JP2002086500A - Method and apparatus for detecting defective product, and molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the short of a fine part. SOLUTION: A pressure-time chart in injection molding work is a curve wherein a first region R1 small in the difference between the case of good products P, P1, P2 and P3 and the case of defective products and rising slowly, a second region R2 where the case of the good products previously rises as compared with the case of the defective products to steeply rise and a third region R3 small in the difference between the case of the good products and the case of the defective products and slowly rising toward a peak are continuously constituted. Two monitor sections W1 and W2 are set and products passing through these sections are judged to be good products and, in other case, the products are judged to be the defective products. When the generation of short defectiveness is judged in molding work, molded articles judged to be defective are sorted and the molding conditions of the molding work by the injection molding machine are changed to prevent the generation of short defectiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the production of a resin molded product using a mold, a portion of the mold that is not filled with resin or a portion that is insufficiently filled (referred to as underfill or short shot) may occur. However, the portion does not have the designed shape but becomes a defective product. The present invention relates to a molding apparatus capable of detecting occurrence of such a short shot or automatically controlling molding conditions so as to avoid occurrence of such a short shot.

[0002]

2. Description of the Related Art A short shot refers to a case where a molded product has a resin-unfilled portion. Generally, a "short-end portion" generated at a final filling portion on the opposite side of a gate and a short-circuit between a gate and a final filling portion. There is a "fine part short-circuit" that occurs in an intermediate fine part.

It is known that, of the two shorts, the "end short" can be relatively easily detected from the peak pressure of the cavity forming the molded article.

[0004]

However, in the case of "fine short-circuit", it cannot be managed simply by the peak pressure alone. In some cases, short-circuiting did not occur even at low pressure, and in other cases, short-circuiting occurred at high pressure, making detection difficult. For example, FIG. 5 is a perspective view of a resin molded product related to the occurrence of the “fine part short-circuit”.
Fine stepped ribs 100 each having a side of less than about 0.3 mm are formed on the inner surface of the m-shaped hole. Here, in FIG. 5, the arrow (A) indicates the filling direction and the filling position of the resin, that is, the sign (B) is near the gate and the sign (C) is the filling end in the mold of this part. . In this case, a minute short-circuit is likely to occur between the vicinity (B) of the gate and the intermediate portion (E) between the filling end portion (C). FIG. 6A shows a normal shape (normal rib 100) of the portion (E).
(B) is a state diagram at the time of short-circuit (short rib 1).
01).

SUMMARY OF THE INVENTION An object of the present invention is to detect a short circuit in a fine portion, which has been conventionally difficult to detect, and to control a molding apparatus so that such a defect does not occur.

[0006]

According to a first aspect of the present invention, there is provided a method for detecting a defective product, the method comprising: filling a resin in a mold to form a molded product; The first region (R1) where the molding pressure in the mold with respect to the elapsed time after the start of the detection gradually rises in a state where the difference between the non-defective product and the defective product is relatively small, and relatively rapidly increases. Forming in which the second region (R2) and the third region (R3) which gradually rises toward the peak in a state where the difference between the non-defective product and the non-defective product is relatively small continuously progress. This is a detection method for detecting a defective product regarding resin filling in a product molding process. The feature is that a monitoring section (W1) having a relatively short pressure width equal to or higher than a predetermined pressure and a relatively long time width is set close to the first region, and a mold of a product to be molded is set. When the molding pressure in the inside enters from the lower surface of the monitoring section and escapes from the upper surface, it is determined to be a good product, otherwise, it is determined to be a defective product.

According to a second aspect of the present invention, there is provided a method for detecting a defective product, wherein when a resin is filled in a mold to form a molded product, the filling of the resin is detected by a pressure sensor, and an elapsed time after the detection is started. The first region (R1) where the molding pressure in the mold for the non-defective product and the molding pressure for the non-defective product gradually rises with a relatively small difference, and the second region (R2) where the molding pressure rises relatively rapidly ) And a molding process of a molded product that continuously passes through a third region (R3) in which the difference between the non-defective product and the defective product is relatively small and gradually rises toward the peak. This is a detection method for detecting a defective product regarding resin filling. And the feature is that it is close to the second area,
A monitoring section (W2) having a relatively long pressure width of a predetermined pressure or more and a relatively short time width is set, and the molding pressure in the mold of the product being molded enters from the side of the frame of the monitoring section. A good product is determined when it comes off the side of the frame, and a defective product otherwise.

