JP3128048B2 - Injection compression molding method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a mold in which a molten resin is filled in a mold in a state where the toggle mechanism is not fully extended, and the mold is slightly opened by the filled resin pressure, and then the toggle mechanism is fully extended on the mold clamping side. TECHNICAL FIELD The present invention relates to an injection compression molding method and apparatus for performing compression in a compressed state.

[0002]

2. Description of the Related Art When injection compression molding is performed by controlling a mold clamping operation, the amount of mold opening during injection filling becomes excessive depending on the initial mold clamping force setting conditions, so that the resin flow state in the mold cavity is injected. Discontinuity occurs when switching between the filling step and the compression step, resulting in defects such as flow marks.
For this purpose, injection / mold-clamping interlocking control that overlaps the mold-clamping operation with the injection-filling operation is necessary, and this timing control of mold-clamping start is an important control for stably supplying high-quality molded products. Becomes

[0003] The conventional injection / mold clamping interlocking control is as follows. That is, by monitoring the retreat amount of the movable platen or the mold during injection filling, and when the retreat amount ≧ set value, or by monitoring the change amount of the mold clamping driving force during injection filling, the change amount ≧ setting When the value reaches the value, the mold clamping operation is started (based on the mold clamping side signal). The state of filling (for example, pressure and temperature) of the molten resin in the mold cavity during injection filling is monitored, and when the monitored value becomes equal to or greater than the set value, the mold clamping operation is started (based on the mold side signal).

[0004] By monitoring the stroke of an injection cylinder or an injection screw during injection filling, a stroke position ≧
When the set value is reached, the mold clamping operation is started (based on the injection side signal). Completion of initial mold closing operation or start of injection filling
It is known that a mold clamping operation is started based on a time-out signal of a timer that is started based on an arbitrary step in a molding step (timer signal reference).

[0005]

However, the conventional injection / mold clamping interlocking control has the following problems. (1) The retreating behavior of the movable platen or the mold during injection filling tries to maintain the mold opening reaction force generated by the increase in the pressure of the filled resin in the mold cavity due to the injection filling and the set mold opening amount. This is caused by the balance with the mold clamping force on the mold clamping side. Therefore, depending on the control state (control accuracy / responsiveness) of the mold clamping force, the retreating behavior is greatly changed.

Further, when a mold is mounted on a movable platen, the movable platen has a considerable weight, and it is difficult to accurately express the mold opening reaction force accompanying injection filling, and the response is low. This significantly affects the change of the mold clamping driving force, and as a result, there is a problem that the detection is delayed in many cases and the optimal mold clamping start timing is shifted.

In order to solve the above problem, it is conceivable to set a reference value for timing control to a lower value in consideration of a detection delay or the like. However, since there is no reference for the degree of consideration of the set value, it is difficult. Conversely, one of the effects of injection compression molding is due to the compression action from both the injection filling and the mold clamping operation due to the start of the early mold clamping operation due to overdown.
There is a problem that it is expected that low distortion due to the effect of reducing the resin pressure in the mold cavity cannot be achieved.

In particular, in an injection molding machine which performs mold clamping via a toggle mechanism, a toggle characteristic which advantageously acts only when mold clamping is performed is a state in which the toggle mechanism is stopped halfway (the toggle is in a bent state). In contrast, it can be said that the injection compression molding used in the above is not suitable for detecting the retreat amount or the change amount of the mold clamping driving force.

(2) Although it can be said that the detection accuracy is higher than that of the above method (1), the detection signals from the detection sensors such as pressure and temperature are all pinpoint measurements, and depending on the sensor mounting location (actually, the ejector The mounting place is limited due to the presence of the pin or the like), and it is extremely likely that a completely different judgment is made.

It is conceivable to cope with the above problem by increasing the number of sensors. However, since it is a mere aggregate detection signal of pinpoint data, the behavior of the resin in the mold cavity is generally observed. Things impossible. Further, there is a problem that a great merit cannot be found because both software and hardware for signal processing are complicated.

[0011] Further, the disadvantages are large because special processing is required for the dies for mounting the sensors and the like to the dies, and the number of mounting steps is required for each of the dies.

