JP2018114615A - A device and a program for setting a gate position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a program for setting a gate position, which have a technology that can set the gate position with high speed and high accuracy compared with manual setting by users.SOLUTION: The device 10 for setting the gate position can acquire a cavity side face of a 3D model of a mold made by injection molding of a resin to calculate a center of gravity of the 3D model. The device 10 for setting the gate position can set automatically a position closest to the center of gravity of the 3D model among positions on the cavity side face. Further, the device 10 for setting the gate position can determine the number of gates according to dimensions of the 3D model, divide the 3D model according to the number of gates and set automatically the gate position for each divided part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gate position setting device and a program.

  2. Description of the Related Art Conventionally, a technique for determining a gate position for injecting a resin when resin molding is performed using an injection molding machine is known.

  Patent Document 1 includes an input unit that receives an input of analysis conditions, a gate position determination unit, and a storage unit. The gate position determination unit includes a gate position determination device that includes a flow analysis unit and a gate position improvement unit. Has been. The gate position improvement unit reads the analysis result, determines the moving direction of the gate position based on the result, and determines the moving amount of the gate position based on the moving direction.

  In Patent Document 2, a gate model is created in which a set model of elements included in a region boundary specified by a condition input unit is created by a region division processing unit, and the final filling position is simultaneously filled in each region of the created set model. It is described that the position is searched by an in-region gate position search unit. Perform flow analysis using the searched gate position as the resin injection part to obtain the required molding pressure required for filling for each region, and compare these required molding pressures or the required molding pressure and molding limit pressure. Areas to be subdivided including the corresponding area when the comparison is performed in the result evaluation unit and the required molding pressure is greater than the molding limit pressure and the required molding pressure difference between each area is not within a certain range. The boundary line is instructed by the subdivision instructing unit. In other cases, the flow rate adjusting unit adjusts the filling resin injection flow rate so that the pressure difference between the gates becomes uniform.

  In Patent Document 3, a gate setting means for setting a possible number of gates at an edge portion of each basic surface corresponding to an edge portion of a molded product according to a predetermined condition, and a plurality of gates set by the gate setting means. For each of the gates, a resin flow path that separates in multiple directions is set on the basic surface including the gate, and the flow length of each resin flow path is calculated. Calculate the flow length of each resin flow path by setting a resin flow path that separates in multiple directions on the next continuous basic surface from the tip position, and calculate the total flow length of each resin flow path that continues from the gate It is described that the operation is performed until there is no continuous basic surface or until the total of the calculated flow lengths exceeds the flow length set as the flow limit of the corresponding resin.

JP 2010-5893 A JP-A-7-137109 JP-A-4-361379

  In general, the user manually inputs the gate position. However, if the gate position is inappropriate, molding defects such as burrs and short shots may occur in the molded product. In the above technique, although the gate position is optimized, the user needs to manually set the first input. If this setting is inappropriate, it takes time for the optimization process.

  An object of the present invention is to provide a technique capable of setting a gate position at high speed and with high accuracy as compared with a case where a user manually sets.

  The invention according to claim 1 is a face acquisition unit that acquires a cavity-side face of a 3D model of a molded product formed by injection molding a resin, a center-of-gravity calculation unit that calculates the center of gravity of the 3D model, A gate position setting device that automatically sets a position closest to the center of gravity as the gate position.

  The invention according to claim 2 includes an area setting unit for setting a gate position setting area on the face, and the gate position setting unit is included in the gate position setting area in the position on the face. The gate position setting device according to claim 1, wherein the position closest to the center of gravity is automatically set as a gate position.

  A third aspect of the present invention is the gate position setting device according to the second aspect, wherein the area setting unit sets an area that is a predetermined distance away from an edge of the 3D model as the gate position setting possible area.

  According to a fourth aspect of the present invention, the gate position setting unit automatically sets a position closest to the centroid as a gate position among a plurality of positions on the face close to the centroid. It is a position setting device.

  The invention according to claim 5 includes an area setting section that sets a gate position setting area on the plurality of faces, and the gate position setting section includes the gate position among positions on the plurality of faces. 5. The gate position setting device according to claim 4, wherein a position within a settable region and closest to the center of gravity is automatically set as a gate position.