According to a third aspect of the present invention, there is provided a defective product detection device, wherein when a resin is filled in a mold and a molded product is formed, the pressure sensor detects the filling of the resin, and the elapsed time after the start of the detection. The first region (R1) where the molding pressure in the mold for the non-defective product and the molding pressure for the non-defective product gradually rises with a relatively small difference, and the second region (R2) where the molding pressure rises relatively rapidly ) And a molding process of a molded product that continuously passes through a third region (R3) in which the difference between the non-defective product and the defective product is relatively small and gradually rises toward the peak. This is a detection device for detecting a defective product regarding resin filling. And the feature is that it is close to the first area,
A monitoring section (W1) having a relatively long time width with a relatively short pressure width equal to or higher than a predetermined pressure is set, and the molding pressure in the mold of the product being molded enters from the lower surface of the monitoring section. There is provided a control unit that determines a non-defective product when it comes off from the top surface, and otherwise determines a defective product.

According to a fourth aspect of the present invention, there is provided an apparatus for detecting a defective product, wherein when a resin is filled in a mold to form a molded product, the pressure sensor detects the filling of the resin, and the elapsed time after the start of the detection. The first region (R1) where the molding pressure in the mold for the non-defective product and the molding pressure for the non-defective product gradually rises with a relatively small difference, and the second region (R2) where the molding pressure rises relatively rapidly ) And a third region (R3), which gradually rises toward the peak in a state where the difference between the non-defective product and the non-defective product is relatively small, forms a continuous curve. This is a detection device for detecting a defective product with respect to the filling. The feature is that, in the vicinity of the second region, a monitoring section (W2) having a relatively long pressure width equal to or higher than a predetermined pressure and a relatively short time width is set, and a mold of a product being molded is formed. A control unit that determines a non-defective product when the molding pressure inside the frame enters from the side of the frame of the monitoring section and exits from the side of the frame, and otherwise determines a defective product.

According to a fifth aspect of the present invention, there is provided a molding apparatus comprising: an injection device for injecting a resin; a pressure sensor for supplying a resin from the injection device to form a molded product and detecting a pressure of the resin inside. And a control unit.
And the control part controls the control condition of the said injection apparatus as follows. In other words, the resin filling is started by the pressure sensor, and the molding pressure in the mold with respect to the elapsed time after the start of the detection gradually increases in a state where the difference between the non-defective product and the defective product is relatively small. Region (R1) and the second region (R
2) and a third region (R3) in which the difference between the non-defective product and the non-defective product is relatively small and rises toward the peak.
In the molding process of a molded product with a continuous curve
A monitoring section (W1) having a relatively short pressure width equal to or higher than a predetermined pressure and a relatively long time width is set close to the first region,
The control condition of the injection device is controlled such that the molding pressure in the mold of the product to be molded enters from the lower surface of the monitoring section and escapes from the upper surface.

According to a sixth aspect of the present invention, there is provided a molding apparatus comprising: an injection device for injecting a resin; a pressure sensor for receiving the resin from the injection device to form a molded product and detecting a pressure of the resin inside. And a control unit.
And the control part controls the control condition of the said injection apparatus as follows. In other words, the resin filling is started by the pressure sensor, and the molding pressure in the mold with respect to the elapsed time after the start of the detection gradually increases in a state where the difference between the non-defective product and the defective product is relatively small. Region (R1) and the second region (R2) that rises relatively sharply
In the molding process of the molded product, the third region (R3), which gradually rises toward the peak in a state where the difference between the non-defective product and the defective product is relatively small, has a continuous curve. The above-described monitoring section (W2) having a relatively long pressure width and a relatively short time width is set close to the second area, and the molding pressure in the mold of the product being molded is adjusted to the monitoring section. Is controlled to enter from the side of the frame and exit from the side of the frame.

[0012]

1 and 2 are sectional views showing the basic structure of a molding die having an ejector pin with a sensor as a pressure detecting means. The present inventors have conducted intensive studies on the occurrence of the aforementioned “fine short-circuit” using this molding die. It should be noted that if the control means described later is combined with the molding die, the molding apparatus of the present invention can be detected, and the occurrence of short defective products can be detected at the time of molding, and the molding operation can be controlled so that short defective products do not occur. Can be.