(3) The injection / mold clamping interlocking control in which the mold filling operation is overlapped with the injection filling operation by directly detecting the filling behavior at the position where the injection filling amount is controlled has been conventionally used. It can be said that this is the most accurate control method among the techniques described above. However, in the conventional method in which the timing control is performed only based on the injection stroke position, the detection method includes a variation in the amount of resin caused by a variation in the measured value and a variation in the operation state of the check ring. It cannot be said that the behavior has been accurately detected.

Furthermore, the conventional method has not yet grasped the filling behavior of the resin in the mold at the same time. Therefore, it is not possible to cope with the fluctuation of the resin temperature during molding (total from the injection cylinder to the mold). It is difficult to respond, and it is not possible to supply high-quality molded products stably.

(4) This is the simplest control method among the above-mentioned prior arts. However, the control level is the lowest, and therefore, when used alone, high precision injection compression molding is required.
Adaptation is insufficient for mold-clamping control. It has many problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a high-precision injection compression compression control that stably supplies a high-quality molded product by controlling the start timing of mold clamping. It is to provide a molding method and apparatus.

[0016]

According to a first aspect of the present invention, a hydraulic clamping cylinder is driven to open and close a mold via a toggle mechanism. The low pressure mold clamping is performed in a state where the toggle mechanism does not extend completely, and after detecting that the injection pressure of the injection mechanism during the injection filling process has reached a set value, the toggle mechanism is extended in the direction to extend the high pressure mold clamping. In addition, the mold filling pressure and the injection pressure are controlled synchronously so that the injection-filled resin does not flow back to the injection mechanism side. Further, in the second invention, a mold clamping force detecting unit incorporated in the tie bar is used. Then, the state where both molds are touched is detected, the stroke of the mold clamping cylinder connected to the toggle mechanism is set at the origin, and after the set clamping force in the low pressure mold clamping is detected by the mold clamping force detecting unit, the origin is set. Of the mold clamping cylinder from the set position And sets the stroke forward amount, during the injection filling process and to control the hydraulic pressure of the mold clamping cylinder so as to hold the movable mold to the forward position set.

In the third aspect of the present invention, the detection of the injection pressure during the injection and filling process is performed at the advance limit of the injection cylinder stroke and at the injection cylinder stroke position in the area near the completion of the injection filling up to the advance limit. According to the fourth aspect of the present invention, in the injection filling step, the amount of cooling, solidification, and shrinkage of the resin is calculated in advance, and the amount of the resin obtained by adding the calculated amount of the resin is filled into the mold cavity. Until the set value is reached, and after reaching the set value, the injection pressure control is performed.

A mold clamping force setting section for setting a mold clamping force, a mold clamping cylinder stroke sensor for detecting a stroke of a mold clamping cylinder, and a mold clamping force incorporating detection of a mold touch point in a mold clamping process into a tie bar. A mold touch point setting unit for setting a stroke of a mold clamping cylinder to an origin based on a detection signal of the mold clamping force detection unit, a set value of the mold clamping force setting unit, and a detection of the mold clamping force. A mold clamping control unit that performs mold clamping by controlling a stroke of a mold clamping cylinder to which a toggle mechanism is connected by comparing a detection signal of a mold part and a detection signal of a mold clamping cylinder stroke sensor, and an injection control unit that performs injection filling. An injection pressure detection unit that detects an injection pressure during the injection filling step, a position setting unit that sets a detection range of the injection pressure, and the mold clamping control based on a detection signal from the injection pressure detection unit. Department A comparison control unit for transmitting a high-pressure mold-clamping start signal and a switching signal from speed to pressure control to the injection control unit; and a synchronization control unit for synchronously controlling the mold-clamping force and the injection pressure after the start of high-pressure mold-clamping. Configure.

[0019]

After detecting that the injection pressure of the injection mechanism has reached the set value during the injection filling process, a high-pressure mold clamping is performed to perform a compression process. Is detected directly at the point where the injection filling process is controlled. Furthermore, by using the amount of change in the injection cylinder oil pressure (injection driving force) as the timing signal, the filling behavior of the molten resin in the mold cavity is also detected. It is possible to comprehensively grasp the filling behavior of the resin up to the inside, and it is possible to realize extremely accurate injection and mold clamping interlock control.

As a result, high-precision injection compression molding can be controlled without being affected by disturbance factors such as variations in the filling amount caused by fluctuations in the operation of the measurement value check ring and fluctuations in the resin temperature during molding. High quality molded products can be supplied stably.