  The invention according to claim 6 includes a gate setting unit that sets the number of gates according to the dimensions of the 3D model, and a dividing unit that divides the 3D model into a plurality of parts according to the number of gates, The face acquisition unit acquires the face for each part, the center of gravity calculation unit calculates the center of gravity for each part, and the gate position setting unit automatically sets the gate position for each part. The gate position setting device according to any one of Items 1 to 5.

  The invention according to claim 7 includes a flow analysis unit that performs flow analysis of the 3D model using the gate position automatically set by the gate position setting unit, and the gate position setting unit includes the flow analysis unit. The gate position setting device according to claim 6, wherein when the analysis result is not appropriate, the gate number is changed and the gate position is automatically set again.

  According to an eighth aspect of the present invention, a computer obtains a cavity side face of a 3D model of a molded product formed by injection molding a resin, calculates a center of gravity of the 3D model, This is a program for executing a step of automatically setting a position closest to the center of gravity among the positions as a gate position.

  According to the first and eighth aspects of the invention, the gate position can be set at high speed and with high accuracy as compared with the case where the user manually sets the gate position.

  According to the second and third aspects of the invention, it is possible to prevent the gate position from being set to an inappropriate position of the 3D model.

  According to the fourth and fifth aspects of the present invention, the gate position can be set with higher accuracy as compared with the case of setting on one face.

  According to the sixth aspect of the present invention, the number of gates and the gate position can be automatically set.

  According to the seventh aspect of the present invention, the number of gates and the gate position can be optimized using the result of the flow analysis.

It is a block diagram of the configuration of the gate position setting device. It is a functional block diagram of a gate position setting device. It is a whole process flowchart of a gate position setting apparatus. It is a detailed flowchart of a gate position setting process. It is dimension explanatory drawing of 3D model. It is gate point determination matrix explanatory drawing. It is explanatory drawing in case of the number of gate points. It is division | segmentation explanatory drawing in the case of 3 gate points. It is a schematic diagram of gate position setting. It is a schematic diagram of gate position setting. It is explanatory drawing of a gate position setting possible area | region.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of a gate position setting device 10 according to this embodiment. The gate position setting device 10 includes a CPU 12, a ROM 14, a RAM 16, an input unit 18, a display unit 20, a communication interface (I / F) 22, and a storage unit 24.

  The CPU 12 implements various functions by reading a processing program stored in the ROM 14 or the storage unit 24 and executing the processing program using the RAM 16 as a working memory.

  The input unit 18 is a keyboard, a mouse, or the like, and inputs various data and instructions.

  The display unit 20 is a liquid crystal display, an organic EL display, or the like, and displays the processing result of the CPU 12.

  The communication I / F 22 transmits / receives data to / from other devices via a communication network such as a LAN or the Internet. Other devices that transmit and receive data include server computers, cloud computers, and other gate position setting devices.

  The storage unit 24 is a hard disk drive, an SSD, or the like, and stores a processing program and a three-dimensional CAD model (3D model) that is a processing target of the CPU 12. The 3D model is shape data representing the shape of a molded product obtained by injection molding of resin, and may be input from the input unit 18 and stored in the storage unit 24, or from a network via the communication I / F 22. You may download it. Or you may memorize | store in portable storage media, such as an optical disk. The file format of the 3D model is arbitrary.

  The gate position setting device 10 can be constituted by, for example, a personal computer or a tablet terminal.

  FIG. 2 shows functional blocks implemented by the CPU 12. These functions are realized by the CPU 12 executing a processing program stored in the ROM 14 or the storage unit 24. The CPU 12 includes a model dividing unit 121, a face extracting unit 122, a centroid calculating unit 123, a distance calculating unit 124, and a gate position setting unit 125.

  The model dividing unit 121 acquires the X dimension and the Y dimension, which are dimensions in the X direction and the Y direction, which are two directions orthogonal to each other, of the 3D CAD model (3D model) to be processed, and is created in advance and stored in the storage unit 24. The number of gate points is calculated using the determined gate point number determination matrix, and the number of divisions of the 3D model to be processed is determined based on the number of gate points. The number of gate points is one point, two points, three points, etc., and the model dividing unit 121 does not divide the 3D model when the number of gate points is one, and when the number of gate points is two points. Divides the 3D model into two so that the volume is equally divided, and when the number of gate points is three, the 3D model is divided into three so that the volume is equally divided. In general, when the number of gate points is n, the 3D model is divided into n parts so that the volume is equally divided.

