JP6876910B2 - Gate position setting device and program - Google Patents

Description

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

Conventionally, there has been known a technique for determining a gate position for injecting a resin when molding a resin using an injection molding machine.

Patent Document 1 describes a gate position determining device including an input unit for receiving input of analysis conditions, a gate position determining unit, and a storage unit, and the gate position determining unit includes a flow analysis unit and a gate position improving unit. Has been done. The gate position improvement unit reads the analysis result, determines the movement direction of the gate position based on the result, and determines the movement amount of the gate position based on the movement direction.

In Patent Document 2, a gate in which a set model of elements included in the area boundary line specified by the condition input unit is created by the area division processing unit and the final filling position is simultaneously filled in each area of the created set model. It is described that the position is searched by the in-region gate position search unit. Flow analysis is performed with the searched gate position as the resin injection part, the required molding pressure required for filling is obtained for each region, and the required molding pressures are compared or the required molding pressure and the molding limit pressure are compared. When the comparison is performed by the result evaluation section and the required molding pressure is larger than the molding limit pressure and the required molding pressure difference between each region is not within a certain width, the region to be subdivided including the corresponding region. The boundary line is indicated by the subdivision indicating unit, and in other cases, the flow rate adjusting unit adjusts the injection flow rate of the filling resin so that the pressure difference between the gates becomes uniform.

Patent Document 3 describes a gate setting means for setting a possible number of gates on the edge portion of each basic surface corresponding to the edge portion of the molded product according to predetermined conditions, and a plurality of gate setting means set by the gate setting means. For each of the gates, set resin flow paths to be separated in multiple directions on the basic surface including the gate, calculate the flow length of each resin flow path, and calculate the flow length of each resin flow path on the basic surface including the gate of each resin flow path. The flow length of each resin flow path is calculated by setting resin flow paths that are further separated in multiple directions on the basic surface that is continuous from the tip position, and the total flow length of each resin flow path that is continuous from the gate is calculated. It is described that the operation such as is performed until the continuous basic surface disappears or the total of the calculated flow lengths exceeds the flow length set as the flow limit of the corresponding resin.

JP-A-2010-5893 Japanese Unexamined Patent Publication No. 7-137109 Japanese Unexamined Patent Publication No. 4-361379

Generally, the gate position is manually input by the user, but 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, and if this setting is inappropriate, the optimization process will take time.

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 the case where a user manually sets the gate position.

The invention according to claim 1 is a face acquisition unit that acquires a face on the cavity side of a 3D model of a molded product obtained by injection molding a resin, a center of gravity calculation unit that calculates the center of gravity of the 3D model, and a center of gravity calculation unit on the face. Of the positions, the gate position setting unit that automatically sets the position closest to the center of gravity to the gate position, the division unit that divides the 3D model into a plurality of parts according to the number of gates, and the gate position setting unit automatically sets the gate position. A flow analysis unit that performs flow analysis of the 3D model using the set gate position is provided , the face acquisition unit acquires the face for each part, and the center of gravity calculation unit obtains the face for each part. The center of gravity is calculated, and the gate position setting unit automatically sets the gate position for each part, and further, when the analysis result by the flow analysis unit is not appropriate, the number of gates is changed to change the gate. It is a gate position setting device that automatically sets the position again.

The invention according to claim 2 includes an area setting unit for setting a gate position settable area on the face, and the gate position setting unit is within the gate position settable area of the positions 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 the gate position.

The invention according to claim 3 is the gate position setting device according to claim 2, wherein the area setting unit sets a region separated from the edge of the 3D model by a predetermined distance as the gate position settable area.

The gate according to claim 1, wherein the gate position setting unit automatically sets the position closest to the center of gravity to the gate position among the plurality of positions on the face close to the center of gravity. It is a position setting device.

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

Invention according to claim 6, wherein a gate setting unit that sets the number of the gate depending on the size of the 3D model, the dividing unit, the 3D depending on the number of gates set by the gate setting unit The gate position setting device according to any one of claims 1 to 5 , wherein the model is divided into the plurality of parts.

