JP5698331B2 - Injection molding machine - Google Patents

Description

The present invention relates to an injection molding machine that can accurately measure the displacement of a mold .

  Stereo measurement can be performed by imaging the same mark using two cameras (Patent Document 1). When performing general stereo measurement, the optical axes of the lenses of the two cameras are arranged in parallel to each other, and the positions of the principal points of the lenses of the two cameras are matched with respect to the optical axis direction. The position of the target mark can be detected by simultaneously imaging one target mark with two cameras.

JP 2003-242485 A

  In conventional stereo measurement, high accuracy is required for the position and orientation of the two cameras. In addition, since it is necessary to capture one mark with two cameras at the same time, the camera installation conditions during measurement are restricted. Although it is useful for measuring the position of a stationary mark, it is not suitable for measuring the time calendar of the displacement of the mark position. In particular, if the camera itself is displaced during the measurement period, an error is superimposed on the measurement result.

According to one aspect of the invention,
An observation device that images the measurement target mark and the reference mark and obtains image data;
A control device for inputting image data acquired by the observation device and performing image analysis;
Have
The controller is
By performing image analysis, the displacement amount of the measurement target mark is calculated from the position information of the measurement target mark at different times,
Based on the displacement between the different times of the image of the reference mark, the amount of displacement of the observation device is calculated,
A displacement measuring device for correcting the displacement amount of the measurement target mark based on the displacement amount of the observation device is provided.

According to another aspect of the invention,
Capturing the measurement target mark and the reference mark with an observation device at at least two times to obtain image data;
Calculating a time calendar of the position of the measurement target mark based on the image data of the measurement target mark and the reference mark;
Calculating the displacement of the observation device based on the displacement between the two times of the image of the reference mark based on the image data of the reference mark;
And a step of correcting a time calendar of the position of the measurement target mark based on a displacement amount of the observation device.

  Since the time calendar of the position of the measurement target mark is corrected based on the displacement amount of the observation apparatus itself, the time calendar of the position of the measurement target mark is not affected by the displacement and orientation change of the observation apparatus itself during the measurement period. Can be requested.

  FIG. 1 shows a schematic diagram of a displacement measuring apparatus according to an embodiment. A stage 12 is arranged in a space in which an XYZ orthogonal coordinate system (global coordinate system) is defined, and a measurement object 10 is placed thereon and fixed. A plurality of measurement object marks A are fixed on the surface of the measurement object 10. The measurement target mark A may be formed by drawing directly on the surface of the measurement target 10, or a member on which the mark is formed may be attached to the surface of the measurement target 10.

  The measuring object 10 is deformed when an external force is applied. When the measurement object 10 is deformed, the measurement object mark A is displaced.

  A first reference member 13 and a second reference member 14 are fixed on the stage 12. A plurality of first reference marks E 1, E 2, E 3 are fixed to the surface of the first reference member 13, and a plurality of second reference marks F 1, F 2, F 3 are fixed to the surface of the second reference member 14. Has been.

  The first observation device 20 and the second observation device 30 observe the measurement target mark A. For the first observation device 20 and the second observation device 30, for example, an imaging device such as a digital camera is used. When the observation object mark A is assigned a serial number from 1 to n, some of the observation object marks A1 to Ai are observed by the first observation device 20, and the other observation object marks Ai + 1 to An are the second observation device. Observed at 30. Note that all the observation target marks A1 to An may be observed by both observation apparatuses 20 and 30, or some of the observation target marks Aj to Aj + m are observed by both observation apparatuses 20 and 30. You may be made to do.

  The first reference marks E1 to E3 are observed by the first observation device 20, and the second reference marks F1 to F3 are observed by the second observation device 30.

  Each of the first observation device 20 and the second observation device 30 includes a lens and an image receiving surface. A first local coordinate system fixed to the first observation device 20 is defined, and a second local coordinate system fixed to the second observation device 30 is defined. The first local coordinate system is defined by a W axis that coincides with the optical axis of the lens of the first observation apparatus 20, a U axis and a V axis that are perpendicular to the W axis and orthogonal to each other. Matches the principal point of The image receiving surface is parallel to the UV surface. The second local coordinate system is defined by a T-axis that coincides with the optical axis of the lens of the second observation device 30, an R-axis and an S-axis that are perpendicular to the T-axis and orthogonal to each other, and the origin is the lens Matches the principal point of The image receiving surface is parallel to the RS surface.

  Image data captured by the first observation device 20 and the second observation device 30 are input to the processing device 40. The processing device 40 processes the input image data and obtains a time calendar of the shape change of the observation object 10. The time calendar of the shape change is displayed on the image display device 41 as an image.

