JPH1119996A - Injection molding machine and injection molding method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new injection molding machine for core compression molding that can perform respective controls suitably and quickly in an injection molding process for core compression injection molding of an ultra-precision molded piece such as a CD or DVD substrate. SOLUTION: An injection molding machine A for use for a core compression injection molding method for precision molding comprises a mold 1, an injection mechanism portion (a) for injecting resin into the mold 1, a core mold 5 that is incorporated into a mold 1 and constituting a part of a mold cavity 2, and a pressure sensor 54 for detecting a reaction force of the core mold 5 due to loaded resin in the mold cavity 2 and controlling based on output data therefrom at least either an injection process for loading resin into the mold cavity 2 or a pressure maintaining process for core compressing the loaded resin in the mold cavity 2 or the whole or part of those processes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention detects a reaction force of a core mold caused by a resin filling a mold cavity, controls the filling speed of the resin into the mold cavity based on the output data, and performs a subsequent pressure-holding process. The present invention relates to an injection molding machine for ultra-precision molding and a method of injecting the same, which properly or entirely or partially controls a core compression control and a position control.

[0002]

2. Description of the Related Art Injection molding machines and injection molding methods are constantly evolving with the precision of injection molded products. Recently, digital technology has become common in various fields such as data processing, video and music, and as a natural consequence, for example, CD and M
Digital substrates such as D or DVD have been put to practical use. Especially for DVD substrates, it is required to accurately transfer the ultra-fine irregularities engraved on the mold to the molded product, and this is not useful for conventional injection molding machines. An injection molding machine that uses many servo motors is being developed. In such an injection molding machine, the following matters affect the precision of the substrate.

For example, in the case of molding an optical disc substrate, warpage of a molded product, adhesion of foreign matter, voids, gas burn, molding cycle and the like are extremely important factors, but the biggest problems are ultra-fine pitch and depth. Pit transferability and birefringence of 50 nm or less can be achieved, and the birefringence can be suppressed by relaxing (photoelastic coefficient × principal stress difference “= shear stress + thermal stress”).

[0004] In the molding of a substrate, microvoids and microflow marks can be cited as factors that hinder transferability of fine irregularities. When the resin flows along the fine irregularities, a phenomenon of entrainment of air in the resin flow occurs before and after the wall of the fine irregularities, and a fine air pocket is formed. This fine air pool causes a decrease in transferability, and as a countermeasure, the filling is completed by minimizing the solidification of the resin due to the high-speed filling. The timing of injection compression is also an important factor.

[0005]

In view of the above, the control of the injection speed of the metering resin into the mold cavity, the timing of gate cut, the compression speed of the core compression and the pressure control of the core compression, It was necessary to appropriately control the position of the core die to keep the thickness constant, and it could not be achieved at all with the capability of the conventional apparatus which adopted the core compression molding method by hydraulic drive. This point will be described with reference to FIG. 7 by comparing the present invention with a conventional example. The problem to be solved by the present invention is how to perform each of the above controls appropriately and promptly. For this purpose, there has been a demand for the development of a new injection molding machine for core compression molding and an injection molding method therefor.

[0006]

Means for Solving the Problems Claim 1 is an example of an injection molding machine (A) for achieving the above-mentioned object, which is an injection molding machine (A) used in a core compression injection molding method for precision molding. ,
Mold (1) and injection mechanism (a) for injecting resin into mold (1)
And a core mold (5) that is incorporated in the mold (1) and forms a part of the mold cavity (2), and a core mold (5) formed by a resin filling (3) in the mold cavity (2). The reaction force is detected, and at least one of the injection step or the subsequent pressure-holding step of filling the resin (3) into the mold cavity (2) based on the output data, or the whole or a part of the step And a pressure sensor (54) for performing the above-mentioned control. "

In the injection step in which the mold cavity (2) is filled with the measuring resin (3a), the pressure sensor (54) detects the filling resin.
The output related to (3) is obtained because the filled resin (3) is a core type
This is after the contact with (5) is started (indicated by the point (px) in FIG. 7). Therefore, the output regarding the filling resin (3) is obtained from the pressure sensor (54) only when the filling resin (3) is completely cured from the point (px) at which the filling resin (3) starts to contact the core mold (5). Until the end of the pressure holding process (shown by a point (P3) in FIG. 7). During these periods, since the data on the filling resin (3) (ie, the reaction force directly received from the filling resin (3)) is obtained directly from the pressure sensor (54), each process must be accurately controlled in real time. become. Incidentally, the control is a part of the injection process until the gate cut after the filling resin (3) starts to contact the core mold (5), the timing of gate cutting to close the gate (2a) of the filling resin (3), Through the entire process of the core compression of the filling resin (3), which is the front stage of the pressure holding process, the position control, which is the rear stage of the pressure holding process, or any of the processes, or a part of each process Is applied.

