JP3549824B2 - Control device for injection molding machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an injection molding machine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an injection molding machine for molding a disk substrate as a molded product includes an injection device. The injection device is provided with a heating cylinder having an injection nozzle at a front end. The vehicle includes an installed screw and an injection cylinder as a drive unit for rotating and moving the screw forward and backward. Then, in the injection step, the screw is advanced, the resin heated and melted in the heating cylinder is injected from the injection nozzle, and is filled in the cavity space of the mold apparatus. The resin in the space is cooled, solidified, and perforated to form a disk substrate. The mold device is composed of a fixed mold and a movable mold, and the movable mold is moved toward and away from the fixed mold by a mold clamping device, so that the mold device can be closed, clamped, and opened. Done.
[0003]
When the disk substrate is formed, it is necessary to uniformly flow the resin radially outward from the center in the cavity space. For this purpose, it is preferable to use a cold runner type one-piece mold device. However, using a one-piece mold device not only lowers the production efficiency but also increases the cost of the disk substrate. Would.
[0004]
Therefore, a hot runner type multi-cavity (2-cavity or 4-cavity) mold apparatus is provided. In the hot runner type multi-cavity mold apparatus, a plurality of cavity spaces are formed in the mold apparatus, and a heating means is provided in each runner for supplying a resin to each cavity space, and the heating means is provided. This heats the resin in the runner. In this case, since the resin in the runner can be maintained in a molten state, the resin can be uniformly flowed radially outward from the center in each cavity space.
[0005]
By the way, when the pressure of the resin filled in the cavity space, that is, the filling pressure becomes high, stress remains in the resin after overpacking and solidification occurs, or the resin is removed from between the fixed mold and the movable mold. Leaks to form burrs, and molding defects occur.
[0006]
Therefore, the hydraulic pressure in the injection cylinder is detected, and when the detected hydraulic pressure is equal to or more than a threshold value, it is determined that molding failure has occurred, and the operation of the injection molding machine is stopped.
[0007]
[Problems to be solved by the invention]
However, in the conventional injection molding machine, the resin injected from the injection nozzle passes through each runner and is filled in each cavity space. For example, even if the filling pressure in one cavity space becomes high, If the filling pressure in the cavity space is normal, the oil pressure in the injection cylinder may not exceed the threshold.
[0008]
Also, when one cavity space is filled with a large amount of resin and another cavity space is not filled with a sufficient amount of resin, the oil pressure in the injection cylinder may not exceed the threshold value.
[0009]
In that case, it cannot be determined that molding failure has occurred, and the operation of the injection molding machine cannot be stopped.
[0010]
Therefore, if the operation of the injection molding machine is continued as it is, a molding defect occurs in the disk substrate in each cavity space.
[0011]
The present invention solves the problems of the conventional injection molding machine, and provides a control device for an injection molding machine that can reliably determine that a molding defect has occurred when a molding defect occurs. Aim.
[0012]
[Means for Solving the Problems]
Therefore, in the control device of the injection molding machine of the present invention, a plurality of resin supply systems for filling the resin injected from the injection nozzle into the plurality of cavity spaces, and a filling of the resin filled in each of the cavity spaces are provided. Filling pressure detecting means for detecting the pressure; and when one of the filling pressures detected by the filling pressure detecting means reaches a predetermined value, a differential pressure between at least two filling pressures is calculated. A control unit that determines that molding failure has occurred in any molded product when the pressure exceeds the monitoring set pressure.
[0014]
In another control device of the injection molding machine of the present invention, the differential pressure is continuously calculated based on each filling pressure.
[0015]
In still another control device for an injection molding machine of the present invention, the control unit stops the injection step and skips to another predetermined step when a molding defect occurs.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a functional block diagram showing a control device of the injection molding machine according to the first embodiment of the present invention.
