JP2002096364A - Apparatus for controlling injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely judge generation of defective molding when the defective molding is generated. SOLUTION: A plurality of resin feeding systems for filling a resin injected from an injection nozzle into a plurality of cavity spaces, filling pressure detecting means for respectively detecting filling pressures of the resin filled in each of the cavity spaces and a control part for judging generation of defective molding when pressure difference between at least two filling pressures among detected filling pressures exceeds a set pressure for superintendence are provided. When the filling pressure in one cavity space is high, even when filling pressures in other cavity spaces are normal and hydraulic pressure in the injection cylinder does not reach a threshold value, the generation of the defective molding can be surely judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, an injection molding machine for molding a disk substrate as a molded product is provided with an injection device.
A heating cylinder provided with an injection nozzle at the front end, a screw rotatably disposed within the heating cylinder, and capable of moving forward and backward, 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 the resin is filled into the cavity space of the mold apparatus. The resin in the space is cooled, solidified, and perforated to form a disk substrate. The mold apparatus is composed of a fixed mold and a movable mold, and the movable mold is brought into contact with and separated from the fixed mold by a mold clamping device, so that mold closing, mold clamping and mold opening of the mold apparatus are performed. Done.

When the disk substrate is molded, 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.

Therefore, a multi-cavity hot-runner type (2
A single-piece or four-piece mold apparatus is provided. In the hot runner type multi-cavity mold device, a plurality of cavity spaces are formed in the mold device, and a heating means is provided in each runner for supplying a resin to each cavity space. This heats the resin in the runner. In this case, the resin in the runner can be kept in a molten state, so that 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 increases, stress remains in the resin after overpacking and solidification.
Resin leaks out from between the fixed mold and the movable mold to form burrs, and molding defects occur.

Therefore, the oil pressure in the injection cylinder is detected,
When the detected oil pressure becomes 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]

However, in the above-described conventional injection molding machine, the resin injected from the injection nozzle passes through each runner and fills each cavity space. Even if the filling pressure increases, if the filling pressure in the other cavity space is normal, the oil pressure in the injection cylinder may not exceed the threshold.

Further, 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. .

In this case, it cannot be determined that a molding defect has occurred, and the operation of the injection molding machine cannot be stopped.

Therefore, if the operation of the injection molding machine is continued as it is, molding defects will occur in the disk substrates in each cavity space.

The present invention solves the above-mentioned problems of the conventional injection molding machine, and provides a control device for an injection molding machine that can reliably determine that molding failure has occurred when molding failure occurs. The purpose is to do.

[0012]

For this purpose, a control device for an injection molding machine according to the present invention comprises a plurality of resin supply systems for filling a plurality of cavity spaces with a resin injected from an injection nozzle. Filling pressure detecting means for detecting the filling pressure of the resin to be filled into the cavity space, and molding failure occurs when the differential pressure of at least two of the detected filling pressures exceeds the monitoring set pressure. And a control unit for determining.

In another control apparatus for an injection molding machine according to the present invention, the differential pressure is calculated when one of the filling pressures reaches a predetermined value.

In still another control apparatus for an injection molding machine of the present invention, the differential pressure is continuously calculated based on each filling pressure.

In another control apparatus for an injection molding machine according to the present invention, when a molding defect occurs, the control section stops the injection step and skips to another predetermined step.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a functional block diagram showing a control device of an injection molding machine according to a first embodiment of the present invention.

In the figure, reference numerals 51 and 52 denote sprue bushes as a plurality of resin supply systems for filling the resin injected from an injection nozzle (not shown) into a plurality of cavity spaces (not shown). A filling pressure sensor as a filling pressure detecting means for detecting a filling pressure of the resin to be filled, a molding failure 73 occurs when a differential pressure of at least two of the detected filling pressures exceeds a monitoring set pressure. CP as a control unit that determines that an error has occurred
U.

FIG. 2 is a sectional view showing a main part of the injection molding machine according to the first embodiment of the present invention, and FIG. 3 is a pressure holding step after the injection step is started in the first embodiment of the present invention. FIG. 6 is a diagram showing an example of a filling pressure until the completion of the process. In FIG. 3, the horizontal axis represents time, and the vertical axis represents filling pressure.