The invention according to claim 7 includes a step of acquiring a face on the cavity side of a 3D model of a molded product obtained by injection molding a resin into a computer, a step of calculating the center of gravity of the 3D model, and a step on the face. Among the positions, the step of automatically setting the position closest to the center of gravity to the gate position, the step of dividing the 3D model into a plurality of parts according to the number of gates, and the step of using the automatically set gate position to perform the 3D In the step of executing the flow analysis of the model and the step of acquiring the face, the face is acquired for each part, and in the step of calculating the center of gravity, the center of gravity is calculated for each part. In the step of automatically setting the gate position, a program that automatically sets the gate position for each part, and further changes the number of gates to automatically set the gate position again when the result of the flow analysis is not appropriate. Is.

According to the inventions of claims 1 and 7 , 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 inventions of claims 2 and 3, it is possible to further prevent the gate position from being set to an inappropriate position in the 3D model.

According to the inventions of claims 4 and 5, the gate position can be set with higher accuracy than when the gate position is set on one face.

According to the invention of claim 6, the number of gates and the gate position can be automatically set.

According to the inventions of claims 1 and 7, the number of gates and the gate position can be further optimized by using the result of the flow analysis.

It is a block diagram of the gate position setting apparatus. It is a functional block diagram of the gate position setting device. It is the whole processing flowchart of the gate position setting apparatus. It is a detailed flowchart of a gate position setting process. It is a dimensional explanatory drawing of a 3D model. It is explanatory drawing of the gate point number determination matrix. It is explanatory drawing in the case of one gate point. It is a division explanatory drawing in the case of 3 gate points. It is a schematic diagram of the gate position setting. It is a schematic diagram of the gate position setting. It is explanatory drawing of the gate position settingable area.

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

FIG. 1 shows a block diagram of the gate position setting device 10 according to the present 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 realizes various functions by reading the processing program stored in the ROM 14 or the storage unit 24 and executing the processing program using the RAM 16 as the 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 another device via a communication network such as a LAN or the Internet. Other devices that send and receive data include server computers, cloud computers, or other gate positioning devices.

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

The gate position setting device 10 may be configured by, for example, a personal computer, a tablet terminal, or the like.

FIG. 2 shows a functional block realized 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 extraction unit 122, a center of gravity calculation unit 123, a distance calculation unit 124, and a gate position setting unit 125.

The model division unit 121 acquires the X and Y dimensions, which are the dimensions of the 3D CAD model (3D model) to be processed, which are two directions orthogonal to each other, the X direction and the Y direction, and stores the X dimension and the Y dimension in the storage unit 24 in advance. The number of gate points is calculated using the obtained gate point 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 1, 2, 3, ..., etc., and the model dividing unit 121 does not divide the 3D model when the number of gate points is 1, and when the number of gate points is 2. 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 evenly divided. Generally, when the number of gate points is n, the 3D model is divided into n so that the volume is evenly 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”) on the cavity (female mold of the injection molding die) side of the 3D model. To 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 a 3D model is known. For example, assuming that the coordinates of the 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 other. Draw a line toward each other, where each of the four lines intersects, and the center of gravity Gi of this triangular pyramid is
Gi = (R1 + R2 + R3) / 4
It is calculated by. The center of gravity position G is calculated by multiplying this by the volume Vi of the triangular pyramid as a weight, adding all the polygons, and dividing by the total product. When the model dividing unit 121 divides the 3D model into a plurality of parts, the center of gravity calculation unit 123 calculates the center of gravity for each of the divided parts.

The distance calculation unit 124 calculates the distance between the center of gravity position calculated by the center of gravity 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. Instead of extracting 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 having a short distance. When the 3D model is divided into a plurality of parts by the model dividing unit 121, the distance calculation unit 124 calculates the distance between the center of gravity position and the face of each divided portion.