[0018]
In the drawing, 51 and 52 are sprue bushes as a plurality of resin supply systems for filling a plurality of cavity spaces (not shown) with a resin injected from an injection nozzle (not shown), and 71 and 72 are filled in the respective cavity spaces. A filling pressure sensor as a filling pressure detecting means for detecting a filling pressure of the resin, 73 indicates that a molding defect has occurred when a differential pressure between at least two of the detected filling pressures exceeds a monitoring set pressure. It is a CPU as a control unit for making a determination.
[0019]
FIG. 2 is a cross-sectional view illustrating a main part of the injection molding machine according to the first embodiment of the present invention, and FIG. 3 is a diagram illustrating a main part of the injection molding machine according to the first embodiment of the present invention. It is a figure which shows the example of the filling pressure up to. In FIG. 3, time is plotted on the horizontal axis, and filling pressure is plotted on the vertical axis.
[0020]
In FIG. 2, reference numeral 11 denotes a fixed mold unit, 12 denotes a movable mold unit, 13 denotes a fixed platen, 14 denotes a fixed mold, and 15 denotes a mold for attaching the fixed mold 14 to the fixed platen 13. It is a mold mounting plate. The fixed mold 14 includes a manifold plate 16, an intermediate plate 17, and a mold plate 18. Reference numeral 19 denotes a movable mold which is disposed so as to be able to advance and retreat (move in the left-right direction in FIG. 2) so as to face the fixed mold 14, and the movable mold 19 includes a receiving plate 21 and a mold plate 22. . Then, a concave portion 23 is formed at two positions of the template 22 by opening a surface facing the template 18. A mold device is constituted by the fixed mold 14 and the movable mold 19.
[0021]
A movable platen (not shown) is provided at the back (left side in FIG. 2) of the movable mold 19 so as to be able to advance and retreat, and a mold clamping device (not shown) is provided further behind the movable platen. When the movable platen is advanced and retracted by operating the mold clamping device, the movable mold 19 is similarly advanced and retracted, and the mold closing, mold clamping and mold opening of the mold device are performed. Accordingly, a plurality of, in this embodiment, two cavity spaces C1 and C2 having a disk shape are formed by the concave portions 23.
[0022]
An injection device is provided behind the fixed platen 13 (to the right in FIG. 2). The injection device includes a heating cylinder provided with an injection nozzle 26 at a front end, a screw (not shown) rotatably disposed within the heating cylinder, and a reciprocatingly movable screw, and a drive for rotating and reciprocating the screw. It has an injection cylinder (not shown) as a part. Then, the screw is advanced, and the resin heated and melted in the heating cylinder is injected from the injection nozzle 26, filled in the cavity spaces C1, C2, and cooled in the cavity spaces C1, C2. Then, the disk substrate is formed as a molded product by solidifying and subjecting to a perforation process.
[0023]
For this purpose, a recess 24 having a conical shape is formed in the center of the surface of the fixed platen 13 facing the injection device, and the fixed mold 14 is positioned in the recess 24 with respect to the fixed platen 13. A locating ring 25 is provided. In addition, a manifold chamber 27 is formed in the manifold plate 16, and a manifold 28 is disposed in the manifold chamber 27 in an insulated state. For this purpose, spacers 31 and 32 made of heat insulating material are provided between the mold mounting plate 15 and the manifold 28, and spacers 33 made of heat insulating material are provided between the intermediate plate 17 and the manifold 28. A heat insulating space is formed around it. A bush 34 is formed at the center of the manifold 28 so as to protrude rearward, and a rear end face (the right end face in FIG. 2) of the bush 34 and a front end (the left end in FIG. 2) of the injection nozzle 26 face each other. Let me do. A sprue 35 is formed in the manifold 28 at the rear end face of the bush 34 and is connected to the sprue 35 and extends in a direction away from the sprue 35 (vertical direction in FIG. 2). Runners 36 and 37 are formed, and the tips of the runners 36 and 37 are bent into an “L” shape, and are opened at both ends of the manifold 28 toward the movable mold 19. Note that the cavity spaces C1 and C2 are formed at positions separated from the sprue 35 by an equal distance.
