JP2002178375A - Mold apparatus for injection molding and method for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold apparatus for injection molding and a method for injection molding capable of preventing a deformation of a molding by uniformly holding a mold release balance in the case of releasing the molding by alleviating a close contact force between the molding and a mold. SOLUTION: The method for injection molding comprises the steps of measuring the close contact force between the molding 23 and a dowel 35 of a movable mold in the case of releasing the molding 23, and vibrating the dowel 35 by vibrating units 24 and 25 based on a measured result of the force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die apparatus and an injection molding method for releasing a molded product after injection molding from a die.

[0002]

2. Description of the Related Art In general, when a so-called bite occurs in which an injection molded product comes into close contact with the inner surface of a mold, a release agent is applied to the inner surface of the mold, or the inner surface of the mold is polished. In order to reduce the adhesion between the mold and the molded product, various measures have been taken. However, if application of the release agent or polishing of the mold becomes insufficient due to restrictions on the structure of the mold, etc., the adhesion between the molded article and the mold remains strong, and The mold release resistance force until the mold is separated from the mold increases. This release resistance is
There is a tendency that the stronger the adhesion between the molded product and the mold, the greater the size. If the release resistance varies at each position where the molded product is ejected by the ejector pin, the timing at which the molded product separates from the mold is shifted for each position of the ejector pin, and the balance of the molded product at the time of release is deteriorated. However, there is a possibility that the molded product may be deformed. At the same time, when the molded product is released from the mold, the surface of the molded product may be damaged. At present, the release balance is improved by disposing many ejector pins in a portion where it is difficult to release, or by devising an arrangement position of the ejector pins.

[0003]

However, there are cases where the desired number and positions of the ejector pins cannot be realized due to various restrictions such as the configuration of the mold. In addition, unexpected release resistance may be generated due to various states, and the projected balance of the molded product projected by the ejector pins may be lost at the beginning. Further, when the mold release balance of the molded product is lost, the ejector plate for pushing the ejector pins is inclined, and the ejector pins may be rubbed, exerting an adverse effect on the ejection force, or possibly causing deformation of the molded product.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the adhesive force between a molded article and a mold, thereby keeping the mold release balance when removing the molded article uniform and preventing the molded article from being deformed. An object of the present invention is to provide an injection molding die apparatus and an injection molding method which can be performed.

[0005]

According to the present invention, there is provided an injection molding apparatus for removing an injection-molded article from a mold by removing the molded article from the mold. Measuring means for measuring the adhesive force between the article and the mold; adhesive force reducing means for reducing the adhesive force between the molded article and the mold; and And control means for controlling the adhesion reducing means.

According to the injection molding method of the present invention, there is provided an injection molding method in which a molded article after injection molding is released from a mold and taken out of the mold, wherein the close contact between the molded article and the mold is performed when the molded article is taken out. The method is characterized in that a force is measured, and based on a result of the measurement of the adhesive force, an adhesive force reducing means for reducing the adhesive force between the molded article and the mold is controlled.

[0007]

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

In FIG. 1, reference numeral 30 denotes a mold plate on a fixed mold side,
Reference numeral 31 denotes a mold plate on the movable mold side. Ejector plates 33 and 34 have a role of projecting the ejector pins 2. The injection molding cycle begins with filling of the resin into the mold, and after a pressure-holding and cooling process after completion of the filling of the resin, the mold plate 30 on the fixed mold side and the movable mold side on the movable mold side by a mold opening operation. The ejector pins 32 are ejected by the ejector plates 33 and 34 to separate the template plate 31 from the template plate 31.
This is a series of operations for ejecting the injection-molded article 23 from.

Reference numeral 22 denotes a mold opening detection sensor which detects the start of mold opening of the fixed mold side mold plate 30 and the movable mold side mold plate 31 and outputs a start signal. Reference numeral 21 denotes a load sensor, which measures a release resistance generated between the molded product 23 and the movable-die-side piece 35 based on a reaction force when the ejector pin 32 projects the molded product 23. . Reference numeral 20 denotes a minute ejecting device, which ejects the ejector pin 32 by a minute amount in the ejecting direction. Numerals 24 and 25 denote vibrating devices constituting the adhesion reducing means, which minutely vibrate the movable mold side piece 35. The detection signal of the mold opening sensor 22 is
The signal is taken into the CPU 11 through the signal converter 12 and the interface 11. Similarly, the mold release resistance force when the molded product 23 projects is detected by the load sensor 21, and the detection signal is taken into the CPU 1 through the signal converter 10 and the interface 9.
Further, the vibrating devices 24 and 25 operate according to the minute vibration operation command determined based on the command processed in the CPU 1. That is, the signals instructed from the CPU 1 through the interfaces 13 and 14 are transmitted to the driving devices 15 and 1
The driving force is converted into driving force of the vibration devices 24 and 25 by the vibration device 6, and the driving force is transmitted to the vibration devices 24 and 25 that generate minute vibrations.