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

The flow analysis unit 126 divides the 3D model to be processed into minute elements (mesh), generates an analysis model for performing flow analysis, applies analysis conditions to this analysis model, and executes flow analysis. .. The analysis conditions are injection pressure, injection speed, mold clamping force, mold temperature, gate temperature, number of gates, gate position, etc. Of these, the number of gates and the gate position are automatically set by the gate position setting unit 125. Is 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-A-2010-5893 can be used. As an example, in the flow analysis, nodes are extracted in each radial direction at an equal angle centered on the gate position set by the gate position setting unit 125, 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 Newtonian fluid is created, and the pressure at each node is calculated by giving the flow rate Q. The flow analysis unit 126 displays the result obtained by the flow analysis, that is, the pressure at each node of the 3D model on the display unit 20. Further, 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 division unit 121 changes the division of the 3D model, and the center of gravity calculation unit 123, the distance calculation unit 124, the gate position setting unit 125, and the flow analysis unit 126 are subdivided. Perform the recalculation based on the 3D model. As a result of the evaluation, when the pressure is appropriate, the flow analysis unit 126 outputs the automatically set gate position, that is, its three-dimensional coordinates to the outside. The flow analysis unit 126 does not necessarily have to be realized by the CPU 12 in the gate position setting device 10, but may be realized by the CPU of an external computer.

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

First, the CPU 12 reads out the 3D model to be processed stored in the storage unit 24, acquires the X and Y dimensions of the 3D model, and uses a gate point determination matrix created in advance and stored in the storage unit 24. The number of gate points of the 3D model is calculated (S101). The gate point 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, the Y dimension is divided into a plurality of stages, and the X dimension is divided. The number of gate points is associated with each combination of Y-dimensional divisions. In general, the larger the X dimension, the larger the number of gate points, and the larger the Y dimension, the larger the number of gate points. It can be said that the gate point determination matrix divides the area according to the X dimension and the Y dimension, and assigns the corresponding number of gate points to each area. The minimum number of gate points is 1, and the maximum 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 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 number of divisions is divided. The number is 3, that is, divided into 3 parts.

Next, the CPU 12 divides the 3D model so that the volume is equally divided (S103). If the number of gate points is 1, there is no division, so this process is not executed. When the number of gate points is 2 and the number of divisions is 2, the volume of the 3D model is divided into two so as to be equally divided. Specifically, the position of the center of gravity of the 3D model is calculated, and the calculated center of gravity position is used as a reference for dividing into two in the vertical direction (Z direction). 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 surface is determined so that the volume of each part is 1/3, and 3 is determined based on the determined division surface. To divide.

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

After setting the gate position, the CPU 12 executes the 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, mold clamping force, mold temperature, gate temperature, number of gates, gate position, etc. Among them, the number of gates and the gate position are the number of gates and the gate position automatically set in S104. Is used.

After performing the flow analysis, whether or not the resulting filling pressure distribution is appropriate, specifically, whether or not the pressure distribution is within a predetermined range and the peak value is below the threshold value. Judgment (S106). If the pressure distribution is within a predetermined range and is uniform, the residual strain of the molded product can be suppressed, and if the peak value is reduced to below the threshold value, the mold clamping force is reduced, and molding is performed with a molding machine having a small mold clamping force. Is possible. Normally, if the pressure peak value at the completion of filling is below the threshold value, it can be estimated that the pressure distribution is almost uniform accordingly. Therefore, only whether or not the peak value is below the threshold value is determined. You may.

If the filling pressure peak value obtained by the flow analysis is equal to or less than the threshold value, it is determined to be 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 to be NG, the number of gate points determined in S101 is changed, and the processing after S102 is repeated. For example, if the number of gate points is set to 1 point, the gate position is set without division, and the flow analysis is performed at the set gate position, and the pressure peak value at the time of filling exceeds the threshold value, the CPU 12 sets the number of gate points to 1 point. Change from to 2 points, divide the 3D model into 2 parts, reset the gate position, and re-execute the flow analysis. 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, the flow analysis program is installed in a computer, the 3D model data to be processed is input, and the user specifies the gate position to execute the flow analysis. However, in the present embodiment, the number of gates and the gate position are determined. Please note that it is set automatically. When executing the flow analysis, it is desirable that the CPU 12 displays the gate position automatically set together with the 3D model on the display unit 20 with an arbitrary marker or icon.

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 surface of the 3D model on the cavity side as a face (S201). If there are a plurality of surfaces on the cavity side, 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 associates the calculated center of gravity with the part of the 3D model and stores it in the RAM 16. In the case of no division, the entire 3D model and the calculated center of gravity G are associated 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 portions P2 and G2 are associated with each other. And store it in 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 portions P2 and G2 are associated and stored in the RAM 16, and the portions P3 and G3 are associated and stored in the RAM 16.