[0024]
Hot chips 41 and 42 are attached to both ends of the manifold 28, and sprue bushes 51 and 52 are disposed in front of the hot chips 41 and 42 (left side in FIG. 2). At the front ends (left ends in FIG. 2) of the hot chips 41, 42, nozzle portions 43, 44 are formed, and the sprue bushes 51, 52 comprise outer tubes 61, 62 and inner tubes 45, 46, respectively. The front ends of the nozzle portions 43 and 44 and the rear ends (right ends in FIG. 2) of the inner cylinders 45 and 46 are opposed to each other. Further, chip runners 47 and 48 are formed in the hot chips 41 and 42, and cold sprues 49 and 50 are formed in the inner cylinders 45 and 46, and the runner 36, the chip runner 47 and the cold sprue 49 are communicated with each other. The runner 37, the chip runner 48 and the cold sprue 50 are communicated. The manifold 28, the hot chips 41 and 42, and the sprue bushes 51 and 52 constitute a resin supply system for filling the cavity spaces C1 and C2 with the resin injected from the injection nozzle 26.
[0025]
The front ends of the sprue bushes 51 and 52 are disposed facing the cavity spaces C1 and C2, and are opened at the front end surface (the left end surface in FIG. 2) to form dies 53 and 54. Further, inner stamper holders 55 and 56 are provided so as to surround the front ends (left ends in FIG. 2) of the sprue bushes 51 and 52. The inner stamper holders 55 and 56 are screwed together with the intermediate plate 17 and the template 18, and press the stampers 81 and 82 against the template 18.
[0026]
In order to heat the resin passing through the runners 36 and 37 and keep the resin in a molten state, a heater H1 as first heating means is disposed on the outer peripheral surface of the manifold 28. Further, in order to heat the resin passing through the chip runners 47 and 48 and maintain the molten state, the hot chip 41 is provided with a heater H2 as a second heating means, and the hot chip 42 is provided with a heater H3 as a third heating means. H3 is buried.
[0027]
On the other hand, on the movable mold 19 side, cylindrical cut punches 55 and 56 are disposed at portions facing the dies 53 and 54 so as to advance and retreat, and sprue rods 57 and 58 are provided in the cut punches 55 and 56. However, ejector sleeves 59 and 60 are disposed radially outward from the cut punches 55 and 56 so as to be able to advance and retreat, respectively. A drive means (not shown) for drilling holes is provided for moving the cut punches 55 and 56, and a drive means (not shown) for protrusion is provided for moving the sprue rods 57 and 58 and the ejector sleeves 59 and 60. You.
[0028]
Next, the operation of the injection molding machine when molding a disk substrate will be described.
[0029]
The mold clamping device is driven, and the mold device is closed and clamped to form cavity spaces C1 and C2. Subsequently, when the injection process is started in the injection device, the screw is advanced, and the molten resin is injected from the injection nozzle 26, the resin passes through the sprue 35 and then branches into the runner 36 and the runner 37. Let me do. After passing through the runner 36, the resin passes through the chip runner 47 and the cold sprue 49, and then is filled in one cavity space C 1. The resin passing through the runner 37 passes through the chip runner 48 and the cold sprue 50. Is filled in the other cavity space C2. In this case, the resin is heated while passing through the runners 36 and 37 and the chip runners 47 and 48, so that the molten state is maintained. Therefore, in each of the cavity spaces C1 and C2, the resin can be uniformly flowed from the center outward in the radial direction, so that the quality of the disk substrate can be improved.