  FIG. 2 shows a flowchart of the displacement measuring method according to the embodiment. First, in step SA1, the shape of the measurement object is defined using CAD. The shape of the measurement object is defined in the CAD coordinate system.

  In step SA2, a global coordinate system (XYZ coordinate system) associated with the CAD coordinate system is defined. Usually, the CAD coordinate system may be adopted as the global coordinate system.

  In step SA3, the measurement object defined by CAD is virtually divided into a plurality of finite elements.

  FIG. 3 shows the measurement object 10 divided into finite elements. A plurality of measurement object marks A are fixed to the surface of the measurement object 10. FIG. 3 shows an example in which the measurement object 10 is divided into a large number of cubic elements. A node B is defined at the vertex of each element. Each element may have an arbitrary three-dimensional shape having a polygonal surface. In this case, the vertex of the polygonal surface is the node B. The control device 40 stores the position of each node B in the global coordinate system.

  In step SA4, the position of the measurement target mark A attached to the actual measurement object 10 in the global coordinate system is stored in the control device 40. Further, the positions of the first reference marks E1 to E3 and the second reference marks F1 to F3 in the global coordinate system are stored in the control device 40.

  In step SA5, the first observation device 20 and the second observation device 30 are arranged and fixed in the space in which the global coordinate system is defined. The control device 40 stores the positions and orientations of the first observation device 20 and the second observation device 30 in the global coordinate system. The position of the first observation device 20 is specified by the global coordinates of the principal point of the lens. The attitude of the first observation device 20 is specified by the optical axis of the lens, that is, the direction of the W axis and the direction of the U axis. Similarly, the position of the second observation device 30 is specified by the global coordinates of the principal point of the lens, and the posture is specified by the directions of the T axis and the R axis.

  In the embodiment, the W axis of the first local coordinate system fixed to the first observation device 20 is parallel to the Z axis of the global coordinate system, and the second local coordinate system fixed to the second observation device 30 is used. The first and second observation devices 20 and 30 are arranged so that the T axis of the coordinate system is parallel to the X axis of the global coordinate system. In this arrangement, the first observation device 20 observes the displacement in the direction orthogonal to the W axis, that is, the XY in-plane direction, and the second observation device 30 is in the direction orthogonal to the T axis, that is, in the YZ plane. Directional displacement can be observed.

  It is preferable to arrange the first and second observation devices 20 and 30 according to the deformation expected for the observation object 10. For example, if the direction of the external force is parallel to the XY plane and the magnitude thereof is substantially constant with respect to the Z direction, the deformation of the measurement object 10 is predicted to occur in a direction substantially parallel to the XY plane. This deformation can be observed mainly by the first observation device 20.

  In the following description, a case will be described in which the observation object 10 is predicted to deform mainly in a direction parallel to the XY plane.

  In step SA6, while applying an external force to the measurement object 10, the observation object mark A and the first reference marks E1 to E3 are imaged by the first observation device 20, and the observation object mark A and the second reference mark F1 are captured. -F3 is imaged by the second observation apparatus 30. The captured image data is input to the control device 40. The control device 40 measures the position of the image of the observation target mark A in the image receiving plane by performing image analysis. In the following steps, processing of image data acquired by the first observation apparatus 20 will be described. Processing of the image data acquired by the second observation apparatus 30 is performed in the same manner.

  The image receiving plane of the first observation apparatus 20 is parallel to the UV plane of the first local coordinate system. For this reason, the position in the image receiving surface is specified by the U coordinate and the V coordinate. By analyzing the image data at the observation times t0, t1, t2,..., The positions of the observation target marks A at the observation times, that is, (U, V) coordinates are detected. Hereinafter, an example of a method for detecting the position of the observation target mark A1 will be described.

  First, a rectangular area including the observation target mark A1 is cut out from the image data. The (U, V) coordinates of the clipped area, for example, the (U, V) coordinates of one vertex of the rectangle are stored. The cut image data is subjected to processing such as a low-pass filter or contraction / expansion operation for the purpose of noise removal. Using the image data from which the noise has been removed, the position of the observation target mark A1 within the clipped region is detected.

  For the detection of the mark position, it is preferable to use the center of gravity calculation or the peak value detection method. Since the mark image may be blurred, position detection by the edge detection method or pattern matching method is not suitable. By setting a threshold value for the light intensity and performing the centroid calculation only for pixels that are equal to or greater than the threshold value, it is possible to make it less susceptible to the influence of the background light intensity.