Next, the CPU 12 reads out 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 undivided, one center of gravity G is calculated, and the distance between this center of gravity G and one or more extracted faces is calculated. For example, assuming that 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 The distance to the center of gravity G is calculated, and these calculated distances are stored in the RAM 16. When the 3D model is divided into two, the center of gravity G1 and G2 are calculated for each part P1 and P2, the distance between the center of gravity G1 and one or more faces extracted from the part P1 is calculated, and the distance between the center of gravity G2 and the part P2 is calculated. Calculate the distance to one or more extracted faces. For example, assuming that the face identification numbers extracted from the portion 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, and the distance between the face c1 and the center of gravity G1. The distances between the face d1 and the center of gravity G1 are calculated, and these calculated distances are stored in the RAM 16. The same applies to the partial P2.

Next, the CPU 12 reads out the distance between the face and the center of gravity stored in the RAM 16 and extracts a predetermined number of faces having a short distance from the center of gravity, for example, the upper three faces (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 to face a) <(Distance to face b) <(Distance to face c) <(Distance to 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 are extracted for each part.

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

Next, the CPU 12 sets a gate position settable area for each face on which a point is set (S206). The gate position settable area is stored in the storage unit 24 as a rule in advance, and specifically, an area within a predetermined distance from the edge of the 3D model, for example, 5 mm is defined as a gate position unsettable area, and is defined as an area other than this. To. A predetermined distance may be set according to the type of the 3D model or the molded product, or a region 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 the point closest to the center of gravity of the gate position settable area for each face (S207). 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 settable area, 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 settable area. If the 3D model is not divided and 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 settable area, 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 settable area, the point closest to the center of gravity G of the face b is calculated again, and similarly, the face c and the center of gravity are calculated again. If the point on the face c when calculating the distance to G is not within the gate position settable 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. Let the point on the face a be ap, the point on the face b be bp, and the point on the face c be cp.

Next, the CPU 12 selects the point closest to the center of gravity G among the coordinates of the three points stored in the RAM 16 and sets this as the gate position (S208). For example
(Distance from ap) <(Distance from bp) <(Distance from cp)
If so, the point a on the face a is set at the gate position. In general,
(Distance to face a) <(Distance to face b) <(Distance to face c) <(Distance to 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 settable area and the point on the face b is in the gate position settable area. As a result, the point on the face b can be the point closest to the center of gravity G. In this sense, it is significant to extract a plurality of faces close to the center of gravity G in S204. When the 3D model is divided into two or three, the point closest to the center of gravity of each part is set at the gate position in the same manner.

After setting the gate position, the CPU 12 outputs the coordinates (x, y, z) of the point of the set gate position 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 a later flow analysis.

In injection molding, the pressure of the resin injected from the gate position has the highest pressure distribution when filling into the mold of the molded product is completed, and the filling pressure of the gate reaches the peak value. If the gate position is not appropriate and the position is biased with respect to the 3D model, it becomes difficult for the resin to flow by that amount, and the peak value of the filling pressure increases. As described above, the increase in the peak value causes an increase in the mold clamping force and a residual strain of the molded product. In the present embodiment, it is generally considered desirable as the gate position to be a position where the filling distance (or filling time) until the completion of filling is almost equal in the 3D model. Therefore, paying attention to the position of the center of gravity of the 3D model, the cavity side It can be said that the point closest to the position of the center of gravity of the surface 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 perform high speed without depending on the experience and intuition of a skilled engineer who manufactures an injection molding die. Moreover, the gate position can be set with high accuracy and the flow analysis can be performed.

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

FIG. 5 shows a plan view (plan view projected on the XY plane) of the 3D model 30. The dimensions in each of 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 score determination matrix 32. Depending on the size x of the X dimension and the size y of the Y dimension,
Area A: 0 <x≤x1, 0 <y≤y1
Area B: 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
The number of gate points is divided into 9 areas in total, and the number of gate points is divided into A area: 1 point, B area and C area: 2 points, D area and E area: 3 points, F area, G area and H area: 4 points, I area: 5 points. And. For example, x1 = y1 = 210 mm, x2 = y2 = 400 mm, x3 = y3 = 600 mm, but the present invention is not limited thereto. If the X dimension and the Y dimension of the 3D model to be processed correspond to the A region, the number of gate points is 1, and if the 3D model to be processed corresponds to the E region, the number of gate points is 3. The gate point number determination matrix 32 may be created for each type of molded product and stored in the storage unit 24.