[0030]
Next, a pressure holding step is started in the injection device, and the injection cylinder is driven to maintain the pressure of the resin in the cavity spaces C1 and C2 at a predetermined value. Subsequently, a cooling process is started in the mold device, and the resin in the cavity spaces C1 and C2 is cooled and solidified. Then, in the pressure-holding step or the cooling step, when the driving means for drilling is driven and the cut punches 55, 56 are advanced (moved to the right in FIG. 2), the front ends of the cut punches 55, 56 (Right end in FIG. 2) is fitted (canned) into the dies 53 and 54, and a hole is formed in the resin in the cavity spaces C1 and C2. Thus, the disk substrate is formed.
[0031]
Thereafter, as the mold apparatus is opened, the drive means for ejection is driven, and the sprue rods 57, 58 and the ejector sleeves 59, 60 are advanced, so that the disk substrate is ejected and released. Can be
[0032]
Subsequently, a measuring step is started in the injection device, the screw in the heating cylinder is rotated, and the molten resin is stored in front of the screw head. Accordingly, the screw is retracted.
[0033]
By the way, in the injection step, when the filling pressures P1 and P2 in the cavity spaces C1 and C2 increase, stress remains in the resin after overpacking and solidification, or the fixed mold 14 and the movable mold 19 The resin leaks out from the gap to form burrs, and molding failure occurs. Further, when the filling pressures P1 and P2 in the cavity spaces C1 and C2 are low, sinks, short circuits, and the like are formed on the disk substrate, and molding defects occur.
[0034]
Therefore, in the resin supply system, in the present embodiment, the sprue bushes 51, 52 are provided with filling pressure sensors 71, 72 as filling pressure detecting means facing the cold sprues 49, 50. The sensors 71 and 72 detect the pressure of the resin in the cold sprues 49 and 50 as filling pressures P1 and P2 in the cavity spaces C1 and C2. In FIG. 3, L1 is a line indicating the filling pressure P1, and L2 is a line indicating the filling pressure P2. A filling pressure sensor is disposed on the mold plate 18 or the mold plate 22 so as to face the cavity spaces C1 and C2, and the pressure of the resin in the cavity spaces C1 and C2 is directly applied by the filling pressure sensors P1 and P2. Or the hot chips 41, 42 are provided with filling pressure sensors facing the chip runners 47, 48, and the filling pressure sensors detect the pressure of the resin in the chip runners 47, 48 by the filling pressures P1, P2. Or a filling pressure sensor is disposed on the manifold 28 so as to face the runners 36 and 37, and the pressure of the resin in the runners 36 and 37 is detected as the filling pressures P1 and P2 by the filling pressure sensor. You can also.
[0035]
When the filling pressures P1 and P2 in the cavity spaces C1 and C2 are detected by the filling pressure sensors 71 and 72, a detection signal is sent to the CPU 73 as a control unit at all times or at predetermined timings. When one of the filling pressures P1 and P2 reaches a predetermined value based on the detection signal, a condition satisfaction determination processing means (not shown) of the CPU 73 determines that the filling pressure P1 than but each time it reaches the monitoring point pressure pa~pc that is set in advance, to calculate a differential pressure ΔPa~ΔPc filling pressures P1, P2, the monitoring set pressure [Delta] P _TH 1 differential pressure ΔPa~ΔPc the first Then, it is determined that the process stop condition for stopping the injection process has been satisfied.
[0036]
Subsequently, when it is determined that the process stop condition is satisfied, the process skip processing means (not shown) of the CPU 73 determines that a molding defect has occurred in each of the cavity spaces C1 and C2, and performs injection before the injection process is completed. The process and the pressure holding process are stopped, and the process is skipped to another predetermined process, the next process in the present embodiment. That is, the process skip processing means opens the mold, treats the unfinished disk substrates in each of the cavity spaces C1 and C2 as defective, and starts the weighing process. Further, the CPU 73 warns that molding failure has occurred by warning means (not shown).
[0037]
Then, when the shot in which the molding failure has occurred continues for a predetermined number of times, the operation stop processing means (not shown) of the CPU 73 stops the operation of the injection molding machine and displays the occurrence of the abnormality by the display means (not shown).
