JPH11105089A - Injection molding machine and injection molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine high in repeated reproducibility at every molding shot and capable of realizing high weighing injection even when there is a slight increase or decrease in the containing state of gas or air in a molten resin. SOLUTION: An injection molding machine is provided with a compressive metering control part 6 sending a molten resin 3 into the front part of an injection drive member 2 to complete the metering thereof and subsequently once pressing the injection drive member 2 forwardly to control the compression of the molten resin in the front part. A filling control part 5 for setting the position where the injection drive member 2 is moved by forwardly compressing the resin by the compressive metering control part 6 as a moving start position P and forwardly moving the injection drive member 2 by a predetermined stroke on the basis of the moving start position P is provided. A start point memory device storing the moving start position P and a terminal memory device storing the stroke terminal point of the predetermined stroke are provided and the injection drive member 2 is always driven at a constant stroke from the moving start position P stored in the start point memory device to the stroke terminal point stored in the terminal memory device by the compressive metering control part 6 and the filling control part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine and an injection molding method.

[0002]

2. Description of the Related Art The injection structure of a conventional injection molding machine has the following configuration.

In the in-line system, the resin supplied rearward is melted by rotating an injection screw in an injection cylinder, and is fed to the front of the injection screw via a check ring.

[0004] The molten resin fed into the front portion pushes out the injection screw which has retreated backward, pushes forward the molten resin, injects the molten resin into the mold from the nozzle portion at the front end of the injection cylinder, and further applies the injection screw forward. It is configured to keep the resin injected into the mold by pressing.

In the pre-plasticizer system, a supply section is connected to the front of the injection cylinder via a check valve, and the supply screw in the supply section is rotated to melt the supply section into the front of the injection cylinder. The resin is fed in, the injection plunger in the injection cylinder retreated backward by the fed molten resin is pushed forward, the molten resin is injected into the mold from the nozzle portion at the front end of the injection cylinder, and the injection screw is further moved. It is configured to keep the pressure of the resin injected into the mold by pressing it forward.

In such a conventional injection molding machine,
A driving device (actuator) for controlling the ejection of the injection screw or the injection plunger is provided.

That is, by controlling this driving device, after a predetermined amount of the molten resin is fed forward (after the completion of the measurement),
An injection driving body such as an injection screw or an injection plunger is driven to be pushed forward, and then pressurized and held for a predetermined time thereafter.

[0008]

However, in such a conventional injection molding machine, the filling drive and the dwelling drive are performed by one driving device.

Specifically, when the weighing is completed for each molding shot, control for pushing out the injection driving body to a predetermined position and pressure holding control for applying pressure further forward for a predetermined time from the extrusion completion position are performed.

Therefore, in the control of the injection driving body in the conventional injection molding machine, the filling and the dwelling pressure are controlled by one driving device. It is necessary to switch to the pressurization control to perform the constant pressure control, and the pressure switching control (switching from filling to holding pressure) must be performed during the movement of the injection driving body.

Therefore, there is a problem that the reproducibility of each molding shot is poor.

That is, even if the injection screw and the supply screw are rotated to accurately measure the amount of molten resin that is always fed in front of the injection driving body, the injection control of the injection driving body cannot be performed with high accuracy. (The reproducibility is not always 100%.) Therefore, there arises a problem that an accurate amount of molten resin cannot be injected into the mold.

More specifically, if the accurately measured amount cannot always be injected into the mold, the amount is too large and unnecessary resin pressure is applied into the mold, causing burrs on the molded product or the amount being too small. If the injection pressure is insufficient and the holding pressure does not act sufficiently (the holding pressure works only before cooling progresses and until the resin has fluidity, so the shortage cannot be completely refilled by the holding pressure In some cases) and incompletely formed defective products.

On the other hand, since the measured molten resin contains gas and air, the actual amount of resin that is pressurized and injected into the mold fluctuates. Without taking into account the air and air content, it has been found that even if the feed metering in front of the injection drive is accurate, high-precision metering cannot be performed.

The present invention has been made in view of the above circumstances, and provides an innovative injection molding machine and an injection molding method which can solve the latter problem and can also solve the former problem. It is an object.