[0008] [Claim 2] is an injection molding machine (A) of claim 1
[Indicator (7)] is added to "Injection molding machine (A) used in the core compression injection molding method of precision molding, which is measured by the mold (1) and the mold (1). The injection mechanism (a) for injecting the resin (3a), and the mold cavity incorporated in the mold (1)
Core mold (5) forming part of (2) and mold cavity (5)
Detects the reaction force of the core mold (5) by the filling resin (3) inside, and based on the output data, fills the resin (3) into the mold cavity (2) in the injection step or the subsequent pressure-holding step. A pressure sensor (54) for controlling at least one or all or part of the process, and a display unit for digitally or analogly displaying all or part of the control process
(7) ". According to this, in addition to the above-described operation, all or a part of the control process by the pressure sensor (54) is displayed on the display unit (7) by digital or analog display, so that the process management becomes clear at a glance, and the process is very controlled. Easier to do.

Claim 3 is an example of an injection molding method using the injection molding machine (A), which includes "a mold (1) and a mold cavity (2) incorporated in the mold (1). Core type forming part
(5) and a precision molding injection molding machine (A) equipped with a pressure sensor (54) for detecting a reaction force of the core mold (5) by the filling resin (3) in the mold cavity (2). In the core compression injection molding method, the pressure control of the filling resin (3) by the core mold (5) based on the output data from the pressure sensor (54), or the filling resin (3) by the position control of the core mold (5). ) At least one of the thickness control is performed. " According to this, in the pressure-holding step, the control, which is an important factor, is performed by the reaction force directly obtained from the filling resin (3), so that real-time and accurate control can be performed.
The pressure control of the core mold (5) and the thickness control of the filling resin (3) by the position control of the core mold (5) may be performed on either one or both.

[0010] Claim 4 is another example of the injection molding method, wherein "a mold (1) and a mold cavity incorporated in the mold (1)".
Core mold (5) forming part of (2) and mold cavity (2)
Precision molding with a pressure sensor (54) that detects the reaction force of the core mold (5) due to the filling resin (3) inside, and a gate cut pin (30) that opens and closes the mold gate (2a) Injection molding machine
(A) In the core compression injection molding method, the pressure sensor
Gate cut pin (30) based on output data from (54)
Control the operation timing of the device. " According to this, in the injection molding process, the timing control of the gate cut, which is one of the important factors, is performed by the reaction force obtained directly from the filling resin (3), so that real-time and accurate control is performed. Becomes possible.

A fifth aspect of the present invention relates to a still another example of the injection molding method, wherein a mold (1) and a core mold incorporated in the mold (1) and forming a part of the mold cavity (2). (5) and mold cavity
(2) a pressure sensor (54) for detecting a reaction force of the core mold (5) by the filled resin (3), and an injection mechanism (a) for injecting the resin (3) into the mold (1). Injection molding machine for precision molding (A)
In the core compression injection molding method, the pressure sensor (54)
Mold from injection mechanism (a) based on output data from
(1) Resin injection speed control is performed. "
According to this, the injection process, which is one of the important factors in the injection molding process, in particular, the injection speed control is performed by the reaction force obtained directly from the filling resin (3), so that it is real-time and accurate. Control becomes possible.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In addition, in the attached drawings, FIGS. The injection molding machine (A) of the present invention is roughly divided into an injection mechanism (a) and a mold mechanism (b) as shown in FIG. The injection mechanism (a) includes a drive mechanism (10) for moving the screw (4) forward and backward, a rotation servomotor (11) for rotating the screw (4), and moving the screw (4) forward and backward. Servo motor for injection (12), screw (4) for kneading and injecting resin, injection cylinder (13) containing screw (4) that can move forward and backward, and heater wound around injection cylinder (13) (14), an injection load cell (15), which is disposed between the screw (4) and the drive mechanism (10) and detects the pressure applied to the screw (4), a raw material supply hopper (16), and Pulse generators (11a) (12) attached to servo motors (11) (12)
a).