The molding die 1 has a fixed mounting plate 10 mounted on a fixed holder of a molding machine and a movable mounting plate 11 mounted on a movable holder of the molding machine. A fixed mold plate 12 having a female cavity 12a is attached to the fixed attachment plate 10.
A movable mold plate 13 having a male core 13 a is attached to the movable attachment plate 11 via a receiving plate 14 and a spacer block 15.

The molding die B can be divided between the fixed mold plate 12 and the movable mold plate 13. In accordance with the movement of the holder of the molding machine, the movable mold plate 13 moves with respect to the fixed mold plate 12 in a direction perpendicular to the plate surface, thereby opening and closing the fixed mold plate 12 and the movable mold plate 13. Is performed. The fixed mold plate 12 is provided with a guide bush 19, the movable mold plate 13 is provided with a guide post 18, and the guide post 1 is provided.
8 is slidably inserted into the guide bush 19. Opening and closing of the fixed mold plate 12 and the movable mold plate 13 is guided by the guide bush 19 and the guide post 18.
When the fixed mold plate 12 and the movable mold plate 13 are closed, the cavity 12a and the core 13a are combined at an accurate position to constitute a cavity portion that becomes a molded product.

A sprue 16 serving as a path for injecting molten resin into the molding die B from a nozzle of a cylinder of the molding machine and a molding die B of the molding machine are mounted on the fixed side mounting plate 10. A locating ring 17 serving as a positioning means when attaching to the nozzle of the cylinder is attached.

An eject plate 21 is provided on the side of the movable mounting plate 11. Eject plate 21
Is provided with an ejector pin with a pressure sensor (hereinafter, referred to as an ejector pin) 24 which projects from the core 13a and projects the molded product out of the mold when the molding die B is opened. Further, the eject plate 21 is provided with a return pin 22 for retracting the ejector pin 24 by returning the eject plate 21 to a predetermined position when the molding die B is closed.

As shown in FIG. 2, the ejector pins 2
4 is a rod-like portion 25 having a circular cross section which protrudes the molded product at the tip end.
have. A substantially disk-shaped flange portion 26 is formed at the rear end of the ejector pin 24. Flange part 2
Reference numeral 6 has a lower center protruding downward, and a tip end thereof is a rounded pressing portion. The shapes of the flange portion and the pressing portion are merely examples, and other shapes may be used. For example, the entire lower surface of the flange may be a convex curved surface such as a part of a spherical surface.

The ejector pin 24 has a flange portion 26 housed in a metal housing 27, and a bar portion 25 protruding from an opening of the housing 27. Inside the housing, there is a rod-shaped portion 2
5 is provided with a strain-generating portion 28 that elastically deforms by receiving a load applied from the pressing portion of the flange portion 26 and a strain sensor 29 that detects elastic deformation of the strain-generating portion 28. As the strain sensor, a resistance wire strain gauge or the like can be used. In this example, a device using an ejector pin and a strain sensor is used as a pressure sensor. However, it is needless to say that any device that can detect the pressure in the mold can be used. In addition, the position where it is provided is also the fixed side of the mold device,
Any of the movable sides may be provided, and furthermore, it may be provided on the slide core.

As shown by the display of “sensor signal” in FIG. 4, the conductor from the strain sensor is led out and connected to the control means 50. The signal from the strain sensor is input to the control unit 50, and the control unit 50 detects the pressure in the cavity. The quality of the molded product is determined based on the pressure detected by the control means 50, and the injection device 6 is determined accordingly.
The operating condition of 0 can be controlled manually or automatically.
Further, the control means 50 sends a mold clamping signal to the molding die 1 to start the mold clamping operation. When the molding die 1 is clamped in a normal state, a feedback signal for confirming the clamping is sent from the molding die 1 to the control means 50, and the control means 50 receives the feedback signal. After that, a molding operation such as injection of resin may be started.