[0016]

The gist of the present invention will be described with reference to the accompanying drawings.

The molten resin 3 is fed into a front portion of an injection driving body 2 such as an injection screw or an injection plunger in the injection cylinder 1 and the injection driving body 2 retreated backward by the molten resin 3 fed into the front portion is moved forward. So that the molten resin 3 is injected from the front end of the injection cylinder 1 into the mold 4, and the injection driving body 2 is further pressed forward to maintain the pressure of the resin fed into the mold 4. In the injection molding machine described above, after the molten resin 3 is fed into the front portion of the injection driving body 2 and the measurement is completed, the injection driving body 2 is once pressed forward to compress the front molten resin 3. A compression weighing control unit 6 for controlling is provided, and a position where the injection driving unit 2 is compressed and moved forward by the compression weighing control unit 6 is set as a movement start position P, and the injection driving unit 2 is moved forward with respect to the movement start position P. Place The filling control unit 5 which allowed to only forward movement stroke provided, the starting point storage unit A that stores the movement start position P, the stroke end point Q of the predetermined stroke
And an end-point storage device B for storing the data from the movement start position P stored by the start-point storage device A to the stroke end point Q stored by the end-point storage device B. The present invention relates to an injection molding machine characterized in that a constant-stroke injection drive 2 is driven.

Further, the molten resin 3 is fed into a front portion of an injection driving body 2 such as an injection screw or an injection plunger in the injection cylinder 1, and the injection driving body 2 retreated backward by the molten resin 3 fed into the front portion. To inject the molten resin 3 into the mold 4 from the front end of the injection cylinder 1, and further pressurize the injection driving body 2 to keep the resin fed into the mold 4 pressed. In the injection molding method described above, after the molten resin 3 is fed into the front part of the injection driving body 2 to complete the measurement,
Pressurizes the injection driving body 2 once to compress the molten resin 3 in the front part.
The starting point storage device A sets the position where the object has moved as the movement start position P.
The injection drive 2 is moved forward by a predetermined stroke to inject the molten resin 3 to the stroke end point Q stored from the end point storage device B based on the movement start position P by the filling control unit 5 as a reference. The present invention relates to an injection molding method.

Further, the filling control unit 5 and the compression and weighing control unit 6 do not use a common driving device, but are separate driving devices that are separately driven and controlled. The filling drive device (5) that pushes forward by a predetermined stroke, and the compression / metering control unit (6) is a pressure-holding drive device that performs the pressure-holding control. The present invention relates to an injection molding machine or an injection molding method.

Further, a movement detecting section 8 is provided on the injection driving body 2 or a member which moves with the movement of the injection driving body 2, and a detecting section 9 for detecting a moving position of the movement detecting section 8 is provided.
A and 9B are arranged at the predetermined stroke intervals, and the positions of the detection units 9A and 9B are held as the movement start position P and the stroke end point Q, respectively. The movement start position P and the stroke end point Q are detected when the movement detection unit 8 comes into contact with or comes close to the detection units 9A and 9B, and the ejection driving body 2 is moved from the movement start position P to the stroke. The injection molding machine and the injection molding method according to any one of claims 1 to 3, wherein drive control is always performed for a predetermined stroke up to an end point Q.

Further, when the injection driving body 2 is once compressed by the compression and metering control unit 6, the movement of the injection driving body 2 is maintained while the movement detection unit 8 is kept in contact with or close to the detection unit 9A. 3. The apparatus according to claim 2, wherein the actuator is configured to move relative to the injection driving body without moving.
The present invention relates to an injection molding machine and an injection molding method according to any one of (1) to (4).

Further, the driving speed of the injection driving body 2 is controlled by reaching a predetermined stroke distance based on the movement start position P. 1. An injection molding machine and an injection molding method according to item 1.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention (how to implement the invention) will be briefly described with reference to the drawings, showing the operational effects thereof.

When the feeding of the molten resin 3 to the front of the injection driving body 2 is completed, the compression / metering control unit 6 pressurizes and temporarily compresses the molten resin 3 which has been stopped at a predetermined pressure.

At this time, the position at which the injection driving body 2 has moved forward by the start point storage device A is stored as the movement start position P.