Next, the mold mechanism (b) will be described. The mold (1) is composed of a movable / fixed mold (1b) (1b), the fixed mold (1b) is attached to the fixed die plate (17), and the movable mold is attached to the movable die plate (18). (1a) is attached. The movable die plate (18) is provided with a core-type opening / closing toggle mechanism (T2), and the tailstock to which the housing (50) of the core-type opening / closing toggle mechanism (T2) and one end of the tie bar (19) are fixed. A mold opening / closing toggle mechanism (T1) is disposed between the mold opening and closing mechanism (T1).

A guide hole (29) is formed in the movable mold (1a), and a core die (5) is slidably disposed in the guide hole (29). A mold cavity (2) is formed between the stationary mold (1b). On the surface (5a) of the core mold (5) on the mold cavity (2) side, for example, fine irregularities for CDs and DVDs are formed, and the side fine irregularities engraved surface (5a) is similar to ultra-mirror surface processing. Extremely high smoothness (for example, Rmax 0.01μ)
m, flatness = 0.1 μm), parallelism is required to be, for example, 0.005 mm or less, and coaxiality between the core mold (5) and the guide hole (29) is required to be extremely high, for example, 0.005 mm. . In addition, the gate cut pin (3
0) is slidably disposed.

Next, the mold opening / closing toggle mechanism (T1) will be described. The tailstock (20) has a die control servomotor (3
1) is attached, a drive pulley (32) attached to the rotary drive shaft thereof, and a driven pulley (34) rotatably arranged on the tailstock (20) via bearings by a timing belt (34). 33) Connected. A pulse generator (31a) is mounted on the mold control servomotor (31). The driven pulley (34) is threaded with a male screw rod (30a) so as to be able to advance and retreat, and the protruding end of the male screw rod (30a) is attached to the mold opening / closing crosshead (35). The mold opening / closing toggle connects each of the long and short arms (36) to a link mechanism, one end of which is rotatably connected to the tailstock (20) and the other end is rotatably connected to the housing (50). The other end is attached to the mold opening / closing crosshead (35). Since this link mechanism is a known technique, further details will be omitted.

Next, the core type opening / closing toggle mechanism (T2) will be described. The housing (49) constituting the front end of the core type opening / closing toggle mechanism (T2) is connected to the movable die plate (18), and further to the housing (50) constituting the rear end portion via the core type opening / closing toggle. It is connected. A core-type control servomotor (40) is attached to the housing (50), and a drive pulley (41) mounted on its rotary drive shaft and a housing
A driven pulley (43) rotatably held via bearings to (50) is connected by a transmission belt (42). The driven pulley (43) is attached to an operation nut (44), and a core operation screw rod (45) is threadably mounted on the operation nut (44) so as to be able to advance and retreat. An intermediate pin (30b) connected to the gate cut pin (30) is slidably inserted into the core actuating screw rod (45), and the tip is connected to the pressure plate (59), and the rear end is Is adapted to come into contact with the tip of the male screw part (30a). The core type control servo motor (40)
Is provided with a pulse generator (40a).

The core-type opening / closing toggle used in the above is similar to the mold opening / closing toggle, in which various long and short arms (47) are connected to a link mechanism. The structure itself is a known structure.
At the rotation connection part (H), a rotation pin serving as a rotation center
This is different from the conventional example in that a bearing (46) is interposed between the arm (48) and the arm (47) so that the arm (47) operates smoothly without play. Although the type of the bearing (46) does not matter, a type capable of carrying a large load, such as a roller bearing or a needle bearing, is selected because a load is applied. To briefly describe the structure, one end of each of the long and short arms (47) is connected to the housing (49), and the other end is the housing (50).
And the other end is attached to a core operating crosshead (55) provided at the tip of the core operating screw rod (45).