Further, by detecting the timing signal within the range near the end of injection filling near the advance limit of the injection cylinder stroke, the correlation between the filling behavior on the injection mechanism side and the filling behavior in the mold cavity is most accurately determined. Since the timing of starting mold clamping can be controlled in a region where the mold filling operation can be detected, the injection / mold clamping interlocking control in which the mold clamping operation overlaps the injection filling operation can be accurately realized.

Further, the injection filling process up to the start of high-pressure mold clamping is performed by injection speed control, and after the start of high-pressure mold clamping, switching to injection pressure control is performed, and synchronous control of the mold clamping force and injection pressure is performed. In the compression process by the tightening operation, the backflow of resin from the mold cavity to the injection side, which has been particularly problematic in the past, can be prevented, so that the weight of the molded product is stabilized and the deformation of the molded product caused by the backflow of the resin Can be prevented and a high quality molded product can be supplied stably. Further, since a shut-off valve or the like conventionally provided for preventing backflow is not required, cost reduction can be achieved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an injection compression molding method and apparatus according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a control conceptual diagram of an injection molding machine according to the present invention, FIG. 2 is a flowchart of setting initial mold clamping conditions, FIG. 3 is an explanatory diagram of an injection filling operation, and FIG. 4 is a flowchart of a molding operation.

The injection molding apparatus 100 in the present embodiment
Toggle type mold clamping device 50, injection device 40, and control unit 60
It is composed of

FIG. 1 shows an injection molding apparatus 100 provided with a toggle-type mold clamping apparatus 50. An upper half of the center line shows a low pressure mold clamping state, and a lower half of the center line shows a high pressure mold clamping state. . 1 includes a link housing 1, a fixed platen (fixed platen) 2, a movable platen (movable platen) 3, a mold 4 (fixed mold 4b and movable mold 4).
a), cavity 5, toggle mechanism 6, crosshead 7,
It comprises a mold clamping cylinder (die lock cylinder) 8, a piston rod 9 and a guide rod 10.

In the injection molding apparatus 100 having the double toggle type mold clamping device 50, as shown in FIG. 1, three toggle links 6a are provided between the movable platen 3 and the link housing 1.
A pair of upper and lower toggle mechanisms 6b and 6c are provided, and a mold clamping cylinder (die-lock cylinder) 8 is mounted substantially at the center of the outer end surface of the link housing 1, and the tip of the piston rod 9 of the mold clamping cylinder 8 is crossed. A guide rod 10 connected to the head 7 and having the crosshead 7
And the toggle mechanism 6 is operated via the crosshead 7 to move the movable platen (movable platen) 3 with respect to the fixed platen 2 to perform a mold clamping operation. . Reference numeral 11 denotes a tie bar.

Next, the injection device 40 will be described. In this embodiment, the injection device 40 includes a screw 4 in a barrel 41.
2 is provided, and the resin material in the hopper 43 is supplied to the supply zone,
It is configured to be heated and compressed in a compression zone, melt metered in a metering zone, and injected into a nozzle 44 via an injection zone.

A heater for externally heating the resin material is provided on the outer peripheral surface of the barrel 41, and the resin material is fed forward by the rotation of the screw 42.

Reference numeral 46 denotes an injection cylinder, and 47 denotes a forward / reverse rotation motor which is directly connected to the screw 42 so as to rotate the screw 42 forward / reverse.

Next, the control unit 60 will be described.

The control unit 60 includes an injection pressure detection unit 61, a position setting unit 62, an injection control unit 63, a comparison control unit 63a, a timer 65, hydraulic control valves 64 and 67, a mold clamping control unit 66, and hydraulic supply sources 68a and 68b. , Synchronization control section 69, mold clamping force detection section 7
0, a mold touch point setting unit 71, a mold clamping force setting unit 72, a mold clamping cylinder stroke sensor 74, and a pressure sensor 75.

The synchronization control unit 69 is connected to the injection control unit 63, and the injection control unit 63 controls the hydraulic control valve 64 for controlling the operation of the injection cylinder 46 and the control device (not shown) for controlling the operation of the forward / reverse rotation motor 47. Each is connected to the tightening control unit 66.