FIG. 7 schematically shows how the 3D model 30 is divided into two parts. The center of gravity G of the 3D model 30 is calculated, and the center of gravity G is divided into two in the vertical direction with reference to the partials P1 and P2. One or more faces on the cavity side are extracted from each portion P1 and P2, the center of gravity is calculated again at each portion P1 and P2, and the point closest to the center of gravity is extracted from each portion P1 and P2.

FIG. 8 schematically shows the state of the 3D model 30 divided into three parts. The 3D model 30 is divided into a plurality of equal parts, the divided surfaces are determined so that the volume of each portion is 1/3, and the divided surfaces are divided into three parts P1, P2, and P3 based on the determined divided surfaces. Extract one or more faces on the cavity side in each part P1, P2, P3, recalculate the center of gravity G1, G2, G3 in each part P1, P2, P3, and recalculate the center of gravity G1 in each part P1, P2, P3, respectively. , G2, 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 surface on the cavity side of the 3D model as a face.

9 (b) and 9 (c) show the processes of S202 to S204 of FIG. 4, that is, the process 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 portion having a relatively high density indicates a face that is close to the center of gravity. This is a case where the upper three faces near the center of gravity are extracted, and these faces are shown as faces a, b, and c.

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

10 (b) and 10 (c) show the process of S206 of FIG. 4, that is, the process of setting the gate position settable area. Of the extracted faces, a point separated from the edge of the 3D model by 5 mm or more is set as a gate position settable area.

10 (d) and 10 (e) are the processes of S207 to S208 of FIG. 4, that is, the points closest to the center of gravity in the gate position settable region are calculated for each face, and the points closest to the center of gravity are calculated for each face. The 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 among these is finally selected as the gate position.

FIG. 11 schematically shows a gate position settable area. 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. As the edges of the 3D model 30, since these edges 30a and 30b exist in addition to the edges defining the outer edges, 30c, 30d, and 30e are set as the edges defining the region 5 mm from the edges. The gate position settable region is a region 30f determined by these edges 30c, 30d, and 30e, and is indicated by diagonal lines in the figure.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and various modifications are possible. Hereinafter, a modified example will be described.

<Modification example 1>
In the embodiment, as shown in the processing flowchart of FIG. 3, the number of gate points is determined using the gate point 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 premised on the 3D model division process of the embodiment, and the gate position is set without dividing the 3D model or after executing another 3D model division process. You may. The user may manually set whether or not to execute the processes of S101 to S103 of FIG.

Alternatively, it is also possible to combine the processes of S101 to S103 of FIG. 3 with other gate position setting processes. The processing of S101 to S103 of FIG. 3 may be executed by another computer, the result may be input to the gate position setting device 10 via the communication I / F22, and the processing of S104 of FIG. 3 may be executed. 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 CPU 12 of the gate position setting device 10 executes the process of FIG. 4, but one or more of the processes of S201 to S209 of FIG. 4 may be executed by a plurality of computers. The computer as a whole functions as a gate position setting device 10 or a gate position setting system. Further, in the embodiment, the processing of FIG. 4 is realized by the CPU 12 executing the processing program, but one or more of the processes of S201 to S209 of FIG. 4 may be realized by hardware. Hardware processing can be performed using, for example, a circuit such as an ASIC or FPGA (Field Programmable Gate Array).

Further, in the embodiment, one or a plurality of processes of FIGS. 3S101 to S106 may be executed by a plurality of computers. Specifically, in the first computer and the second computer connected to each other by the communication network, the first computer executes the processes of S101 to S104 and transmits the result to the second computer, and the second computer performs the processes of S105 and S104. The process of S106 may be executed and the result may be returned to the first computer. In this case, the first computer functions as a gate position setting device, and the second computer functions as a flow analysis device. Explaining with reference 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 from the first computer, the 3D model, and other analysis conditions, 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 number of gates is changed and the gate position is automatically set again by the gate position setting unit 125. , Send to the second computer.

