JPH10278091A - Injection molding method and injection molding machine - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to directly detect the pressure applied to a filling resin and to control the pressure applied to the filling resin to a predetermined pressure. This aims to solve the problem caused by the conventional control using only the output value of the load cell for injection. SOLUTION: In a servo motor driven injection molding method, a pressure of a filling resin in a mold cavity (2) is sensed, and an injection speed control in an injection step or an injection pressure control in a pressure holding step is performed based on the sensing data. It is characterized in that at least one of them is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for measuring a resin pressure of a resin filled in a mold cavity, at least at a stage prior to an injection step or a pressure-holding step or during the entire pressure-holding step. The present invention relates to an injection molding method and an injection molding machine capable of controlling an injection speed optimally in an injection step, applying a predetermined pressure in a pressure-holding step, and immediately taking an alarm or a stop procedure in an emergency.

[0002]

2. Description of the Related Art An injection molding machine (A ') is roughly divided into an injection mechanism (a') and a mold mechanism (b '). When the resin (3 ′) is injected into the mold cavity (2 ′) of the mold (′), after the injection is completed, in the pressure-holding step until the mold is opened, the injection of the resin (3 ′) at a predetermined pressure from the injection mechanism (a ′) side. 3 ′) is applied (more precisely, a screw injection servomotor (not shown) is controlled, and an injection load cell (not shown) disposed between the screw (4 ′) and the servomotor. ) Is maintained at a constant value, and the screw (4 ') is charged with a resin (3') from the tip of the injection cylinder (13 ') to the runner (5') at a constant pressure. ) Side to apply pressure to the filling resin (3 ')), and in response to the shrinkage of the resin (3') that occurs with the temperature drop after the filling of the filling resin (3 '), the injection mechanism section Continuous supply of new resin (3 ') from (a') And, sink marks without sound molded article is to be produced.

However, in this method, the resin in the runner (5 ') is
Since both (3 ′) and the resin (3 ′) in the mold cavity (2 ′) gradually increase in viscosity as they cool, even if the value of the injection load cell shows a constant value, the mold cavity gradually increases. The pressure applied to the filling resin (3 ') in (2') decreases.

FIG. 6 is a graph showing this state. The portion shown by the broken line is a line showing the pressure change represented by the injection load cell and the pressure change applied to the filling resin in the conventional pressure holding process. That is, in the pressure-holding step, the injection servomotor was controlled so that the value of the load cell for injection was constant at a predetermined value. Stages and '' are rear stages)
Therefore, the pressure applied to the filling resin (3 ') is gradually decreasing (in the portions indicated by' and '' in the figure, 'is the front stage of holding pressure and''is the rear stage). Here, insufficient pressurization in the pressure-holding step causes serious defects such as “sink”, so it is necessary to avoid this.However, in the conventional method, the pressure applied to the filling resin (3 ′) is reduced. Since it was not possible to know directly, it was not possible to specifically grasp the pressure drop during the dwelling stage, and there was a major problem in molding a resin having a large shrinkage.

In the conventional method, since the control is performed only by the output value of the injection load cell as described above, the mold (1 ')
Even if an abnormality occurs on the side, the abnormality cannot be detected because the abnormality does not appear in the injection load cell, and therefore, the occurrence of an abnormal situation in such a case is overlooked, causing an accident. In addition, in the injection step, the injection speed of the screw (4 ') is determined by an injection speed / position detecting device (not shown in FIG. 7).
In this case, the mold cavity (2 ')
Since it was not possible to detect the resin pressure of the resin (3 ′) being filled in, there is no other way but to perform without feeding back the resin pressure, and the injection speed is controlled regardless of the resin pressure at the time of filling. I was Also, in this case, similarly to the above, since the control is performed only by the output value of the injection speed / position detecting device alone, even if an abnormality occurs on the mold (1 ′) side, the abnormality does not appear in the injection speed / position detecting device. Above, it was impossible to detect, and therefore, the occurrence of an abnormal situation in such a case was overlooked, causing an accident.

[0006]

Therefore, in the present invention, the pressure applied to the filling resin is directly detected in at least one of the injection step and the pressure-holding step, and in the injection step, the injection is performed based on the data. The speed is controlled so that the pressure applied to the resin in the pressure-holding step is controlled to be a predetermined pressure, whereby the output of the conventional injection load cell or the injection speed / position detecting device is controlled. The purpose of the present invention is to solve the problem caused by control using only values.

