Injection molding machine and viscosity measuring method

Abstract

To provide an injection molding machine and a viscosity measuring method capable of measuring viscosity with higher accuracy.SOLUTION: An injection molding machine includes: an injection cylinder to which a viscosity measuring unit can be attached and detached; an injection shaft in the injection cylinder; an injection drive device that drives the injection shaft; and a control device that controls the injection drive device to drive the injection shaft back and forth. The control device calculates an injection speed Vk based on a following formula (1) using each of three or more preset shear rate values γk (k is a natural number), where D is an inner diameter of the injection cylinder or an outer diameter of the injection shaft, and d is a capillary inner diameter of a capillary die attached to the viscosity measuring unit, and automatically sets the calculated injection speed Vk that is within a predetermined range as the injection speed for viscosity measurement.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an injection molding machine and a viscosity measurement method using an injection molding machine. [Background technology]

[0002] In injection molding, the viscosity of the molten resin is one of the main factors that affect the quality of the product. The viscosity of the molten resin can be measured by a dedicated device such as a capillary rheometer. However, it is generally difficult to strictly reproduce the conditions during actual molding when measuring using these devices. For these reasons, there is a demand to measure the viscosity of the molten resin on an injection molding machine used for mass production. For example, the following Patent Document 1 discloses an in-line screw injection molding machine that calculates the viscosity of the molten resin by obtaining the injection pressure with a load cell at the rear end of the screw when the mold is not in contact with the nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-142204 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, regarding the setting of the injection speed during viscosity measurement, although Patent Document 1 proposes that the injection speed be constant within a predetermined range, no specific guidelines are given as to what numerical value should be used. Currently, the setting of the injection speed is left to the discretion of the operator who uses the injection molding machine, and it is possible that an injection speed value that is not appropriate for measuring the viscosity of molten resin is set. In addition, since the injection speed setting is not necessarily constant for each measurement, it is not easy to simply compare data from different lots of materials or measurement dates. [Means for solving the problem]

[0005] According to the present invention, the following inventions are provided. [1] A viscosity measurement unit is detachably attached to an injection cylinder, an injection shaft in the injection cylinder, an injection drive device for driving the injection shaft, and a control device for controlling the injection drive device to drive the injection shaft back and forth, and the control device controls the injection drive device to drive the injection shaft back and forth, and the control device controls the injection cylinder to drive the injection shaft back and forth, and controls the injection drive device to drive the injection shaft back and forth, and ... k (k is a natural number), the injection speed V is calculated based on the following formula (1) or (2). k Calculate the injection speed V that is within a specified range. k An injection molding machine that automatically sets the injection speed for viscosity measurement.

number

number

[10] The injection molding machine according to any one of [1] to [8], wherein the injection molding machine is an inline screw type injection molding machine and the injection shaft is an inline screw.

[11] Injection speed V k (k is a natural number), a molding material is flowed from an injection cylinder of an injection molding machine through a measurement cylinder of a viscosity measurement unit having a pressure sensor into a capillary or slit of a die attached to the measurement cylinder, a pressure value of the molding material flowing in the measurement cylinder is obtained by the pressure sensor, and the injection speed V kViscosity η according to k and a step of calculating three or more preset shear rate values ​​γ based on the following formula (1) or (2) by the control device of the injection molding machine in the step of pouring the molding material. k Injection speed V corresponding to each k Calculate the injection speed V that is within a specified range. k in the following formulas (1) and (2), D represents an inner diameter of the injection cylinder or an outer diameter of an injection shaft in the injection cylinder, d represents an inner diameter of the capillary, and B and H represent the length and width of the slit, respectively.

number

number

[12]

[11] The viscosity measuring method according to the present invention, k In the step of automatically setting the three or more shear rate values ​​γ k is 1*10 1 sec -1 Above 5*10 5 sec -1 The injection speed is a value selected from the range below (where "*" indicates multiplication), and the predetermined range of the injection speed is 0.05 mm sec -1 More than 200mm sec -1 The viscosity measurement method is as follows.

[13] A viscosity measurement method according to

[11] or

[12] , wherein the step of acquiring the pressure value includes a step of acquiring a pressure value individually by switching between two or more dies into which the molding material is introduced via the measuring cylinder. Effect of the Invention

[0006] According to at least any of the embodiments of the present invention, it is possible to perform a more accurate viscosity measurement with reduced variability due to the operator. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of an injection molding machine that can be used in an embodiment of the present invention. [Diagram 2] 2 is a schematic cross-sectional view showing the injection unit 10 in a state in which a viscosity measurement unit 5 is attached to a nozzle cylinder 45 instead of an injection nozzle 46. FIG. [Diagram 3] FIG. 2 is a perspective view showing an example of the appearance of a viscosity measurement unit 5. [Figure 4] 11 is a perspective view showing another example of the appearance of the viscosity measurement unit 5. FIG. [Diagram 5] 2 is a schematic diagram showing an exemplary vertical cross section of a viscosity measuring unit 5. FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line VI-VI of FIG. 5. [Figure 7] 2 is a schematic enlarged cross-sectional view of a first capillary die 62. FIG. [Figure 8] 2 is a schematic enlarged cross-sectional view of a second capillary die 63. FIG. [Figure 9] 2 is a block diagram for explaining functions of a control device 7 of the injection molding machine 1. FIG. [Figure 10] FIG. 4 is a diagram showing an example of an image displayed on a touch panel of the control device 7 in a viscosity measurement mode. [Figure 11] 1 is a flow chart outlining an exemplary viscosity measurement method according to an embodiment of the present invention. [Figure 12] 13 is a diagram for explaining an example of a graph displayed on the touch panel of the operation panel when a graph drawing button 86 is pressed. FIG. [Figure 13] FIG. 13 is a diagram for explaining an example in which a graph showing the most recent measurement result and a graph showing the past measurement result are displayed in a superimposed manner. [Figure 14] FIG. 13 is a diagram showing an example of an image displayed on a touch panel of the control device 7 in a Burley correction mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The features of the embodiments described below can be combined with each other. Also, each feature can be an invention independently.

[0009] <1. Overall configuration of injection molding machine> Fig. 1 shows an example of an injection molding machine applicable to an embodiment of the present invention. The injection molding machine 1 shown in Fig. 1 includes an injection unit 10 that injects molding material, a mold clamping unit 8 that opens and closes a mold, and a control device 7 that controls the operations of these units. Fig. 1 shows a schematic cross section of the injection unit 10 of the injection molding machine 1.

[0010] In the configuration illustrated in FIG. 1, the injection unit 10 includes two parts, a plasticizing section 2 and an injection section 4. Of these, the injection section 4 has an injection cylinder 41 and an injection shaft 42 located within the injection cylinder 41. In this specification, the term "injection shaft" is used as a term that collectively refers to an injection plunger or an injection screw disposed inside an injection cylinder (also called a barrel). In the following description, the "injection plunger" is simply referred to as a "plunger." An example of an injection screw is an in-line screw, which will be described later. In the example illustrated in FIG. 1, the injection shaft 42 is a plunger configured to be capable of reciprocating along the axis of the injection cylinder 41.

[0011] The injection unit 4 further includes an injection drive device 43. The injection drive device 43 is any actuator that drives the injection shaft 42 (here, a plunger). Examples of the injection drive device 43 include a hydraulic cylinder or an electric cylinder.

[0012] 1, the injection cylinder 41, the injection shaft 42, and the injection drive unit 43 are arranged in this order in a generally linear manner. For ease of explanation, the injection cylinder 41 side of the injection unit 4 may be referred to as the "front side" or "forward" and the injection drive unit 43 side as the "rear side" or "rear." The injection drive unit 43 drives the injection shaft 42 back and forth inside the injection cylinder 41 based on instructions from the control unit 7.

[0013] 1, a nozzle cylinder 45 is connected to the tip of the injection cylinder 41. As in the example shown in Fig. 1, the injection cylinder 41 and the nozzle cylinder 45 can be configured to be heated to a predetermined temperature by wrapping a heater 47 (e.g., a band heater) around the outer circumferential surface.

[0014] The nozzle cylinder 45 has a nozzle mounting hole 451 on the opposite side to the injection cylinder 41. The nozzle cylinder 45 is configured to allow the injection nozzle 46 to be detachably attached thereto. For example, the inner wall of the nozzle mounting hole 451 has a female thread portion. In this case, the injection nozzle 46 is provided at its rear end with a male thread portion having a shape corresponding to the female thread portion of the nozzle mounting hole 451, thereby allowing the injection nozzle 46 to be detachably attached to the nozzle cylinder 45. As with the injection cylinder 41 and the nozzle cylinder 45, the injection nozzle 46 can be configured to be heated to a predetermined temperature by, for example, wrapping a heater 48 such as a coil heater around the outer circumferential surface.

[0015] In this example, a junction 3 is connected to the side of the nozzle cylinder 45, and the plasticizing section 2 is connected to the nozzle cylinder 45 via the junction 3. As shown in Fig. 1, the plasticizing section 2 has a plasticizing cylinder 21, a plasticizing screw 23 located in the plasticizing cylinder 21, a check device 25, a plasticizing screw driving device 27, and a heater 29. The plasticizing cylinder 21 has a hopper 211 at its rear end.

[0016] As shown in Fig. 1, a supply flow path connecting the junction 3 and the injection cylinder 41, and a discharge flow path connecting the injection cylinder 41 and the injection nozzle 46 are provided inside the nozzle cylinder 45. That is, the injection molding machine 1 shown in Fig. 1 is a so-called screw pre-plasticizer type injection molding machine. As will be understood from the following explanation, the present invention is not limited to screw pre-plasticizer type injection molding machines, and can of course also be applied to in-line screw type injection molding machines.