  The (U, V) coordinates of the observation target mark A1 in the image receiving plane can be calculated from the position of the cut-out region and the position of the observation target mark A1 in the cut-out region. In the same way, the (U, V) coordinates of the other observation target marks A2 to An are obtained. Further, the (U, V) coordinates of the first reference marks E1 to E3 are obtained.

  As shown in FIG. 4, a time calendar table of coordinates and displacement amounts is prepared for each of the observation target marks A1, A2,... And the first reference marks E1 to E3. In this time calendar table, an area for storing (U, V) coordinates and displacement amounts (ΔU, ΔV) is secured for each time. The obtained (U, V) coordinate values are stored in the (U, V) coordinate storage area of the time calendar table shown in FIG.

  In step SA7, the displacement at each observation time for each of the observation target mark A and the first reference marks E1 to E3 from the time calendar in the image receiving plane of each of the observation target mark A and the first reference marks E1 to E3. Calculate For example, when the positions of the observation target mark A1 at times t0 and t1 are (U10, V10) and (U11, V11), the displacement (ΔU11, ΔV11) of the observation target mark A1 at the observation time t1 is (U11−U10). , V11-V10). The displacement amounts (ΔU, ΔV) obtained by calculation are stored in the displacement amount storage area of the time calendar table shown in FIG.

  Next, the displacement amount at a plurality of points (extraction points) extracted on the (U, V) coordinates is calculated for each observation time from the displacement amount for each observation target mark and each observation time, and the calculation result is stored. To do. Hereinafter, a method for calculating the displacement amount of the extraction point will be described.

  FIG. 5 shows an example of a table that stores the calculated displacement amount. A table for storing the displacement amount of the extraction point is prepared for each observation time. For example, the extraction points are extracted so as to coincide with the lattice points of a square lattice provided at certain lattice intervals in the U-axis direction and the V-axis direction. The U coordinates of the extraction points are U1, U2, U3..., And the V coordinates are V1, V2, V3. An area for storing the displacement (ΔU, ΔV) is secured for each extraction point.

With reference to FIG. 6, a method of calculating the displacement amount at the extraction point (Ui, Vj) will be described.
A plurality of observation target marks A1 to An are distributed on the (U, V) plane. The displacement amount ΔU in the U-axis direction of each of the observation target marks A1 to An at the observation time t1 has already been obtained as shown in FIG. The displacement amount at the extraction point (Ui, Vj) can be estimated from the displacement amounts of a plurality of points whose displacement amounts are known, for example, by interpolation calculation. The displacement amount ΔV in the V-axis direction can be similarly estimated. The same processing is performed for each observation time after the observation time t2, and the calculated displacement amount is stored in the displacement amount storage area of the table shown in FIG. 5 for each observation time.

Instead of preparing the displacement amount storage table shown in FIG. 5, an approximate function of the displacement amount may be determined. The approximate functions fu and fv of the displacement amount can be expressed as follows, where the position on the image receiving surface is (U, V) and the elapsed time is t.
ΔU = fu (U, V, t)
ΔV = fv (U, V, t)
In step SA8, in consideration of the lens characteristics, the (U, V) coordinates on the image receiving surface are converted into two polar angles φU and φV with reference to the W axis of the first local coordinate system. Further, the displacement amounts ΔU and ΔV are converted into polar angle variations ΔφU and ΔφV.

  FIG. 7 shows the definitions of the angles φU and φV. When one point (point of interest) is determined on the UV coordinates on the image receiving plane, one vector G passing through the point of interest on the image receiving plane and the origin of the UVW coordinate system is determined in the UVW local coordinate system. The vector G goes to the observation target mark that connects the image to the position of the point of interest on the image receiving surface. An angle formed by an image GU obtained by vertically projecting the vector G on the UW plane and the W axis is defined as φU, and an angle formed by an image GV obtained by vertically projecting the vector G on the VW plane and the W axis is defined by φV. One point on the image receiving surface corresponds to one vector G. The vector G can be represented by angle coordinates (φU, φV). Therefore, one coordinate (U, V) on the image receiving surface corresponds to one angular coordinate (φU, φV). Therefore, (U, V) coordinates on the image receiving surface can be converted into angle coordinates (φU, φV), and displacement amounts (ΔU, ΔV) can be converted into angle change amounts (ΔφU, ΔφV). .

  As shown in FIG. 8, for each observation time, an angle change amount table indicating the relationship between the angle coordinates (φU, φV) corresponding to the extraction point and the angle change amounts (ΔφU, ΔφV) is prepared. In the angle change amount table, an area for storing the angle change amount is secured for each extraction point. The angle change amounts (ΔφU, ΔφV) calculated by the conversion are stored in the storage area for the angle change amount.