The moving die plate (18) has a core type (5).
A pressurizing block (57) for pressurizing is disposed slidably, and is in contact with the housing (49) via a pressure sensor (54). A pin pressing rod (30c) is slidably penetrated through the pressure block (57), the pressure sensor (54) and the housing (49), and the tip thereof abuts on the gate cut pin (30), It is in contact with the pressure plate (59) via the casing of the cylinder (60) provided at the other end. The cylinder
The protruding pin (61) slidably inserted into the pin pressing rod (30c) is connected to (60). The cylinder (60) is connected with a protruding operating pin (61) slidably inserted through a pin pressing rod (30c). The protruding operation pin (61) is, for example, a product protruding pin (e.g., a protruding and protruding pin ( 61a) and the center pin (61b) inserted in the gate cut pin (30). Product protruding pin (61a) and center pin (61b)
What is the structure as long as the product (26) and the gate resin (2b) adhering to the product (26) when the mold is opened can be released after the mold is opened, as described later. It may be something.

(8) is a control device which controls the entirety of the injection molding machine (A). One of the functions is a load cell for injection (15), a pressure sensor (54), a servo motor, (1
1) Pulse generator (11a) mounted on (12), (31) and (40)
(12a) (31a) and (40a) or the signals from other sensors are obtained to control the servo motors (11), (12), (31) and (40). All drive system controls are performed by servo motors (1
1) Since it is performed by (12), (31) and (40), any condition such as a composite operation can be created by programming. (7) is a display unit connected to the control device (8), which displays all or a part of the injection molding process digitally or analogly. FIG. 7 is an example in which the control states in the injection step and the pressure-holding step are represented by a graph. For example, such a graph is displayed. As a result, the process management becomes clear at a glance, and the management becomes very easy.

Referring to FIG. 7, the graph plots pressure on the vertical axis and time on the horizontal axis. The curve shown by the solid line shows a control example of the present invention, the upper solid line shows the set pressure of the core type (5), and the lower solid line shows the actual reaction force of the core type (5). The broken line curve shows a conventional example, the upper broken line is the set pressure of the core type by hydraulic drive, and the lower broken line is the output of a hydraulic sensor (not shown) installed in the hydraulic circuit.

In the conventional example, a hydraulic drive is used for the core compression (the same applies to the injection process and the mold operation), and the compression pressure is detected by a hydraulic sensor installed in the hydraulic circuit, and the hydraulic pressure is controlled so as to match the set pressure. Was. In the case of hydraulic control, indirect detection that the detection of resin pressure is via pressure oil, as well as changes in temperature and viscosity and other various changes in pressure oil, and dynamic friction and static friction of the core type Due to various factors such as the difference from the actual pressure, the actual resin pressure in the mold dynamically changes and shows a waveform, and does not match the set pressure. That is, as shown by the upper broken line, the core compression pressure is set from the start of the injection process to the mold opening, and the hydraulic pressure should be controlled so that the compression pressure of the core mold changes in accordance with the set pressure. Not really. That is, the output from the hydraulic pressure sensor installed in the hydraulic circuit for driving the core mold starts to be injected, the resin starts to be filled into the mold cavity, and the output starts after the resin starts to contact the core mold after a while. . This point is shown by (S). Then, the output of the oil pressure sensor rapidly rises with the filling of the resin, and after reaching the peak (S1), the output waveform of the resin pressure undulates for the above-described reason. In other words,
The resin pressure in the mold cavity will change dynamically,
It does not match the set pressure. Also, there is a limit to the injection speed by hydraulic drive, and injection is performed at a considerably slow speed as shown in (0 → R1) in FIG. Therefore, a thin resin film is generated on the surface of the filling resin (3), which impairs transferability. Point (R1)
Injection process is completed in, the process moves to the core compression process (R1 → R2) which is the previous stage of the dwelling process, but at this stage, the waves applied so that the pressure applied to each part of the filling resin (3) is not constant, Molded product (2
6) The internal stress is increased, and the birefringence is increased.

On the other hand, in the present invention, the pressure sensor (54)
Since the resin pressure of the filling resin (3) is directly detected by the pressure control, it is possible to follow the compression pressure control by the core mold (5) at the front stage of the pressure holding process or the position control at the rear stage in real time. The injection speed can be controlled following the direct detection by the pressure sensor (54) within the range of the injection step (px → P1).

Next, the operation of the present invention will be described. The raw material resin (3c) is charged into the raw material supply hopper (16), and when the screw (4) is rotated by operating the rotation servomotor (11), the raw material resin (3c) is gradually fed toward the injection cylinder (13). Since the injection cylinder (13) is heated by a heater (14) wound around its outer periphery, the injection cylinder (13) is
(13) The raw material resin (3c) entered gradually melts and
It is kneaded by the rotating action of (4).