Although the basic configuration of the mold apparatus is as described above, the arrangement positions of the mold itself and the sensor (ejector pin) are actually as follows. That is, this mold includes a fine portion where a short circuit is likely to occur in the conventional control method. Further, the actual positions of the sensors are near the gate and near the short-circuit occurrence point in the conventional control method. The reason why the sensor is arranged in the vicinity of the short-circuit occurrence point is as follows (1) to (3).

(1) If the sensor position is near the gate, near the short-circuit point, or on the filling flow path from the vicinity of the gate to the vicinity of the short-circuit point, the pressure similarly rises sharply and can be used for detection. Conversely, in other parts, for example, the final filling part, it is difficult to detect when the pressure rises immediately after the resin has reached.

(2) Even if it is desired to assemble the sensor at the short-circuited portion itself, it is usually a fine portion and cannot be assembled.

(3) A sudden increase in pressure due to pressurization occurs almost simultaneously in the entire mold.

The reason why the sensor is provided near the gate is the following (4) to (6) in addition to the above (1) to (3).

(4) The pressure at the time when the resin arrives is higher than other positions, and the detection start timing can be accurately detected. It is also easy to use the timing when the pressure reaches the predetermined pressure as a base point.

(5) Pressure can be detected for the longest time in the mold, and it is convenient for collecting other in-mold information.

(6) The exact short position is known after the start of molding, and it is difficult to predict it at the stage of mold production.

The molding operation is actually performed a plurality of times using such a mold apparatus. As a result, as shown in FIG. 3, a plurality of non-defective products (indicated by pressure waveform diagrams P, P1, P2 and P3) and defective products are obtained. The pressure waveform diagram for (short product) was obtained.

As can be seen from FIG. 3, each pressure waveform has a first region R1 in which the difference between the non-defective product and the non-defective product is small and rises slowly, and the non-defective product is better than the non-defective product. A second region R2 that rises first and rises rapidly, and a third region R3 that gradually rises toward a peak with a small difference between a good product and a defective product are continuously formed. It is a curve. Here, "small difference" is a relative evaluation when a non-defective product and a defective product are compared in each of the three regions. Further, the terms “slow rise” and “rapid rise” are evaluations in a case where the time change of the pressure waveform is relatively compared in the three regions.

As shown in FIG. 3, where the pressure line of the non-defective product and the pressure line of the defective product are dense, they are quite close to each other. However, in the case of non-defective products and defective products,
It has been found that non-defective products have a feature that the pressure is larger and the rise in the second region is generally faster. For example, as shown in a region R2, the pressure lines P1, P2, and P3 are non-defective products, and the others are defective products. Therefore, using this feature, a monitoring section that can reliably discriminate a pressure line of a good product from a pressure line of another product (that is, a defective product),
It was set on the pressure diagram.

First, in the vicinity of the first region R1 and the second region R2, a first rectangular long and narrow rectangle having a relatively short pressure width of a predetermined pressure or more and a relatively long time width is provided. The monitoring section W1 is set. When the molding pressure in the mold of the product to be molded enters the region beyond the lower boundary line of the first monitoring section W1 and goes out of the region beyond the upper boundary surface, a non-defective product is determined. Judgment, otherwise judged as defective.

In addition, a vertically elongated rectangular second rectangle having a relatively long pressure width equal to or higher than a predetermined pressure and a relatively short time width is provided near the second region R2 and the third region R3. The monitoring section W2 is set. When the molding pressure in the mold of the product being molded enters the region beyond the left boundary of the second monitoring section W2 and goes out of the region beyond the right boundary, the product is determined to be non-defective. Otherwise, it is determined to be defective.

The setting of the two monitoring sections W1 and W2 imposes certain conditions on the rise of the pressure in the mold during the molding operation. That is, in the monitoring sections W1 and W2 of the present example shown in FIG. 3, it means that the following conditions are set for the pressure and the time. As for the pressure, after the resin is filled into the mold, the pressure starts to rise sharply,
The pressure at this time is higher than 75 kgf / cm ² , and the pressure before the pressure rise during pressurization becomes gentle is 175 kgf / cm ^2.
/ Cm ² . As for the time, after the molding was started, the pressure was increased to 175 kgf / cm ² within 1.3 seconds, and after the molding was started, the pressure was increased to 75 fk within 1.1 seconds.
g / cm ² .