  The face extraction unit 122 recognizes the cavity direction of the 3D model to be processed, and extracts the surface (hereinafter simply referred to as “face”) of the 3D model on the cavity (female mold of the injection mold) side. Get.

The center of gravity calculation unit 123 calculates the center of gravity of the 3D model to be processed. A method for calculating the center of gravity of the 3D model is known. For example, if the coordinates of three vertices of a polygon are R1, R2, and R3, the center of gravity of the triangular pyramid formed by the origin and the position vectors R1, R2, and R3 is the center of gravity of the triangular surface facing each vertex. A line is drawn toward each other and four lines intersect each other, and the center of gravity Gi of this triangular pyramid is
Gi = (R1 + R2 + R3) / 4
Is calculated by The center of gravity G is calculated by multiplying the volume Vi of the triangular pyramid as a weight, adding all the polygons, and dividing by the total volume. When the model dividing unit 121 divides the 3D model into a plurality of parts, the centroid calculating unit 123 calculates the centroid for each divided part.

  The distance calculation unit 124 calculates the distance between the centroid position calculated by the centroid calculation unit 123 and the face extracted by the face extraction unit 122. Then, the distance calculation unit 124 extracts the face closest to the center of gravity. The distance calculation unit 124 may extract a plurality of faces close to the center of gravity, for example, the top three faces that are close to each other, instead of extracting the face closest to the center of gravity. When the model dividing unit 121 divides the 3D model into a plurality of parts, the distance calculating unit 124 calculates the distance between the center of gravity and the face for each divided part.

  The gate position setting unit 125 calculates a gate position setting region for the face extracted as being close to the center of gravity by the distance calculation unit 124, and sets the point closest to the center of gravity in the gate position setting region as the gate position. Set to. When the model dividing unit 121 divides the 3D model into a plurality of parts, the gate position setting unit 125 sets the gate position for each divided part.

  The flow analysis unit 126 divides the 3D model to be processed into minute elements (mesh), generates an analysis model for performing the flow analysis, and executes the flow analysis by applying analysis conditions to the analysis model. . The analysis conditions are injection pressure, injection speed, mold clamping force, mold temperature, gate temperature, number of gates, gate position, etc. Among them, the gate number and gate position are automatically set by the gate position setting unit 125. And supplied to the flow analysis unit 126. Parameters necessary for flow analysis such as injection pressure are input by the user from the input unit 18 or stored in the storage unit 24 in advance. For the flow analysis, for example, a known flow analysis program described in JP 2010-5893 A can be used. As an example, in the flow analysis, nodes are extracted in each radial direction at an equal angle with the gate position set by the gate position setting unit 125 as the center, and the pressure value of each node is calculated for each time by the finite element method. calculate. Specifically, a matrix of simultaneous linear equations constructed based on the equation of motion when the flow state between nodes is assumed to be a Newtonian fluid is created, and the flow rate Q is given to calculate the pressure at each node. The flow analysis unit 126 displays the result obtained by the flow analysis, that is, the pressure of each node of the 3D model on the display unit 20. In addition, the flow analysis unit 126 evaluates the result obtained by the flow analysis. The evaluation of the result is, for example, the degree of pressure distribution and the degree of pressure peak value. As a result of the evaluation, if it is not always appropriate, the model dividing unit 121 changes the division of the 3D model, and the centroid calculating unit 123, the distance calculating unit 124, the gate position setting unit 125, and the flow analyzing unit 126 are subdivided. Recalculation is performed based on the 3D model. If the pressure is appropriate as a result of the evaluation, the flow analysis unit 126 outputs the automatically set gate position, that is, its three-dimensional coordinates to the outside. Note that the flow analysis unit 126 is not necessarily realized by the CPU 12 in the gate position setting device 10 and may be realized by a CPU of an external computer.

  FIG. 3 is an overall process flowchart of the present embodiment, which is a process realized by the CPU 12 executing a process program.

  First, the CPU 12 reads the 3D model to be processed stored in the storage unit 24, acquires the X and Y dimensions of the 3D model, and uses the gate point determination matrix that is created in advance and stored in the storage unit 24. The number of gate points of the 3D model is calculated (S101). The gate number determination matrix is a table that defines the correspondence between the X and Y dimensions and the number of gate points. The X dimension is divided into a plurality of stages, and the Y dimension is divided into a plurality of stages. The number of gate points is associated with each combination of Y dimension divisions. In general, the number of gate points increases as the X dimension increases, and the number of gate points increases as the Y dimension increases. It can be said that the gate point number determination matrix is obtained by dividing the area according to the X dimension and the Y dimension and assigning the corresponding gate point number for each area. The minimum value of the number of gate points is 1, and the maximum value of the number of gate points is arbitrary. An upper limit may be set for the maximum number of gate points.