With the rotation of the screw (4), the melt-kneaded resin (3
b) is sent toward the tip of the injection cylinder (13), and is stored at the tip. As a result of this reaction, the screw (4) gradually retreats, and eventually reaches a preset retreat stop position. At this point, the resin measurement has been completed. continue,
The rotary servomotor (11) is stopped and the injection servomotor (12) is operated to push the screw (4) forward, and the metered molten kneading resin (3a) accumulated at the tip of the injection cylinder (13) Is injected into the mold cavity (2). During this time, the rotation speed of the screw (4) is obtained by taking the output signal from the pulse generator (11a) into the control device (8), comparing it with the set value, and tracing the set value.
1) feedback control.

The injection speed of the screw (4) is determined by taking the output signal of the injection load cell (15) into the control device (8).
The injection servomotor (12) is feedback-controlled so as to compare with the set value and trace the set value. The rotation speed of the injection servomotor (12) is detected by the pulse generator (12a). Since the injection speed is directly and preferably controlled by the resin pressure of the filling resin (3) in the mold cavity (2), at the point (px), the filling resin (3) becomes the core mold (5). When the pressure sensor (54) comes into contact and starts outputting data relating to the resin pressure, the injection speed control by the injection load cell (15) may be switched to the injection speed control by the pressure sensor (54). This point will be described with reference to FIG.
In the region (1), the injection process is performed, so that the speed control is performed. Among them, (0 → px) is controlled by the injection load cell (15), and (px → P1) is controlled by the pressure sensor (54). Injection speed control according to ()) is performed. It goes without saying that the injection speed control by the injection load cell (15) may be performed throughout (0 → P1). Since the injection of the metering resin (3a) is performed by the injection servo motor (12), high-speed injection very close to the set value can be performed, and the thin resin film is filled with the resin.
Injection can be completed before it occurs on the surface of (3), and transferability can be significantly improved.

Thereafter, a gate cut is performed. At that timing, when the pressure sensor (54) indicates a predetermined value, the gate cut pin (30) operates to perform the gate cut. Therefore, since the gate cut is performed every time the same resin pressure is applied, the same amount of the resin (3) is stably filled in the mold cavity (2) every time.

Next, the process proceeds to the pressure-holding step. In the pressure control region, which is the front stage, the pressure sensor (54) directly detects and controls the resin pressure in the mold cavity (2). A compression pressure almost equal to the set value can be applied to the filling resin (3), and the internal stress can be further reduced.
When moving to position control, which is the latter stage of the pressure holding process,
(3) is almost cured, and the position of the core mold (5) must be accurately controlled so that its thickness is constant. As described above, a fixed amount of resin (3) is always contained in the mold cavity (2).
Is filled, the thickness becomes constant if the detection value of the pressure sensor (54) is constant. Therefore, if control is performed so that the detection value of the pressure sensor (54) becomes the set value in the position control stage, the position of the core type (5) also becomes a constant position by itself,
The thickness of the molded product (26) is also constant.

The above steps will be described as the movement of the mold (1). First, as shown in FIG. 6, mold clamping is performed. That is, the mold control servomotor (31) is operated, and the driving pulley is driven.
(32) and the transmission belt (33)
(34), and when the driven pulley (34) is rotated, the male screw rod (30a) screwed on the driven pulley (34) advances rightward from the lower state in FIG. , Crosshead
Push (35) to extend the mold opening and closing toggle. At this time, the core opening / closing toggle mechanism (T2), the movable die plate (18), and the movable mold (1a) attached thereto move to the fixed mold (1b) side according to the extension, and the fixed mold ( Moving mold (1a) to 1b)
Is pressed at a predetermined pressure. At this time, the core opening and closing toggle mechanism
(T2) is not operating, and the core type (5) is located at the retreat limit.