In FIG. 2, 11 is a fixed mold unit, 12 is a movable mold unit, 13 is a fixed platen, 14 is a fixed mold, and 15 is a fixed mold 14 attached to the fixed platen 13. 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 capable of moving forward and backward (moving in the left-right direction in FIG. 2) so as to face the fixed mold 14.
Has a receiving plate 21 and a template 22. Then, a concave portion 23 is formed at two positions of the template 22 by opening a surface facing the template 18. The fixed mold 14 and the movable mold 1
9 constitutes a mold apparatus.

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. You. 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 disk-shaped, in this embodiment, two cavity spaces C1 and C2 are formed by the concave portions 23.

Also, the rear of the fixed platen 13 (FIG. 2)
The right side of the figure) is provided with an injection device. 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 capable of moving forward and backward, and a drive for rotating and moving the screw forward and backward. An injection cylinder (not shown) is provided 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, and is filled in the cavity spaces C1 and C2.
The disk substrate as a molded product is formed by cooling and solidifying the resin in C2 and performing perforation processing.

For this purpose, a concave portion 24 having a conical shape is formed in the center of the surface of the stationary platen 13 facing the injection device. A locate ring 25 for positioning the position 14 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. To this end, the mold mounting plate 15 and the manifold 28
Spacers 31 and 32 made of a heat insulating material are provided between the intermediate plate 17 and the manifold 28, and a spacer 33 made of a heat insulating material is provided between the intermediate plate 17 and the manifold 28, so that a heat insulating space is formed around the manifold 28. Also, at the center of the manifold 28,
A bush 34 is formed so as to protrude rearward, and the rear end face (the right end face in FIG. 2) of the bush 34 and the injection nozzle 2
6 is opposed to the front end (the left end in FIG. 2). 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). Runner 36, 3
7 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.

At both ends of the manifold 28, hot chips 41 and 42 are attached.
The sprue bushes 51 and 52 are disposed forward of (to the left in FIG. 2). The nozzles 4 are provided at the front ends (left ends in FIG. 2) of the hot chips 41 and 42.
3 and 44 are formed, and the sprue bushes 51 and 52 are formed.
Are composed of outer cylinders 61, 62 and inner cylinders 45, 46, respectively. The front ends of the nozzle portions 43, 44 and the inner cylinders 45, 4
6 is opposed to the rear end (the right end in FIG. 2). In addition, the chip runner 4 is provided in the hot chips 41 and 42.
7, 48 are cold sprue 4 in the inner cylinders 45, 46.
9 and 50 are formed, and the runner 36 and the chip runner 4 are formed.
7 and the cold sprue 49 are communicated, and the runner 37, the chip runner 48 and the cold sprue 50 are communicated. The manifold 2
8, hot chips 41 and 42 and sprue bush 5
The resin supply system for filling the resin injected from the injection nozzle 26 into each of the cavity spaces C1 and C2 is constituted by the components 1 and 52.

The sprue bushes 51, 52
Are arranged facing the cavity spaces C1 and C2, and are opened at the front end face (the left end face in FIG. 2).
3, 54 are formed. 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
And the stamper 81, 8
2 is pressed against template 18.

In order to heat the resin passing through the runners 36 and 37 to maintain a molten state, a heater H1 as a first heating means is disposed on the outer peripheral surface of the manifold 28. 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.
2 embeds a heater H3 as a third heating means.

On the other hand, on the movable mold 19 side, cylindrical cut punches 55 and 56 are provided at portions facing the dies 53 and 54 so as to be able to advance and retreat.
Sprue rods 57 and 58 are provided in the inside and outside of the cut punches 55 and 56, respectively, and ejector sleeves 59 and 60 are provided so as to be able to advance and retreat, respectively. And
In order to advance and retreat the cut punches 55 and 56, driving means (not shown) for drilling holes is provided with sprue rods 57 and 58.
In addition, a driving means (not shown) for projecting is provided for moving the ejector sleeves 59 and 60 forward and backward.

Next, the operation of the injection molding machine when molding a disk substrate will be described.