[0038]
Further, the condition satisfaction judgment processing means, when the differential pressure ΔPa~ΔPc exceeds the second monitoring set pressure [Delta] P _{TH 2,} the operation stop condition for stopping the operation of the injection molding machine is determined to be satisfied. Then, the operation stop processing means stops the operation of the injection molding machine and displays on the display means that an abnormality has occurred.
[0039]
Incidentally, the monitoring point pressure pa~pc and first monitoring set pressure [Delta] P _{TH 1} is or fixed to a certain value, or can be set to an arbitrary value by setting device not shown. Further, in the present embodiment, each time the filling pressure P1 reaches a preset monitoring point pressure pa to pc, the differential pressure ΔPa to ΔPc between the filling pressures P1 and P2 is calculated. Each time the pressure P2 reaches a preset monitoring point pressure, the differential pressure between the filling pressures P1 and P2 can be calculated. In the present embodiment, the filling pressures P1 and P2 in the two cavity spaces C1 and C2 are detected. However, in a mold apparatus having three or more cavity spaces, A filling pressure in the space is detected, and a differential pressure between at least two of the filling pressures is calculated. For example, each time one of the filling pressures reaches a preset monitoring point pressure, the differential pressure between the one filling pressure and each of the other filling pressures can be calculated. In this case, when the highest differential pressure among the differential pressures exceeds the first monitoring set pressure, it is determined that the process stop condition for stopping the injection process has been satisfied.
[0040]
As described above, since it is determined that the process stop condition is satisfied based on the differential pressures ΔPa to ΔPc of the filling pressures P1 and P2 in the respective cavity spaces C1 and C2, for example, the filling pressure in one cavity space is determined. Is high, the filling pressure in the other cavity space is normal, and it can be reliably determined that molding failure has occurred even if the oil pressure in the injection cylinder does not exceed the threshold.
[0041]
Also, when one cavity space is filled with a large amount of resin, and the other cavity space is not filled with a sufficient amount of resin, the oil pressure in the injection cylinder may not exceed the threshold value. Also in this case, it can be reliably determined that molding failure has occurred.
[0042]
Therefore, the injection process is stopped, and the unfinished disk substrates in each of the cavity spaces C1 and C2 are treated as defective products, so that non-defective products and defective products are not mixed.
[0043]
When the process stop condition is satisfied, the injection process and the pressure-holding process are stopped, but the operation of the injection molding machine is not stopped, and the process is skipped to the next process, that is, the measurement process. Driving can be continued. Therefore, the operation efficiency of the injection molding machine can be improved.
[0044]
Next, a second embodiment of the present invention will be described.
[0045]
FIG. 4 is a diagram showing an example of the filling pressure from the start of the injection step to the completion of the pressure holding step in the second embodiment of the present invention. In the figure, the horizontal axis represents time, and the vertical axis represents filling pressure.
[0046]
In the figure, L1 is a line indicating the filling pressure P1, and L2 is a line indicating the filling pressure P2. In this case, when the filling pressures P1 and P2 in the cavity spaces C1 (FIG. 2) and C2 are detected by the filling pressure sensors 71 (FIG. 1) and 72 as the filling pressure detecting means, the detection signal is constantly or at a predetermined timing. Are continuously sent to the CPU 73 as a control unit. The condition satisfaction determination processing means (not shown) of the CPU 73 continuously calculates the differential pressure ΔP between the filling pressures P1 and P2 based on the detection signal, and the differential pressure ΔP is used as the first monitoring set pressure ΔP _TH11. Is exceeded, it is determined that the process stop condition for stopping the injection process is satisfied.