A molded product of the pressure line P which has passed through any one of the two monitoring sections W1 and W2 in a predetermined form is guaranteed to be a good product. In FIG. 3, where the pressure lines of the non-defective product and the defective product are dense, a part of the non-defective product (for example, P1, P2, P3) does not cover the two monitoring sections W1, W2. If the molding operation is controlled so that the pressure line intersects the monitoring sections W1 and W2 in a regular manner, the risk of short defective products can be eliminated.

The control means 50 shown in FIG. 4 stores data of the monitoring sections W1 and W2 set in advance based on the basic data of the pressure waveform as described above. And
During molding, the pressure sensor (ejector pin 2) of the molding die 1
4) and the monitoring signals W1 and W
The data of No. 2 are compared to determine whether the currently molded product is good or defective. Specifically, it is determined whether or not the molding pressure in the mold with respect to the elapsed time after the start of the resin filling crosses the first and second monitoring sections W1 and W2 in the above-described manner. .

When the control means 50 determines that a short-circuit defect has occurred in the molding operation, the control means 50 displays the fact to the outside. The operator selects molded products determined to be defective in accordance with the display, and further changes the molding conditions of the molding operation by the injection device 60 so that short-circuit defects do not occur thereafter. That is, the occurrence of a defective product means that the pressure line of the product is monitored in the monitoring sections W1 and W1 in FIG.
2 means that they do not intersect in a regular manner,
By changing the molding conditions, the pressure line is quickly raised in FIG. 3 to cross the monitoring sections W1 and W2 in a normal state.

The control of the injection device 60 is generally performed using either the screw speed or the resin pressure itself obtained by driving the screw as an index. In this example, the control of the injection device 60 is controlled with speed superiority. However, in the case where the control is performed by the screw speed until the time of the first or second monitoring section W1 or W2 is exceeded, if the pressure line does not cross the monitoring sections W1 and W2 properly,
Thereafter, control is performed using the pressure as an index, and the pressure value is increased to the target value in the monitoring sections W1 and W2.

In the example described above, the pressure in the mold is detected based on the signal from the sensor of the molding mold 1 and the relationship with the preset monitoring sections W1 and W2 is not as expected. It was determined that the product was defective, and based on the determination, the removal of the defective product and the resetting of the molding conditions were manually performed.

However, resetting of the molding conditions may be automatically performed by a control signal from the control means 50. Specifically, from the time when the sensor detects the resin pressure in the mold to the time when the pressure suddenly increases due to pressurization and reaches the predetermined pressure, the filling speed, the filling pressure, and the filling pressure are obtained so as to be obtained within a predetermined time. , The holding pressure, and the speed control-pressure control switching position are automatically controlled for each shot.

In the above example in which the two monitoring sections W1 and W2 are set, if either one passes, it may be determined that there is a good product. Is also good. Also, only one monitoring section may be set.

[0041]

According to the present invention, in a molding operation having a pressure-time curve of a predetermined pattern, a monitoring section of time and pressure is provided corresponding to the pattern, so that short defective products and non-defective products can be reliably identified. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a molding die.

FIG. 2 is a cross-sectional view of an ejector pin with a built-in sensor provided in a molding die.

FIG. 3 is a diagram showing an in-mold pressure-time curve in a molding operation of a molding die and a monitoring section set in this example.

FIG. 4 is a diagram showing a configuration of a mold apparatus of the present example.

FIG. 5 is an enlarged perspective view showing an example of a molded part in which a short shot has conventionally been a problem.

6A is a partially enlarged view of the molded part of FIG. 5 in which a short shot does not occur, and FIG. 6B is a partially enlarged view of the molded part of FIG. 5 in which a short shot has occurred.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 molding die 50 control means 60 injection device R1 first region R2 second region R3 third region W1 first monitoring section W2 second Monitoring section.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AM32 AP03 AR20 CA11 CB01 CK11 CM03 4F206 AM32 AP03 AR20 JA07 JM04 JN25 JP01 JP11 JQ81

Claims (6)