FIG. 6 shows a state immediately before injection.
Here, the core mold (5) moves to the forward limit. That is, when the core opening / closing servomotor (40) is operated, its rotational force is transmitted via the driving pulley (41) and the transmission belt (42) to the driven pulley (43).
To the driven pulley (43) and rotate the driven pulley (43).
The core operation screw rod (45) screwed in 3) moves forward to the right in the figure, and the core operation screw rod (45) is attached. Is extended. At this time, the housing (49), to which one end of the arm (47) of the core opening / closing toggle is pivoted, is pushed toward the fixed mold (1b) side in accordance with the extension, and the pressure sensor (54) and the pressure block (57) The core mold (5) moves to the fixed mold (1b) side via. The pressurized pressure of the core type (5) is detected by a pressure sensor (54), and the data is input (30) to the control device (8), and the core type control servomotor (40) is set so that the pressurized pressure becomes a set value. )
Is controlled. The rotation speed of the core-type control servomotor (40) is detected by a pulse generator (40a).

Turning now to FIG. In this state, the injection servo motor (12) is operated as described above, and the screw mechanism (10)
Is operated to move the screw (4) toward the mold (1), and the molten resin (3a) at the tip of the cylinder (13) is injected into the mold cavity (2). The injection speed is optimally controlled by the control device (8). When the resin (3a) is injected and filled into the mold cavity (2), the resin (3a) contacts and presses the core mold (5), and the core mold (5) is pushed back by the filling pressure, and the portion is pressed. The melt-kneaded resin (3) is excessively filled. In the above process (0 → P1), (0 → px) is controlled by the injection load cell (15), and (px → P1) is controlled by the pressure sensor (54).
In addition, since the injection process is performed by the injection servomotor (12) so as to follow the set value, the filling is completed before a thin resin film is generated in the filling resin (3).

Next, as shown in FIG. 6, the gate is cut. When the pressure sensor (54) indicates a predetermined value, the gate is cut immediately and the mold cavity is cut.
The supply of the resin (3a) to (2) is immediately stopped. That is, when the mold control servomotor (31) is further operated while the mold (1) is being clamped, the male screw bar (30a) will move further forward. Since the arm (36) connected to the mold opening / closing crosshead (35) to which the tip of the male screw rod (30a) is connected is oriented at right angles to the male screw rod (30a), the mold A slight advance of the opening / closing crosshead (35) is hardly affected and there is almost no increase or decrease in the mold clamping force. on the other hand,
The tip of the male screw rod (30a) is the intermediate pin (30b) and the pin pressing rod.
(30c) is connected to the gate cut pin (30), so that the male threaded rod (30a) advances and the gate cut pin (30)
Also moves forward to close the gate (2a) of the fixed mold (1b) at its tip. As a result, the mold cavity (2) is completely shut out from the outside world in a state where the resin (3) is filled by an amount corresponding to the retreat of the core mold (5). At the time of this gate cutting, the product projecting pin (61a) and the center pin (61b) do not project together with the gate cutting pin (30), and the ends thereof are kept flush with the cavity surface (5a).

Next, we move to FIG. As mentioned above, after the gate cut, the core open / close servomotor is again
Activate (40) to advance the core mold (5) to the forward limit, press the filling resin (3) with extremely strong pressure, and cure the fine irregularities of the core mold (5) while the filling resin (3) is hardening. Transfer to a certain filling resin (3). During this time, since the resin is compressed while directly detecting the resin pressure by the pressure sensor (54), uniform core compression can be performed with high reproducibility every time. Subsequently, while the resin pressure is directly detected by the pressure sensor (54) in this state, the core mold (5) is held so that the resin pressure becomes a predetermined value, and the filling resin (3) is cured. Thereby, the molded product (26) has a uniform thickness every time with high reproducibility. When the curing of the filling resin (3) is completed, as shown in FIG. 6, the core type control servomotor (40) is operated in reverse to separate the core type (5) from the fixed die (1b) side. Next, referring to FIG. 6, the mold control servomotor (31) is operated in reverse to move the movable mold (1a) away from the fixed mold (1b). At this time, the molded product (26) moves together with the movable mold (1a) while being fitted into the mold cavity (2) of the movable mold (1a).

Finally, referring to FIG. 6, when the mold opening is completed, the ejecting cylinder (60) is operated, and the ejecting pin (61) is ejected so that the product ejecting pin (61a) and the center pin are ejected.
(61b), the gate resin (2b) is released, the molded product (26) is released, and the product is recovered by a product removal device (not shown).