[0047]
Subsequently, when it is determined that the process stop condition is satisfied, the process skip processing means (not shown) of the CPU 73 determines that a molding defect has occurred in each of the cavity spaces C1 and C2, and performs injection before the injection process is completed. The process and the pressure holding process are stopped, and the process is skipped to another predetermined process, the next process in the present embodiment. That is, the process skip processing means opens the mold, treats the unfinished disk substrates in each of the cavity spaces C1 and C2 as defective, and starts the weighing process. Further, the CPU 73 warns that molding failure has occurred by warning means (not shown).
[0048]
Then, when the shot in which the molding failure has occurred continues for a predetermined number of times, the operation stop processing means (not shown) of the CPU 73 stops the operation of the injection molding machine and displays the occurrence of the abnormality by the display means (not shown).
[0049]
When the differential pressure ΔP exceeds the second monitoring set pressure ΔP _TH12 , the condition satisfaction determination processing means determines that an operation stop condition for stopping the operation of the injection molding machine has been satisfied. Then, the operation stop processing means stops the operation of the injection molding machine and displays on the display means that an abnormality has occurred.
[0050]
In each of the above embodiments, an example in which the present invention is applied to a hot runner type mold apparatus is described, but the present invention can be applied to a cold runner type mold apparatus. Further, in each of the above embodiments, the disk substrate is formed as a molded product, but it is also possible to form a product other than the disk substrate.
[0051]
It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.
[0052]
【The invention's effect】
As described above in detail, according to the present invention, in the control device of the injection molding machine, a plurality of resin supply systems for filling the plurality of cavity spaces with the resin injected from the injection nozzle, Filling pressure detecting means for detecting the filling pressure of the resin to be filled into the space, and when one of the filling pressures detected by the filling pressure detecting means reaches a predetermined value, at least two of the filling pressures A control unit that calculates a differential pressure and determines that a molding failure has occurred in any of the molded products when the differential pressure exceeds a monitoring set pressure.
[0053]
In this case, when the differential pressure between at least two of the filling pressures exceeds the monitoring set pressure, it is determined that molding failure has occurred.For example, the filling pressure in one cavity space is determined. Is high, the filling pressure in the other cavity space is normal, and it can be reliably determined that molding failure has occurred even if the oil pressure in the injection cylinder does not exceed the threshold.
[0054]
Also, as one cavity space is filled with a large amount of resin, and when the other cavity space is not filled with a sufficient amount of resin, the oil pressure in the injection cylinder may not exceed the threshold value. Also in this case, it can be reliably determined that molding failure has occurred.
[Brief description of the drawings]
FIG. 1 is a functional block diagram illustrating a control device of an injection molding machine according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a main part of the injection molding machine according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of a filling pressure from the start of an injection process to the completion of a pressure holding process according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of a filling pressure from the start of an injection process to the completion of a pressure holding process according to a second embodiment of the present invention.
[Explanation of symbols]
26 Injection nozzle 28 Manifold 41, 42 Hot tip 51, 52 Sprue bush 71, 72 Filling pressure sensor 73 CPU
C1, C2 Cavity space Pa to Pc Monitoring point pressure ΔP, ΔPa to ΔPc Differential pressure

Claims (4)

(A) a plurality of resin supply systems for filling the plurality of cavity spaces with the resin injected from the injection nozzle;
(B) filling pressure detecting means for detecting a filling pressure of the resin filled in each cavity space;
(C) When one of the filling pressures detected by the filling pressure detecting means reaches a predetermined value, a differential pressure between at least two filling pressures is calculated, and the differential pressure exceeds a monitoring set pressure. A control unit for determining that a molding failure has occurred in any of the molded products when the injection molding machine is in use . Before Kisa圧the controller of the injection molding machine according to claim 1 continuously calculated based on each filling pressure. The control device for an injection molding machine according to claim 1, wherein the control unit stops the injection step and skips to another predetermined step when a molding defect occurs. The control device for an injection molding machine according to any one of claims 1 to 4, wherein the filling pressure detecting means is provided on a sprue bush.

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