[0007]

A first aspect of the present invention is based on the injection molding method of the present invention. In the injection molding method driven by a servomotor, the pressure of a filling resin in a mold cavity (2) is sensed, Based on the sensing data, at least one of the injection speed control in the injection step and the injection pressure control in the pressure-holding step is controlled. "

According to the method of the present invention, in the injection step, the actual resin pressure being filled in the mold cavity (2) is directly used in the dwelling step, and the filled actual resin pressure is directly used. The injection speed and injection pressure can be controlled while measuring, and the most appropriate injection molding management becomes possible. The measurement of the resin pressure of the filling resin (3) in the mold cavity (2) and the control based on the data may be performed only in the injection step, may be performed only in the pressure-holding step, or may be performed through both the injection and pressure-holding steps. You may. In addition, the above control may be performed throughout the pressure holding process, or only the preceding stage may be performed, and control can be performed at an arbitrary stage.

A second aspect of the present invention relates to a control example in an injection step, wherein "in a servo motor driven injection molding method, the resin pressure in the injection step of the resin (3) filled in the mold cavity (2) is sensed, Switching from the injection process to the pressure-holding process when the filling resin pressure reaches a predetermined pressure '', according to which the resin pressure of the resin (3) filled in the mold cavity (2) is increased. , The timing of switching from the injection process to the pressure holding process can be determined more accurately.

A third aspect of the present invention relates to a control example in the pressure-holding step. In the injection molding method driven by the servomotor, the pressure of the filling resin in the mold cavity (2) is adjusted to the front stage of the pressure-holding step or the whole pressure-holding step. And the injection pressure from the injection cylinder (13) is controlled in accordance with the resin pressure to maintain the filling resin pressure at a predetermined pressure. "

By applying the method of the present invention to the pressure-holding step, new resin is supplied as needed from the injection cylinder (13) in accordance with shrinkage of the filling resin (3) in the mold cavity (2). It is possible to mold any kind of resin or molded article of any shape without causing sink marks. Further, if applied to the later stage of the pressure-holding step, deformation such as “warpage”, “bending”, and “bulging” due to insufficient pressurization during cooling can be eliminated. In the embodiment to be described later, the pressure-holding step is divided into two stages before and after. However, the pressure-holding step is not limited to this and may be divided into three or more stages, or may be performed in one stage.

A fourth aspect of the present invention relates to an abnormality detection method utilizing the control in the injection step of the first aspect. The resin pressure is sensed to control the injection speed of the screw (4) of the injection cylinder (13) in the injection process, and when the injection speed of the screw (4) indicates an abnormal value, at least a warning issuance or an emergency stop is performed. "Claim 5" is characterized in that the "injection molding method of servo motor drive" is an abnormality detection method using the control in the pressure holding step of "Claim 1". In, the pressure of the filling resin in the mold cavity (2) is sensed throughout the pre-stage of the pressure-holding step or throughout the pressure-holding step, and the injection pressure from the injection cylinder (13) is controlled in accordance with the resin pressure to fill the resin. Predetermined resin pressure It is characterized in that "actuating at least one of issuance or emergency stop of the alarm when the injection pressure from the injection cylinder (13) with keeping the force exhibited abnormal values.

According to this, in addition to the function and effect described in claim 1, it is possible to immediately detect the occurrence of abnormal speed or abnormal pressure in the front stage of the injection step or the pressure holding step or in the entire pressure holding step. It is possible to take countermeasures at the same time as the occurrence of abnormalities, and to take quick responses to prevent accidents.

Claim 6 is a specific mechanism for carrying out the method of the present invention. "In a servo motor driven injection molding machine, it is exposed in the mold cavity (2) and comes into contact with the filling resin (3). A sensing member (6) or (6a), a pressure sensor (7) installed on the sensing member (6) or (6a), and at least an injection cylinder (13) in an injection step by an output of the pressure sensor (7). And a control device (8) for controlling either the injection speed of the screw (4), the injection pressure from the injection cylinder (13) in the front stage of the pressure-holding process, or the entire pressure-holding process. '' And

According to the present invention, the pressure sensor (7) enables the direct measurement of the resin pressure of the filling resin (3), and the pressure sensor (7) installed on the sensing member (6) or (6a). )
By outputting the resin pressure, accurate feedback (or feedforward) control of the resin pressure becomes possible. As a result, in the injection process, it becomes possible to inject the resin at an appropriate injection speed in all processes, and in the pressure-holding process, it starts eliminating shape defects due to insufficient resin pressure. By cooperating with (27) and the injection load cell (15), it is possible to detect the occurrence of an abnormality in the front stage of the injection step or the pressure holding step or in the entire pressure holding step.