[0017] 2 shows the injection unit 10 in a state where the viscosity measurement unit 5 is attached to the nozzle cylinder 45 instead of the injection nozzle 46. In this embodiment, the nozzle cylinder 45 has a nozzle attachment hole 451, so that the injection nozzle 46 can be replaced with the viscosity measurement unit 5.

[0018] The viscosity measurement unit 5 includes a measurement cylinder 50 having a flow path formed therein. In the configuration illustrated in FIG. 2, the measurement cylinder 50 has a rear cylinder 51, a front cylinder 52, and a fastening means 53. The rear cylinder 51 and the front cylinder 52 are connected by the fastening means 53. An example of the fastening means 53 is a cover nut 531 shown in FIGS. 4 and 5 described later. A male thread portion having a shape corresponding to the female thread formed on the inner surface of the cover nut 531 can be formed at the rear end of the front cylinder 52. The front cylinder 52 is connected to the rear cylinder 51 by, for example, the cover nut 531 as the fastening means 53, and the front cylinder 52 and the rear cylinder 51 are integrated, so that the flow path in the front cylinder 52 communicates with the flow path in the rear cylinder 51. At least one of a capillary die and a slit die is attached to the front cylinder 52 as described later. A pressure sensor for measuring the pressure of a fluid (typically molten resin) flowing in the flow path is also attached to the front cylinder 52.

[0019] As shown in FIG. 2, the viscosity measurement unit 5 is coupled to the nozzle cylinder 45 by inserting the rear end of the rear cylinder 51 into the nozzle mounting hole 451 of the nozzle cylinder 45. In this manner, the nozzle cylinder 45 is configured to be able to detachably mount not only the injection nozzle 46 but also the viscosity measurement unit 5. Here, it can be said that the injection nozzle 46 and the viscosity measurement unit 5 are indirectly detachable from the injection cylinder 41 using the nozzle cylinder 45. The nozzle cylinder 45 may be configured as a part of the injection cylinder 41. In that case, it can be said that the injection nozzle 46 and the viscosity measurement unit 5 are directly detachable from the injection cylinder 41. In this specification, the phrase "the injection cylinder 41 to which the viscosity measurement unit 5 can be detachably mounted" is interpreted to include both the injection cylinder 41 to which the viscosity measurement unit 5 can be directly detachably mounted and the injection cylinder 41 to which the viscosity measurement unit 5 can be indirectly detachably mounted.

[0020] As will be described in detail later, the injection molding machine 1 is capable of measuring the viscosity of a molding material (e.g., molten resin) flowing through the viscosity measuring unit 5 in a state where the viscosity measuring unit 5 is attached to the injection cylinder 41 via the nozzle cylinder 45. The injection molding machine 1 can be configured, for example, to be able to switch the operation mode between a molding mode and a viscosity measuring mode based on an instruction from the control device 7.

[0021] In the viscosity measurement mode, the control device 7 of the injection molding machine 1 calculates the injection speed based on a predetermined relational expression using a preset shear rate value and a parameter value determined from the geometric properties of the injection cylinder 41. The control device 7 further automatically sets the calculated value as the injection speed during viscosity measurement, and operates the injection shaft 42 at that injection speed to discharge the molding material from the viscosity measurement unit 5.

[0022] At this time, the pressure sensor of the viscosity measurement unit 5 can obtain the pressure value of the molten resin, which is the molding material, in a state close to that during actual molding. The control device 7 calculates the viscosity of the molding material from a predetermined relational expression based on the measured value obtained from the pressure sensor, the parameter values ​​that define the shape of the capillary or slit of the die attached to the viscosity measurement unit 5, and the shear rate value used to calculate the injection speed. The calculated viscosity value is presented to the operator of the injection molding machine 1. The operator can determine the conditions for actual molding by referring to the viscosity obtained by measurement.

[0023] According to an embodiment of the present invention, the injection speed used in the viscosity measurement mode is automatically set based on a preset shear rate value, so that it is possible to perform highly accurate viscosity measurement without relying on the experience or intuition of the operator. In addition, in a typical embodiment of the present invention, three or more values ​​selected from an appropriate range are prepared as the shear rate used to calculate the injection rate. Then, the injection rate is calculated for each of these shear rates, and the injection rates corresponding to each shear rate are presented to the operator as candidates for viscosity measurement. However, among these injection rates obtained by calculation, values ​​outside a predetermined range are not presented to the operator. In other words, an injection rate (typically multiple injection rates) suitable for viscosity measurement is automatically calculated on the injection molding machine side and set as a condition for viscosity measurement. As a result, it is possible to expect the execution of a more accurate viscosity measurement under an injection rate suitable for viscosity measurement.

[0024] <2. Details of Viscosity Measurement Unit 5> 3 and 4 show an example of the appearance of the viscosity measurement unit 5 shown in FIG. 2. FIG. 5 shows a schematic diagram of an example of a cross section of the viscosity measurement unit 5 cut along a plane including a flow path inside the measurement cylinder 50. As described above, the viscosity measurement unit 5 includes the measurement cylinder 50 having three members, the rear cylinder 51, the front cylinder 52, and the cover nut 531. As in the example shown in FIGS. 3 to 5, the viscosity measurement unit 5 may further include a band heater 67 wound around the outer circumferential surface of the cover nut 531.

[0025] As shown in FIG. 3, here, the viscosity measurement unit 5 further includes a flow path switching pin 64 and a fixed plate 65. The flow path switching pin 64 is inserted into a flow path switching pin mounting hole 522 (see FIG. 5) provided near the center of the front cylinder 52 so as to be rotatable around the axis of the front cylinder 52 inside the flow path switching pin mounting hole 522. The fixed plate 65 is a plate-shaped member fixed to the front surface of the front cylinder 52 by a bolt or the like, and has a through hole near the center. In the example shown in FIG. 3, a part of the flow path switching pin 64 is exposed from a through hole provided near the center of the fixed plate 65. The fixed plate 65 covers another part of the flow path switching pin 64 to prevent the flow path switching pin 64 from falling off from the front cylinder 52.

[0026] In the example shown in FIG. 3, the front cylinder 52 has a first hole 525 and two second holes 526 opening on its side surface. The first hole 525 is provided for mounting a pressure sensor 61, which will be described later, to the front cylinder 52. The second holes 526 are through holes for inserting a positioning rod 66. Each of the second holes 526 extends radially inside the front cylinder 52 from an opening on the side surface of the front cylinder 52 to near the center of the front cylinder 52. FIG. 3 illustrates a state in which a T-shaped positioning rod 66 is inserted into one of the second holes 526. Here, the front cylinder 52 further has third holes 527 at two locations on the front surface. As will be described later, these third holes 527 define a space for arranging a heater inside.

[0027] As shown in Fig. 4, here, the viscosity measuring unit 5 further includes a first capillary die 62 and a second capillary die 63, each of which is attached to the measuring cylinder 50. In the example shown in Fig. 4, these dies 62, 63 are arranged at intervals in the circumferential direction on the side surface of the cylindrical front cylinder 52.

[0028] Refer to FIG. 5. The rear cylinder 51 has a flange 513 and a plug portion 512. The flange 513 is a portion that contacts a wall surface 531a at the rear end of the cover nut 531 when the rear cylinder 51 and the front cylinder 52 are connected to each other by the cover nut 531. The wall surface 531a of the cover nut 531 has a function of pressing the rear cylinder 51 toward the front cylinder 52. The plug portion 512 of the rear cylinder 51 is a portion of the viscosity measurement unit 5 that protrudes rearward from the cover nut 531, and is inserted into the nozzle mounting hole 451 of the nozzle cylinder 45 when the viscosity measurement unit 5 is attached to the nozzle cylinder 45. When a female thread portion is formed on the inner wall of the nozzle mounting hole 451, a male thread portion corresponding to the female thread of the nozzle mounting hole 451 is provided on the outer circumferential surface of the plug portion 512. In this case, the plug portion 512 is connected to the nozzle mounting hole 451 by fitting these female threads and male thread portions together.

[0029] The rear cylinder 51 has an internal flow path 511 that passes through the front and rear of the rear cylinder 51. The flow path 511 communicates with a flow path inside the nozzle cylinder 45 when the viscosity measurement unit 5 including the measuring cylinder 50 is attached to the nozzle cylinder 45 (see FIG. 2). In addition, as shown in FIG. 5, the flow path 511 of the rear cylinder 51 also communicates with a flow path 521 inside the front cylinder 52 when the rear cylinder 51 and the front cylinder 52 are joined together.

[0030] As described above, the front cylinder 52 has a first hole 525 on its side surface. As shown typically in Fig. 5, the first hole 525 reaches a flow passage 521 extending in the axial direction of the front cylinder 52, and a pressure sensor 61 is disposed in the first hole 525. The pressure sensor 61 is a pressure transducer that acquires the value of the pressure of the molding material flowing through the flow passage 521. As shown typically in Fig. 5, the flow passage 521 of the front cylinder 52 extends to a flow passage 641 provided in a flow passage switching pin 64 in a flow passage switching pin mounting hole 522.

[0031] Fig. 6 shows a cross section taken along line VI-VI in Fig. 5. Fig. 6 shows a schematic cross section of the measuring cylinder 50 as viewed in the axial direction of the measuring cylinder 50. As shown typically by hatched circles in Fig. 6, a heater 68 (cartridge heater) is disposed inside each of the third holes 527 opening to the front surface of the front cylinder 52.

[0032] In a typical embodiment of the present invention, the viscosity measuring unit 5 is configured to be capable of mounting two or more dies. In the example shown in Fig. 6, a first capillary die 62 is mounted on one of two die mounting holes 524 provided on the side surface of the front cylinder 52 of the measuring cylinder 50, and a second capillary die 63 is mounted on the other. Here, the first capillary die 62 and the second capillary die 63 are dies with different specifications. More specifically, the first capillary die 62 and the second capillary die 63 have a first capillary 621 and a second capillary 631, respectively, and at least one of the inner diameter and the effective length of the capillary is different between these dies.