Next, a description will be given of a change in the release resistance with time.

In FIG. 1, after the injection molded article 23 has gone through a cooling process, when the mold plates 30, 31 are completely opened,
It is protruded by the ejector pin 32. At this time, it was confirmed by an experiment that the release resistance applied to the load sensor 21 from the ejector pin 32 changes with time as shown in FIG. As shown in FIG. 2, the release resistance measured by the load sensor 21 increases with time, and the protruding force applied to the molded product 23 becomes larger than the force of the molded product 23 closely adhering to the piece 35. At this time, the molded article 23 starts to separate from the piece 35. In this way, by measuring the load applied to the ejector pins 32 when the molded product 23 projects, the maximum protrusion load Rp in FIG. 2 can be obtained. If there is a deep rib portion or the like in the molded product 23 and the contact area between the molded product 23 and the mold is large,
The release resistance tends to increase.

When the release resistance is large, the molded product 23
The force required to protrude the resin increases, and the resin molded product 2
3 is deformed or the ejector pin 32 buckles,
As shown in FIG. 3, it was confirmed by experiments that the release resistance repeatedly increased and decreased. In the present embodiment, in order to prevent such deformation of the molded product 23 and buckling of the ejector pins 32, the molded product 23 and the bridge are set before the peeling resistance force enters a region exceeding the value a in FIG. In order to reduce the adhesion with 35,
Vibration devices 24 and 25 apply minute vibration to the piece 35.

FIG. 4 is a flowchart for explaining a processing procedure when the molded article 23 is taken out.

After the filling, holding and cooling steps in the molding cycle, the mold is opened and the molded article 23 is removed. When the mold opens, the mold opening sensor 2
2 (step S1). When the start of mold opening is sensed by the sensing sensor 22, the condition is that the number of times of driving of the vibration devices 24 and 25 described below is not repeated a predetermined number of times or more (step S9).
The ejector pin 32 is pushed out by a predetermined amount (step S2). The protrusion amount of the ejector pin 32 is a predetermined amount according to the type of the molded product 23, and is based on the protrusion amount data read from the storage unit 6.
A command is issued from the driving device 8 to the minute projection device 20.

Next, the ejection time is obtained from the ejection speed and the ejection distance of the ejector pin 32, and the release resistance at that time is obtained (step S3). Then, the obtained release resistance is compared with the release resistance measured by the load sensor 21, and based on the difference between them, the vibration device 2 stored in the storage unit 6 in advance.
4, 25 amplitude and frequency are selected (step S
4). Under the selected conditions, the vibrating devices 24 and 25 are driven for a predetermined time previously stored in the storage means 6 to generate minute vibrations (step S5). This minute vibration stops after a lapse of a predetermined time stored in the storage means 6 in advance.

After stopping the minute vibration, the release resistance is measured by the load sensor 21 again (step S6). If the re-measurement resistance is lower than the predetermined value, a release OK signal for permitting the release operation is output to the injection molding machine (steps S7 and S7).
8) As a result, the molding machine performs the ejecting operation by the ejector pins 32 according to the normal molding cycle. If the release resistance measured again does not fall below the predetermined value, the process returns from step S7 to step S9, and the driving of the vibration devices 24 and 25 is repeated. Vibration device 2
If the mold release resistance does not fall below the predetermined value even after the drive of steps 4 and 25 is repeated a predetermined number of times, a mold release failure alarm is generated and the molding operation is stopped (steps S9 and S10).

In the processing shown in FIG. 4, after a minute vibration is applied for a certain period of time under set conditions, the minute vibration is stopped (step S5), and then the ejector pin 32 is moved by the minute ejecting device 20. Extrude only a small amount. Then, the reaction force at that time is applied to the load sensor 21.
Is determined, and it is determined whether or not it is necessary to further reduce the degree of close contact between the molded article 23 and the mold in the stationary state (step S).
7).