At this time, for example, since the cooling resin in the mold 4 has been filled and maintained by the last molding shot, it is in an injection impossible state and is compressed even if pressurized. So that

Therefore, by this compression, the gas and air components in the molten resin 3 can be compressed and exhausted, or the capacity under constant pressure compression can be measured.

That is, the compressed state may be maintained. However, once the pressurization is stopped, the injection driving body 2 is sucked back, the mold 4 is opened to discharge the molded product, and the mold 4 is again discharged. Is closed and is ready to be injected, the charging control unit 5 is operated to inject the molten resin 3. At this time, a correction is made such that the position P, at which the injection driving body 2 has advanced by compression, is the starting point of a certain stroke. Do. That is, the corrected position is set as a stroke start reference (movement start position P), and the stroke is always driven from the movement start position P to the stroke end point Q stored in the end point storage device B, so that the drive is always performed by a constant stroke advance. To do.

As a result, the molten resin 3 which is always measured once
Is performed, and injection control is performed to advance a predetermined stroke based on the position (movement start position P) obtained by this compression. Therefore, even if the molten resin 3 contains gas or air, it is always constant. The volume of compression can be injected by extruding a fixed stroke, and the amount of resin actually injected into the mold 4 becomes constant for each molding shot, realizing dramatically higher precision metering than before. Is done.

That is, in the prior art, even if the feeding and metering to the front of the injection cylinder is accurate, there is a variation in the actual amount of the injection resin that is extruded and injected by applying the injection pressure, and the highly accurate metering and injection is performed. However, according to the present invention, the weighing accuracy is dramatically improved.

Further, the filling control unit 5 and the compression / weighing control unit 6 do not use a common driving device, but are separate driving devices for separately controlling the driving. If the filling drive device 5 that pushes forward by a predetermined stroke is used, and the compression metering control unit 6 is a pressure-holding drive device that performs the pressure-holding control, the high-precision metering injection is realized and the following It has the following functions and effects.

After the molten resin 3 is fed to the front of the injection driving body 2 such as an injection screw or an injection plunger, the injection driving body 2 is pushed forward by the filling driving device 5 of one of the driving devices separately provided so as to be controllable. When driven, a predetermined amount of the molten resin 3 is injected into the mold 4.

The injection driving body 2 is further pressed forward by the pressure-holding driving device 6 of the other driving device separately provided so as to be capable of driving control, and keeps the pressure of the resin fed into the mold 4.

More specifically, for example, the injection driving unit 2 is driven and controlled by a predetermined stroke from a predetermined position by a filling driving unit 5 (filling control unit 5) at every molding shot. The weighing control unit 6) is configured to control the pressurization at a predetermined pressure for a certain time thereafter.

Therefore, as compared with the conventional case where these driving devices share a common actuator, control for switching the driving state (driving pressure) during the movement of the injection driving body 2 becomes unnecessary. Only the predetermined stroke drive control is performed, and only the constant pressure control is performed by the other pressure-holding drive device 6.

Therefore, the conventional control is complicated and has poor reproducibility (control in which the control output is changed during the movement).
Instead, a simple structure and simple control are sufficient, and the reproducibility of each molding shot is high, thus eliminating the instability of switching from the filling process to the pressure-holding process, resulting in highly accurate weighing Injection becomes possible.

In addition, since the control for once compressing and compressing the molten resin 3 is performed by the pressure-holding driving device 6, there is no hindrance to the control of the filling driving device 5 (filling control section 5) for performing the constant stroke control. And can be done easily.

Further, in order to always accurately control a constant stroke, a start point storage device A and an end point storage device B are provided, and the movement start position P stored by the start point storage device A is stored by the end point storage device B. It is configured to be easily realized only by driving to the stroke end point Q. Therefore, an extremely innovative injection molding machine and an injection molding method that are excellent in mass productivity and feasibility are provided.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described with reference to the drawings.