[0033] Here, the front cylinder 52 has two flow paths 523 each extending radially from the center of the front cylinder 52. As shown in FIG. 6, one of the flow paths 523 communicates with a first capillary 621 of a first capillary die 62, and the other communicates with a second capillary 631 of a second capillary die 63.

[0034] In the example shown in Fig. 6, one of the two flow paths 523 that communicates with the second capillary 631 is connected to a flow path 641 of the flow path switching pin 64 arranged inside the flow path switching pin mounting hole 522. As can be seen from Figs. 5 and 6, the flow path switching pin 64 has a flow path 641 that is bent 90 degrees from the axial direction to the radial direction. That is, in the state shown in Fig. 6, the molding material sent from the injection section 4 of the injection unit 10 to the viscosity measurement unit 5 reaches the second capillary die 63 via the above-mentioned flow paths 511 and 521, and the flow path 641 of the flow path switching pin 64, and is discharged from the second capillary 631 to the outside of the front cylinder 52.

[0035] As shown in Fig. 5, the flow path switching pin 64 has a socket 642 that opens on the front surface of the flow path switching pin 64. The socket 642 is, for example, a hexagonal hole, and is shaped to fit the tip of a hexagonal wrench. In this embodiment, the flow path switching pin 64 is located on the central axis of the front cylinder 52, and from the state shown in Fig. 6, the positioning rod 66 is removed from the second hole portion 526, a hexagonal wrench is inserted into the socket 642 of the flow path switching pin 64 through a through hole in the center of the fixed plate 65, and the flow path switching pin 64 is rotated counterclockwise around the axis, whereby the flow path of the molding material can be switched to the first capillary die 62 side.

[0036] Here, the flow path switching pin 64 has a recess 643 on its side. As can be seen from FIG. 6, the recess 643 is provided at a position symmetrical to the outlet of the flow path 641 with respect to the center of the flow path switching pin 64. In addition, when the outlet of the flow path 641 is connected to any of the flow paths 523, the second hole 526 is also at a position symmetrical to the outlet of the flow path 641 with respect to the center of the flow path switching pin 64. Therefore, after rotating the flow path switching pin 64, a positioning rod 66 is inserted from the other second hole 526, and the tip of the positioning rod 66 is inserted into the recess 643 of the flow path switching pin 64, thereby fixing the orientation of the flow path switching pin 64 in the flow path switching pin mounting hole 522. This makes it possible to prevent unintended rotation of the flow path switching pin 64 in the flow path switching pin mounting hole 522.

[0037] In this way, the injection molding machine 1 of the present invention is configured to be able to switch the discharge destination of the molding material between two or more dies of different specifications by making the viscosity measurement unit 5 detachable. In the example described here, the number of flow paths 523, die attachment holes 524, and second holes 526 of the front cylinder 52 is two. However, this is not limited to this example, and the front cylinder 52 may be provided with flow paths 523, die attachment holes 524, and second holes 526 in the number corresponding to the number of dies to be used for viscosity measurement. The viscosity measurement unit 5 may be configured to be able to detachably mount three or more dies. These multiple dies may be arranged in the same plane perpendicular to the central axis of the front cylinder 52 as in the example shown in FIG. 6. However, this is not limited to this example, and the multiple dies may be arranged at positions offset from each other along the central axis of the front cylinder 52. The viscosity measurement unit 5 may be configured to be able to detachably mount a slit die instead of or in addition to a capillary die, as will be described later.

[0038] In this embodiment, a female thread is formed on the inner wall of each of the die attachment holes 524, and a male thread is formed on the outer peripheral surface of each of the first capillary die 62 and the second capillary die 63, the male thread being shaped to correspond to the female thread of the die attachment hole 524. The first capillary die 62 and the second capillary die 63 are provided with sockets 622 and 632, respectively, into which a tool can be inserted. The sockets 622 and 632 are, for example, hexagonal holes, and are configured to be able to receive the tip of a hexagonal wrench. In this case, the die can be easily attached to and detached from the die attachment hole 524 using the hexagonal wrench.

[0039] FIG. 7 is a schematic enlarged view of the cross section of the first capillary die 62. The first capillary die 62 has a first capillary 621. The first capillary 621 has a circular cross section with a predetermined inflow angle, inner diameter, and effective length. "d1" and "L1" shown in FIG. 7 represent the inner diameter and effective length of the first capillary 621, respectively. Here, the inflow angle of the capillary refers to the magnitude of the taper angle of the taper portion that can be formed at the capillary inlet. FIG. 7 illustrates the first capillary 621 having a shape without a taper portion. The inflow angle of the capillary without a taper portion is 180°.

[0040] FIG. 8 is a schematic enlarged view of the cross section of the second capillary die 63. Here, the second capillary die 63 has a second capillary 631 without a tapered portion, similar to the example shown in FIG. 7. The second capillary 631 has an inner diameter d2 and an effective length L2 smaller than the effective length L1 of the first capillary 621. For simplicity, in the following, unless otherwise specified, the inner diameter d2 of the second capillary 631 is assumed to be the same as the inner diameter d1 of the first capillary 621 shown in FIG. 7. When applying a die having a capillary without a tapered portion, such as the first capillary die 62 and the second capillary die 63 of this embodiment, the diameter of the flow path of the part other than the capillary may be set to a size large enough to ignore pressure loss.

[0041] <3. Operation example of injection molding machine 1 in viscosity measurement mode> 9 is a block diagram for explaining the function of the control device 7 of the injection molding machine 1. The control device 7 controls the injection unit 10 and the mold clamping unit 8, and also calculates the viscosity of the molding material based on the pressure value of the molding material acquired by the viscosity measurement unit 5.

[0042] In the configuration illustrated in Fig. 9, the control device 7 has a calculation device 71, a storage device 72, an input device 73, and a display device 74. The calculation device 71 is composed of an arithmetic circuit such as a CPU, and performs various calculations for controlling each part of the injection molding machine 1, as well as calculations related to viscosity measurement. The storage device 72 stores programs for controlling each part of the injection molding machine 1, data necessary for calculations by the calculation device 71, and the like. The storage device 72 can be realized by any combination of RAM, ROM, and auxiliary storage devices. These devices may be realized by any combination of hardware and software.

[0043] The input device 73 is an input interface such as a keyboard, and the display device 74 is an output interface such as a liquid crystal display. The input device 73 and the display device 74 may each be a standalone device, or may be a single device in which the functions of both are integrated, such as a touch panel. In this embodiment, an operation panel equipped with both a touch panel and multiple physical buttons is exemplified as a device equipped with the functions of the input device 73 and the display device 74.

[0044] In this embodiment, three or more different shear rate values ​​are stored in advance in the storage device 72. Hereinafter, k is a natural number, and these shear rate values ​​are collectively referred to as γ k In this embodiment, the shear rate value γ k is selected from the region where the molten resin as the molding material behaves as a non-Newtonian fluid, that is, the region where the viscosity decreases with increasing shear rate. k is 1*10 1 sec -1 Above 5*10 5 sec -1 The γ values ​​may be three or more different values ​​that are distributed as widely as possible within the following range (where "*" indicates multiplication): k is 1*10 1 sec -1 Above 5*10 5 sec-1 It is preferable that the γ values ​​are three or more different values ​​that are within the following range and are distributed as evenly as possible on a logarithmic scale. k But 1*10 1 sec -1 Above 5*10 5 sec -1 It is more useful to have three or more distinct values ​​that are as widely spread as possible within the range below, and that are as evenly spaced as possible when expressed on a logarithmic scale.

[0045] In this embodiment, γ k is 1*10 1 sec -1 Above 5*10 5 sec -1 The value is chosen within the following range: k For example, let R be a number between 1 and 5, and R*10 1 sec -1 , R*10 2 sec -1 , R*10 3 sec -1 , R*10 4 sec -1 and R*10 5 sec -1 Five values ​​can be adopted:

[0046] As described below, in a typical embodiment of the present invention, the apparent viscosity η ap Calculate.

[0047] Apparent viscosity η ap (unit: Pa s) is the apparent shear stress τ ap (unit: Pa) is the apparent shear rate γ ap (The unit is sec -1 In this embodiment, the apparent shear rate γ ap Instead of the above shear rate γ k Using the apparent viscosity η ap The viscosity η kThat is, the shear rate γ k When the viscosity is given by the following equation (3), k Request.

number

[0048] When using a capillary die, the apparent shear stress τ ap is the capillary geometry of the die and the shear rate γ k The pressure P of the molding material when it is poured under this pressure (unit: Pa) can be calculated based on the following relational equation (4).

number

[0049] Here, the injection speed of the molding material is V (unit: mm sec -1 ), the volumetric flow rate Q (unit: mm 3 ·sec -1 ) and the apparent shear rate γ apIt is known that there is a relationship represented by the following formula (5) between them. In the following formula (5), D represents the inner diameter of the injection cylinder or the outer diameter of the injection shaft (unit: mm). In the configuration illustrated in FIG. 2, the outer diameter of the injection shaft 42, i.e., the outer diameter of the plunger disposed in the injection cylinder 41, may be adopted as D.

number

[0050] The apparent shear rate γ in the above formula (5) ap As mentioned above, the shear rate γ k Using this, we obtain the following relation (1).

number

[0051] In this embodiment, the shear rate γ k Injection speed V according to k γ k That is, the shear rate γ k For example, if five values ​​are stored in advance in the storage device 72, five injection speeds V k is calculated. k The calculation of may be performed by the arithmetic unit 71. This process may be performed by the arithmetic unit 71 reading instructions written in a program stored in the storage unit 72.