[Claims] When a resin is filled in a mold to form a molded product, the filling of the resin is detected by a pressure sensor, and when the molding pressure in the mold with respect to an elapsed time after the start of the detection is a good product. And the second region, which rises relatively slowly in a state where the difference is relatively small between the case of defective products and the case of defective products. In a molding process of a molded product that continuously passes through a third region that gradually rises toward a peak in a small state, a method for detecting a defective product regarding resin filling is provided. Proximity, set a monitoring section of a relatively long time width with a relatively short pressure width equal to or higher than a predetermined pressure, and the molding pressure in the mold of the product being molded enters from the lower surface of the monitoring section. Judge as good if it comes off from the top, otherwise judge it as defective Detection method for defective products characterized by and. 2. A method according to claim 1, wherein when the resin is filled in the mold to form a molded product, the pressure sensor detects the filling of the resin, and the molding pressure in the mold with respect to an elapsed time after the start of the detection is a good product. And the second region, which rises relatively slowly in a state where the difference is relatively small between the case of defective products and the case of defective products. In a molding process of a molded product that continuously passes through a third region that gradually rises toward a peak in a small state, a method for detecting a defective product with respect to resin filling is provided. Set a monitoring section in close proximity with a relatively long pressure width of a predetermined pressure or more and a relatively short time width, and the molding pressure in the mold of the product being molded enters from the side of the frame of the monitoring section. Is judged to be non-defective when it comes off the side of the frame, otherwise it is judged to be defective Detection method of defective products, characterized in Rukoto. 3. When a resin is filled in a mold to form a molded product, the pressure sensor detects the filling of the resin, and the molding pressure in the mold with respect to the elapsed time after the start of the detection is a good product. And the second region, which rises relatively slowly in a state where the difference is relatively small between the case of defective products and the case of defective products. In a molding process of a molded product that continuously passes through a third region that gradually rises toward a peak in a small state, a detection device that detects a defective product regarding resin filling is provided. In close proximity, a monitoring section with a relatively short pressure width of a predetermined pressure or more and a relatively long time width is set, and the molding pressure in the mold of the product being molded enters from the lower surface of the monitoring section. Is judged to be good when it comes off from the top surface, otherwise it is defective Defective detection apparatus characterized by comprising a control unit for determining that. 4. When a resin is filled in a mold to form a molded article, the pressure sensor detects the filling of the resin, and a molding pressure in the mold with respect to an elapsed time after the start of the detection is a non-defective product. And the second region, which rises relatively slowly in a state where the difference is relatively small between the case of defective products and the case of defective products. In the molding process of the molded article, the third region which gradually rises toward the peak in a small state forms a continuous curve. A monitoring section having a relatively long pressure width and a relatively short time width that is equal to or greater than a predetermined pressure is set, and the molding pressure in the mold of the product being molded enters from the frame side of the monitoring section. Is judged to be good when it comes out of the product, otherwise it is judged to be defective. Defective detection apparatus characterized by comprising a control unit for. 5. An injection device for injecting a resin, a mold provided with a pressure sensor for receiving a resin from the injection device to form a molded product, and detecting a pressure of the resin inside, and a resin by the pressure sensor. A first region where the molding pressure in the mold with respect to the elapsed time after the start of the detection is gradually increased with a relatively small difference between a good product and a defective product; The process of forming a molded product is a process in which a second region that rises rapidly to a third region and a third region that rises gradually toward the peak with a relatively small difference between a good product and a defective product are continuous. In the first, a monitoring section having a relatively short pressure width equal to or higher than a predetermined pressure and a relatively long time width is defined as a first monitoring section.
A control unit that controls the control conditions of the injection device such that the molding pressure in the mold of the product being molded enters from the lower surface of the monitoring section and escapes from the upper surface, which is set close to the region of Having molding equipment. 6. An injection device for injecting a resin, a mold provided with a pressure sensor for receiving a resin from the injection device to form a molded product, and detecting a pressure of the resin inside, and a resin by the pressure sensor. A first region where the molding pressure in the mold with respect to the elapsed time after the start of the detection is gradually increased with a relatively small difference between a good product and a defective product; The process of forming a molded product is a process in which a second region that rises rapidly to a third region and a third region that rises gradually toward the peak with a relatively small difference between a good product and a defective product are continuous. In the above, a monitoring section having a relatively long pressure width and a relatively short time width which is equal to or more than a predetermined pressure
A control unit that controls the control conditions of the injection device so that the molding pressure in the mold of the product being molded enters from the side of the frame of the monitoring section and exits from the side of the frame. A molding apparatus comprising: