processes, and the upper and lower sand mold merging process ST350 is executed based on the results. The upper sand mold cleaning process ST330 is the same as the lower sand mold cleaning process ST310, but only the differences are described below.

[0051] In the lower sand mold cleaning process ST310, firstly, the lower sand mold ML, which has completed the cutting process, is placed on any one of the first placement surface 135a to the third placement surface 135c of the placement surface 135 with the mating surface Sm facing upwards. Then, the positions of multiple transverse positioning surfaces SL are measured using the detection element 136a of the first coordinate measuring sensor 136. The lower sand mold ML is held by the holding robotic arm 132, causing the lower sand mold ML to rotate in reverse around the reversal axis parallel to the X-axis and enter the air cleaning chamber 133a of the air cleaning compartment 133. Air is blown from the bottom to the cavity C side using the air nozzle 133b for cleaning.

[0052] Then, the molded surface Sm is placed upwards on any one of the first to third mounting surfaces 135a to 135c of the mounting surface 135, around the reversal axis. Then, the position of the molded surface Sm and the lateral positioning surface SL is measured by the detection element 136a of the first coordinate measuring sensor 136 of the holding robot arm 132 as described later, and the molded surface is facing the mold.

[0053] In the sand mold cleaning process ST330, the process is the same up to the cleaning stage, but differs in the following aspects. With the mating surface Sm facing downwards, the sand mold MU held by the holding robotic arm 132 is brought close to the detection element 137a of the second coordinate measuring sensor 137 on the base ground 134, and the positions of the mating surface Sm and the lateral positioning SL are measured as described later, so that the mold faces the mating surface.

[0054] Regarding the mating surface Sm, such as Figure 7 , Figure 8 As shown, in the upper mating surface SmU, the Z coordinates of at least three points PU1 to PU3 that are not on the same straight line are identified. Similarly, in the lower mating surface SmL, the Z coordinates of at least three points PL1 to PL3 that are not on the same straight line are identified. Even if different lateral positions are chosen, the result is, for example, as described later. Figure 9 As shown, the attitude of the upper MU is adjusted by the molding robot 131 so that the inclination of the lower molding surface SmL is parallel to the inclination of the upper molding surface SmU, so that the two molding surfaces SmU and SmL approach and join.

[0055] Regarding the lateral positioning surfaces SU and SL, such as 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 attitude of the upper sand mold MU is adjusted by the molding robot 131 so that the positions of each positioning surface of the upper sand mold MU are consistent with the positions of each positioning surface of the lower sand mold ML. Then, the two molding surfaces SmU and SmL are brought close together and joined.

[0056] If only the lateral positions are to be consistent, then in both the upper and lower sand molds MU and ML, there can be one lateral positioning surface for the X and Y axes, respectively. However, by measuring the two lateral positioning surfaces SUWY1, SUWY2, SLWY1, and SLWY2 at separate locations, the tilt around the axis parallel to the Z axis can be corrected.

[0057] Regarding the matching of coordinates of the fit, through Figure 7 , Figure 8 The measurement of three points PL1 to PL3 on the transverse positioning surfaces SLWX1, SLWY1, and SLWY2 of the lower sand mold ML and the lower mating surface SmL, with reference to the XYZ coordinate axes shown by the single-dot dashed line on the mating equipment 130, was performed. Figure 9 (a) shows the positions and orientations of the Xl, Yl, and Zl coordinate axes specified for the side surface of the lower sand mold ML and the mating surface SmL. Similarly, for the XYZ coordinate axes indicated by the single-dot dashed lines, the positions and orientations of the Xl, Yl, and Zl coordinate axes are determined by... Figure 9The positions and orientations of the Xu, Yu, Zu coordinate axes specified by the side of the upper sand mold MU and the mating surface SmU are shown in (a). (-Z is a vector representing the negative direction of Z, and -Zl is a vector representing the negative direction of Zl, which are essentially the same).

[0058] Next, the position and posture of the holding robotic arm 132 of the molding robot 131 are adjusted so that the Xl, Yl, Zl coordinate axes are aligned with the Xu, Yu, Zu coordinate axes and brought close together, thereby completing the coordinate matching and enabling accurate molding.

[0059] Additionally, as a horizontal coordinate check, after fitting, such as Figure 7 , Figure 8 As shown, in both the upper and lower sand molds MU and ML, one Y-axis transverse positioning surface SUNY2, SLNY2 and one X-axis transverse positioning surface SUNX2, SLNX2 are measured respectively. By aligning these coordinates vertically, the accuracy of the mold assembly can be checked.

[0060] After the above-mentioned mold assembly process, the mold M is sent to the known casting process. The casting is then poured from the gating gate W1 side to complete the casting.

[0061] Finally, other embodiments of the present invention will be described. The present invention is not limited to the embodiments described above and below, and modifications can be made without departing from the spirit of the invention. Furthermore, in the following description, components identical to those in the above embodiments will be labeled with the same reference numerals.

[0062] The X, Y, and Z axes do not necessarily need to be configured to intersect each other at 90 degrees, but if they are configured to intersect at 90 degrees, it is easier to control the coordinates. If the intersection angle of the lateral positioning surface is the same as the intersection angle of the X and Y axes, positioning can be achieved by controlling the coordinates in only the X or Y axis direction.

[0063] Regarding the XYZ coordinate axes, if the position is determined by appropriately performing coordinate transformations using known methods, it facilitates the control of the mold assembly. For example, in the mold assembly process ST300, if the lower sand mold assembly surface SmL is not parallel to the XY plane, coordinate transformations can be performed from the origin O using the lower sand mold assembly surface SmL as a reference plane to make the vertical axes orthogonal to it. Thus, by measuring the vertical directions at the above three points, the upper sand mold assembly surface SmU can be kept parallel to the lower sand mold assembly surface SmL. Similarly, if the surfaces defined by the first and second lower Y-axis transverse positioning surfaces SLNY1 and SLNY2 are not parallel to the XZ plane, coordinate transformations can be performed from the origin O using the surfaces defined by the first and second lower Y-axis transverse positioning surfaces SLNY1 and SLNY2 as reference planes to determine the position of each transverse positioning surface.

[0064] The above selection of the lateral fitting surface is an example; you can also select the lateral fitting surface at any corner.

[0065] The above implementation uses a sand block that is roughly square when viewed from above, but the shape of the sand block can be appropriately changed to a rectangle, a polygon with a triangle or more, etc.

[0066] The mating surfaces can be one continuous surface in the upper and lower sand molds, or they can be divided into two or more points. In the latter case, measurements can be taken at one point on each of the multiple mating surfaces, with three points measured at each point on both the upper and lower sides. Alternatively, measurements can be taken separately on mating surfaces that separate the three points. The key is that the mating surfaces are parallel to each other in the upper and lower sand molds. Based on the above... Figure 9 The matching method, regarding the Z coordinates of at least three points PU1~PU3 and PL1~PL3 that are not located on the same straight line, does not require selecting locations in the upper and lower sand molds with the same lateral coordinates. However, by selecting locations in the upper and lower sand molds with the same lateral coordinates, if the ratio between the measured points on the Z coordinates of each location is known, the inclination of the mating surfaces SmU and SmL can be easily derived, which also simplifies the control parameters during mating.

[0067] At least three points PU1-PU3 and PL1-PL3 that are not on the same straight line can be measured separately, or four or more points can be measured separately. As long as four or more points are measured separately to estimate the surface, the upper and lower mating surfaces can be estimated using mathematical and / or geometric methods such as removing points suspected of error. The surfaces can be made close to each other while keeping them parallel. This is not limited to... Figure 9 The method for matching coordinates.

[0068] Industrial utilization potential

[0069] This invention can be used as a method for manufacturing casting molds. It can provide casting molds that are particularly suitable for multi-variety, small-batch production and have small dimensional errors.

[0070] Label Explanation

[0071] 100: Processing equipment; 101: Robot; 110: Molding equipment; 111: Molding mold; 112: Compression plate; 113: Lower plate; 113a: Sprue mold; 113b: Positioning pin; 120: Cutting equipment; 121: Cutting robot; 121a: Base platform; 121b: Arm; 122: Processing head; 123: Tool; 124: Base ground; 125: Placement surface; 126: Positioning plate; 126X: X-axis positioning plate; 126Y: Y-axis positioning plate; 127: Pressing plate; 127X: X-axis pressing plate; 1 27Y: Y-axis pressing plate; 130: Molding equipment; 131: Molding robot; 131a: Base platform; 131b: Arm; 132: Holding robotic arm; 132a: Holding surface; 133: Air cleaning compartment; 133a: Air cleaning chamber; 133b: Air nozzle; 134: Base ground; 135: Placement surface; 135a~c: First~Third placement surfaces; 136: First coordinate measuring sensor; 136a: Detection piece; 137: Second coordinate measuring sensor (other coordinate measuring sensors); 137a: Detection piece;

[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 mating surface; SmL: Lower sand mold mating surface; O: XYZ origin (reference point for spatial coordinates); Z-axis (vertical axis); XY axis orthogonal to the Z-axis (lateral axis); C: Cavity; C1: Upper cavity; C2: Lower cavity;

[0073] W1: Gate; W2: Runner; W3: Runner (gutter); SU, SL: Lateral positioning surfaces; SU: Upper lateral positioning mating surface; SL: Lower lateral positioning mating 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: (Example) upper wide first X-axis lateral positioning surface; SLNY2: (Example) 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: Full 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 assembly process; ST310: Lower sand mold cleaning process; ST330: Upper sand mold cleaning process; ST350: Upper and lower sand mold assembly process.

Claims

1. A method for manufacturing a casting mold, comprising mixing molding sand and a binder, filling the mixture into a sand box, pressurizing it to solidify within the sand box, removing the mixture from the sand box to form a sand block, and manufacturing the sand mold through a cutting process and a mold assembly process, wherein, have: The processing head, operated by a robot, cuts the sand block to create upper and lower sand molds; The robotic arm, operated by a robot, holds the upper sand mold, ensuring that the mating surfaces of the forming cavities in the upper and lower sand molds align; and A coordinate measuring sensor detects coordinates by bringing a sensing element into contact with at least the upper sand mold held by the gripping robotic arm. The sides of the sand mold have an incline that approaches the opposing surfaces as they near the mating surface. The gripping surface of the robotic arm also has the same slope as the side surface of the sand mold. The Z-axis of the Z-coordinate is defined as being oriented vertically. In the cutting process, the machining head cuts and forms mating surfaces on the upper and lower sand molds respectively, and forms the cavity on the upper and lower sand molds respectively with the mating surfaces as reference. In the molding process, at least three points not located on the same straight line are measured on the molding surface of the lower sand mold placed on the mounting surface, the Z coordinates of each point are identified, and the molding surface of the lower sand mold is estimated. Similarly, at least three points not located on the same straight line are measured on the molding surface of the upper sand mold held by the gripping surface of the gripping robot arm abutting against the side, the Z coordinates of each point are identified, and the molding surface of the upper sand mold is estimated. Then, the molding is performed using the gripping robot arm in an attitude that keeps the estimated molding surfaces of the upper and lower sand molds parallel.

2. The method for manufacturing a casting mold according to claim 1, wherein, Having XY coordinates defined by an XY axis orthogonal to the Z-axis, the machining head, in the cutting process, cuts near the mating surface of the upper and lower sand molds to form at least two lateral positioning surfaces oriented at the intersection angle of the XY axes, respectively. In the mating process, the XY coordinates of each of the lateral positioning surfaces of the upper and lower sand molds are identified, and the mating is performed by the holding robotic arm to make the lateral positions of the upper and lower sand molds consistent.

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 locations.

4. The method for manufacturing a casting mold according to claim 3, wherein, The sand blocks that make up the upper and lower sand molds are convex polygons when viewed from above, and the lateral positioning surface is formed at the corner of the convex polygon.

5. The method for manufacturing a casting mold according to claim 4, wherein, The convex polygon is rectangular, and the lateral positioning surface makes the cutting length different at adjacent corners and opposite corners of the rectangle, so that the cutting length is the same in the upper and lower sand molds respectively.

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 near the mating surface of the upper and lower sand molds, which are all processed by the robot and are not parallel to each other. The mating is confirmed by identifying the XY coordinates of two points on the other lateral positioning surfaces of the upper and lower sand molds respectively.

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

8. The method for manufacturing a mold according to any one of claims 1 to 7, wherein, The holding robotic arm is equipped with a coordinate measuring sensor that measures coordinates by contacting the detection element. After the lower sand mold is placed on the mounting surface, the coordinate measuring sensor identifies each coordinate of the lower sand mold placed on the mounting surface. Other coordinate measuring sensors are installed at the locations connected to the mounting surface where the lower sand mold is placed. For the upper sand mold held by the holding robotic arm, these other coordinate measuring sensors identify each coordinate of the upper sand mold in the holding state.

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