[0052] As described below, in a typical embodiment of the present invention, the injection velocity V thus obtained is k The pressure of the molding material is measured under the above conditions, and the viscosity η of the molding material is calculated from the pressure value obtained by the measurement using the above formulas (3) and (4). k However, in this embodiment, the injection speed V obtained from the above formula (1) is calculated. k Among them, V that is outside the specified range kis not adopted as the injection speed in pressure measurement. That is, even if the number of preset shear rates is, for example, five (i.e., in the case of k=5), the number of injection rates actually applied to viscosity measurement may be less than five.

[0053] The specified range of injection speed is, for example, 0.05 mm sec -1 More than 200mm sec -1 The range is as follows: Injection speed V k If the value is within this range, it is 1*10 6 sec -1 Shear rates up to about γ k It is possible to accommodate.

[0054] Viscosity measurement of the molding material on the injection molding machine 1 is performed by attaching a viscosity measurement unit 5 to the injection cylinder 41 of the injection unit 10 via a nozzle cylinder 45, as shown in Fig. 2. Here, in addition to a pressure sensor 61, for example, the above-mentioned first capillary die 62 and second capillary die 63 are attached to the front cylinder 52 of the viscosity measurement unit 5. As will be described later, instead of the capillary die, a slit die having a slit of a predetermined shape may be attached to the front cylinder 52 to measure the viscosity.

[0055] Fig. 10 shows an example of an image displayed on the touch panel of the control device 7 in the viscosity measurement mode. The GUI 8 shown in Fig. 10 includes a mode switching button 82. Fig. 10 shows a state after the mode switching button 82 displayed on the touch panel of the control device 7 is pressed to transition the screen on the operation panel from "molding mode" to "viscosity measurement mode." Note that a contact switch or a non-contact switch may be provided on the nozzle cylinder 45 so that the attachment of the viscosity measurement unit 5 is mechanically or electrically detected to automatically switch the mode of the injection molding machine 1 to the viscosity measurement mode.

[0056] 11 is a flowchart showing an example of a viscosity measurement method according to an embodiment of the present invention. As shown in FIG. 11, the viscosity measurement method according to the embodiment of the present invention generally includes a step S1 of flowing a molding material into a capillary or slit of a die attached to a measuring cylinder 50, a step S2 of acquiring a pressure value of the molding material flowing in the measuring cylinder 50 by a pressure sensor 61 of a viscosity measurement unit 5, and a step S3 of calculating an injection speed V using the acquired pressure value. k Viscosity η according to k and a step S3 of calculating

[0057] (Step S1 of pouring molding material into a capillary or slit) In the example shown in FIG. 10, the GUI 8 includes a measurement condition input form 811 in addition to the above-mentioned mode switching button 82. The measurement condition input form 811 has input fields for the inner diameter and effective length of the capillary of the die attached to the measuring cylinder 50. In the example shown in FIG. 10, the "die diameter" and "die length" in the measurement condition input form 811 correspond to the inner diameter and effective length of the capillary, respectively. If the flow path 641 of the flow path switching pin 64 inserted into the flow path switching pin mounting hole 522 is in the direction shown in FIG. 6, for example, the molding material introduced into the measuring cylinder 50 selectively flows into the second capillary die 63 through the flow path 641. Therefore, in this case, the operator of the injection molding machine 1 inputs the value of the inner diameter d2 and the value of the effective length L2 of the second capillary 631 into the "die diameter" and "die length" in the measurement condition input form 811, respectively.

[0058] 10, the measurement condition input form 811 also has an input field for the injection speed used in viscosity measurement. Here, five fields, "injection speed 1" to "injection speed 5," are displayed on the screen. Conventionally, these fields are fields in which an operator manually calculates candidates for injection speed and inputs them.

[0059] In this embodiment, the "injection speed 1" to "injection speed 5" columns are filled with the preset shear rate γ k The injection speed V calculated by the control device 7 based onk This value is automatically input as a candidate for the injection speed when measuring the viscosity. In other words, according to this embodiment, the operator does not need to calculate the injection speed each time by relying on his / her own experience and intuition and input it to the injection molding machine 1.

[0060] The inner diameter of the injection cylinder 41 or the outer diameter of the injection shaft 42 is a known parameter determined by the specifications of the injection molding machine 1. In other words, the value of D in the above-mentioned relational expression (1) is known and is stored in advance in the storage device 72. When the calculation device 71 of the control device 7 accepts the input of "die diameter" and "die length" in the measurement condition input form 811, it calls up the value of D (here, the outer diameter of the plunger) from the storage device 72 and calculates γ k Every V k In this embodiment, the control device 7 calculates V obtained by calculation and automatically sets it as the injection speed when measuring the viscosity. k The values ​​are displayed in the five columns "Injection Speed ​​1" to "Injection Speed ​​5" as the injection speeds for viscosity measurement.

[0061] However, V k Depending on the parameter values ​​used to calculate the viscosity, results that are not suitable for viscosity measurement may be obtained. In extreme cases, the injection speed V k Therefore, in this embodiment, the injection speed V calculated by the control device 7 may be outside the specification of the injection drive device 43. k Within a specified range (for example, 0.05 mm sec -1 More than 200mm sec -1 V within the range k In other words, the control device 7 automatically sets the value of V within a predetermined range as the injection speed during viscosity measurement. k The value of V is displayed on the display device 74, and the value of V outside the predetermined range is k If V is obtained, those V outside the specified range k The values ​​should not be displayed in the "Injection Speed ​​1" to "Injection Speed ​​5" columns.

[0062] Here, the shear rate γ kSince five values ​​are prepared in advance, the number of candidates for the injection speed displayed on GUI8 is a maximum of five. For example, some of the "injection speed 1" to "injection speed 5" columns may be displayed as blanks with no numbers. In the example shown in Fig. 10, 0.2mm / s, 2mm / s, 20mm / s, and 200mm / s are presented on GUI8 as "injection speed 1" to "injection speed 4," respectively, while the "injection speed 5" column is blank with no numbers.

[0063] As described later, the shear rate γ is adjusted so that there are at least three candidates for the injection rate displayed on GUI8. k It is advantageous to select the value of D. For example, the following cases are assumed for the values ​​of d and D to be substituted into the above formula (1). (a) D is within the range of 12 mm to 22 mm and d is within the range of 1 mm to 3 mm (b) D is within the range of 23 mm to 27 mm and d is within the range of 1 mm to 4 mm. (c) D is within the range of 28 mm to 32 mm and d is within the range of 1.5 mm to 4 mm. (d) D is within the range of 33 mm to 39 mm and d is within the range of 1.5 mm to 5 mm. (e) D is within the range of 40 mm to 60 mm and d is within the range of 2 mm to 5 mm. In each of these cases, γ k For example, the value of R*10 1 sec -1 , R*10 2 sec -1 , R*10 3 sec -1 , R*10 4 sec -1 and R*10 5 sec -1 (R is a number between 1 and 5) If we use five of these, the five calculated V k At least three of the values ​​are less than 0.05 mm sec -1 More than 200mm sec -1 falls within the following range:

[0064] In addition, γ k Depending on the values ​​of d and D, V k In some cases, it may not be possible to obtain a round number for the calculated V k Alternatively, the control unit 7 may perform rounding according to the range of values ​​of V. k If the calculation result is less than 1, the calculation result is rounded off to the nearest 0.01, if it is between 1 and less than 10, the calculation result is rounded off to the nearest 0.1, and if it is 10 or more, the calculation result may be rounded off to the nearest 1. -1 More than 200mm sec -1 (within the range below) k The injection speed may be automatically set as a candidate for the injection speed when measuring viscosity. k As, 5*10 1 sec -1 , 5*10 2 sec -1 , 5*10 3 sec -1 , 5*10 4 sec -1 and 5*10 5 sec -1 This is an example where the five values ​​above are used, with d = 2 mm and D = 16 mm. However, in Figure 10, the setting values ​​are entered in the "Injection Speed ​​1" to "Injection Speed ​​4" columns in ascending order of value after appropriate rounding. γ k The value is 5*10 5 sec -1 When V k is outside the above range, so the "Injection Speed ​​5" column is left blank with no numbers entered.

[0065] In this manner, in the viscosity measuring method according to the embodiment of the present invention, the control device 7 calculates V based on a predetermined relational expression, for example, the above-mentioned relational expression (1). k Calculate V within the specified range. kThe process includes a step of automatically setting the value of the injection speed for viscosity measurement as the injection speed for viscosity measurement. By automatically calculating the injection speed for viscosity measurement and selectively and automatically setting an appropriate injection speed value for viscosity measurement, it is possible to perform highly accurate viscosity measurement that does not depend on the experience and intuition of the operator. Note that, for example, an "automatic input button" may be provided in the measurement condition input form 811. When the operator presses the automatic input button, the previously set shear rate γ k The injection speed V calculated by the control device 7 based on k The values ​​may be automatically input into the "Injection Speed ​​1" to "Injection Speed ​​5" columns as candidates for the injection speed during viscosity measurement.

[0066] The operator selects one of the candidates for the injection speed displayed on the GUI 8. For example, the operator touches one of the injection speeds displayed in the columns "injection speed 1" to "injection speed 5" (in the example shown in FIG. 10, the columns "injection speed 1" to "injection speed 4") to select the V to be passed to the injection drive unit 43. k The value of V is acquired by the calculation device 71. k By selectively displaying the value of on the display device 74, it is possible to prevent the operator from erroneously selecting an injection speed that is inappropriate for viscosity measurement.

[0067] When the operator selects an injection speed and presses the measurement start button 83 of the GUI 8, the control device 7 starts the measurement at the selected injection speed V k A control signal is sent to the injection drive device 43 so as to drive the injection shaft 42. That is, based on the input data and set values, the molding material is injected from the viscosity measuring unit 5 and the viscosity of the molding material is measured.

