JPH06297523A - Injection molding method and injection molding machine - Google Patents

Abstract

PURPOSE:To provide an injection molding method which can obtain a molding item which is stabilized by preventing a blur or the like from occurring and an injection molding machine which can carry out the injection molding method suitably by a method wherein in the case where, for example, a metal mold is filled excessively with resin or in the case where it is filled, with slight shortage, therewith, the case can be easily coped with. CONSTITUTION:After completing clamping of metal molds 6, 7, an injector pin is preliminarily protruded to an advanced position or an intermediate position between the advanced position and a retreated position, and melt resin is injected into the clamped metal mold while pressure in the advance direction is applied to the protruded ejector pin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel injection molding method capable of preventing burrs and the like from being generated in a molded product and an injection molding machine capable of suitably carrying out this injection molding method.

[0002]

2. Description of the Related Art In a general injection molding method using a conventional injection molding machine, a mold is clamped by a mold clamping device, and heat-melted resin is injected from the injection device into the mold which has been clamped. After cooling for a period of time to solidify the molded product, the mold is opened, and a series of operations of ejecting the molded product from the mold by ejecting it by an ejector device are repeated.

[0003]

In the above-mentioned conventional injection molding method, a control device attached to the injection device is used to control the injection molding according to various molding conditions such as the shape or size of the molded product. Set the resin pressure and speed in multiple stages,
It is customary to inject and supply the resin into the mold according to these set conditions. However, the following problems remain in such an injection molding method.

When the resin is excessively filled in the mold, the resin is controlled from the injection device side, or a so-called holding pressure is used to cool the mold by applying a predetermined pressure until the product solidifies. Control cannot correct well.

It is difficult to avoid the phenomenon that the resin pressure in the mold becomes abnormally high at the time of completion of injection, which causes burr formation.

A resin is supplied into the mold from an injection device through a sprue and a gate portion, and then a holding pressure control is performed in which a predetermined pressure is applied to the mold until the product is solidified. If the gate portion in the middle of the resin passage solidifies before the solidification of the product, the effect of holding pressure control cannot be obtained.

Contrary to the above, when the amount of resin filled in the mold is small, it cannot be corrected from the injection device side after the midway portion of the resin passage such as the gate portion has solidified.

It is impossible to judge when the resin is excessively supplied or, conversely, when the resin is insufficient.

The present invention can easily cope with the case where the mold is overfilled with resin, prevent the occurrence of burrs and the like to obtain a stable molded product, and conversely supply less resin. It is possible to easily deal with the case, and in addition, to provide an injection molding method and an injection molding machine that can suitably perform the injection molding method that can judge the filling amount of the resin even if it is excessive or insufficient. To do.

[0010]

In order to achieve the above object, the invention according to claim 1 is such that, after completion of mold clamping of the mold, the ejector pin is preliminarily protruded to an advance position, and is ejected to the advance position. The molten resin is injected into the mold which is clamped while applying a forward pressure to the ejector pin.

According to the second aspect of the invention, after the die is completely clamped, the ejector pin is preliminarily protruded to an intermediate position between the forward movement position and the backward movement position, and pressure is applied to the ejected ejector pin in the forward movement direction. The molten resin is injected into the mold that has been clamped.

According to a third aspect of the invention, in addition to the second aspect of the invention, a position detection sensor is attached to either the ejector pin or a related component that moves integrally with the ejector pin, and the mold is clamped. When the molten resin is injected into the mold, the quality of the molded product molded in the mold is determined based on the output signal generated from the position detection sensor.

According to a fourth aspect of the present invention, a mold device including a pair of molds, a mold clamping device that clamps the mold at a predetermined pressure, and a molten resin is injected into the mold that has been clamped. In an injection molding machine equipped with an injection device and an ejector device for ejecting a molded product from the mold opened after molding, the ejector device is configured to have a multi-stage ejection speed and ejection pressure for ejecting the molded product. A control device for setting the above is attached.

According to the invention of claim 5, in addition to the invention of claim 4, a position detection sensor is attached to either the ejector pin or a related component that moves integrally with the ejector pin, and the position detection sensor is attached. A determination device for determining the quality of the molded product molded in the mold based on the output signal from the device is provided.

[0015]

[Function] Looking at the change in the resin pressure when the resin is filled in the mold, as shown by the solid line in FIG. 4, the resin pressure gradually increases as the resin filling progresses, and the final stage filling is completed. Immediately before, the resin pressure in the mold tends to rise sharply.
However, according to the first aspect of the present invention, since the ejector pin is preliminarily projected to the forward movement position and is pressed in the forward movement direction with a constant pressure, when the resin pressure in the mold suddenly rises, a pressure difference may occur. This ejector pin retracts and absorbs the resin pressure. As a result, the resin pressure does not become so high as indicated by the broken line in the figure.
Moreover, even when the pressure-holding step is subsequently performed, the ejection force of the ejector pin can keep the inside of the mold at a substantially constant pressure, and eventually, defects such as burrs can be prevented from occurring in the molded product. .

According to the second aspect of the invention, the ejector pin is preliminarily projected to an intermediate position between the forward movement position and the backward movement position, and in this state, it is pressed in the forward movement direction with a constant pressure. Therefore, it is possible to prevent the ejector pin from retracting when the resin is filled in the mold and the resin pressure in the mold from suddenly rising, as described above. Further, in the present invention, when the filling amount of the resin is insufficient, the ejector advances to reduce the volume in the mold, which causes bubbles and the like that tend to occur when the resin filling is insufficient. Alternatively, it is possible to prevent the occurrence of defects such as insufficient strength.

Further, in the third aspect of the invention, for example, when the amount of resin in the mold is insufficient, the ejector pin tries to move forward to increase the resin pressure.
When it reaches the forward end, it cannot move any further. At this time, it can be seen that the molded product is insufficiently filled with the resin amount based on the signal emitted from the position detection sensor. On the contrary, when the amount of resin in the mold is considerably large, the ejector pin retreats to the retreat end and cannot retreat any further. At this time, it can be seen that the molded product is excessively filled with the resin amount based on the signal emitted from the position detection sensor.

[0018]

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

First Embodiment FIGS. 1 to 5 show a first embodiment of the present invention. In these figures, reference numeral 1 is a machine frame. An injection device 2, a mold device 3, and a mold clamping device 4 are provided on the machine frame 1. The injection device 2 includes a heating cylinder 5 having a screw that is pressed and moved by a hydraulic cylinder 5.
Mainly a, the mold device 3 is composed of the molds 6 and 7 individually attached to the fixed platen 8 and the movable platen 9. The mold clamping device 4 includes a hydraulic mold clamping cylinder 11 and a toggle mechanism 12. The movable platen 9 is moved with respect to the fixed platen 8 to perform mold clamping and mold opening.

The mold clamping cylinder 11 and the toggle mechanism 12 are provided on the end plate 13. The end plate 13 is connected to the fixed platen 8 by a plurality of tie rods 14, and a movable platen 9 is slidably attached to the tie rods 14. The movable platen 9 is provided with an ejector device 15 for ejecting a molded product to be released from the mold 7. The ejector device 15 includes a hydraulic ejector cylinder 17 attached to the die 7, and a pair of ejector plates 18a, 18b movably provided in the die 7 and pressed by a piston rod 17a of the ejector cylinder 17. And ejector plates 18a, 1
8b and ejector pin 19 that actually ejects the molded product. The basic structure of the above injection molding machine is well known.

In the hydraulic circuit of each of the cylinders 5, 11 and 17, solenoid valves 21, 22, 23, a flow rate proportional control valve 24,
25 and pressure proportional control valves 26, 27 are provided.
The solenoid valves 21, 22, 23 are used for the cylinders 5, 11, 17 respectively.
The flow proportional control valves 24 and 25 change the operating speed of the cylinders 5, 11 and 17, and the pressure proportional control valves 26 and 27 change the operating directions of the cylinders 5 and 1 respectively.
The operating pressures of 1 and 17 are controlled respectively. The heating cylinder 5a has a detection sensor 29 for detecting the moving position of the screw.
And a detection sensor 3 for detecting the protruding position of the ejector pin 19 on the ejector cylinder 17.
1 is attached to the piston rod 17a of the ejector cylinder. Each detection sensor 29, 31 is composed of an encoder.