A seventh aspect is a more specific example of the mechanism of the sixth aspect, characterized in that "the sensing member (6) or (6a) is an eject bar for projecting a molded product".
Thereby, the object of the present invention can be achieved without making any changes to the conventional apparatus, and the conventional injection molding machine (A)
Can be given more added value.

An eighth aspect is another specific example of the mechanism according to the sixth aspect, wherein the sensing member (6) is a local compression mold member for compressing a local portion of a molded product to form a thin wall. Is ". According to this, since the local compression mold member is in direct contact with the mold cavity filling resin (3), similarly to the above-described eject bar, the resin pressure can be detected, and the same operation and effect as in the preceding paragraph can be obtained. You can get it. The local compression molding member may be separate from the eject bar, or the eject bar may be used as a local compression molding member as shown in the embodiment of the present invention. The added value can be further increased without making any changes.

Claim 9 relates to the molding of a molded article (26) having a thin portion (26a) by local compression, whereas Claims 7 and 8 relate to the "sensing member" when the whole is compressed. (6a) is a compression mold member that compresses the entire molded product (26) and applies a uniform compression pressure to the entire molded product (26). ''
It is characterized by.

A tenth aspect of the present invention relates to an injection molding machine (A) according to the sixth to ninth aspects of the present invention, in which a configuration is added to the injection molding machine (A). At least one of the injection pressure and the injection speed of the screw (4) can be displayed on the display (9). "

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 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. Injection mechanism
(a) is a drive mechanism (10) for moving the screw (4) forward and backward, and a rotation servomotor for rotating the screw (4).
(11), an injection servomotor (12) for moving the screw (4) forward and backward, a screw (4) for mixing and injecting the raw resin, and an injection cylinder (13 ), A heater (14) wound around an injection cylinder (13), and an injection device that is disposed between the screw (4) and the drive mechanism (10) and detects the pressure applied to the screw (4). Load cell (1
5), Material supply hopper (16) and injection speed / position detection device
(27).

On the other hand, the mold mechanism (b) is a movable / fixed mold.
(1a) A mold (1) composed of (1b), a fixed die plate (17) equipped with a fixed mold (1a), and a movable die plate (18) equipped with a movable mold (1b). ), A tie bar (19) to which a movable die plate (18) is slidably attached, a tailstock (20) to which one end of the tie bar (19) is fixed,
The end face is exposed to the mold cavity (2) through the movable mold (1b), and the mold cavity (2) is reciprocated.
Sensing member (6) or (6a) whose tip protrudes inside
<< The sensing member (6) is thin for local compression molding or the sensing member (6a) is thick for overall compression. In this embodiment, in order to avoid complexity, the sensing member will be described with reference to (6), and (6a) will be used only in the case of whole compression. 》,
The movable die plate (18) is disposed so as to penetrate therethrough, and a tip portion thereof is connected to the sensing member (6) via a pressure sensor (7), and is rotatably held by the movable die plate (18). Ball screw (22) screwed into the driven pulley (21),
The pressure sensor generally configured by a load cell
(7) The driving pulley (23) mounted on the movable die plate (18) and mounted on its rotating spindle, and the driving pulley (23)
And a servomotor (24) for transmitting the rotational force to a driven pulley (21) via a timing belt (25) suspended from the motor.

A control device (8) controls the entirety of the injection molding machine (A). One of the functions is a load cell (15) for injection, a pressure sensor (7), an injection speed (7). The signals from the position detection device (27) [other detection devices (11a) and (24a)] are obtained, and the rotation servomotor (11), the injection servomotor (12), and the servomotor ( 24) is controlled. The signal from the injection speed / position detection device (27) is transmitted to the position detection unit (8a) and the speed detection unit (8b) in the control device (8).
The output is further input to a servo motor controller (8c), and the output of the servo motor controller (8c) is input to an injection servo motor (12). (9) is a monitor display, in which screens necessary for control are displayed one after another by selection of an operator, and a graph such as that shown in FIG. 6 is also displayed.

Next, the operation of the present invention will be described. The raw material resin (3) 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 (3) 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 (3) entered gradually melts and
It is kneaded by the rotating action of (4).

With the rotation of the screw (4), the melt-kneaded resin is sent toward the tip of the injection cylinder (13) and is stored at the tip. As a reaction, the screw (4) gradually recedes,
Eventually, retreat will be reached. At this point, the resin measurement has been completed.

Subsequently, the rotation servomotor (11) is stopped and the injection servomotor (12) is operated to push the screw (4) forward, so that the metering amount accumulated at the tip of the injection cylinder (13) is measured. The melt-kneaded resin (3) is injected into the mold cavity (2). In FIG. 6, the injection speed rises rapidly with the start of injection, and is maintained at a certain speed when the injection speed is reached. Immediately before the injection is completed, the injection speed is rapidly reduced until the injection process is completed. The speed decreases very slowly until the mold is opened, and finally reaches zero. Such an injection speed is detected by the injection speed / position detecting device (27) of the drive mechanism (10), input to the control device (8), and controls the injection servomotor (12).

Next, if we look at the output of the pressure sensor (7), the molten resin (3) enters the mold cavity (2), contacts the sensing member (6), and sends it to the pressure sensor (7). Until pressure is detected, its output is zero. When the molten resin (3) is injected and filled into the mold cavity (2) and comes into contact with and presses the sensing member (6), the pressure increases once, and thereafter, the mold cavity ( Until the inside of the mold (2) is filled, the output from the pressure sensor (7) does not increase and remains substantially constant, and when the resin (3) is filled into the mold cavity (2), the output value rapidly increases. Start up and continue until the injection process is completed.
This data is input to the control device (8), and the injection speed is controlled based on this data. As described above, the injection speed is controlled by the injection speed / position detection device (2).
It is detected by 7), is input to the control device (8), and is controlled momentarily by feedback (or feedforward) control so that the optimum injection speed is obtained.

On the other hand, the output value of the load cell for injection (15) rises rapidly with the start of injection, falls rapidly after exceeding a peak, and then shows a substantially constant value while slightly decreasing. It increases rapidly until the end of the injection process.
This data is input to the control device (8). The above is a change in the injection process, and this portion is the same in the conventional example and the present invention.

When the injection process is completed and the dwelling process is started, the speed control is not performed and the resin filled in the mold cavity (2) is
Control is performed so that the resin pressure of (3) is kept constant (or set pressure). Therefore, the resin pressure is transmitted to the pressure sensor (7) via the sensing member (6) held at the surface position on the inner peripheral surface of the mold cavity (2), and the resin pressure in the mold cavity (2) is Is directly detected and output to the control device (8), and the injection servomotor (12) is controlled based on the data. That is, when entering the pressure holding process, the mold cavity
The resin (3) in (2) gradually increases in viscosity and accordingly its volume gradually decreases. If the pressure applied to the filling resin (3) in the pressure-holding process gradually decreases as in the past, the supply of new resin from the injection cylinder (13) side will be insufficient due to the volume decrease, and the shortfall will be reduced. It will appear on the molded product as "finish". However, in the case of the present invention, the injection servomotor is directly detected and kept constant.
Since (12) is controlled to gradually increase the pressing force of the screw (4), the above-described shortage of resin supply does not occur, and the sink can be eliminated.

This can be done in two stages before and after the pressure holding step (of course,
As described above, the output value of the injection load cell (15) is not limited to two stages as in the present embodiment, but may be one stage or three or more stages.
The output value of this part was controlled to be constant as indicated by ',', but gradually increased in both front and rear stages as indicated by the solid line, and the pressing force of screw (4) was reduced. The output value of the pressure sensor (7) is made constant by the gradual increase.

When the front stage of the pressure-holding process is completed and the process moves to the rear stage, the pressure is rapidly reduced because the filling resin (3) has hardened to some extent, and is maintained at a certain value until the pressure-holding is completed. To do it. During this time, the volume of the filled resin (3) is gradually reduced by cooling, but almost no resin is supplied, and the injection speed gradually decreases toward zero. Therefore, the output value from the injection load cell (15) decreases rapidly with the completion of the front stage and the start of the rear stage of the pressure holding stage, but the output value of the pressure sensor (7) is kept constant. Immediately before being controlled, the degree of decrease in the injection pressure decreases, and the resin pressure reverses near the point where the resin pressure is controlled to a substantially constant value (or set value), and then rapidly increases. To complete the rear phase. By controlling the output value of the pressure sensor (7) to be substantially constant (or set value) at the rear stage in this way, it is possible to prevent the molded product from being deformed such as "warp", "bend", and "bulge". .

When the rear stage is completed, the mold is opened as shown in FIG. 4, and the molded product (26) moves together with the movable mold (1b) and separates from the movable mold (1a). Thereafter, the servomotor (24) is operated, the ball screw (22) is protruded, the sensing member (6) is protruded from the mold cavity (2) via the pressure sensor (7), and the molded product (26) is removed. Protrude from the mold cavity (26). The protruding molded product (26) is taken out by a take-out device (not shown), and after the parting surface of the mold (1) and the mold cavity (2) are cleaned, the mold is closed. Return to the injection process again.

In the above-described embodiment, the case where the sensing member (6) also serves as the eject bar has been introduced. In addition, sensing members (6)
May be used as an eject bar as described above, or may be used as a local compression mold member for compressing a local portion of a molded product (26) to form a thin wall.
That is, as shown in FIG. 5, after filling the resin cavity (3) into the mold cavity (2), the servo motor (24) is operated to operate the ball screw (22).
Is slightly advanced, and the sensing member (6) is projected through the pressure sensor (7) into the filling resin (3) as shown by a virtual line,
A thin portion is formed locally. In this state, the process proceeds to the pressure-holding step, and through the same steps as described above, a molded product (26) having a locally thin portion is obtained.

In the figure, the part indicated by (6a) is a sensing member.
This is an example in which (6) is used as an entire compression mold member of a molded product (26) and also used as an eject bar. Needless to say, it may be configured separately as described above.

Next, the case where the pressure sensor (7) and the injection speed / position detecting device (27) or the injection load cell (15) are used for detecting an abnormality by cooperating with each other will be described. As shown in FIG. 6, in the injection step, an upper limit value (upper limit) and a lower limit value (lower limit) are set in advance for the injection speed, and the output of the pressure sensor (7) is screwed.
The injection servomotor (12) is controlled every moment so that the injection speed of (4) becomes a predetermined value, so that the injection is performed at the optimum injection speed. The injection speed is monitored by the injection speed / position detection device (27) as described above.If the value changes within a predetermined range (upper limit) to (lower limit), the injection process is normally operated. It is determined that the alarm has occurred, and conversely, if the value crosses the upper limit (upper limit) or lower limit (lower limit), it is determined that there is an abnormality, and at least one of the issuance of an alarm and the emergency stop is activated. As a result, the occurrence of abnormal pressure in the injection process can be directly detected, and it is possible to take measures at the same time as the occurrence of abnormalities, thereby enabling quick response.

The same applies to the front stage (the front stage may be applied or the rear stage may be applied) of the pressure holding step.
The upper and lower limit values (before (a), (before (b)), (after (b)), and (after (b)) that change with the output value of the injection load cell (15) either fixedly or as the dwell time elapses are preset. Servo motor for injection so that the output of the pressure sensor (7) is constant (or set value)
If the output value of the injection load cell (15) obtained as a result of controlling (12) increases within a predetermined range (before (a), (before (b)), (after (a), (after b)), the pressure holding step Is determined to be operating normally, and if it deviates from the set value, it is determined to be an abnormal value, and at least one of the issuance of an alarm and the emergency stop is activated. This makes it possible to directly detect the occurrence of abnormal pressure in the front stage (same in the rear stage) of the pressure-holding process, to take measures at the same time as the occurrence of abnormalities, and to quickly respond.