[0034]

According to the apparatus of the present invention, the reaction force of the core mold due to the filling resin in the mold cavity is detected by the pressure sensor, and the resin is filled into the mold cavity based on the output data. Since at least one of the following pressure-holding steps or the whole or a part of the above-mentioned steps is controlled, during this period, data relating to the filling resin (that is, a reaction force directly received from the filling resin) is directly obtained. Therefore, each process can be accurately controlled in real time. In addition, by providing a display unit in the injection molding machine, all or a part of the control process by the pressure sensor is displayed by digital or analog display, and the process control becomes clear at a glance, making it very easy to control. Further, according to the method of the present invention, based on the output data from the pressure sensor pressure control of the filling resin by the core type,
Alternatively, since at least one of the thickness control of the filling resin by the core type position control is performed, the operation timing of the gate cut pin is controlled based on the output data from the pressure sensor, and therefore, based on the output data from the pressure sensor. Since the resin injection speed is controlled from the injection mechanism into the mold, real-time and accurate control can be performed in any case.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic structure of a main part of an injection molding machine according to the present invention.

FIG. 2 is a drawing of the mold mechanism of FIG. 1, in which the upper half is an enlarged sectional view when the mold is clamped, and the lower half is an enlarged sectional view when the mold is opened.

FIG. 3 is an enlarged cross-sectional view showing a state where the mold is being filled with resin in the mold mechanism of FIG. 2;

FIG. 4 is an enlarged cross-sectional view of the mold mechanism of FIG. 2 when the mold is clamped by a core mold.

FIG. 5 is a detailed enlarged sectional view of a core-type opening / closing toggle mechanism in the mold mechanism section of FIG. 2;

FIG. 6 is a cross-sectional view showing an operation state of a mold in all injection steps of the present invention.

FIG. 7 is a graph comparing the change of the set pressure and the output of the pressure sensor according to the present invention with the output of the set pressure and the oil pressure sensor of the conventional example.

[Explanation of symbols]

 (A) Injection molding machine (a) Injection mechanism (b) Mold mechanism (1) Mold (2) Mold cavity (3) Resin (3a) Measurement resin (3b) Kneading resin (4) Screw (5) Core type (8) Controller (11) (12) (31) (40) Servo motor (30) Gate cut pin (54) Pressure sensor

Claims (5)

[Claims] 1. An injection molding machine for use in a core compression injection molding method for precision molding, comprising: a mold; an injection mechanism for injecting a resin into the mold; The core mold forming a part and the reaction force of the core mold due to the filling resin in the mold cavity is detected, and based on the output data, the injection step of filling the mold cavity with the resin or the subsequent pressure-holding step An injection molding machine, comprising: a pressure sensor for controlling at least one of the steps or the whole or a part of the process. 2. An injection molding machine used in a core compression injection molding method for precision molding, comprising: a mold; an injection mechanism for injecting a resin into the mold; and a mold cavity incorporated in the mold. The core mold forming a part and the reaction force of the core mold due to the filling resin in the mold cavity is detected, and based on the output data, the injection step of filling the mold cavity with the resin or the subsequent pressure-holding step A pressure sensor that controls at least one of the steps or the whole or a part of the step; a pressure sensor that controls the whole or a part of the injection molding step; Alternatively, an injection molding machine characterized by comprising an analog display section. 3. A mold, a core mold incorporated in the mold and forming a part of the mold cavity, and a pressure sensor for detecting a reaction force of the core mold due to a filling resin in the mold cavity are provided. In the core compression injection molding method of a precision molding injection molding machine, based on output data from the pressure sensor, pressure control of the filling resin by the core mold, or thickness control of the filling resin by position control of the core mold. An injection molding method characterized by performing at least one of the following. 4. A mold, a core mold incorporated in the mold and forming a part of the mold cavity, a pressure sensor for detecting a reaction force of the core mold due to a filling resin in the mold cavity, and a mold. In a core compression injection molding method of a precision molding injection molding machine having a gate cut pin for opening and closing a gate of a mold, an operation timing of the gate cut pin is controlled based on output data from the pressure sensor. Injection molding method. 5. A mold, a core mold incorporated in the mold and forming a part of the mold cavity, a pressure sensor for detecting a reaction force of the core mold due to a filling resin in the mold cavity, and a mold. In a core compression injection molding method of an injection molding machine for precision molding in which an injection mechanism for injecting a resin into a mold is installed, based on output data from the pressure sensor, the mold is injected into the mold from the injection mechanism. Injection molding method characterized by performing the following resin injection speed control.