FIG. 3 shows a part of the control device of this injection molding machine. In the figure, reference numeral 38 is a sequence circuit. A speed / pressure setter switching circuit 40 is connected to the sequence circuit 38. Speed / pressure setter switching circuit 40
Includes a mold closing speed setting device 41, a mold opening speed setting device 42, a mold closing ejector speed setting device 43, a mold closing ejector pressure setting device 44, and a molded product ejecting ejector speed setting device 4
5. An ejector pressure setting device 46 for ejecting a molded product and an injection speed / pressure setting device 47 are connected in parallel. Further, each solenoid valve 21, 22, 23 is connected to the sequence circuit 38 via a solenoid valve output circuit, and the flow rate proportional control valves 24, 25 and the pressure proportional control valves 26, 27 are controlled via a control valve output circuit 49. It is connected to the sequence circuit 38.

The sequence circuit 38 includes a mold closing speed set by the setter 41, a mold opening speed set by the setter 42, and a speed of the ejector pin 19 during mold closing set by the setter 43. When the ejector pin 19 is set to the setter 44 during mold closing, the ejector pin 19 is set to the setter 45 when ejected, and when the setter 46 is set to eject the molded product. According to the ejecting pressure of the ejector pin 19, the injection speed and the injection pressure of the resin by the heating cylinder 5 set in the setting device 47, the solenoid valves 21, 22, 23, the proportional flow control valves 24, 25 and the proportional pressure control valves. 26 and 27 are controlled respectively. The setting content for each setting device is displayed on a display screen (not shown) as needed.

The ejector pressure setting device 4 during mold closing
4 and the ejector speed setting device 43 during mold closing are provided for pressing the ejector pin in the forward direction at the time of resin injection, and may be those which can set only one step value, and the resin filling process and the pressure holding process. The value may be set in multiple stages so that different values can be set depending on the process.

Next, an injection molding method in the injection molding machine configured as described above will be described.

First, the solenoid a of the solenoid valve 22 is turned on by a command signal from the sequence circuit 38, the mold clamping cylinder 11 extends and the movable platen 9 advances, and mold clamping is performed. After the mold clamping is completed, a hydraulic cylinder (not shown) extends to move the heating cylinder 5 forward so that its tip comes into contact with the resin injection port of the fixed platen 8. The extension speed of the hydraulic cylinder 11 at the time of mold clamping is preset by the mold closing speed setting device 41, and the sequence circuit 38 commands the flow rate proportional control valve 24 and the pressure proportional control valve 26 to reach the set value. A signal is emitted.

Next, the solenoid a of the solenoid valve 23 is turned on by the command signal of the sequence circuit 38, and the ejector cylinder 17 extends to eject the ejector plates 18a, 1
The ejector pin 19 is moved to the forward position via 8b (FIG. 5 (a) → FIG. 5 (b)). Then, in that state, a forward pressing force is applied to the ejector pin 19 via the ejector cylinder 17 so that the pressing force set by the setting device 44 can be obtained. In addition, this ejector pin 1
The speed and pressure at the time of moving
It is preset at 3, 44.

In this state, the molten resin is injected from the heating cylinder 5 into the cavities of the molds 6, 7. That is, the solenoid b of the solenoid valve 21 is turned on by the command signal of the sequence circuit 38, and the screw moving cylinder 5 extends to advance the screw in the heating cylinder to inject the molten resin. At this time, the injection speed and the pressure of the molten resin are preset by the setter 47.

At the time of resin injection, the resin pressure in the molds 6 and 7 first rises sharply as shown in FIG. 4, then temporarily decreases, and thereafter gradually increases as the filling progresses, and the filling process is completed. It peaks in the vicinity. In addition,
In this figure, the vertical axis indicates the screw moving cylinder 5.
The pressure value of the pressure oil applied to the cylinder is proportional to the resin pressure in the mold, and its behavior is equivalent to that of the resin pressure. Therefore, the change in the cylinder pressure value is equivalent to the change in the resin pressure in the mold.

Here, as described above, the ejector pin 1
9 is pressed in the forward direction with the pressure value set by the setter 44, and when the resin pressure in the mold becomes higher than the pressing force of the ejector pin, the ejector pin 19 moves backward to move the inside of the mold. Suppresses the rise of resin pressure (Fig. 5
(See (c)). Therefore, the peak of the resin pressure in the injection molding machine of this embodiment is lower than that of the conventional injection molding machine as shown by the broken line in FIG. In this way, the resin pressure of the mold is absorbed by the retreat of the ejector pin 19 to lower the peak of the resin pressure and prevent the occurrence of defects such as burrs that are likely to occur when the resin pressure becomes too high. can do.

Thereafter, the pressure-holding process is started, but at this time also, the ejector pin 19 is still applied with the pressing force in the forward direction, and the ejector pin 19 slightly moves forward at the moment of entering the pressure-holding process (see FIG. 5 ( D))). This is because, as shown in FIG. 4, the pressing force of the cylinder 5 for moving the screw is lower than that at the time of filling. The pressing force of the ejector pin 19 in the advancing direction and the pressing force of the screw in the advancing direction in the pressure holding step are also preset by the setters 44 and 47.

As described above, not only in the filling step but also in the pressure holding step, the ejector pin 19 is pressed in the forward direction with a predetermined value, so that, for example, the gate portion in the resin passage is solidified before the molded product. Even in such a case, the resin pressure in the mold can be maintained substantially constant by the pressing force of the ejector pin 19, and as a result, the uniformity and stabilization of the molded product can be improved.

In the pressure-holding step, it is possible to set a wider range of molding conditions by varying the pressing force of the ejector pin 19 with time.

When the injection of the resin is completed, the solenoids b and a of the solenoid valves 21 and 23 are deenergized based on the command signal from the sequence circuit, and the solenoid valves 21 and 23 are once brought to the neutral position. At the same time, the solenoid b of the solenoid valve 22 is turned on by the command signal of the sequence circuit 38, the hydraulic cylinder 11 is contracted, and the mold opening is started. The sequence circuit 38 controls the flow rate proportional control valve 24 and the pressure proportional control valve 26 so that the mold opening speed and the mold opening pressure at this time become the values set in the setter 42.

When the die 7 reaches the retracted position, a command signal is issued from the sequence circuit 38 based on the signal from the detection sensor attached to the hydraulic cylinder 11, and the excitation of the solenoid b of the solenoid valve 22 is released. At the same time, the solenoid a of the solenoid valve 23 is turned on again. Then, the ejector cylinder 17 extends to eject the ejector pin 19. The sequence circuit 38 controls the control valves 24 and 26 so that the ejecting speed and the ejecting pressure of the ejector pin 19 at this time become the values set in the setters 45 and 46.

Through the above steps, a molded product having a predetermined shape is ejected.

Second Embodiment FIGS. 6 to 9 show a second embodiment of the present invention. This embodiment differs from the first embodiment in that the ejector pin 19
Is ejected to an intermediate position between the forward movement position and the backward movement position, and the molten resin is injected into the mold while pressure is applied to the ejected ejector pin 19 in the forward direction. The position of the piston rod 17a of the ejector cylinder 17 to the position detection sensor 5
The quality of the molded product molded in the mold is judged by the judgment device 58 based on the output signal generated by the position detection sensor 50.

Explaining the concrete structure, as shown in FIG. 6, the detection sensors 29 and 31 are connected to the comparators 53 and 54 through the detection sensor input circuits 51 and 52, respectively. Are connected to the sequence circuit 38. The comparator 53 includes a screw movement position setter 56.
Is connected to the comparator 54, and the ejector pin 19 protrusion amount setting device 57 is connected to the comparator 54.