[0036]

As described above, according to the present invention, the injection speed or the filling resin pressure is directly detected and the injection speed or the filling resin pressure is controlled so as to be a predetermined speed or pressure. Various problems caused by control using only the output value of the position detecting device or only the output value of the injection load cell could be solved. That is, optimal injection speed control can be performed in the injection step, and injection pressure control can be performed in the dwelling step, so that the most appropriate injection molding management can be performed. The timing of switching from the injection process to the pressure holding process can be determined more accurately. It has become possible to mold any kind of resin or molded article of any shape without causing sink marks. An abnormality detection method in the injection process and an abnormality detection method in the pressure-holding process have become possible, and it is possible to take countermeasures at the same time as the occurrence of an abnormality, thereby enabling quick response. By using the eject bar also as a sensing member and / or a local compression mold member, the object of the present invention can be achieved without adding any change to the conventional device, and the added value can be increased. Further, by changing the shape, the whole can be compressed. By displaying the resin pressure detected by the pressure sensor on the display, it is possible to visually observe the change in the resin pressure in all the steps of the injection molding, so that the operator can more easily grasp the entire process.

[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 an enlarged cross-sectional view of the mold mechanism of FIG. 1;

FIG. 3 is an enlarged cross-sectional view when a mold of a mold mechanism of FIG. 2 is in a mold open state;

FIG. 4 is an enlarged sectional view at the time of ejecting in the mold mechanism of FIG. 2;

FIG. 5 is an enlarged cross-sectional view of the mold mechanism of FIG. 2 when a sensing member is protruded so that a tip thereof is immersed in a filling resin and a local thin portion is formed in the resin.

FIG. 6 is a comparison graph showing changes in the output of the injection speed, the injection load cell, and the pressure sensor in the injection and pressure holding processes of the present invention and the conventional example.

FIG. 7 is an enlarged sectional view of a conventional mold mechanism.

[Explanation of symbols]

 (A) Injection molding machine (a) Injection mechanism (b) Mold mechanism (1) Mold (2) Mold cavity (3) Resin (4) Screw (5 ') Runner (6)… Sensing member (7)… Pressure sensor (8)… Control device (9)… Display

Claims (10)

[Claims] In a servo motor driven injection molding method, a pressure of a filling resin in a mold cavity is sensed, and at least one of an injection speed control in an injection step and an injection pressure control in a pressure holding step is detected based on the sensing data. An injection molding method characterized by controlling the above. 2. In a servo motor driven injection molding method, a resin pressure in a step of injecting a resin filled in a mold cavity is sensed, and when the charged resin pressure reaches a predetermined pressure, the injection step is switched to a pressure-holding step. Injection molding method characterized by switching to. 3. In a servo motor driven injection molding method, a pressure of a filling resin in a mold cavity is sensed in a front stage of a pressure holding process or throughout the pressure holding process,
An injection molding method characterized in that the injection pressure from an injection cylinder is controlled in accordance with the resin pressure to maintain the filling resin pressure at a predetermined pressure. 4. An injection molding method driven by a servomotor, wherein the injection speed of a screw of an injection cylinder in an injection process is controlled by sensing a pressure of a filling resin in a mold cavity in an injection process, and the injection speed of the screw becomes an abnormal value. Wherein an alarm issuance or an emergency stop is actuated. 5. In a servo motor driven injection molding method, a pressure of a filling resin in a mold cavity is sensed in a front stage of a pressure holding process or throughout the pressure holding process.
The injection pressure from the injection cylinder is controlled in accordance with the resin pressure, and the charged resin pressure is maintained at a predetermined pressure, and when the injection pressure from the injection cylinder indicates an abnormal value, at least one of issuing a warning or emergency stop. An injection molding method characterized in that one is operated. 6. A servo motor driven injection molding machine, comprising: a sensing member exposed in a mold cavity and in contact with a filling resin; a pressure sensor installed on the sensing member; And a control device for controlling either the injection speed of the screw of the injection cylinder of the injection cylinder, the injection pressure from the injection cylinder in the front stage of the pressure holding process or the entire pressure holding process. 7. The injection molding machine according to claim 6, wherein the sensing member is an eject bar for projecting a molded product. 8. The injection molding machine according to claim 6, wherein the sensing member is a local compression mold member for compressing a local portion of the molded product to form a thin wall. 9. The injection molding machine according to claim 6, wherein the sensing member is a compression mold member that compresses the entire molded product and applies a uniform compression pressure to the entire molded product. 10. The injection molding machine according to claim 6, wherein at least one of a resin pressure detected by a pressure sensor, an injection pressure from an injection cylinder, and a screw injection speed can be displayed on a display. An injection molding machine characterized by the following.