The mold clamping control section 66 is connected to a hydraulic control valve 67 for controlling the operation of the mold clamping cylinder 8. Note that 68
a and 68b are simplified hydraulic supply sources.

A pressure sensor 75 attached to the injection cylinder 46 is connected to the injection pressure detector 61.
The injection pressure detecting section 61 includes a position setting section 62 and a comparison control section 63.
a. Further, the comparison control section 63a is connected to the timer 65 and the synchronization control section 69, respectively.

A mold clamping force detecting unit 70 incorporated in the tie bar 11 for detecting a mold clamping force in the mold clamping process is connected to a mold touch point setting unit 71.

A clamping cylinder stroke sensor 74 is provided on the side of the clamping cylinder 8 opposite the crosshead 7 on the way of the piston rod 9 and detects a stroke of the clamping cylinder 8 when a set clamping pressure is reached. Then, it is used as a means for fixing the operation of the mold clamping cylinder 8 by holding the position.

The mold clamping point setting section 72 connected to the mold touch point setting section 71 and the mold clamping cylinder stroke sensor 74 is connected to the mold clamping control section 66. The operation of the injection compression molding apparatus configured as described above will be described.

First, as shown in FIG.
The mold clamping controller 66 controls the hydraulic control valve 67 based on the mold clamping force set value (S value) to perform mold clamping.

Next, the mold clamping force detecting section 70 incorporated in the tie bar 11 detects the touch state of the two molds 4a and 4b during the mold clamping operation, and sets the mold touch point setting section 71 as the mold touch point.
And the origin of the clamping cylinder stroke connected to the toggle mechanism 6 is set as a so-called mold touch point.

In this embodiment, embedding the mold clamping force detector 70 in the tie bar 11 has the following advantages. That is, the tie bar 11 which is the principle of generating the mold clamping force of the toggle mechanism 6 is used.
Since the elongation (stress) behavior is directly measured, the measurement accuracy is the highest. Since the position is irrelevant to the mold mounting portion, the handleability is extremely good.

After the mold touch point is set, the mold clamping advance operation is further performed, and the mold clamping cylinder stroke when the detection signal of the mold clamping force detector 70 reaches the S value is detected by the mold clamping cylinder stroke sensor 74. , Initial mold clamping control set value (S1 value)
Is stored in the mold clamping force setting section 72.

In the molding operation, the hydraulic pressure of the mold clamping cylinder is controlled by the hydraulic control valve 67 so as to maintain the S1 value, thereby controlling the mold clamping force (S value) (mold clamping cylinder position holding control). Here, the characteristics of the toggle mechanism (even if the clamping cylinder stroke fluctuates, for example, by 1 mm, the movable platen 3
Is 1/10 mm or less, and the setting accuracy of the mold clamping force is extremely high. Actually, the clamping cylinder stroke is 1
It can be held with an accuracy of / 10 mm. ) Makes it possible to easily control the mold clamping force with extremely high accuracy and high reproducibility.

Next, the procedure for setting the high-pressure mold clamping start timing signal will be described in detail with reference to FIG.

First, the injection filling amount (the amount of resin obtained by adding the cooling, solidification, and shrinkage amount of the resin) and the injection speed (1
Injection filling is performed based on the set value of (stage or multistage injection speed).

The range for detecting the timing signal for starting the high-pressure mold clamping is defined as the forward limit of the injection cylinder stroke (E
The injection cylinder stroke position in the area near the completion of injection filling up to the point (point) and the forward limit (point E) is set by the position setting unit 62 as a position set value (monitoring start point, V). By doing so, the correlation between the filling behavior on the injection mechanism side and the filling behavior in the mold cavity 5 can be detected most accurately, and the injection / mold clamping in which the mold clamping operation overlaps the injection filling operation. Interlocking control can be controlled accurately.

At the same time, the comparison controller 63a sets a timing signal for starting high-pressure mold clamping as a comparison set value (K value) based on the injection pressure on the injection mechanism side. By setting the timing signal by the injection pressure, the injection mechanism side can comprehensively grasp the filling behavior of the resin in the mold cavity 5, so that the measured value, the variation of the filling amount due to the fluctuation of the operation of the check ring, and the molding process are being performed. Thus, the timing signal can be detected stably and accurately without being affected by disturbance factors such as fluctuations in the resin temperature.