FIG. 5 is a flowchart for explaining another example of the processing procedure when the molded article 23 is taken out.

In this example, after step S4, the ejector pin 32 is pushed out by a minute amount by the minute ejecting device 20 (step S5a). In the protruding state, the vibrating devices 24 and 25 are driven under the conditions selected in step S4 to vibrate the piece 35 (step S6a). When the release resistance measured by the load sensor 21 becomes equal to or less than a predetermined value, it is determined that the adhesion has been reduced, the vibration is stopped, and a release OK signal for permitting the release operation is transmitted to the injection molding machine. (Step S
7a, S11a). On the other hand, when the release resistance does not fall below the predetermined value, the ejector pin 32 is ejected by a minute constant amount by the minute ejecting device 20 (step S9a), and the process returns to step S6a. Then, such an operation is repeated until the release resistance measured by the load sensor 21 becomes equal to or less than a predetermined value. However, if the release resistance does not decrease below the predetermined value even after repeating such an operation a predetermined number of times, a release failure alarm is generated and the molding operation is stopped (steps S8a and S10).
a).

As described above, in both cases of FIGS. 4 and 5, the movable mold-side piece 3 is set in accordance with the measured value of the release resistance.
By applying vibration to 5, the molded product 23 is prevented from biting during release.

[0021]

As described above, the present invention measures the adhesion between the molded article and the mold when removing the molded article,
Based on the result of the measurement of the adhesive force, by controlling the adhesive force reducing means for reducing the adhesive force between the molded product and the mold, the mold release balance at the time of removing the molded product is kept uniform, and the molding is performed. Deformation of the product can be prevented. In addition, the adhesion between the molded article and the mold can be measured based on the mold release resistance applied to an ejector pin that applies a release force to the molded article. Means can be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part for describing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a temporal change in a mold release resistance when adhesion between a molded product and a mold is low.

FIG. 3 is an explanatory diagram of a change with time of a mold release resistance when adhesion between a molded product and a mold is high.

FIG. 4 is a flowchart illustrating an example of a processing procedure at the time of removing a molded product according to the present invention.

FIG. 5 is a flowchart for explaining another example of the processing procedure at the time of removing a molded product according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 2 Keyboard 3 CRT 4 ROM 5 RAM 6 Storage means 7, 9, 11, 13, 14 Interface 8, 15, 16 Driving device 20 Micro ejecting device 21 Load sensor 22 Mold opening detection sensor 23 Injection molded product 24, 25 Vibration Apparatus 30 Template on fixed mold side 31 Template on movable mold side 32 Ejector pin 33, 34 Ejector plate 35 Piece on movable mold side

Claims (8)

[Claims] 1. An injection molding apparatus for removing a molded product after injection molding by releasing the molded product from a mold, wherein the adhesive force between the molded product and the mold is measured when the molded product is taken out. Measuring means, an adhesive force reducing means for reducing the adhesive force between the molded article and the mold, and a control means for controlling the adhesive force reducing means based on the measurement result of the measuring means. An injection molding die apparatus characterized by the above-mentioned. 2. The adhesive force reducing means reduces the adhesive force between the molded article and the mold according to the amount of action thereof, and the control means responds to the adhesive force measured by the measuring means. The injection molding die apparatus according to claim 1, wherein the amount of action of the adhesion reducing means is controlled. 3. The apparatus according to claim 1, wherein the measuring unit measures the adhesion force based on a release resistance applied to an ejector pin for applying a release force to the molded product.
5. The injection mold apparatus according to claim 1. 4. The injection molding die apparatus according to claim 1, wherein the adhesion reducing means has a function of vibrating the die. 5. An injection molding method for removing a molded product after injection molding from a mold by removing the molded product, wherein, when removing the molded product, measuring an adhesion force between the molded product and the mold; An injection molding method, comprising: controlling an adhesion reducing means for reducing an adhesion between the molded article and the mold based on a measurement result of the adhesion. 6. The adhesive force reducing means reduces the adhesive force between the molded article and the mold in accordance with the amount of action thereof, and is measured between the molded article and the mold. The injection molding method according to claim 5, wherein the amount of action of the adhesion reducing means is controlled according to the adhesion. 7. The adhesive force between the molded product and the mold is measured based on a release resistance applied to an ejector pin for applying a release force to the molded product. Or the injection molding method according to 6. 8. The injection molding method according to claim 5, wherein the adhesion reducing means has a function of vibrating the mold.