[0068] Inside the injection cylinder 41, the tip of the injection shaft 42 moves at an injection speed V k4, the injection cylinder 41 is moved toward the nozzle cylinder 45 under the pressure, whereby the molding material inside the injection cylinder 41 is sent out via the nozzle cylinder 45 toward the flow path inside the measuring cylinder 50. The injection section 4 of the injection molding machine 1 may have an encoder 44 (see FIG. 9) in addition to the injection drive device 43. The encoder 44 is a sensor that reads the position of the plunger serving as the injection shaft 42 along the axial direction within the injection cylinder 41. The moving speed of the injection shaft 42 (corresponding to the injection speed) can be calculated based on the position information of the injection shaft 42 read by the encoder 44 and, for example, timing by a timer. To calculate the viscosity using the above-mentioned formula (3), the injection speed V k Alternatively, an actual measurement value of the injection speed calculated based on the output of the encoder 44 may be used.

[0069] (Step S2 of acquiring the pressure value of the molding material flowing in the measuring cylinder) The molding material introduced into the flow path inside the measuring cylinder 50 flows into the capillary die attached to the front cylinder 52 through the measuring cylinder 50 including the front cylinder 52 to which the pressure sensor 61 is attached. Here, the molding material introduced into the measuring cylinder 50 passes through the flow paths 511, 521 and 641 in this order (see FIG. 5) and reaches the second capillary die 63.

[0070] In the present embodiment, the calculation of the viscosity uses the actual measured value of the pressure of the molding material flowing in the viscosity measurement unit 5. In the process in which the molding material passes through the flow path 521 of the front cylinder 52, the control device 7 can obtain the measured value of the pressure of the molding material flowing through the flow path 521 by the pressure sensor 61. The pressure value detected by the pressure sensor 61 may vary during the injection of the molding material. The pressure value used to calculate the viscosity may be the value at the time when the detected pressure value becomes almost constant. Alternatively, it may be the time average of a predetermined period after a certain period has elapsed since the start of driving the injection shaft 42. This is because the pressure of the molding material is expected to be within a substantially constant range in the latter half of the injection.

[0071] The pressure sensor 61 may be attached to the flow passage in the measuring cylinder 50 at any position upstream of the first capillary die 62 and the second capillary die 63. However, it is advantageous for the pressure sensor 61 to be located as close as possible to the first capillary die 62 and the second capillary die 63. In this embodiment, the pressure sensor 61 is fixed to the first hole portion 525 to measure the pressure of the molding material flowing in the flow passage 521 of the front cylinder 52.

[0072] (Injection speed V k Viscosity η according to k Step S3) of calculating The arithmetic unit 71 of the control device 7 receives the measured value obtained by the pressure sensor 61, and calculates the currently selected injection speed V based on the above-mentioned relational expressions (3) and (4). k Viscosity η according to the value of k The control device 7 calculates the viscosity η k The value of viscosity η k The value of V is the injection velocity used to measure the pressure. k The value of and shear rate γ k This is displayed together with the value of in the "current" row of the measurement result display table 812. The measurement result display table 812 is a portion of the GUI 8 that displays the data obtained by the current viscosity measurement and the parameters used in the measurement at that time.

[0073] The above-mentioned pressure measurements and viscosity calculations can be performed multiple times with different injection speed settings. In an exemplary embodiment of the present invention, the V k In the example shown in FIG. 10, the control device 7 operates the injection drive device 43 for each injection speed shown in the columns "injection speed 1" to "injection speed 4", and measures the pressure and calculates the viscosity at each injection speed. That is, V k At least four measurement results are obtained according to the value of the injection speed V k , shear rate γ k and viscosity ηk The values ​​are displayed in a list in the measurement result display table 812 for each measurement.

[0074] In this manner, in this embodiment, three or more preset shear rate values ​​γ k is stored in the storage device 72, and by inputting, for example, the inner diameter d of the die capillary, a plurality of injection speeds according to the specifications of the injection shaft 42 are automatically input. This eliminates the need for the operator to select an appropriate shear rate and then calculate and input the injection rate each time. k Since values ​​that are not dependent on the operator's experience or intuition are prepared in advance, the injection speed V during viscosity measurement is a backed-up value. k The viscosity measurement results are used to calculate the viscosity of the sample, and the variation in measurement conditions between operators can be eliminated. In other words, it is possible to realize more accurate viscosity measurement that is not dependent on the operator. In addition, it is easy to compare the viscosity measurement results with those obtained in the past by other operators.

[0075] For example, the inner diameter d of the die capillary and the appropriate injection speed V k The values ​​of d and d are stored in the form of a table in the storage device 72, and by referring to the table, the injection speed V corresponding to the value of d is calculated. k However, as in the present embodiment, the injection speed V is automatically input in response to the input of the inner diameter d of the capillary. k By having the arithmetic device 71 calculate the above, an advantage is obtained in that an appropriate injection speed can be automatically presented even in a case where a capillary die with specifications that have never been used before is used.

[0076] Viscosity η k Once the measurement results of viscosity η are obtained, k and the shear rate value γ k10, the GUI 8 includes a select button 851, a deselect button 852, and a graph drawing button 86. For example, the operator can tentatively select one or more rows of data displayed in the measurement result display table 812 by tapping on those rows. Next, when one or more rows of the measurement result display table 812 are tentatively selected, the operator presses the select button 851 to select the tentatively selected rows. The deselect button 852 is a button for canceling the selection at this time. When the graph drawing button 86 is pressed while one or more rows in the measurement result display table 812 are selected, the control device 7 calculates a shear rate value γ based on the data of the selected rows. k and viscosity η k A graph showing the relationship between the value of and is displayed on the display device 74. For example, the control device 7 detects the pressing of the graph drawing button 86 and presents a logarithmic or semi-logarithmic rheological curve (sometimes called a flow curve) to the operator.

[0077] FIG. 12 shows an example of a graph displayed on the touch panel of the operation panel by pressing the graph drawing button 86. FIG. 12 shows three different injection speeds V k Viscosity η under k The horizontal axis of the graph shown in FIG. 12 is the shear rate γ k The vertical axis represents viscosity η k It represents.

[0078] As shown in FIG. k The measurement results of shear rate γ k (or injection speed V k), the operator can visually and intuitively grasp the viscosity characteristics of the molding material at the molding site. In other words, the operator can easily grasp the viscosity characteristics of the molding material without measuring the viscosity every time molding is performed. The graph data may be stored, for example, as image data, in an auxiliary storage device of the storage device 72 or in an external storage medium 75 such as a flash memory (see FIG. 9).

[0079] As shown in Figure 12, for one die, the V k It is preferable that the shear rate value γ be three or more, in other words, that there are three or more plotted points. k On the horizontal axis, viscosity η k This is because at least a straight line fitting is possible when the vertical axis is taken. Four or more points may be plotted. In this case, curve regression is possible.

[0080] In this way, in order to present the viscosity characteristics to the operator in the form of a graph, it is necessary to measure the viscosity of the molding material under at least three different injection speed values. At this time, it is desirable that there is no bias in the injection speed values ​​used in the viscosity measurement, in other words, the set values ​​of the injection speed used in the viscosity measurement are appropriately distributed. In order to set multiple injection speeds suitable for such viscosity measurement, the operator is usually required to have advanced knowledge. Therefore, it is not so easy for an inexperienced operator to obtain the viscosity characteristics of the molding material in the form of a graph. Moreover, even for an experienced operator, determining three or more effective and mutually different injection speeds is a complicated task that requires a lot of time and effort.

[0081] However, according to an embodiment of the present invention, as described above, three or more preset shear rate values ​​γ k Based on these γ kTherefore, it is possible to measure viscosity at an appropriate injection speed while eliminating the need for complicated calculations by the operator, and it is possible to obtain a graph showing the viscosity characteristics of the molding material regardless of the operator's level of skill.

[0082] The control device 7 may be configured to be capable of drawing a graph based on data obtained by past viscosity measurements. In the configuration illustrated in Fig. 10, the GUI 8 includes a read result display table 813 that displays a list of data obtained by past viscosity measurements for each injection speed, in addition to a measurement result display table 812. As illustrated in Fig. 10, the GUI 8 also includes a data read button 841, and when the control device 7 detects pressing of the data read button 841, it refers to data stored in the auxiliary storage device of the storage device 72 or the external storage medium 75, and displays the data in the read result display table 813.

[0083] The operator can select data in the read result display table 813 in the same manner as selecting data in the measurement result display table 812. Note that the tentative selection step may be omitted when selecting data from the measurement result display table 812 and the read result display table 813. For example, the operator may directly select rows in these tables by tapping on the tables. In this case, the selection button 851 may be omitted from the GUI 8.

[0084] When it is detected that the graph drawing button 86 has been pressed by the operator with multiple rows selected in the read result display table 813, the control device 7 displays the results of past viscosity measurements in the form of a graph on the display device 74 based on the data of the selected rows. At this time, in addition to the data included in the read result display table 813, data included in the measurement result display table 812 may also be made selectable, and multiple graphs relating to the measurement results may be displayed superimposed on one screen.

[0085] FIG. 13 shows an example in which a graph showing the latest measurement result and a graph showing the past measurement result are displayed in a superimposed form. In the example shown in FIG. 13, while the injection speed is the same, data obtained by measurements under different heater temperatures, for example, are displayed on the screen as graphs C1 to C3. In this way, according to this embodiment, it is easy to compare the viscosity between data under different conditions at the time of measurement, for example, data measured on different days, and it is possible to visually grasp differences in the behavior of the molding material due to differences in material lots, etc. In addition, by adjusting the heater temperatures of each part of the injection molding machine 1, it is also easy to make the behavior of the molding material closer to the behavior during past molding when good results were obtained (tuning of molding conditions). Therefore, mass production can be performed by selecting more suitable conditions.