Instead of the angle change amount table shown in FIG. 8, an approximate function of the angle change amount may be determined. The approximate functions fφU and fφV for the angle change amount can be expressed as follows, where the elapsed time is t.
ΔφU = fφU (φU, φV, t)
ΔφV = fφV (φU, φV, t)
In step SA9, based on the displacement of the images of the reference marks E1 to E3, the displacement of the first observation device 20 and the change in posture are obtained. The reference marks E1 to E3 are not moved during the observation period. If the images of the reference marks E1 to E3 are observed as if they have moved, it is considered that the first observation device 20 itself has moved or its posture has changed. Hereinafter, a method for obtaining the displacement and the posture change of the first observation apparatus 20 will be described.

  FIG. 9 shows the relationship between the displacement and posture change caused by the disturbance of the first imaging device 20 and the local coordinate system. The displacements in which the first imaging device translates in the U, V, and W axis directions are denoted by ΔUD, ΔVD, and ΔWD, respectively. Further, the displacements in the rotational direction around the U axis, the V axis, and the W axis are denoted by ΔθUD, ΔθVD, and ΔθWD, respectively. Further, the distance from the origin to the reference mark E1 is d.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the angle change ΔθUD due to disturbance occurs in the first observation device 20 is expressed by the following equation or approximate equation: Is done.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the angle change ΔθVD due to disturbance occurs in the first observation device 20 is expressed by the following equation or approximate equation: Is done.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the displacement ΔUD due to disturbance occurs in the first observation device 20 is expressed by the following approximate expression.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the displacement ΔVD due to disturbance occurs in the first observation device 20 is expressed by the following approximate expression.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the angle change ΔθWD due to the disturbance occurs in the first observation device 20 is expressed as follows, where the proportionality constant is k1. It is expressed by an approximate expression.

  The amount of change (ΔφUD, ΔφVD) of the angle coordinates (φU, φV) of the first reference mark E1 when the displacement ΔWD due to the disturbance occurs in the first observation device 20 is set to the following approximation with the proportionality constant as k2. It is expressed by a formula.

  From the above equation and the approximate equation, the angular coordinates (φU, φV) of the first reference mark E1 when displacement (ΔUD, ΔVD, ΔWD, ΔθUD, ΔθVD, ΔθWD) due to disturbance occurs in the first observation device 20. ) Change amount (ΔφUD, ΔφVD) is considered to be expressed by the following approximate expression.

  Among the above approximate expressions, the angle change amounts ΔφUD and ΔφVD are obtained by observing the reference mark E1. The distance d to the reference mark E1 and the angle coordinates (φU, φV) of the reference mark E1 are known. There are six unknowns: ΔUD, ΔVD, k2ΔWD, ΔθUD, ΔθVD, and k1ΔθWD. If the displacements of the three reference marks E1 to E3 are observed, six simultaneous equations can be obtained. Therefore, the six unknowns can be determined. That is, the displacement amount of the first observation device and the change amount of the posture are determined. Note that the three fiducial marks E1 to E3 are arranged at positions where one set of solutions can be determined from the six simultaneous equations.

  The angle change amounts (ΔφU, ΔφV) stored in the angle change amount table shown in FIG. 8 are based on the premise that the first observation apparatus 20 does not move and its posture does not change. When displacements (ΔUD, ΔVD, ΔWD, ΔθUD, ΔθVD, ΔθWD) are generated in the first observation device 20, the angular displacement amounts (ΔφU, ΔφV) stored in the angle variation table are corrected. Must.

  In step SA10, based on the displacements (ΔUD, ΔVD, ΔWD, ΔθUD, ΔθVD, ΔθWD) caused by the disturbance generated in the first observation device 20, the angle change amounts (ΔφU, ΔφV) stored in the angle change amount table. Correct. For example, when the angular coordinates of the extraction point are (φU0, φV0), the distance from the origin of the local coordinates to the extraction point is d0, and the amount of change in angle before correction is (ΔφU0, ΔφV0), The angle change amounts (ΔφU, ΔφV) are expressed by the following approximate expressions.

  Displacement and attitude changes ΔUD, ΔVD, ΔWD, and ΔθWD due to disturbance of the first observation device 20 are measured regardless of the distance from the observation object 10 to the first observation device 20 if the amount of change is small. The effect on the result is small. On the other hand, when the distance from the observation object 10 to the first observation device 20 is long, the change amounts of the posture changes ΔθUD and ΔθVD due to the disturbance of the first observation device 20 are minute. However, the influence on the measurement result is increased.