The mold clamping device is driven, and the mold device is closed and clamped to form cavity spaces C1 and C2. Subsequently, the injection process is started in the injection device, the screw is advanced, and the molten resin is injected from the injection nozzle 26.
, And is branched into a runner 36 and a runner 37. 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, and the resin passing through the runner 37 becomes the chip runner 48 and the cold sprue 50.
After that, the other cavity space C2 is filled. In this case, since the resin is heated while passing through the runners 36 and 37 and the chip runners 47 and 48, the molten state is maintained. Therefore, each cavity space C1, C2
Since the resin can be uniformly flowed radially outward from the center in the inside, the quality of the disk substrate can be improved.

Next, a pressure holding step is started in the injection device, and the injection cylinder is driven to drive the cavity space C.
1. The pressure of the resin in C2 is maintained at a predetermined value. Subsequently, a cooling step is started in the mold apparatus, 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 are moved forward. Die 5 (right end in FIG. 2)
3, 54, and are inserted into the cavity spaces C1, C
The resin in 2 is perforated. Thus, the disk substrate is formed.

Thereafter, as the mold apparatus is opened, the drive means for ejection is driven, and when the sprue rods 57, 58 and the ejector sleeves 59, 60 are advanced, the disk substrate is ejected, It is released.

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.

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 occurs, or the fixed mold 14 and the movable mold The resin leaks out from the space between the mold 19 and forms burrs, and molding failure occurs. Further, when the filling pressures P1 and P2 in the cavity spaces C1 and C2 are low, sinks, shorts, and the like are formed on the disk substrate, and molding defects occur.

Therefore, in the resin supply system, in this 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 filling pressure sensor 7
Reference numerals 1 and 72 denote the pressures of the resin in the cold sprues 49 and 50 and the filling pressures P1 and P2 in the cavity spaces C1 and C2.
Detected as In FIG. 3, L1 is a line indicating the filling pressure P1, and L2 is a line indicating the filling pressure P2. The template 1
8 or the mold plate 22 is provided with a filling pressure sensor facing the cavity spaces C1 and C2, and the pressure of the resin in the cavity spaces C1 and C2 is directly increased by the filling pressure P by the filling pressure sensor.
1, hot chips 41, 42
In addition, a filling pressure sensor is provided so as to face the chip runners 47, 48, and the chip runners 47, 4 are provided by the filling pressure sensors.
8 is detected as filling pressures P1 and P2, or a filling pressure sensor is provided in the manifold 28 so as to face the runners 36 and 37, and the runner 3 is detected by the filling pressure sensor.
It is also possible to detect the pressure of the resin inside 6, 37 as filling pressures P1, P2.

Then, the charging pressure sensors 71 and 72
The filling pressures P1, P in the cavity spaces C1, C2
2 is detected, the detection signal is constantly or at a predetermined timing.
The data is sent to the CPU 73 as a control unit for each event. The CP
The condition satisfaction determination processing means (not shown) of U73
One of the filling pressures P1, P2 based on the output signal
When the filling pressure reaches a predetermined value,
The filling pressure P1 is set at a monitoring point pressure p set in advance.
Each time the pressure reaches a to pc, the pressure difference Δ between the filling pressures P1 and P2
Pa to ΔPc are calculated, and the differential pressures ΔPa to ΔPc
Monitoring set pressure ΔP _THIf it exceeds 1, stop the injection process
It is determined that the condition for stopping the process is satisfied.

Subsequently, when it is determined that the process stop condition is satisfied, the not-shown process skip processing means of the CPU 73 determines that molding failure has occurred in each of the cavity spaces C1 and C2, and the injection process is completed. The injection step and the pressure-holding step are stopped before, and skipped to another predetermined step, the next step 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. The CPU 73 warns that molding failure has occurred by a warning means (not shown).

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 a display means (not shown). indicate.

Further, the condition satisfaction judgment processing means, when the differential pressure ΔPa~ΔPc exceeds the second monitoring set pressure [Delta] P _TH 2, and the operation stop condition for stopping the operation of the injection molding machine is established to decide. 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.

The monitoring point pressures pa to pc and the first
The monitoring set pressure ΔP _TH 1 can be fixed to a constant value or set to an arbitrary value by a setting device (not shown). In the present embodiment, the charging pressure P1
Calculates the differential pressure ΔPa to ΔPc between the filling pressures P1 and P2 every time the pressure reaches the preset monitoring point pressures pa to pc. However, the charging pressure P2 reaches the preset monitoring point pressure. Each time the filling pressure P1, P2
Can be calculated. In the present embodiment, the filling pressures P1 and P2 in the two cavity spaces C1 and C2 are detected.
In a mold device with more than one cavity space,
A filling pressure in each cavity 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, each differential pressure between the one filling pressure and each of the other filling pressures can be calculated.
In this case, if 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.