[0086] (Switching the discharge destination of molding material) As described with reference to FIG. 5 and FIG. 6, in this embodiment, the discharge destination of the molding material can be changed among a plurality of dies by rotating the flow path switching pin 64 arranged in the flow path switching pin mounting hole 522 around the axis of the measuring cylinder 50 to change the direction of the outlet of the flow path 641. According to the injection molding machine 1 according to the embodiment of the present invention, the discharge destination of the molding material can be easily switched among a plurality of dies without making a major change to the injection section 4. For example, when performing the Burghley correction, two pressure measurements are required to calculate the viscosity, and the die needs to be switched. As described below, according to the embodiment of the present invention, the Burghley correction can be performed relatively easily on the injection molding machine 1 without the need to prepare multiple devices for viscosity measurement.

[0087] The Burghley correction is a correction for obtaining a true shear stress τ by taking into account the pressure loss occurring at the inlet and outlet of the die capillary. When it is desired to know the viscosity of the molding material more accurately, it is advantageous to perform the Burghley correction. As described above, the GUI 8 includes the mode switching button 82. The control device 7 may be configured to transition the screen from the "simple measurement mode" shown in FIG. 10 to the "Burghley correction mode" shown in FIG. 14 by pressing the mode switching button 82. In this way, the "measurement mode" of the injection molding machine 1 may have two or more modes. The "measurement mode" of the injection molding machine 1 may further have a mode for performing the Rabinowicz correction described later.

[0088] 14, the measurement condition input form 811 for the "Burgley correction mode" has two input fields for "die length." For example, when the above-mentioned first capillary die 62 and second capillary die 63 are attached to the measuring cylinder 50, the effective length L1 of the first capillary 621 and the effective length L2 of the second capillary 631 are input into the two "die length" input fields.

[0089] When the molding material passes through a capillary, pressure loss generally occurs at the inlet, inside, and outlet of the capillary. By subtracting the estimated pressure P0, which is assumed to be 0 mm when the effective length of the capillary is assumed to be 0 mm, from the pressure value P of the molding material when using a capillary die, the pressure value (P-P0) can be estimated assuming that no pressure loss occurs at the capillary inlet and outlet. In this case, the true shear stress τ taking into account the Burgley correction is expressed by the following formula (6).

number

[0090] Here, the estimated pressure P0 can be obtained by knowing the pressure value obtained when a certain capillary die is used and the pressure value obtained when another capillary die with different specifications from the certain die is used. For example, if the pressure value of the molding material when the above-mentioned first capillary die 62 is used is P1 and the pressure value of the molding material when the second capillary die 63 is used is P2, the estimated pressure P0 for the first capillary die 62 can be obtained by the following formula (7).

number

[0091] As is clear from the above formula (7), when performing the Burgley correction, it is necessary to perform pressure measurements at least twice by switching the die to be used, and to grasp the pressure value P1 when using the first capillary die 62 and the pressure value P2 when using the second capillary die 63. Therefore, when it is desired to perform the Burgley correction, it is useful to be able to easily switch the die to be used.

[0092] As described with reference to Fig. 5, according to the embodiment of the present invention, the discharge destination of the molding material can be easily switched between the first capillary die 62 and the second capillary die 63. That is, as can be seen from Fig. 6, the positioning rod 66 is pulled out from the second hole portion 526, the flow path switching pin 64 is rotated by an appropriate angle, and then the positioning rod 66 is inserted from the other second hole portion 526 and the tip of the positioning rod 66 is inserted into the recess 643 of the flow path switching pin 64. This allows the discharge destination of the molding material to be switched from the second capillary die 63 to the first capillary die 62.

[0093] First, the pressure value P2 of the molding material is acquired with the second capillary die 63 as the destination of the molding material. After acquiring the pressure value P2, for example, the control device 7 displays a message on the touch panel of the operation panel prompting the die to be switched. The operator switches the direction of the flow path switching pin 64 to switch the destination of the molding material to the other die (here, the first capillary die 62). Upon receiving the completion of the die switching, for example, by input from the operator, the control device 7 switches the injection speed V k Then, the pressure of the molding material is measured using the first capillary die 62.

[0094] By switching the discharge destination of the molding material to the first capillary die 62 and flowing the molding material into the first capillary 621 of the first capillary die 62, the pressure value P1 of the molding material can be obtained by the pressure sensor 61. Therefore, the Burghley correction can be performed by a simple operation without making a major change to the injection molding machine 1 itself. In this way, the process of obtaining the pressure value of the molding material may include a process of obtaining the pressure value individually by switching between two or more dies, each of which is a destination of introduction of the molding material via the measuring cylinder 50. Note that, when the inner diameter d2 of the second capillary 631 and the inner diameter d1 of the first capillary 621 are different, an appropriate injection speed V for each capillary can be obtained. k can be automatically set.

[0095] The die switching is not limited to switching between two capillary dies with different specifications. For example, the viscosity measurement unit 5 may be configured to be able to switch the discharge destination of the molding material between a capillary die and a slit die having a rectangular cross-sectional slit. Alternatively, the viscosity measurement unit 5 may be configured to be able to switch the discharge destination of the molding material between a plurality of slit dies.

[0096] In this embodiment, a female thread is formed on the inner wall of the die attachment hole 524 of the front cylinder 52. That is, it is easy to attach a slit die having a male thread on its outer circumferential surface that has a shape corresponding to the female thread of the die attachment hole 524 to the front cylinder 52 instead of the first capillary die 62 or the second capillary die 63.

[0097] When measuring viscosity using a slit die instead of a capillary die, the apparent shear stress τ ap If the effective length of the slit is L (unit: mm), it can be calculated from the following formula (8) instead of the above formula (4). (Here, for simplicity, the inlet angle of the slit is assumed to be 180°.) In the following formula (8), P s is the pressure value (unit: Pa) of the molding material when a slit die is used. In addition, in the following formula (8), H represents the slit length (unit: mm), and B represents the slit width (unit: mm). Note that the "slit length" and "slit width" in this specification correspond to the "slit gap" and "slit width" in JIS K 7199:1999, respectively.

number

[0098] Apparent shear rate γ ap As an equation expressing this, the following equation (9) may be used instead of the above equation (5).

number

[0099] The apparent shear rate γ in the above formula (9) ap As the shear rate γ k Using the above, we finally obtain the following relation (2).

number

[0100] When applying the capillary die, similar to the above, the control device 7 uses the shear rate γ k to automatically set, within a predetermined range, the injection speed V k calculated based on the above formula (2) as the injection speed during viscosity measurement. Further, the control device 7 operates the injection drive device 43 under the injection speed selected from these V k and receives the measured value from the pressure sensor 61, thereby calculating the viscosity η k corresponding to V k from the above formula (3). k

[0101] When performing the Bagley correction using two slit dies with different specifications, instead of the above formula (6), the following formula (10) may be applied to obtain the true shear stress τ. To obtain the estimated pressure P0 in formula (10), P1 and P2 in the above formula (7) are respectively replaced with the pressure values of the molding material when using the first slit die and the pressure values of the molding material when using the second slit die, and L1 and L2 (assuming L2 < L1) are respectively replaced with the effective length of the slit of the first slit die and the effective length of the slit of the second slit die.

Equation

[0102] When switching and using a plurality of dies, even under the same injection speed V k the actual magnitude of the shear rate can vary due to differences in the geometric shape of the capillary or slit. When presenting the viscosity measurement results in a graph for the operator as in the example described with reference to FIGS. 12 and 13, it is convenient to align the values of the shear rate γ k used for calculating the injection speed V k among the plurality of dies, as this facilitates comparison of the measurement results.

[0103] ​The controller 7 may be configured, for example by operator selection, to perform a Rabinowitsch correction instead of or in addition to the Burghley correction. By performing at least one of the Burghley correction and / or the Rabinowitsch correction, and preferably both, a more accurate viscosity measurement can be obtained.

[0104] The apparent shear rate γ ap is the shear rate value when the structural viscosity index n of the molding material being measured is 1, that is, when the molding material is a Newtonian fluid. However, since actual molding materials are generally non-Newtonian fluids, the true shear rate γ and the apparent shear rate γ ap The Rabinovich correction is a method to apply a certain coefficient determined by the structural viscosity index n to the apparent shear rate γ ap This is a correction to obtain the true shear rate γ by multiplying it by

[0105] When a capillary die is used, the true shear rate γ obtained by Rabinowicz correction is expressed by the following formula (11): When a slit die is used, the true shear rate γ obtained by Rabinowicz correction is expressed by the following formula (12):

number

number

[0106] Here, the structural viscosity index n is calculated by the following formula (13).

number

[0107] The true shear stress τ and the true shear rate γ are obtained by the Burghley correction and the Rabinovich correction, respectively. In this case, the true viscosity η is obtained by dividing τ by γ (τ / γ). The Rabinovich correction may be always performed, or the operator may be able to arbitrarily switch between performing and not performing the Rabinovich correction. When priority is given to saving calculation costs and memory space, the Rabinovich correction may be omitted. When only the Rabinovich correction is performed without the Burghley correction, the apparent shear stress τ is used instead of the true shear stress τ. ap can be used in the calculation.

[0108] In this manner, in this embodiment, the introduction destination of the molding material can be switched between the two flow paths 523 depending on the orientation of the flow path switching pin 64, and the viscosity measurement unit 5 is configured to be able to alternatively select a die to be used for viscosity measurement. In the above-described example, the flow path switching pin 64 is manually rotatable using a tool. However, this is not limited to this example, and the flow path switching pin 64 may be automatically rotatable in the flow path switching pin mounting hole 522 by any actuator such as a hydraulic cylinder, a pneumatic cylinder, or an electric motor. Die switching by the rotation of the flow path switching pin 64 may be controlled by the control device 7. By automatically rotating the flow path switching pin 64 under the control of the control device 7, manual switching by an operator during viscosity measurement is not required, and therefore the viscosity measurement can be performed more efficiently.