First, a basic configuration of the present invention will be described with reference to FIGS. 1 to 6 by taking as an example a case where the basic configuration is applied to a pre-plastic injection molding machine. (The in-plastic method employs a pre-plastic method in consideration of the possibility that the check ring (check ring) will not return to its original position if it sucks back after compression. A supply cylinder 7 is connected via a check valve mechanism, and a supply screw 8 in the supply cylinder 7 is rotated so that a front portion of the injection drive unit 2 (injection plunger) in the injection cylinder 1 is rotated from the supply cylinder 7. To molten resin 3
The injection driving body 2 retreated backward by the molten resin 3 fed into the front portion is pushed forward to inject the molten resin 3 into the mold 4 from the front end of the injection cylinder 1 and further to drive the injection drive. Press the body 2 forward and press the mold 4
In the injection molding machine configured to be able to hold the pressure of the resin fed into the inside, after the molten resin 3 is fed into the front part of the injection driving body 2 and the measurement is completed, the injection driving body 2 is once pressed forward. A compression metering control unit 6 is provided to control the molten resin 3 in the front part to compress the molten resin 3 at the front part. A filling control unit 5 for moving the injection driving body 2 forward by a predetermined stroke based on the start position P is provided.

Further, the filling control unit 5 and the compression and weighing control unit 6 do not use a common driving device, but are separate driving devices that are separately driven and controlled. A filling driving device 5 for pushing out a predetermined stroke forward is used, and the compression / weighing control unit 6 is a pressure holding driving device for performing the pressure holding control.

In this embodiment, a filling driving device 5 (filling control unit 5) and a pressure-holding driving device 6 (compression metering control unit 6) are disposed in series behind the injection driving body 2, respectively. The apparatus 5 and the pressure-holding driving device 6 are set from a predetermined position by the filling driving device 5 at every molding shot without variably controlling the movement stop position or the pressure during the movement of the injection driving body 2 for each molding shot. The injection drive unit 2 is controlled so as to move forward by the stroke, and is controlled so that the injection drive unit 2 is pressurized at a constant pressure for a predetermined time by the pressure-holding drive unit 6 at every molding shot.

More specifically, the charging driving device 5 is configured to advance and retreat by the advance and retreat of the driving rod portion of the pressure-holding driving device 6, and the injection driving body 2 is advanced and retracted. The injection driving body 2 is configured to advance and retreat even when the driving rod portion advances and retreats.

In the present embodiment, the drive rod of the rear compression metering control unit 6 and the cylinder body of the filling control unit 5 in front of it are integrally formed, and the filling is performed by the advance and retreat of the drive rod unit of the compression metering control unit 6. The control unit 5 is configured to move forward and backward.

As described above, in the present invention, the meaning that the filling control unit 5 and the compression and weighing control unit 6 are separately configured (“configured by separate driving devices that separately drive and control”) means:
This means that, instead of one common drive device, a drive device that can separately control the filling and the holding pressure can be used, and the filling control unit 5 and the compression / weighing control unit 6 can be separately controlled as in the present embodiment. This naturally includes the case where they are integrally connected to each other.

Reference numeral 10 in the figure denotes a piston stroke adjusting rod for changing the return position of the drive rod unit of the filling control unit 5 at the time of weighing to adjust the original amount of resin to be measured when the cavity is changed. It is.

Next, this embodiment will be further clarified by specifically describing the injection method.

At the completion of the metering for feeding the molten resin 3 in front of the injection driving body 2 shown in FIG. 1, the molten resin 3 once stopped at a predetermined pressure by the pressure-holding driving device 6 as shown in FIG. Compress.

At this time, for example, since the cooling resin in the mold 4 has been filled and maintained by the last molding shot, it is in a non-injectable state and is compressed only when pressurized. Like that.

By this compression, the gas content and the air content in the molten resin 3 are compressed and exhausted, or the capacity under constant pressure compression is measured.

That is, the compressed state may be maintained, but in this embodiment, as shown in FIG. 3, by temporarily stopping the pressurization, the injection driving body 2 is sucked back and the mold 4 is opened. When the mold is discharged and the mold 4 is closed again to be ready for injection, the filling driving device 5 is operated to inject the molten resin 3 as shown in FIG. Correction is performed so that the position at which the body 2 moves forward is set as the start point position of the fixed stroke. That is, the correction position is set as a stroke start reference (movement start position P), and control is performed such that the injection driving body 2 is always driven forward by the constant stroke filling driving device 5 from the movement start position P.

In other words, the actual injection stroke of the filling driving device 5 is obtained by adding the correction stroke amount to the reference stroke. That is, although the stroke is always constant from the movement start position P, in the case of the sucked-back position in FIG. Therefore, in the present embodiment, the actual stroke length of the filling driving device 5 is successively adjusted and varied by the compression inspection for each molding shot.

Further, the filling driving device 5 always has a constant stroke, and the compensation stroke amount is equivalent to the pressure-holding driving device 6.
Alternatively, the pressure may be simultaneously driven by the pressure-holding driving device 6 again by the same compression stroke (correction stroke) by detecting the liquid amount at the time of compression.

As a result, the molten resin 3 which is always measured once
Is performed, and injection control is performed to advance a predetermined stroke based on the position (movement start position P) obtained by this compression. Therefore, even if the molten resin 3 contains gas or air, it is always constant. The capacity in the compression can be injected by extrusion with a constant stroke, and the amount of resin actually injected into the mold 4 becomes constant for each molding shot, so that a highly precise metering injection is realized compared to the past. You.

That is, in the related art, even if the feeding and metering to the front of the injection cylinder is accurate, there is a variation in the actual amount of resin extruded and injected by applying the injection pressure, so that highly accurate metering and injection cannot be performed. However, according to the present invention, the measurement accuracy is dramatically improved.

Furthermore, since the control for once compressing and compressing the molten resin 3 is performed by the pressure-holding driving device 6, the control can be easily performed without causing any trouble in the control of the filling driving device 5 for performing the constant stroke control. You will get.

According to the present invention, in order to easily realize such a concept, the molten resin 3 which has been fed and measured in front of the injection driving unit 2 is moved forward of the injection driving unit 2 based on the compression and measurement control unit 6. A starting point storage device A which stores the position of the injection driving body 2 which has been compressed and has moved slightly forward from the weighing completion position as a movement start position P, and a predetermined value based on the movement start position P based on the filling control unit 5. An end point storage device B for storing in advance a stroke end point Q for controlling the drive of the stroke injection driving body 2 is provided.

A specific embodiment of the configuration which is the gist of the present invention will be described below with reference to FIGS.

Injection driver 2 employing in-line method
A (movement detection unit 8) that moves with this drive is provided on the (drive rod of the injection screw) so as to be slidable along the drive rod.

A detection section 9A for detecting the movement detection section 8 to determine the movement start position P and a detection section 9B for detecting the movement detection section 8 and determining the stroke end point Q are provided by the injection drive. It is disposed and fixed at a predetermined stroke interval at a position where the movement detection unit 8 that moves with the body 2 abuts.

That is, in this embodiment, the detection section 9A is set at the movement start position P which is the compression position (specifically, the detection section 9A is moved forward with the movement of the injection driving body 2 as described later). The moving detection unit 8
Is set at a position where it is relatively slid backward with respect to the injection driving body 2), the detection unit 9B is set at the stroke end point Q, and the injection driving body 2 is moved from the movement start position P to the stroke end point Q. By performing the injection drive control until the injection position is reached, it is possible to always perform the injection drive from the compression position for a certain stroke.

Therefore, by configuring the distance between the detection units 9A and 9B so as to be adjustable and fixed, the constant stroke can be changed and adjusted according to various conditions.

As described above, regarding the stroke end point Q,
The stroke end point Q can be stored in advance by moving and fixing the detection unit 9B. However, in the present embodiment, the movement start position P is maintained in the compressed state in the present embodiment. Rather than performing injection driving, the compression position (movement start position P) must be able to be stored because compression is performed so as to temporarily suck back after compression and wait for injection to perform injection all at once to the stroke end point Q.

In this respect, in this embodiment, the detection unit 9A
Is fixed, and the movement detection unit 8 is slidably movable along the injection driving body 2 (drive rod of the injection screw) so that the compression operation is performed while the movement detection unit 8 is in contact with the detection unit 9A. doing.

That is, when the injection drive unit 2 moves forward during compression, the movement detection unit 8 comes into contact with the detection unit 9A, and the injection drive unit 2 further moves to the compression end position (in a predetermined state) in this contact state. (Pressure pressure value). Therefore, at the time of compression, the movement detection unit 8 does not move even if the injection driving body 2 moves forward while abutting on the detection unit 9A, and moves relatively backward with respect to the injection driving body 2.