  When the displacement and posture change due to the disturbance of the first observation object 20 are very small, ΔUD, ΔVD, ΔWD, and ΔθWD are approximately set to 0, and the angle change amount table is based on only ΔθUD and ΔθVD. The stored angle change amounts (ΔφU, ΔφV) may be corrected. In this case, it is not necessary to observe three reference marks, and correction can be performed by observing one reference mark.

  In step SA11, based on the corrected angle change amount table shown in FIG. 8, each angle change amount (ΔφU, ΔφV) of each node B on the surface observed by the first observation device 20 is observed. Calculate for each time.

  The global coordinates of node B are already stored in step SA3. Since the relationship between the global coordinate system and the first local coordinate system is already stored in step SA5, the angle coordinates (φU, φV) of the node B can be obtained from the global coordinates of the node B. With reference to the corrected angle change amount table shown in FIG. 8, from the angle coordinates (φU, φV) of the node B, the angle change amounts (ΔφU, ΔφV) can be calculated by interpolation calculation or the like.

  As shown in FIG. 10, a table for storing the time calendar of the angle change amounts (ΔφU, ΔφV) of the nodes B1, B2,. In this table, an area for storing the amount of change in angle (ΔφU, ΔφV) is secured for each node and each observation time. The calculated angle change amounts (ΔφU, ΔφV) are stored in the angle change amount storage area of the table shown in FIG.

  In step SA12, each angle change amount (ΔφU, ΔφV) of the node B on the surface observed by the first observation device 20 is converted into a displacement amount (ΔX, ΔY) in the global coordinate system.

  With reference to FIG. 11, a method of converting the angle change amount (ΔφU, ΔφV) of the node B1 into the displacement amount (ΔX, ΔY) in the global coordinate system will be described. Since the first observation apparatus 20 measures the displacement in the direction perpendicular to the W axis of the first local coordinate system, it is assumed that the displacement direction of the node B1 is perpendicular to the W axis.

  A virtual plane Sw including the node B1 and perpendicular to the W axis is defined. In the first local coordinate system, the intersection of the virtual straight line extending in the (φU, φV) direction and the virtual plane Sw coincides with the node B1 at time t = ti. The intersection of the virtual line extending in the (φU + ΔφU, φV + ΔφV) direction and the virtual plane Sw coincides with the node B1 at time t = ti + 1. In this way, the displacement (ΔX, ΔY) of the node B1 from time ti to ti + 1 can be calculated.

  When the external force is uniform in the Z direction and the direction is parallel to the XY plane, the displacement amount of each node is considered to be substantially constant in the Z direction. Under this condition, the displacement amount of the nodes other than the nodes on the surface observed by the first observation device 20 can be calculated. Specifically, the displacement amount of the node of the point (X, Y, Z) is the same as the (X, Y) coordinate of the node and is observed by the first observation device 20. It is presumed that the amount of displacement of the node located on the surface is the same.

  As shown in FIG. 12, a displacement time calendar table for storing the displacements (ΔX, ΔY) of the nodes B1, B2,. In this table, an area for storing displacement (ΔX, ΔY) is secured for each node and each observation time. The calculated displacement amount is stored in the corresponding storage area of the displacement amount time calendar table.

  Based on the image data obtained by the second observation device 30, the displacement (ΔY, ΔZ) at each observation time of each node on the surface observed by the second observation device 30 is obtained in the same manner. If the displacement ΔY of each node calculated based on the image data obtained by the second observation device 30 is substantially constant in the Z direction, the calculation is performed based on the image data obtained by the first observation device 20. It is confirmed that the prediction that the displacement (ΔX, ΔY) made is substantially constant in the Z direction was valid.

  In step SA13, the change of the shape of the measuring object 10 is displayed on the image display device 41 as a moving image based on the nodal displacement amount time calendar table shown in FIG.

  FIG. 13 shows a schematic diagram of the image display device 41. An object display area 42 is secured in the display screen, and an operation unit 43, an elapsed time display bar 44, and a display command unit 45 are displayed on the outside thereof. In the object display area 42, the object is displayed three-dimensionally. Through the operation unit 43, operations such as display start, display stop, and display pause are performed. In the elapsed time display bar 44, the elapsed time up to the currently displayed time is displayed in a bar shape. In addition, the elapsed time from the start of observation can be specified via the elapsed time display bar, and the change in shape from the specified time can be displayed.