Next, the start of high-pressure mold clamping is controlled based on the set values (V value, K value) described above. When the injection cylinder stroke reaches the monitoring start point (V), the injection pressure detector 61 starts monitoring the injection pressure. In order to maintain the injection speed set in accordance with the filling behavior in the mold cavity 5, the injection pressure needs to be increased, and when the detection signal of the injection pressure detector 61 reaches the K value (the set pressure reaching point,
P) The injection filling operation is switched from injection speed control to injection pressure control (V → P switching), and a high-pressure mold clamping operation is started (compression step).

Next, simultaneously with the start of high-pressure mold clamping (start of the injection / mold-clamp interlocking section), synchronous control of the mold clamping force and the injection pressure is performed. By doing so, in the compression step by the mold clamping operation, the backflow of the resin from the inside of the mold cavity 5 to the injection side can be prevented, and as a result, there is no deformation of the molded article due to the backflow, and the backflow is prevented. No shut-off valve is required. The synchronous control is to maintain the resin pressure balance between the nozzle 44 of the injection device 40 and the mold cavity 5, and the injection control is performed in consideration of the compression conditions (molding speed, mold clamping pressure) by mold clamping. The pressure control on the mold clamping side and the injection side is performed simultaneously so that the cylinder 46 does not move backward. That is, the injection pressure is increased at the same time as the start of the increase of the mold clamping force, so that the tree finger pressure in the mold cavity 5 becomes equal to the injection pressure, thereby preventing the resin from flowing backward.

Next, a molding operation procedure subsequent to the initial condition setting will be described with reference to FIG.

The low-pressure mold clamping is performed based on the previously set mold-clamping force set value (S1 value), and after this low-pressure mold clamping is completed, injection filling is performed. At the same time, the timing control of the start of high-pressure mold clamping is performed based on the previously set position set value (V value) and comparison set value (K value).

After the injection cylinder stroke reaches point V, the injection pressure detector 61 starts monitoring the injection pressure. After detecting that the detection signal of the injection pressure detection unit 61 has reached the K value, the comparison control unit 63a sends a V (speed) -P (pressure) switching signal to the injection control unit 63 via the synchronization control unit 69. A high-pressure mold-clamping start signal is transmitted to the mold-clamping controller 66, and the timer 65 is started.

Thus, the synchronous control section 69 performs synchronous control of the mold clamping force and the injection pressure, and performs injection compression molding in conjunction with the injection and mold clamping.

Here, the timer 65 is set to start measuring (t1).
), The mold clamping completion time (t2) is set in advance. By the way, t1 is set based on the time of the gate seal, and t2 is set by calculating the cooling time of the resin from the resin temperature, mold cooling capacity, molded product shape and the like.

Thereafter, the injection and the mold clamping after the start of the high-pressure mold clamping are controlled based on the timeout signal of the timer 65.

[0056]

As is apparent from the above description, the present invention provides: (1) After detecting that the injection pressure during the injection filling step has reached the set value in the range near the completion of filling, By starting the high-pressure mold clamping and performing the compression process, the injection mechanism is not affected at all by disturbance factors such as variations in the filling amount due to fluctuations in measured values and check ring operation and fluctuations in resin temperature during molding. Since the correlation between the filling behavior and the filling behavior in the mold cavity can be accurately detected and extremely high-precision injection compression molding can be controlled, a high-quality molded product can be supplied stably.

(2) In the compression step, by controlling the injection pressure and the mold clamping pressure synchronously, backflow of the resin from the mold cavity to the injection side can be prevented, so that the quality accuracy of the molded product is extremely improved. At the same time, the cost can be reduced by eliminating the need for a shut-off valve for preventing backflow.

(3) Further, by setting a mold touch point by a mold clamping force detecting unit incorporated in the tie bar, and by holding the mold clamping force by controlling the position of the stroke of the mold clamping cylinder, extremely high precision is achieved. Since the mold clamping force can be set, a high quality molded product can be supplied.

[Brief description of the drawings]

FIG. 1 is a control conceptual diagram of an injection molding machine according to the present invention.

FIG. 2 is a flowchart of setting initial mold clamping conditions of the injection molding machine according to the present invention.

FIG. 3 is an explanatory view of an injection filling operation of the injection molding machine according to the present invention.