  After determining the number of gate points using the X and Y dimensions of the 3D model and the gate point number determination matrix, the CPU 12 calculates the number of divisions of the 3D model for each number of gate points (S102). Specifically, if the number of gate points is 1, the number of divisions is 0, that is, no division, if the number of gate points is 2, the number of divisions is 2, that is, 2 divisions, and if the number of gate points is 3, the division is performed. The number is 3, that is, divided into three.

  Next, the CPU 12 divides the 3D model so that the volume is equally divided (S103). Since there is no division when the number of gate points is 1, this processing is not executed. When the number of gate points is 2 and the number of divisions is 2, the 3D model is divided into two so that the volume is equally divided. Specifically, the center of gravity position of the 3D model is calculated, and divided into two in the vertical direction (Z direction) using the calculated center of gravity position as a reference. When the number of gate points is 3 and the number of divisions is 3, the 3D model is divided into a plurality of equal parts, the division plane is determined so that the volume of each part is 1/3, and 3 is determined based on the determined division plane. To divide.

  Next, the CPU 12 sets a gate position for each of the divided 3D models (S104). This process will be further described later.

  After setting the gate position, the CPU 12 executes flow analysis according to a predetermined flow analysis algorithm and calculates the pressure at each node (S105). The analysis conditions are injection pressure, injection speed, clamping force, mold temperature, gate temperature, number of gates, gate position, etc. Among these, the number of gates and gate position are the number of gates and gate position automatically set in S104. Is used.

  After executing the flow analysis, whether or not the resulting pressure distribution during filling is appropriate, specifically, whether or not the pressure distribution is within a predetermined range and the peak value is below a threshold value. Determine (S106). If the pressure distribution is within the specified range and uniform, residual distortion of the molded product can be suppressed, and if the peak value is reduced below the threshold value, it will lead to a reduction in the clamping force, and molding with a molding machine with a small clamping force. This is because it becomes possible. Normally, if the pressure peak value at the completion of filling is equal to or less than the threshold value, it can be estimated that the pressure distribution is substantially uniform according to this, so it is determined only whether the peak value is equal to or less than the threshold value. May be.

  If the pressure peak value at the time of filling obtained by the flow analysis is equal to or less than the threshold value, it is determined as OK and the process is terminated. On the other hand, if the filling pressure peak value obtained by the flow analysis exceeds the threshold value, it is determined as NG, the number of gate points determined in S101 is changed, and the processes in and after S102 are repeated. For example, if the number of gate points is set to 1 and the gate position is set without division, and the flow analysis is performed at the set gate position, and the pressure peak value during filling exceeds the threshold value, the CPU 12 sets the gate point to 1 point. To 2 points, the 3D model is divided into two, the gate position is reset, and the flow analysis is re-executed. The above processing is repeatedly executed until the result of the flow analysis is determined to be OK. An upper limit may be set for the number of repetitions.

  Normally, a flow analysis program is installed on a computer, 3D model data to be processed is input, and a flow analysis is executed by a user specifying a gate position. In this embodiment, the number of gates and the gate position are Note that it is set automatically. Note that the CPU 12 desirably displays the gate position automatically set together with the 3D model on the display unit 20 with an arbitrary marker or icon when executing the flow analysis.

  FIG. 4 shows a detailed flowchart of the gate position setting (S104) of FIG.

  The CPU 12 recognizes the cavity direction (cavity side) from the 3D model data read from the storage unit 24, and extracts the cavity side surface of the 3D model as a face (S201). If there are multiple cavities, all of them are extracted as faces. The CPU 12 assigns an identification number to the extracted face and stores it in the RAM 16.