  An instruction to enlarge, reduce, rotate, etc. the image displayed in the object display area 42 is given through the display command unit 45. For this reason, the deformation of the observation object 10 can be confirmed from various viewpoints. The displacement amount of each node can be enlarged and displayed. When the change in the shape of the observation object is slight, it is easy to visually recognize the change in the shape by displaying the displacement amount in an enlarged manner.

  By continuously displaying the shape of the measurement object as time passes, the change in the shape of the measurement object 10 can be easily grasped visually. In order to make it easy to grasp the deformation amount of each part, an equal displacement amount line may be displayed, or a contour display in which the display color is changed according to the displacement amount may be performed.

  In the above-described embodiment, it is assumed that the observation object 10 is displaced mainly only in the direction parallel to the XY plane. Next, a case where a displacement in the Z direction is detected by the second observation apparatus 30 will be described.

  As shown in FIG. 14, the observation target mark Ai on the observation target 10 is observed by the first observation device 20, and the observation target mark Aj is observed by the second observation device 30. According to the analysis of the image data acquired by the first observation apparatus 20, the observation target mark Ai is changed from Ai (t = ti) to Ai (t = ti + 1) in the direction perpendicular to the W axis, that is, the direction parallel to the XY plane. ). Similarly, from the analysis of the image data acquired by the second observation device 30, the observation target mark Aj is changed from Aj (t = ti) to Aj (Aj (t = ti) in the direction perpendicular to the T axis, that is, the direction parallel to the YZ plane. It is estimated that the displacement was made at t = ti + 1).

  The displacement of the node Bk near the observation target marks Ai and Aj is affected by the displacement of the observation target marks Ai and Aj. Considering only the displacement of the observation target mark Ai, the displacement destination of the node Bk is predicted as the point Bki displaced in the direction parallel to the XY plane. Considering only the displacement of the observation target mark Aj, the displacement destination of the node Bk is predicted to be the point Bkj displaced in the direction parallel to the YZ plane. The actual displacement is a combination of the displacement to the displacement destination Bki and the displacement to the displacement destination Bkj. The actual displacement destination Bk (t = ti + 1) is obtained by weighting and combining the displacement to the displacement destination Bki and the displacement to the displacement destination Bkj. The weighting is performed in consideration of the distance from the node Bk to the observation target marks Ai and Aj.

  In general stereo measurement, one observation target mark must be observed simultaneously by two cameras. In the method according to the above-described embodiment, even when different observation target marks Ai and Aj are observed with the two observation devices 20 and 30, the displacement of the node Bk in the three-dimensional direction can be estimated. Note that the number of observation devices is not limited to one or two. Three or more observation devices may be used.

  Next, a displacement calculation method when observing one observation target mark with the two observation devices 20 and 30 will be described.

  As shown in FIG. 15, one observation target mark Ai is observed by both the first observation device 20 and the second observation device 30. By analyzing the image data acquired by the first observation apparatus 20, a displacement destination Ai1 (t = ti + 1) in a direction perpendicular to the W axis is determined. By analyzing the image data acquired by the second observation apparatus 30, a displacement destination Ai2 (t = ti + 1) in a direction perpendicular to the T axis is determined. The actual displacement destination Ai (t = ti + 1) includes a straight line SL1 connecting the origin of the first local coordinate system and the displacement destination Ai1 (t = ti + 1), and the origin of the second local coordinate system and the displacement destination Ai2 (t = Ti + 1) coincides with the intersection with the straight line SL2. In this way, the actual displacement destination Ai (t = ti + 1) can be calculated.

  In the above embodiment, in step SA8, the positions and displacements of the extraction points are represented by polar angles φU and φV in the local coordinate system. The polar angles φU and φV are not affected by the magnification depending on the distance between the observation apparatus and the observation target mark. Since it is not necessary to perform calculation in consideration of the difference in magnification, it is possible to reduce the calculation time for calculating the displacement.

  Next, with reference to FIG. 16, another configuration example for fixing the measurement target mark to the observation target 10 will be described.

  As shown in FIG. 16, for example, one surface 14 of the observation target object 10 faces the first observation target object 20. A plurality of mark display members 11 are attached to a surface 15 that faces in the lateral direction when viewed from the first observation device 20. Each of the mark display members 15 protrudes from the surface 15 and includes a surface facing the first observation device 20. An observation target mark C is displayed on the surface facing the first observation apparatus 20.

  When the surface 15 is parallel to the W axis, the mark drawn directly on the surface 15 cannot be observed by the first observation device 20. As shown in FIG. 16, by attaching the mark display member 11 protruding from the surface 15, the observation target mark C fixed to the surface 15 can be observed by the first observation device 20.