The comparator 53 compares the screw position of the heating cylinder 5 detected by the detection sensor 29 with the screw position set by each setter 56, and the screw is set by the setter 56.
When it reaches the set position of, the arrival signal is output to the sequence circuit 38. Further, the comparator 54 compares the protruding position of the ejector pin 19 detected by the detection sensor 30 with the protruding position set in the setting device 57, and when the ejector pin 19 reaches the protruding amount of each setting device 57, The signal is output to the sequence circuit 38.

The determination device 58 provided in the control device of the injection molding machine for determining the quality of the molded product will be described. As shown in FIG. 7, a detection sensor 29 for detecting the moving position of the ejector pin 19. Is connected to the sensor receiver 59. The sensor receiving section 59 is connected to the current value display section 60 and the comparing section 61. A maximum value setting unit 62, a minimum value setting unit 63, and a pass / fail judgment unit 64 are connected to the comparison unit 61, and the pass / fail judgment unit 64 includes an output timing setting unit 65.
Are connected.

The comparison unit 61 is set in the current position of the ejector pin 19 output from the detection sensor 29 via the sensor receiving unit 59 and the value set in advance in the maximum value setting unit 62 or the minimum value setting unit 63. Compared with each value,
For example, when the current position of the ejector pin 19 exceeds the value set in the maximum value setting unit 62 within the time set by the output timing setting unit 65 such as a predetermined time from the time when the pressure holding process is started. , Or the upper minimum value setting unit 63
When the value is smaller than the value set in, the signal indicating that the quality determination unit 64 is abnormal is output to the control device body of the injection molding machine.

Incidentally, the other constitution of the control device is the same as the first constitution described above.
This is the same as that of the embodiment, and here, the same components are given the same reference numerals and the description thereof is omitted.

Next, an injection molding method using the injection molding machine shown in the second embodiment will be described. First, the mold clamping device 4
The mold is clamped by, and then the ejector cylinder 17 is extended to advance the ejector pin 19 to stop at a predetermined position in the intermediate portion between the retracted position and the advanced position.

At this time, the detection sensor 31 detects the position of the ejector pin 19 and outputs it to the comparator 54 via the ejector position detection sensor input circuit 52. Comparator 54
Compares the current position of the ejecting amount of the ejector pin detected by the detection sensor 29 with the set value of the ejecting amount set in the setting device 57, and outputs a signal at the same time when the present value of the ejecting amount of the ejector pin 19 reaches the set value. Is output to the sequence circuit 38. When the signal is output from the comparator 54, the sequence circuit 38 turns off the solenoid a of the solenoid valve 23. As a result, the ejector pin 19 temporarily stops.

In this state, the injection apparatus fills the mold with the molten resin. In this resin filling process,
When the screw reaches a predetermined position, a forward pressure is applied to the ejector pin 19 so as to face the resin pressure inside the mold.

That is, the detection sensor 29 detects the moving position of the screw in the heating cylinder 5, and outputs it to the comparator 53 via the screw position detection sensor input circuit 51.
The comparator 53 compares the current position of the screw detected by the detection sensor 29 with the set value set by the setter 56, and at the same time when the current value of the moving position of the screw reaches the set value, a signal is sent to the sequence circuit 38. Output to. When a signal is output from the comparator 53, the sequence circuit 38 causes the solenoid valve 2
The solenoid a of 3 is turned on. As a result, the ejector cylinder 17 extends and presses the ejector pin 19 in the forward direction. The sequence circuit 38 adjusts the pressure of the ejector pin 19 at this time to the value set in the setter 44.
Controls each control valve 26.

In this embodiment, the ejector pin 1
Although the timing of applying the forward pressure to 9 is set based on the screw position as described above, the present invention is not limited to this, and the ejector pin 19 is set based on the elapsed time from the start of injection or the resin pressure in the mold. You may determine the timing which presses.