  Next, the CPU 12 calculates the center of gravity of the 3D model (S202). When the 3D model is divided into a plurality of parts, the center of gravity is calculated for each part. The CPU 12 stores the calculated center of gravity in the RAM 16 in association with the portion of the 3D model. When there is no division, the entire 3D model and the calculated center of gravity G are associated with each other and stored in the RAM 16. In the case of two divisions, assuming that the respective parts are P1 and P2, the center of gravity G1 of the part P1 and the center of gravity G2 of the part P2 are calculated, the parts P1 and G1 are associated and stored in the RAM 16, and the parts P2 and G2 are associated. And stored in the RAM 16. In the case of three divisions, assuming that each part is P1, P2, and P3, the center of gravity G1 of the part P1, the center of gravity G2 of the part P2, and the center of gravity G3 of the part P3 are calculated, and the parts P1 and G1 are associated and stored in the RAM 16. The parts P2 and G2 are associated and stored in the RAM 16, and the parts P3 and G3 are associated and stored in the RAM 16.

  Next, the CPU 12 reads the face and the center of gravity stored in the RAM 16 and calculates the distance between the center of gravity and the face (S203). When the 3D model is not divided, one centroid G is calculated, and the distance between the centroid G and one or more extracted faces is calculated. For example, if the identification numbers of the extracted faces are a, b, c, and d, the distance between the face a and the center of gravity G, the distance between the face b and the center of gravity G, the distance between the face c and the center of gravity G, and the face d and The distance from the center of gravity G is calculated, and the calculated distance is stored in the RAM 16. When the 3D model is divided into two, the centroids G1 and G2 are calculated for each of the parts P1 and P2, the distance between the centroid G1 and one or more faces extracted from the part P1 is calculated, and the centroid G2 and the part P2 are calculated. The distance from the extracted face or faces is calculated. For example, if the face identification numbers extracted from the part P1 are a1, b1, c1, and d1, the distance between the face a1 and the center of gravity G1, the distance between the face b1 and the center of gravity G1, the distance between the face c1 and the center of gravity G1, The distance between the face d1 and the center of gravity G1 is calculated, and the calculated distance is stored in the RAM 16. The same applies to the portion P2.

Next, the CPU 12 reads the distance between the face and the center of gravity stored in the RAM 16 and extracts a predetermined number, for example, the top three faces that are close to the center of gravity (S204). When the 3D model is not divided, there are a distance between the face a and the center of gravity G, a distance between the face b and the center of gravity G, a distance between the face c and the center of gravity G, and a distance between the face d and the center of gravity G.
(Distance with face a) <(Distance with face b) <(Distance with face c) <(Distance with face d)
If so, face a, face b, and face c are extracted as the top three. The same applies to the case where the 3D model is divided into two or three, and the predetermined number of faces is extracted for each portion.

  Next, the CPU 12 sets a point for each face extracted as being close to the center of gravity (S205). Specifically, points are set in a matrix on the extracted face at predetermined intervals, for example, 2 mm intervals. These points are candidate points set as gate positions.

  Next, the CPU 12 sets a gate position settable area for each face for which a point has been set (S206). The area where the gate position can be set is stored in advance in the storage unit 24 as a rule. Specifically, an area within a predetermined distance, for example, 5 mm from the edge of the 3D model is defined as an area where the gate position cannot be set, and other areas are defined. The The predetermined distance may be set according to the type of the 3D model or the molded product, or an area where the gate position cannot be set may be set in addition to the edge.

  After setting the gate position settable area, the CPU 12 calculates a point closest to the center of gravity in the gate position settable area for each face (S207). In addition, since the distance between each face and the center of gravity has already been calculated in S203, if the point to be calculated at this time is within the gate position setting region, the distance and the point can be used as they are. The point closest to the center of gravity is calculated only when the calculation target point is not within the gate position setting region. This is a case where the 3D model is not divided, and if the point on the face a when calculating the distance between the face a and the center of gravity G is within the gate position setting region, the distance and the point calculated in S203 are used as they are. If the point on the face b when calculating the distance between the face b and the center of gravity G is not within the gate position setting region, the point closest to the center of gravity G of the faces b is calculated again. If the point on the face c when calculating the distance to G is not within the gate position setting region, the point closest to the center of gravity G of the face c is calculated again. The CPU 12 stores the calculated position of the point on each face and the distance from the center of gravity G in the RAM 16. A point on the face a is ap, a point on the face b is bp, and a point on the face c is cp.