  The second observation apparatus 30 shown in FIG. 1 cannot detect the displacement in the X-axis direction of the observation target mark fixed to the surface 15 in FIG. By observing the observation target mark C fixed to the surface 15 using the mark display member 11 with the first observation device 20, the displacement of the observation target mark C in the X-axis direction can be detected.

  It is preferable to arrange the mark display members 11 so as not to overlap each other with respect to the direction (V-axis direction in FIG. 16) perpendicular to the W axis and included in the surface 15. With this arrangement, all the observation target marks C fixed on the surface 15 can be observed with the first observation device 20.

  Of the observation target marks C arranged at different positions in the W-axis direction, those located within the depth of field of the first observation device 20 can be imaged on the image receiving surface. Even when the image is not formed on the image receiving surface outside the depth of field, the (U, V) coordinates of the image of the observation target mark C can be detected by using a technique such as centroid calculation.

  FIG. 17 shows a front view of an injection molding machine in which the shape change measuring device according to the above embodiment can be mounted. The injection molding machine 340 includes an injection device 350 and a mold clamping device 370.

  The injection device 350 includes a heating cylinder 351, and a hopper 352 that supplies resin is disposed in the heating cylinder 351. Further, a screw 353 is disposed in the heating cylinder 351 so as to be able to advance and retreat and to be rotatable. The rear end of the screw 353 is rotatably supported by the support member 354. A measuring motor 355 such as a servo motor is attached to the support member 354 as a drive unit. The rotation of the weighing motor 355 is transmitted to the screw 353 of the driven portion via a timing belt 356 attached to the output shaft 361 of the weighing motor 355. A detector 362 is directly connected to the rear end of the output shaft 361 of the weighing motor 355. The detector 362 detects the rotation speed or rotation amount of the metering motor 355. Based on the number of rotations or amount of rotation detected by the detector 362, the rotational speed of the screw 353 is obtained.

  The injection device 350 further includes a screw shaft 357 parallel to the screw 353 so as to be rotatable. The rear end of the screw shaft 357 is connected to the injection motor 359 via a timing belt 358 attached to the output shaft 363 of the injection motor 359 such as a servo motor. Therefore, the screw shaft 357 can be rotated by the injection motor 359. The front end of the screw shaft 357 is screwed with a nut 360 fixed to the support member 354. When the injection motor 359 that is a drive unit is driven and the screw shaft 357 that is a drive transmission unit is rotated via the timing belt 358, the support member 354 moves forward and backward.

  A load cell 365 as a load detector is attached to the support member 354. The forward / backward movement of the support member 354 is transmitted to the screw 353 via the load cell 365, whereby the screw 353 moves forward / backward. Data corresponding to the force detected by the load cell 365 is sent to the control device 310. A detector 364 is directly connected to the rear end of the output shaft 363 of the injection motor 359. The detector 364 detects the rotation speed or rotation amount of the injection motor 359. Based on the number of rotations and the amount of rotation detected by the detector 364, the moving speed of the screw 353 in the forward / backward direction or the position in the forward / backward direction is obtained.

  The mold clamping device 370 includes a movable platen 372 to which a movable mold 371 is attached, and a fixed platen 374 to which a fixed mold 373 is attached. The movable platen 372 and the fixed platen 374 are connected by a tie bar 375. The movable platen 372 is slidable along the tie bar 375. The mold clamping device 370 includes a toggle mechanism 377. The toggle mechanism 377 has one end connected to the movable platen 372 and the other end connected to the toggle support 376. A ball screw shaft 379 is rotatably supported at the center of the toggle support 376. A nut 381 fixed to a cross head 380 provided in the toggle mechanism 377 is screwed onto the ball screw shaft 379. A pulley 382 is disposed at the rear end of the ball screw shaft 379, and a timing belt 384 is bridged between the output shaft 383 of the mold clamping motor 378 such as a servo motor and the pulley 382.

  In the mold clamping device 370, when the mold clamping motor 378 that is a drive unit is driven, the rotation of the mold clamping motor 378 is transmitted to the ball screw shaft 379 that is the drive transmission unit via the timing belt 384. Then, the ball screw shaft 379 and the nut 381 change the direction of motion from rotational motion to linear motion, and the toggle mechanism 377 is operated. By the operation of the toggle mechanism 377, the movable platen 372 slides along the tie bar 375, and mold closing, mold clamping, and mold opening are performed.