In this way, in the middle of the filling process (actually just before the completion of filling), forward pressure is applied to the ejector pin 19 when the screw reaches a predetermined position. Therefore, when the filled resin becomes excessive, the ejector pin 19 retreats to suppress the rise of the resin pressure in the mold, which is likely to occur when the resin pressure is abnormally high, as in the first embodiment. The occurrence of defects such as burrs can be prevented in advance (see FIGS. 8A to 8C).

On the other hand, when the filled resin is insufficient,
On the contrary, the ejector pin 19 moves forward to reduce the volume inside the mold, and it is possible to prevent the occurrence of air bubbles and a decrease in strength that are likely to occur when the resin is insufficient (FIG. 9A).
(See (c)).

Further, in this embodiment, when the resin filling amount is too large or too small, the quality determining section 64 outputs an abnormal signal.

That is, when the amount of resin filled is too large, the ejector pin 19 is retracted by the resin pressure, but when it reaches the retracted end, it cannot be retracted further, and the resin pressure can be absorbed. It becomes impossible (Fig. 8)
(See (d)). At this time, an abnormality signal is issued from the quality determination unit 64.

Specifically, the detection sensor 31 detects the current position of the ejector pin 19 and outputs it to the comparator 61 via the sensor receiver 59. The comparator 61 includes the detection sensor 3
The current position of the ejector pin 19 detected in 1 is compared with the set value set in the setter 62, and the current value of the moving position of the ejector pin 19 reaches the set value, and at this time, the output timing setting unit 65 If it is within the range set in step 3, the quality determination unit 64 issues an abnormal signal to the control device body of the injection molding machine. The maximum value setting unit 6
The set value of 2 is normally set to a value that coincides with the position of the retreat end of the ejector pin 19, but may be set to a position before the retreat end.

On the contrary, when the resin filling amount is too small, the ejector pin 19 moves forward in order to increase the resin pressure, but when it reaches the advance end, it cannot move any further, and the resin pressure increases. It becomes impossible (Fig. 9
(See (d)). At this time, an abnormality signal is issued from the quality determination unit 64. That is, the comparator 61 detects the current position of the ejector pin 19 detected by the detection sensor 31 and the setter 6
2 is compared with the set value set in 2, and the ejector pin 19
When the current value of the moving position reaches the set value, and this time is within the range set by the output timing setting section 65, the abnormality determination section 64 issues an abnormal signal to the control section of the injection molding machine. The set value of the minimum value setting unit 62 is normally set to a value that matches the position of the ejector pin 19 at the forward end, but may be set to a position before the forward end.

Also in this embodiment, after that, the pressure holding step, the mold opening step, and the molding product ejecting step are performed as in the first embodiment.

In this embodiment, the ejector pin 1 is used to determine whether the filling amount of the resin is excessive or insufficient.
The movement amount of the ejector pin 19 is not directly detected but is determined based on the movement amount of the piston rod 17a of the ejector cylinder 17 instead of that. However, the present invention is not limited to this, and the movement amount of the ejector pin 19 is directly detected. , Or ejector plates 18a, 18b as indicated by the broken lines in FIG.
The amount of movement of the ejector pin 19 may be detected, and the point is to select the ejector pin 19 or the one that moves integrally with the ejector pin 19 as a reference.

[0056]

As described above, the present invention has the following excellent effects.

According to the first aspect of the invention, since the ejector pin is preliminarily projected to the forward position and pressed in the forward direction with a constant pressure, the ejector pin is suddenly increased when the resin pressure in the mold rapidly rises. Can retreat and absorb the resin pressure. As a result, the peak of the resin pressure in the mold is lowered, and it is possible to prevent the occurrence of defects such as burrs or non-uniform strength portions in the molded product caused by the resin pressure becoming too high.