Next, the CPU 12 selects the point closest to the center of gravity G from the coordinates of the three points stored in the RAM 16, and sets this as the gate position (S208). For example,
(Distance with ap) <(Distance with bp) <(Distance with cp)
If so, the point ap on the face a is set as the gate position. In general,
(Distance with face a) <(Distance with face b) <(Distance with face c) <(Distance with face d)
If so, the point on the face a is set as the gate position, but the point on the face a is not in the gate position setting area and the point on the face b is in the gate position setting area. As a result, the point on the face b can be the closest point to the center of gravity G. In this sense, it is meaningful to extract a plurality of faces close to the center of gravity G in S204. Similarly, when the 3D model is divided into two or three, the point closest to the center of gravity of each part is set as the gate position.

  After setting the gate position, the CPU 12 outputs the coordinates (x, y, z) of the set gate position point as a predetermined file format, for example, a CSV file, and stores it in the RAM 16 (S209). The CSV file stored in the RAM 16 is read as a file indicating the gate position in the subsequent flow analysis.

  In injection molding, the pressure of the resin injected from the gate position has the highest pressure distribution when filling of the mold of the molded product is completed, and the filling pressure of the gate becomes a peak value. If the gate position is not appropriate and the position is biased with respect to the 3D model, the resin does not flow easily and the peak value of the filling pressure increases. As described above, the increase in the peak value causes an increase in the clamping force and a residual distortion of the molded product. In the present embodiment, since it is considered that a position where the filling distance (or filling time) until filling is almost equal in the 3D model is generally desirable as the gate position, attention is paid to the center of gravity position of the 3D model. It can be said that the point closest to the position of the center of gravity is automatically set as the gate position.

  In this embodiment, since the gate position is automatically set based on the position of the center of gravity of the 3D model, any user can operate at high speed without depending on the experience and intuition of a skilled engineer who manufactures an injection mold. In addition, the flow analysis can be executed by setting the gate position with high accuracy.

  Next, each process of the present embodiment will be described more specifically.

  FIG. 5 shows a plan view of the 3D model 30 (a plan view projected onto the XY plane). The respective dimensions in the XY directions orthogonal to each other, that is, the X dimension and the Y dimension are measured and acquired. When the 3D model 30 has a complicated shape, the X dimension and the Y dimension of the circumscribed circle are measured and acquired.

FIG. 6 schematically shows an example of the gate point number determination matrix 32. According to the size x of the X dimension and the size y of the Y dimension,
A region: 0 <x ≦ x1, 0 <y ≦ y1
B region: 0 <x ≦ x1, y1 <y ≦ y2
C region: x1 <x ≦ x2, 0 <y ≦ y1
D region: 0 <x ≦ x1, y2 <y ≦ y3
E region: x2 <x ≦ x3, 0 <y ≦ y1
F region: x1 <x ≦ x2, y1 <y ≦ y2
G region: x1 <x ≦ x2, y2 <y ≦ y3
H region: x2 <x ≦ x3, y1 <y ≦ y2
I region: x2 <x ≦ x3, y2 <y ≦ y3
A total of 9 regions, and the number of gate points for each region is A region: 1 point B region and C region: 2 points D region and E region: 3 points F region, G region and H region: 4 points I region: 5 points And For example, x1 = y1 = 210 mm, x2 = y2 = 400 mm, and x3 = y3 = 600 mm, but not limited thereto. If the X and Y dimensions of the 3D model to be processed correspond to the A region, the number of gate points is one, and if it corresponds to the E region, the number of gate points is three. The gate point determination matrix 32 may be created for each type of molded product and stored in the storage unit 24.

  FIG. 7 schematically shows a state of the 3D model 30 being divided into two. The center of gravity G of the 3D model 30 is calculated, and the center of gravity G is divided into two parts in the vertical direction, and the parts P1 and P2 are obtained. One or a plurality of cavity-side faces are extracted for each of the parts P1 and P2, the center of gravity is calculated again for each of the parts P1 and P2, and the point closest to the center of gravity is extracted for each of the parts P1 and P2.

  FIG. 8 schematically shows how the 3D model 30 is divided into three parts. The 3D model 30 is divided into a plurality of equal parts, and the division plane is determined so that the volume of each part becomes 1/3, and the three divisions are made into the parts P1, P2, and P3 based on the determined division plane. One or a plurality of cavity-side faces are extracted from each of the parts P1, P2, and P3, and the centers of gravity G1, G2, and G3 are calculated again from the parts P1, P2, and P3, and the centers of gravity G1 are calculated from the parts P1, P2, and P3, respectively. , G2 and G3 are extracted.