<Modification example 3>
In the embodiment, the number of gate points is determined according to the X and Y dimensions of the 3D model using the gate point determination matrix 32, the 3D model is divided into a plurality of parts accordingly, and the gate position is automatically set in each part. Although it is set, the user may manually set only the number of gate points, and the CPU 12 may automatically execute the subsequent 3D model division and gate position setting according to the processing program. That is, in the present invention,
Both (1) manually setting the number of gates and automatically setting the gate position (2) 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 the iterative calculation, there is also the case where the number of gates is automatically increased by 1 by performing the iterative calculation and the gate position is automatically set again (2). It goes without saying that it is included in). The minimum number of gates is desirable regardless of whether it is manual or automatic.

<Modification example 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 number of gates is increased by 1 and the gate position is automatically set again. However, if the pressure peak value does not fall below the threshold value even after repeating the flow analysis a predetermined number of times, it is possible that the setting of the gate position based on the center of gravity of the 3D model is not always effective. Therefore, it is possible to switch to another gate position setting method such as an optimum 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 by the method of the embodiment without performing repeated calculations.

<Modification 5>
In the embodiment, the number of gate points is determined according to the dimensions of the 3D model using the gate point determination matrix 32 as shown in FIG. 6, and the gate point determination matrix 32 is a storage unit similar to the 3D model and the processing program. Although stored in 24, at least one of the 3D model, the processing program, and the gate score determination matrix may be stored in another storage unit (including a storage unit connected by a communication line). Further, when the result of the flow analysis is determined to be OK after the iterative calculation is executed and the number of gates is changed for a certain 3D model, the gate point determination matrix is used for the 3D model similar to the shape of the 3D model. The value of may be adjusted (learned) to the changed value.

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

Claims (7)

A face acquisition part that acquires the face on the cavity side of a 3D model of a molded product made by injection molding resin,
A center of gravity calculation unit that calculates the center of gravity of the 3D model,
A gate position setting unit that automatically sets the position closest to the center of gravity of the positions on the face to the gate position.
A division part that divides the 3D model into a plurality of parts according to the number of gates,
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 a flow analysis unit.
Equipped with a,
The face acquisition unit acquires the face for each of the parts.
The center of gravity calculation unit calculates the center of gravity for each of the parts.
The gate position setting unit automatically sets the gate position for each part, and further, when the analysis result by the flow analysis unit is not appropriate, the gate number is changed and the gate position is automatically set again. Positioning device. An area setting unit for setting a gate position settable area is provided on the face.
The gate position setting device according to claim 1, wherein the gate position setting unit automatically sets a position on the face that is within the gate position settable area and is closest to the center of gravity to the gate position. .. The gate position setting device according to claim 2, wherein the area setting unit sets a region separated from the edge of the 3D model by a predetermined distance as the gate position settable area. The gate position setting device according to claim 1, wherein the gate position setting unit automatically sets the position closest to the center of gravity to the gate position among a plurality of positions on the face close to the center of gravity. An area setting unit for setting a gate position settable area on the plurality of faces is provided.
The gate position according to claim 4, wherein the gate position setting unit is located in the gate position settable region among the positions on the plurality of faces and automatically sets the position closest to the center of gravity to the gate position. Setting device. Gate setting unit that sets the number of the gate depending on the size of the 3D model
With
The gate position setting device according to any one of claims 1 to 5, wherein the dividing unit divides the 3D model into the plurality of parts according to the number of gates set by the gate setting unit. On the computer
The step of acquiring the face on the cavity side of the 3D model of the molded product made by injection molding the resin,
The step of calculating the center of gravity of the 3D model and
A step of automatically setting the position closest to the center of gravity of the positions on the face to the gate position, and
A step of dividing the 3D model into a plurality of parts according to the number of gates, and
A step of performing a flow analysis of the 3D model using the automatically set gate position, and
To run ,
In the step of acquiring the face, the face is acquired for each of the parts.
In the step of calculating the center of gravity, the center of gravity is calculated for each part.
In the step of automatically setting the gate position, a program that automatically sets the gate position for each part, and further changes the number of gates to automatically set the gate position again when the result of the flow analysis is not appropriate. ..

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