Further, according to the second aspect of the invention, the ejector pin is preliminarily projected to an intermediate position between the forward movement position and the backward movement position, and in this state, the resin is injected while pressing in the forward movement direction with a constant pressure. It is possible to prevent the ejector pin from retreating when the resin is filled into the mold, and to prevent the resin pressure in the mold from suddenly increasing.In addition, if the resin supply amount is insufficient, the ejector moves forward and By reducing the volume in the mold, it is possible to increase the resin pressure to a predetermined value, and thus it is possible to prevent the occurrence of bubbles or insufficient strength, which tends to occur when the resin pressure is low.

Further, in the third aspect of the present invention, for example, when the amount of resin in the mold is insufficient, or conversely, when the amount of resin in the mold is large, a good molded product is obtained. If it is difficult to obtain, it is possible to display that fact, and it is possible to prevent the occurrence of many defective products.

According to the invention described in claim 4,
The method invention according to claim 2 or the method invention according to claim 2 can be suitably implemented, and the invention according to claim 5 can suitably implement the method invention according to claim 3.

[Brief description of drawings]

FIG. 1 is a front view of a main part of an injection molding machine for explaining a first embodiment of the present invention.

FIG. 2 is an overall view of the injection molding machine of FIG.

FIG. 3 is a block diagram of a control device of the injection molding machine of FIG.

FIG. 4 is an operation explanatory view of the injection molding machine of FIG.

5 is a diagram showing an injection procedure using the injection molding machine of FIG.

FIG. 6 is a block diagram of a control device of an injection molding machine for explaining a second embodiment of the present invention.

FIG. 7 is a block diagram of a quality determination unit in the injection molding machine of FIG.

8 is a diagram showing an injection procedure using the injection molding machine of FIG.

9 is a diagram showing an injection procedure using the injection molding machine of FIG.

[Explanation of symbols]

 4 Clamping device 5a Heating cylinder 5 Hydraulic cylinder 6,7 Mold 15 Ejector device 17 Ejector cylinder 18a, 18b Ejector plate 19 Ejector pin 29 Screw position detection sensor 31 Ejector pin position detection sensor 58 Judgment device 61 Comparison part 64 Good / bad judgment part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yukio Yoshizawa 2-5-1, Shirooka, Nagaoka City, Niigata Prefecture Niigata Iron Works Nagaoka Factory (72) Inventor Masaru Higuchi 2-5, Shirooka, Nagaoka City, Niigata Prefecture No. 1 Stock Company, Nagaoka Plant, Niigata Iron Works (72) Inventor Masakazu Ohno 2-11-14, Kugahara, Ota-ku, Tokyo Sankyo Kasei Co., Ltd.

Claims (5)

[Claims] 1. After completion of mold clamping of a mold, ejector pins are preliminarily protruded to an advance position, and the ejector pins protruded to the advance position are pressed into the mold while advancing pressure is applied thereto. An injection molding method comprising injecting a molten resin. 2. After completing the mold clamping of the mold, the ejector pin is preliminarily projected to an intermediate position between the forward movement position and the backward movement position, and the ejected ejector pin is clamped while applying pressure in the forward movement direction. An injection molding method comprising injecting a molten resin into a mold. 3. The injection molding method according to claim 2, wherein
A position detection sensor is attached to either the ejector pin or a related component that moves integrally with the ejector pin, and an output signal generated from the position detection sensor is used when a molten resin is injected into the mold that has been clamped. In addition, an injection molding method is characterized in that the quality of a molded product molded in a mold is judged. 4. A mold device comprising a pair of molds, a mold clamping device for clamping the molds with a predetermined pressure, an injection device for injecting a molten resin into the molds which have been clamped, and a post-molding device. In an injection molding machine including an ejector device for ejecting a molded product from the mold opened in, a ejector device ejecting speed and ejecting pressure for ejecting the molded product, a control device for setting a multistage An injection molding machine characterized by being attached. 5. The injection molding machine according to claim 4, wherein a position detection sensor is attached to either the ejector pin or a related component that moves integrally with the ejector pin, and an output signal from the position detection sensor is used as a basis. An injection molding machine characterized in that a judgment device for judging the quality of a molded product molded in the mold is provided in the.