  9 and 10 schematically show the gate position setting process when the number of gate points of the 3D model 30 is one and there is no division.

  FIG. 9A shows the process of S201 of FIG. 4, that is, the process of extracting the cavity side surface of the 3D model as a face.

  FIG. 9B and FIG. 9C show the processing of S202 to S204 of FIG. 4, that is, the processing of calculating the center of gravity G of the 3D model and extracting the face close to the center of gravity G. In the figure, a relatively dark portion indicates a face close to the center of gravity among the faces. This is a case where the top three faces close to the center of gravity are extracted, and these faces are indicated as faces a, b, and c.

  FIG. 10A shows the process of S205 of FIG. 4, that is, the process of setting points at predetermined intervals on the extracted face. Points are set in a matrix at intervals of 2 mm in each of the extracted top three faces a, b, and c.

  FIGS. 10B and 10C show the process of S206 of FIG. 4, that is, the setting process of the gate position settable area. Of the extracted faces, a point 5 mm or more away from the edge of the 3D model is set as a gate position setting region.

  10D and 10E show the processing of S207 to S208 of FIG. 4, that is, the point closest to the center of gravity in the gate position setting region is calculated for each face, and among these, the point closest to the center of gravity is calculated. A process of setting a point as a gate position is shown. In the figure, the X mark indicates the point closest to the center of gravity for each of the three faces a, b, and c, and the point closest to the center of gravity is finally selected as the gate position.

  FIG. 11 schematically shows a gate position settable region. It is assumed that an edge 30a having a circular planar shape and an edge 30b having a rectangular planar shape exist inside the 3D model 30. Since the edges of the 3D model 30 include these edges 30a and 30b in addition to the edges that define the outer edge, 30c, 30d, and 30e are set as the edges that define an area 5 mm from the edge. The gate position setting region is a region 30f determined by these edges 30c, 30d, and 30e, and is indicated by hatching in the drawing.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various modification is possible. Hereinafter, modified examples will be described.

<Modification 1>
In the embodiment, as shown in the process flowchart of FIG. 3, the number of gate points is determined using the gate point number determination matrix, the 3D model is divided according to the number of gate points, and then the gate position setting process is executed. The gate position setting of the embodiment is not necessarily based on the 3D model dividing process of the embodiment, and the gate position is set without dividing the 3D model or after performing another 3D model dividing process. May be. Whether or not the user executes the processing of S101 to S103 in FIG. 3 may be set manually.

  Alternatively, it is possible to combine the processing of S101 to S103 of FIG. 3 with other gate position setting processing. The processing in S101 to S103 in FIG. 3 may be executed by another computer, and the result may be input to the gate position setting device 10 via the communication I / F 22 to execute the processing in S104 in FIG. In this case, the other computer functions as a 3D model dividing device that divides the 3D model in order to determine the number of gates.

<Modification 2>
In the embodiment, the processing of FIG. 4 is performed by the CPU 12 of the gate position setting device 10. However, one or a plurality of processes of S201 to S209 of FIG. 4 may be performed by a plurality of computers. The computer as a whole functions as the gate position setting device 10 or the gate position setting system. In the embodiment, the processing in FIG. 4 is realized by the CPU 12 executing the processing program. However, one or more of the processing in S201 to S209 in FIG. 4 may be realized by hardware. The hardware processing can be performed using a circuit such as ASIC or FPGA (Field Programmable Gate Array).

  In the embodiment, one or a plurality of processes in FIGS. 3S101 to S106 may be executed by a plurality of computers. Specifically, in a first computer and a second computer connected to each other via a communication network, the first computer executes the processes of S101 to S104 and transmits the result to the second computer. You may perform the process of S106 and return the result to a 1st computer. In this case, the first computer functions as a gate position setting device, and the second computer functions as a flow analysis device. Referring to FIG. 2, the model dividing unit 121 to the gate position setting unit 125 are realized by the CPU of the first computer, the flow analysis unit 126 is realized by the CPU of the second computer, and the gate position setting of the first computer is performed. The gate position automatically set by the unit 125 is supplied to the flow analysis unit 126 of the second computer. The flow analysis unit 126 of the second computer executes the flow analysis using the gate position, 3D model, and other analysis conditions from the first computer, evaluates the analysis result, and returns the evaluation result to the first computer. To do. In the first computer, if the evaluation result is not appropriate (the pressure peak value exceeds the threshold value or the pressure distribution exceeds the predetermined range), the gate position is automatically set again by the gate position setting unit 125 by changing the number of gates. To the second computer.