FIG. 4 is a flowchart of a molding operation of the injection molding machine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Link housing 2 Fixed board 3 Movable board 4 Mold 4a Movable mold 4b Fixed mold 5 Cavity 6 Toggle mechanism 7 Crosshead 8 Mold clamping cylinder 9 Piston rod 10 Guide rod 11 Tiebar 40 Injection device 41 Barrel 42 Screw 43 Hopper 44 Nozzle 46 Injection cylinder 47 Forward / reverse rotation motor 48 Injection piston 50 Toggle type mold clamping device 60 Control unit 61 Injection pressure detection unit 62 Position setting unit 63 Injection control unit 63a Comparison control unit 64, 67 Hydraulic control valve 65 Timer 66 Mold clamping control Units 68a, 68b Hydraulic supply source 69 Synchronous control unit 70 Mold clamping force detection unit 71 Mold touch point setting unit 72 Mold clamping force setting unit 74 Mold clamping cylinder stroke sensor 75 Pressure sensor 100 Injection molding device

Continuation of front page (56) References JP-A-7-9518 (JP, A) JP-A-6-285934 (JP, A) JP-A-2-258216 (JP, A) JP-A-61-290025 (JP) JP-A-61-268425 (JP, A) JP-A-60-137625 (JP, A) JP-A-8-150649 (JP, A) JP-A-8-300431 (JP, A) 4-355111 (JP, A) Japanese Utility Model Showa 57-123217 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/64-45/76

Claims (5)

(57) [Claims] When a mold is opened and closed via a toggle mechanism by driving a hydraulic mold clamping cylinder, low pressure mold clamping is performed in a state where the toggle mechanism is not fully extended, and an injection filling step is performed. After detecting that the injection pressure of the middle injection mechanism has reached the set value, the toggle mechanism is extended in the direction in which it extends, high-pressure mold clamping is performed, and the injected resin is prevented from flowing back to the injection mechanism side. An injection compression molding method characterized by synchronously controlling a mold clamping pressure and an injection pressure. 2. Using a mold clamping force detector incorporated in a tie bar, a state where both molds are touched is detected, and a stroke of a mold clamping cylinder connected to a toggle mechanism is set at an origin, and a low pressure mold clamping is performed. After the set mold clamping force is detected by the mold clamping force detection unit, the stroke is set by the stroke advance amount of the mold clamping cylinder from the origin setting position, and the movable mold is held at the set advance position during the injection filling process. 2. The injection compression molding method according to claim 1, wherein the hydraulic pressure of the mold clamping cylinder is controlled. 3. The method according to claim 1, wherein the detection of the injection pressure during the injection and filling step is performed at an advance limit of the injection cylinder stroke and at an injection cylinder stroke position in a region near the completion of injection and filling up to the advance limit. The injection compression molding method according to claim 1, wherein 4. In the injection filling step, a cooling solidification shrinkage amount of the resin is calculated in advance, a resin amount obtained by adding the calculated resin amount is filled in the mold cavity, and the injection pressure is maintained until the injection pressure reaches a set value. 2. The injection compression molding method according to claim 1, wherein the injection compression control is performed by injection speed control, and the injection compression control is performed after the set value is reached. 5. A mold incorporating a mold clamping force setting unit for setting a mold clamping force, a mold clamping cylinder stroke sensor for detecting a stroke of a mold clamping cylinder, and detection of a mold touch point in a mold clamping process in a tie bar. A mold touch point setting unit for setting a stroke of a mold clamping cylinder to an origin based on a detection signal of the mold clamping force detecting unit, a setting value of the mold clamping force setting unit, A mold clamping control unit that performs mold clamping by controlling a stroke of a mold clamping cylinder to which a toggle mechanism is connected by comparing a detection signal of a force detection unit and a detection signal of a mold clamping cylinder stroke sensor, and an injection control that performs injection filling. And an injection pressure detection unit that detects an injection pressure during the injection filling step, a position setting unit that sets a detection range of the injection pressure, and a mold based on a detection signal from the injection pressure detection unit. Tightening control section A comparison control unit for transmitting a high-pressure mold clamping start signal and a switching signal from speed to pressure control to the injection control unit; and a synchronization control unit for synchronously controlling the mold clamping force and the injection pressure after the start of high-pressure mold clamping. An injection compression molding apparatus characterized by the above-mentioned.