[0109] Use of the viscosity measurement unit 5 is particularly effective when viscosity measurements are performed by switching between multiple types of dies. Here, an example has been described in which two types of dies differing only in effective length are attached to the viscosity measurement unit 5, but the present invention is not limited to this example, and multiple dies differing in specifications other than the effective length may be used when performing the Burghley correction.

[0110] Even if the Burghley correction is not performed, it may be advantageous to perform viscosity measurements by switching between multiple dies with different specifications. For example, when investigating the relationship between shear rate and viscosity for a certain molding material, multiple viscosity measurements are performed by changing the injection speed. However, due to restrictions on the specifications of the injection molding machine, there are upper and lower limits to the usable injection speed, and depending on the specifications of the injection molding machine, the desired shear rate may not be achieved. In such cases, in the case of a capillary die, by switching to a die with a different capillary inner diameter, or in the case of a slit die, by switching to a die with a different slit length and / or slit width, it may be possible to perform viscosity measurements under the desired shear rate.

[0111] 4 and 6, when the viscosity measurement unit 5 is attached to the injection cylinder 41 via the nozzle cylinder 45, it is advantageous to have the die attachment hole 524 facing generally downward, since this makes it easier to collect the molding material discharged from the die (the molding material is less likely to scatter). As can be seen from Fig. 6, it is preferable that the angle between a line parallel to the central axis of the die attachment hole 524 and a vertical line passing through the center of the front cylinder 52 is about 40° or less in front view. The vertical line passing through the center of the front cylinder 52 is a line parallel to the direction of gravity.

[0112] The viscosity measurement unit 5 may be attached to the injection cylinder 41 after the front cylinder 52 and the rear cylinder 51 are integrated with a cover nut 531, or may be completed by attaching the rear cylinder 51 to the injection cylinder 41 via the nozzle cylinder 45 and then integrating the front cylinder 52 with the rear cylinder 51. As the fastening means 53 for connecting the front cylinder 52 and the rear cylinder 51, a bolt or the like may be used instead of the cover nut 531. Each member attached to the front cylinder 52, including the flow path switching pin 64, may be attached to the front cylinder 52 after the front cylinder 52 and the rear cylinder 51 are integrated, or may be attached to the front cylinder 52 before they are integrated.

[0113] <4.Other> As described above, according to the embodiment of the present invention, by using the viscosity measuring unit 5 configured to be able to mount a plurality of dies and to be able to selectively switch the destination of the molding material among them, it is possible to obtain a viscosity value with high accuracy without relying on the experience or intuition of the operator. Other parts of the configuration example of the injection molding machine 1 will be briefly described below.

[0114] Please refer to Fig. 9. The control device 7 calculates the viscosity of the molding material and also controls the operation of each part of the injection molding machine 1. More specifically, during injection molding and viscosity measurement, the control device 7 controls the operation of the plasticizing screw drive device 27, the non-return device 25, and the injection drive device 43 of the injection unit 10 shown in Fig. 1 to melt, measure, and inject the molding material.

[0115] The control device 7 heats the plasticizing cylinder 21, the injection cylinder 41, the nozzle cylinder 45, the injection nozzle 46, and the viscosity measurement unit 5 to desired temperatures by controlling the heaters 29, 47, 48, 67, and 68. However, when a molding mode used in molding an actual product is selected, the heaters 67 and 68 are not used, and when a viscosity measurement mode is selected, the heater 48 is not used. These heaters 29, 47, 48, 67, and 68 arranged in each part of the injection molding machine 1 may have a temperature sensor such as a thermocouple. The heaters 29, 47, 48, 67, and 68 may be feedback-controlled by the control device 7 based on the measured values ​​obtained by the temperature sensors.

[0116] As described with reference to FIG. 1, the injection molding machine 1 has, in addition to the injection unit 10, a clamping unit 8 that opens, closes, and clamps the mold into which the molding material is injected. The clamping unit 8 is configured to hold the mold and be able to open, close, and clamp the mold, and when the molding material is injected, it closes the mold and applies a predetermined clamping force to the mold. After the molding material injected from the injection nozzle 46 into the cavity of the mold is cooled, the clamping unit 8 opens the mold, ejects the molded product, and closes the mold again. The clamping unit 8 can be of a known configuration such as a direct pressure type or a toggle type.

[0117] In the injection of the molding material, the injection unit 10 plasticizes the polymer granules, measures a predetermined amount, and then injects the molding material from the injection nozzle 46 or the viscosity measuring unit 5. The polymer granules as raw material are fed from a hopper 211 into the plasticizing cylinder 21. The "molding material" in this specification is not limited to polymer granules, but broadly includes materials that can be injected by an injection molding machine. In addition to materials mainly made of resin, the "molding material" also includes MIM materials in which resin as a binder is added to metal powder, and CIM materials in which resin as a binder is added to ceramic powder. The molding material may be thermoplastic or thermosetting. An example of a thermosetting molding material is a LIM material, which is a thermosetting liquid material.

[0118] The plasticizing cylinder 21 is a hollow cylinder, and is heated to a predetermined temperature by a heater 29 such as a band heater. The molding material supplied into the plasticizing cylinder 21 is melted by the heat from the heater 29 and by shear heat generated by the rotation of the plasticizing screw 23, and is sent to the front of the plasticizing cylinder 21 as the plasticizing screw 23 rotates.

[0119] The plasticizing screw drive device 27 of the plasticizing section 2 is any actuator that rotates the plasticizing screw 23, such as a hydraulic motor or an electric motor. In the configuration illustrated in Figs. 1 and 2, the plasticizing section 2 also has a check device 25. The check device 25 is any actuator that advances the plasticizing screw 23 along the axial direction, such as a hydraulic cylinder, a pneumatic cylinder, or an electric cylinder. The check device 25 has the function of preventing the molding material from flowing back into the plasticizing cylinder 21 during injection by advancing the plasticizing screw 23 when the metering of the molding material is completed and blocking the flow path with the tip of the plasticizing screw 23.

[0120] The molding material sent out from the plasticization section 2 is introduced into the injection cylinder 41 of the injection section 4 through the junction 3 connecting the plasticization section 2 and the injection section 4, and the nozzle cylinder 45. The injection cylinder 41 is a hollow cylinder that is heated to a predetermined temperature by a heater 47 such as a band heater. The junction 3 can also be heated to a predetermined temperature by a heater.

[0121] The molding material sent to the injection cylinder 41 is temporarily stored in front of the injection shaft 42 inside the injection cylinder 41, and thereby a desired amount is measured out. As described above, the injection shaft 42 is a substantially cylindrical plunger provided in the injection cylinder 41 so as to be capable of reciprocating freely.

[0122] After the molding material has been measured, the plasticizing screw 23 is advanced inside the plasticizing cylinder 21 by the non-return device 25, and the tip of the plasticizing screw 23 closes the flow path connecting the plasticizing cylinder 21 and the junction 3. After the forward movement of the plasticizing screw 23 prevents the molding material from flowing back into the plasticizing section 2, the injection shaft 42 advances, and the molding material is sent to the injection nozzle 46 via the nozzle cylinder 45. In this manner, the molding material is injected from the injection nozzle 46.

[0123] In the viscosity measurement mode, with the viscosity measurement unit 5 attached to the injection unit 10 instead of the injection nozzle 46, the molding material is melted, measured, and injected in the same manner as when the molding mode is selected. In this embodiment, the measurement value during viscosity measurement is set to the maximum value measurable by the injection unit 10. That is, when measuring the molding material, the injection shaft 42 is retracted until it reaches the limit position. However, the measurement setting value is not limited to the maximum value measurable, and may be appropriately determined within a range in which stable measurement can be performed.

[0124] The molding material extruded by the injection shaft 42 passes through the nozzle cylinder 45, and then through the flow paths 511, 521, 641, and 523 in the viscosity measurement unit 5, and is discharged from one of the multiple dies. At this time, the pressure sensor 61 measures the pressure of the molding material flowing through the flow path 521.

[0125] Next, other details of the GUI 8 shown in Fig. 10 and Fig. 14 will be described. The GUI 8 is an example of a screen displayed on the display device 74 during viscosity measurement. The GUI 8 for viscosity measurement can be accessed from the GUI for normal injection molding.

[0126] Here, the GUI 8 in the viscosity measurement mode includes a measurement result display table 812 and a read result display table 813. As described above, the measurement result display table 812 is a section where data obtained by the current viscosity measurement and parameters used in the measurement at that time are displayed.

[0127] The measurement condition input form 811 has input fields for data required for calculating viscosity and for set values ​​related to viscosity measurement. In the above-mentioned example, the operator inputs the die specifications (for example, the inner diameter and effective length of the capillary in the case of a capillary die), a measurement name that can be set arbitrarily, and the like, via a touch panel serving as the input device 73. However, in this embodiment, the injection speed field contains a plurality of preset shear rates γ k Supports multiple V kis automatically input. In one embodiment, the control device 7 performs a plurality of viscosity measurements while sequentially changing the injection speed from V1 to V2 to V3, . . . . The shear rate γ k V corresponding to k In addition to the mode in which the injection speed is automatically set, a mode in which the operator can manually input an arbitrary value as the injection speed may be additionally provided.

[0128] The read result display table 813 is a section where data obtained by past viscosity measurements is displayed in a list for each injection speed. The operator can compare the data displayed in the measurement result display table 812 with the data displayed in the read result display table 813. Comparing these data makes it easy to understand the characteristics of the molding material.