As described above, each cavity space C1, C2
Is determined based on the differential pressures ΔPa to ΔPc of the filling pressures P1 and P2 in the above, for example, when the filling pressure in one cavity space is high, the other cavity space Is normal, and even if the oil pressure in the injection cylinder does not exceed the threshold, it can be reliably determined that molding failure has occurred.

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. However, also in this case, it can be reliably determined that molding failure has occurred.

Accordingly, the injection process is stopped, and the unfinished disk substrates in the cavity spaces C1 and C2 are both treated as defective products, so that non-defective products and defective products are not mixed.

When the condition for stopping the process is satisfied, the injection process and the pressure-holding process are stopped. However, the operation of the injection molding machine is not stopped, and the process skips to the next process, ie, the measuring process. The operation of the molding machine can be continued. Therefore, the operation efficiency of the injection molding machine can be improved.

Next, a second embodiment of the present invention will be described.

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.

In the figure, L1 is a line indicating the filling pressure P1,
L2 is a line indicating the filling pressure P2. In this case, the filling pressure P in the cavity spaces C1 (FIG. 2) and C2 is determined by the filling pressure sensors 71 (FIG. 1) and 72 as the filling pressure detecting means.
When 1, P2 is detected, a detection signal is sent to the CPU 73 as a control unit at all times or continuously at predetermined timings. The condition satisfaction determination processing means (not shown) of the CPU 73 determines the filling pressures P1, P2 based on the detection signal.
The pressure difference ΔP is continuously calculated, and when the pressure difference ΔP exceeds the first monitoring set pressure ΔP _TH11, it is determined that the process stop condition for stopping the injection process has been satisfied.

Subsequently, when it is determined that the process stop condition is satisfied, the not-shown process skip processing means of the CPU 73 determines that a molding defect has occurred in each of the cavity spaces C1 and C2, and the injection process is completed. The injection step and the pressure-holding step are stopped before, and skipped to another predetermined step, the next step 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. The CPU 73 warns that molding failure has occurred by a warning means (not shown).

When the shots in which molding failure has occurred continue 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 abnormality by a display means (not shown). indicate.

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.

In each of the above embodiments, an example in which the present invention is applied to a hot runner type mold apparatus is described.
The present invention can be applied to a cold runner type mold device.
Further, in each of the above-described embodiments, the disk substrate is formed as a molded product. However, a product other than the disk substrate can be formed.

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]

As described above in detail, according to the present invention, in a control device for an injection molding machine, a plurality of resin supply systems for filling a plurality of cavity spaces with a resin injected from an injection nozzle. A filling pressure detecting means for detecting a filling pressure of the resin filled in each of the cavity spaces; and a molding failure when a differential pressure between at least two of the detected filling pressures exceeds a monitoring set pressure. And a control unit that determines that the error has occurred.

In this case, when the pressure difference between at least two of the filling pressures exceeds the monitoring set pressure, it is determined that a molding failure has occurred.
If the filling pressure in one cavity space is high,
Even if the filling pressure in the other cavity space is normal and the oil pressure in the injection cylinder does not exceed the threshold, it can be reliably determined that molding failure has occurred.

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. However, 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 showing an example of a filling pressure from the start of an injection step to the completion of a pressure holding step in 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)

[Claims] 1. A plurality of resin supply systems for filling a plurality of cavity spaces with a resin injected from an injection nozzle, and (b) detecting a filling pressure of the resin filled in each of the cavity spaces. And a control unit for determining that molding failure has occurred when a differential pressure between at least two of the detected filling pressures exceeds a monitoring set pressure. Control device of the injection molding machine. 2. The control device for an injection molding machine according to claim 1, wherein the differential pressure is calculated when one of the filling pressures reaches a predetermined value. 3. The control device for an injection molding machine according to claim 1, wherein the differential pressure is continuously calculated based on each filling pressure. 4. 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.