  A detector 385 is directly connected to the rear end of the output shaft 383 of the mold clamping motor 378. The detector 385 detects the rotation speed or rotation amount of the mold clamping motor 378. Based on the number of rotations or the amount of rotation detected by the detector 385, the position of the crosshead 380 that moves forward and backward with the rotation of the ball screw shaft 379, or the driven part connected to the crosshead 380 by the toggle mechanism 377 The position of a certain movable platen 372 is determined. The control device 310 controls the measuring motor 355, the injection motor 359, and the mold clamping motor 378.

  A cavity cav is formed between the movable mold 371 and the fixed mold 373. The cavity cav and the inside of the heating cylinder 351 communicate with each other.

  When the mold clamping is performed, stress is applied to the movable mold 371 and the fixed mold 373, and these molds are slightly deformed. In order to increase the precision of the shape of the injection molded product, it is desired to observe a slight deformation of the mold.

  A plurality of observation target marks are fixed to the side surfaces of the movable mold 371 and the fixed mold 373. By observing these observation target marks using the shape change device according to the above embodiment, the state of deformation of the mold can be confirmed by an image.

  In the above-described embodiment, the digital camera is used for the observation device 20 and 30 for detecting the displacement amount of the observation target mark A. However, the displacement amount may be detected by other methods. For example, it is also possible to detect the displacement amount of the observation target mark using a laser displacement meter.

  In the above embodiment, the coordinates (Ui, Vj) (i, j = 1, 2, 3,...) And the displacements (ΔU, ΔV) of the extraction points shown in FIG. 5 are shown in FIG. As described above, the angle coordinates (φUi, φVj) (i, j = 1, 2, 3,...) Are converted into coordinates (U = 1, 2, 3,...). , V) and their displacements (ΔU, ΔV) can be converted into angular coordinates (φU, φV) and angular variations (ΔφU, ΔφV).

Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

It is the schematic of the shape change measuring apparatus by an Example. It is a flowchart which shows the shape change measuring method by an Example. It is a diagram which shows the state which divided | segmented the measurement object into the some finite element virtually. It is a graph which shows the table which memorize | stores the coordinate of an observation object mark, and the time calendar of displacement amount. 10 is a chart showing a table for storing displacement amounts (ΔU, ΔV) of extraction points (U, V). It is a graph for demonstrating the calculation method of the displacement amount of an extraction point from the displacement amount of an observation object mark. It is a diagram which shows the definition of angle (phi) U and (phi) V of a local coordinate. It is a chart which shows the table which memorizes the angle variation (ΔφU, ΔφV) of the extraction point (φU, φV). It is a diagram showing the definition of displacement (ΔU, ΔV, ΔW, ΔθU, ΔθV, ΔθW) of the observation device. FIG. 5 is a diagram showing a table for storing a time calendar of angle change amounts (ΔφU, ΔφV) of nodes. It is a diagram for explaining a method of converting an angle change amount (ΔφU, ΔφV) into a displacement amount (ΔX, ΔY) of the global coordinate system. It is a diagram which shows the table which memorize | stores the time calendar of the displacement amount ((DELTA) X, (DELTA) Y) of a node. It is the schematic of the image display apparatus used for the shape change measuring apparatus by an Example. To explain how to calculate the displacement of a node based on the displacement of the observation target mark observed by the first observation device and the displacement of other observation target marks observed by the second observation device FIG. FIG. 5 is a diagram for explaining a method of calculating a displacement amount of an observation target mark when one observation target mark is observed by the first and second observation apparatuses. It is a perspective view which shows the other example of the fixing method of an observation object mark. It is a front view of the injection molding machine which can mount | wear with the shape change measuring apparatus by an Example.

10 observation object 11 mark display member 12 stage 13 first reference member 14 second reference member 20 first observation device 30 second observation device 40 processing device 41 image display device 42 object display region 43 operation unit 44 Elapsed time display bar 45 Display command part A, C Observation target mark B Nodes E1-E3 First reference mark F1-F3 Second reference mark XYZ Global coordinate system UVW First local coordinate system RST Second local coordinate system

Claims (2)

An injection device;
A mold clamping device including a mold;
An observation device that images a plurality of measurement target marks in the mold and obtains image data;
A control device that calculates the amount of displacement of the plurality of measurement target marks from position information at different times of the plurality of measurement target marks by inputting image data acquired by the observation device and performing image analysis;
An injection molding machine comprising: an image display device that displays a state of deformation of the mold as a moving image based on the displacement amount at each observation time. The injection molding machine according to claim 1, wherein the image display device can display the displacement amount in an enlarged manner .