[0129] The data displayed in the measurement result display table 812 and the read result display table 813 may include, for example, data on the injection speed, shear rate, measured pressure of the molding material, viscosity, temperature, and measurement name. For each of the injection speed and temperature, either the set value or the actual measured value may be displayed, or both the set value and the actual measured value may be displayed. If the actual measured value is expected to be approximately the same as the set value, the display of the actual measured value may be omitted.

[0130] The data displayed in the measurement result display table 812 and the read result display table 813 may be a part of the data related to the measurement results. The data items displayed in the measurement result display table 812 and the read result display table 813 may be arbitrarily selectable by the operator.

[0131] In addition to the buttons described above, the GUI 8 includes a data clear button 842, a save button 87, a setting button 88, and a close button 89. Of these, the data clear button 842 is a button for instructing the arithmetic device 71 to reset the data displayed in the measurement result display table 812 and the read result display table 813.

[0132] When the save button 87 is pressed, data related to the measurement results is saved in an optional format such as CSV format in the auxiliary storage device of the storage device 72 or in an external storage medium 75 such as a flash memory. The output and saved data may include the die specifications, injection speed, shear rate, pressure measurement value, viscosity, temperature, and measurement name data for each measurement. When a correction such as the Burghley correction is performed, both the viscosity data before and after the correction may be saved in the external storage medium 75.

[0133] The setting button 88 is a button for calling up a predetermined setting screen. In this embodiment, conditions that do not need to be changed for each viscosity measurement are set on a screen other than the screen shown in Fig. 10, which includes a measurement condition input form 811. For example, the diameter of the plunger as the injection axis 42, the shear rate γ k , injection speed V k The range of the temperature, the waiting time for heating, etc. are input from a screen that is displayed by pressing a setting button 88. For these parameters, authentication such as password input may be required when changing the values. Parameters such as the diameter of the plunger that are determined by the specifications of the injection molding machine 1 may be automatically input by referring to data related to the model of the injection molding machine 1, in which case the input fields for these parameters may be omitted.

[0134] The close button 89 is a button for transitioning the screen from the viscosity measurement GUI 8 to the molding mode GUI. When the close button 89 is pressed, the viscosity measurement GUI 8 is closed and the screen transitions to the normal injection molding GUI.

[0135] In this embodiment, the heater temperature of each part of the injection molding machine 1 is set from the GUI for the molding mode. However, this is not limited to this example, and an input field for the heater temperature may be provided in the measurement condition input form 811 of the GUI 8 for viscosity measurement. The same temperature is usually input as the set temperature of the heaters 29, 47, 67, and 68. When performing viscosity measurement, it is desirable that the temperature of each part through which the molding material flows is stable. In this sense, after switching from the GUI for the molding mode to the GUI 8 for viscosity measurement, a restriction may be set so that the viscosity measurement cannot be started until an arbitrarily set temperature rise waiting time has elapsed, thereby ensuring temperature stability. According to this embodiment, the temperature during actual molding can be roughly aligned with the temperature during viscosity measurement, so that viscosity data more in line with actual molding can be obtained.

[0136] As already shown in some concrete examples, the present invention is not limited to the configuration of the embodiment shown in the drawings, and various modifications or applications are possible within the scope of the technical concept of the present invention. For example, an injection molding machine 1 including an injection unit 10 to which a viscosity measuring unit 5 can be attached may be a so-called in-line screw type injection molding machine in which a plasticizing section 2 and an injection section 4 are integrally configured. An in-line screw type injection molding machine has an injection cylinder and an in-line screw as an injection shaft 42 arranged inside the injection cylinder. The in-line screw has both the function of the plasticizing screw 23 in the injection molding machine 1 and the function of a plunger as the injection shaft 42. However, as in the injection molding machine 1 of this embodiment, a screw pre-plasticizing type injection molding machine having a check device 25 that prevents the backflow of the molding material from the injection cylinder 41 by advancing the plasticizing screw 23 is superior in the metering and injection stability of the molding material compared to an in-line screw type injection molding machine. According to this embodiment, by adopting the screw pre-plasticizing method, it is expected that the viscosity of the molding material can be measured more accurately.

[0137] Various embodiments of the present invention have been described above, but these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and modifications thereof are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0138] 1...injection molding machine, 2...plasticization section, 3...junction, 4...injection section, 5...viscosity measurement unit, 7...control device, 8...mold clamping unit, 10...injection unit, 21...plasticization cylinder, 23...plasticization screw, 25...non-return device, 27...plasticization screw drive device, 29...heater, 41...injection cylinder, 42...injection shaft, 43...injection drive device, 44...encoder, 45...nozzle cylinder, 46. ..injection nozzle, 47, 48... heater, 50... measuring cylinder, 51... rear cylinder, 52... front cylinder, 53... fastening means, 61... pressure sensor, 62... first capillary die, 63... second capillary die, 64... flow path switching pin, 65... fixing plate, 66... ​​positioning rod, 67, 68... heater, 71... computing device, 72... storage device, 73... input device, 74... display device, 75... external part storage medium, 82...mode switching button, 83...measurement start button, 86...graph drawing button, 87...save button, 88...setting button, 89...close button, 211...hopper, 451...nozzle mounting hole, 511...flow path, 512...plug part, 513...flange, 521...flow path, 522...flow path switching pin mounting hole, 523...flow path, 524...die mounting hole, 525...first hole, 526...second hole, 527. ..third hole portion, 531...cover nut, 531a...wall surface, 621...first capillary, 622...socket, 631...second capillary, 641...flow path, 642...socket, 643...recess, 811...measurement condition input form, 812...measurement result display table, 813...read result display table, 841...data read button, 842...data clear button, 851...select button, 852...deselect button

Claims

1. an injection cylinder to which a viscosity measuring unit can be attached; an injection axis in the injection cylinder; an injection drive device that drives the injection shaft; A control device that controls the injection drive device to drive the injection shaft back and forth; Equipped with The control device is configured to measure three or more preset shear rate values ​​γ when the inner diameter of the injection cylinder or the outer diameter of the injection shaft is D, the capillary inner diameter of the capillary die and / or the slit die attached to the viscosity measurement unit is d, the slit length is B, and the slit width is H, respectively. ｋ (k is a natural number), the injection speed V is calculated based on the following formula (1) or (2). ｋ Calculate the injection speed V that is within a predetermined range. ｋ An injection molding machine that automatically sets the injection speed for viscosity measurement. [0010] [0025]

2. 2. The injection molding machine according to claim 1, The viscosity measuring unit is The capillary die and / or the slit die; A measuring cylinder equipped with the capillary die and / or the slit die; a pressure sensor for measuring the pressure of the molding material flowing inside the measuring cylinder; An injection molding machine comprising:

3. 3. The injection molding machine according to claim 2, The viscosity measuring unit is configured to be capable of mounting two or more dies having different specifications to the injection molding machine.

4. 2. The injection molding machine according to claim 1, Further comprising a display device, The control device detects the V ｋ and displaying the value of on the display device.

5. 3. The injection molding machine according to claim 2, The control device detects the V ｋ For each value of V, the injection drive unit is operated to calculate the V using the measured value obtained from the pressure sensor. ｋ The viscosity η of the molding material according to the value ｋ Calculate the injection molding machine.

6. 6. The injection molding machine according to claim 5, Further comprising a display device, The control device detects the V ｋ and the viscosity η ｋ and displaying the value of on the display device.

7. 7. The injection molding machine according to claim 6, The control device determines the shear rate value γ ｋ and the viscosity η ｋ and displaying the graph showing the relationship between the value of the injection molding machine and the injection molding machine on the display device.

8. 8. The injection molding machine according to claim 1, The three or more shear rate values ​​γ ｋ is 1*10 １ sec －１ More than 5*10 ５ sec －１ A value selected from the following range (where "*" indicates multiplication): The predetermined range of the injection speed is 0.05 mm sec. －１ 200mm・sec or more －１ Below is an injection molding machine.

9. 8. The injection molding machine according to claim 1, The injection molding machine is a screw pre-plasticizing type injection molding machine, The injection molding machine, wherein the injection shaft is a plunger.

10. 8. The injection molding machine according to claim 1, the injection molding machine is an in-line screw type injection molding machine, The injection molding machine, wherein the injection shaft is an in-line screw.

11. Injection speed V ｋ (k is a natural number), a molding material is flowed from an injection cylinder of an injection molding machine through a measurement cylinder of a viscosity measurement unit having a pressure sensor into a capillary or slit of a die attached to the measurement cylinder; acquiring a pressure value of the molding material flowing in the measuring cylinder by the pressure sensor; Using the pressure value, the injection speed V ｋ Viscosity η according to ｋ and calculating Including, The step of pouring the molding material is performed by controlling the control device of the injection molding machine to control three or more preset shear rate values ​​γ ｋ Injection speed V corresponding to each ｋ Calculate the injection speed V that is within a predetermined range. ｋ automatically setting the value of the injection speed at the time of viscosity measurement, In the following formulas (1) and (2), D represents the inner diameter of the injection cylinder or the outer diameter of the injection shaft in the injection cylinder, d represents the inner diameter of the capillary, and B and H represent the length and width of the slit, respectively. [0010] [0025]

12. The viscosity measuring method according to claim 11, The injection speed V ｋ In the step of automatically setting the three or more shear rate values ​​γ ｋ is 1*10 １ sec －１ More than 5*10 ５ sec －１ The injection speed is a value selected from the range below (where "*" indicates multiplication), and the predetermined range of the injection speed is 0.05 mm sec －１ 200mm・sec or more －１ The viscosity measurement method is as follows.

13. The viscosity measuring method according to claim 11 or 12, The viscosity measuring method, wherein the step of acquiring the pressure value includes a step of acquiring the pressure value individually by switching between two or more dies into which the molding material is introduced via the measuring cylinder.

Images