<Modification 3>
In the embodiment, the number of gate points is determined according to the X dimension and the Y dimension of the 3D model using the gate number determination matrix 32, and the 3D model is divided into a plurality of parts according to this, and the gate position is automatically set in each part. However, the user may manually set only the number of gate points, and the CPU 12 may automatically execute subsequent 3D model division and gate position setting according to the processing program. That is, the present invention includes
(1) Manually setting the number of gates and automatically setting the gate position (2) Any of automatically setting the number of gates and the gate position may be included. In the embodiment, in addition to the case where the number of gates and the gate position are set without performing repetitive calculation, the number of gates is automatically increased by 1 by repeating calculation and the gate position is automatically set again (2). Needless to say, it is included in Regardless of manual or automatic, the minimum number of gates is desirable.

<Modification 4>
In the embodiment, when the pressure peak value at the completion of filling obtained as a result of the flow analysis exceeds the threshold value, it is determined as NG and the number of gates is changed, for example, the gate number is increased by 1 and the gate position is automatically set again. Although the flow analysis is repeatedly executed, if the pressure peak value does not become the threshold value or less even after the predetermined number of repetitions, the setting of the gate position based on the center of gravity of the 3D model may not necessarily be effective. Therefore, it may be switched to another gate position setting method such as an optimal solution search method using a local gradient or a genetic algorithm method. However, the inventors of the present application have confirmed that the gate position can be accurately set with a probability of 90% or more without performing repetitive calculation by the method of the embodiment.

<Modification 5>
In the embodiment, the number of gate points according to the dimensions of the 3D model is determined using a gate point number determination matrix 32 as shown in FIG. 6. However, at least one of the 3D model, the processing program, and the gate number determination matrix may be stored in another storage unit (including a storage unit connected by a communication line). In addition, when a flow analysis result is determined to be OK after iterative calculation is performed and the number of gates is changed for a 3D model, a gate point number determination matrix is obtained for a 3D model similar to the shape of the 3D model. May be adjusted (learned) to the changed value.

10 Gate position setting device, 12 CPU, 14 ROM, 16 RAM, 18 input section, 20 display section, 22 communication I / F, 24 storage section.

Claims (8)

A face acquisition unit that acquires a cavity-side face of a 3D model of a molded product formed by injection molding a resin;
A centroid calculating unit for calculating the centroid of the 3D model;
A gate position setting unit that automatically sets a position closest to the center of gravity among the positions on the face as a gate position;
A gate position setting device comprising: An area setting unit for setting a gate position setting area on the face is provided,
2. The gate position setting device according to claim 1, wherein the gate position setting unit automatically sets, as a gate position, a position that is within the gate position setting region and is closest to the center of gravity among positions on the face. . The gate position setting device according to claim 2, wherein the area setting unit sets an area that is a predetermined distance away from an edge of the 3D model as the gate position setting area. The gate position setting device according to claim 1, wherein the gate position setting unit automatically sets a position closest to the center of gravity among a plurality of positions on the face close to the center of gravity as a gate position. An area setting unit for setting a gate position setting area on the plurality of faces;
5. The gate position according to claim 4, wherein the gate position setting unit automatically sets, as a gate position, a position that is within the gate position setting region and that is closest to the center of gravity among positions on the plurality of faces. Setting device. A gate setting unit for setting the number of gates according to the dimensions of the 3D model;
A dividing unit that divides the 3D model into a plurality of parts according to the number of gates;
With
The face acquisition unit acquires the face for each part,
The centroid calculating unit calculates the centroid for each part,
The gate position setting device according to claim 1, wherein the gate position setting unit automatically sets the gate position for each portion. A flow analysis unit that performs flow analysis of the 3D model using the gate position automatically set by the gate position setting unit;
The gate position setting device according to claim 6, wherein the gate position setting unit automatically sets the gate position again by changing the number of gates when the analysis result in the flow analysis unit is not appropriate. On the computer,
Obtaining a cavity-side face of a 3D model of a molded product formed by injection molding a resin;
Calculating a center of gravity of the 3D model;
A program for executing a step of automatically setting a position closest to the center of gravity among the positions on the face as a gate position.