Then, at the time of suckback, the movement detecting section 8 is separated backward from the detecting section 9A.

When the movement detecting section 8 which has moved slightly backward with respect to the ejection driving body 2 ejects and moves forward again, the position where it comes into contact with the detecting section 9A again is the movement start position P.

Therefore, the movement start position P is automatically (mechanically) stored by the movement detecting section 8 operating as described above.

The operation of this embodiment will be described with reference to FIGS.

For example, from the state shown in FIG. 13, the injection driving body 2 rotates and moves backward while feeding the molten resin 3 forward of the injection driving body 2, and by this feeding, the state shown in FIG. The metering operation of feeding the predetermined amount of resin forward of the injection driving body 2 is completed as shown in FIG.

At this time, the detection units 9A and 9B are configured to be retractable so that the movement detection unit 8 does not come into contact with the detection units 9A and 9B, and are kept in the retracted state.

Next, the compression operation is performed. In this case, for example, when the weighing operation is completed, the movement detection unit 8 is slid forward and set so that the movement detection unit 8 surely (always) comes into contact with the detection unit 9A. It may be configured as follows.

As shown in FIG. 10, when the injection driving body 2 moves forward for compression, the movement detecting section 8
A, and when the ejection driving body 2 moves further forward than the contact state, the movement detection unit 8 slides rearward relative to the ejection driving body 2.

This compression operation is performed by the compression and metering control unit 6. As described above, the compression operation is performed until the pressure value reaches a constant value, and as shown in FIG. The body 2 slightly moves backward (suck back) with the movement detection unit 8.

Therefore, at the time of completion of this compression, even if the amount of forward movement of the injection driving body 2 due to this compression is slightly larger or smaller, the movement detector 8 must be provided to the detector 9A as shown in FIG. Even if the injection driving body 2 is sucked back after compression and the movement detection unit 9B moves backward from the detection unit 9A with this suck back,
In the next injection drive, the movement detecting unit 8 is again
The position in contact with A is the movement start position P, and the movement start position P is automatically and always stored.

Next, when the injection driving body 2 that has been waiting for injection is driven after the compression / suck back, the detection unit 9A is retracted and the movement detection unit 8 is moved to the detection unit 9 as shown in FIG.
Injection driving is performed until it comes into contact with B.

Therefore, since the detecting section 9B is fixed at a position spaced a predetermined stroke from the detecting section 9A in advance,
This means that the injection drive is always performed for a certain stroke from the end of compression.

After the completion of the injection driving, the detecting section 9B
, And the pressure measurement control section 6 controls the pressure holding as shown in FIG.

In the present embodiment, as described above, the detection unit 9A, the detection unit 9B, and the movement detection unit 8 are configured as described above, so that the start point storage device A for storing the movement start position P is provided.
And an end point storage device B for storing the stroke end point Q. When the injection driving body 2 is simply driven forward and compressed, the detection unit 9A and the movement detection unit 8 are kept in contact with each other. During the injection driving, the injection control is performed by the filling control unit 5 until the movement detection unit 8 comes into contact with the detection unit 9B (until the contact sensor detects this contact), and the movement detection unit 8 comes into contact with the detection unit 9B. By detecting this, the detection unit 9B is retracted and the compression and weighing control unit 6 controls to start the pressure holding.

Accordingly, an epoch-making injection molding machine and an epoch-making method which can easily and surely realize an epoch-making injection control method in which injection control is always performed with a constant stroke based on the compression time after the above-mentioned compression is performed. .

In the present embodiment, the movement start position P at the time of completion of compression can be easily stored by employing the above-described configuration.

For example, a proximity switch may be added so as to detect the movement start position P at the time of the injection driving, or a non-contact proximity switch which originally detects the movement detection unit 8 by the detection units 9A and 9B. With this configuration, the movement start position P can be always recognized, and therefore, the speed control of the injection driving body 2 based on the movement start position P can be easily performed.

That is, in general, the speed control is performed in several steps within the range of the predetermined stroke in the injection drive, but conventionally, once the injection stroke at the first step speed is completed, the speed is switched to the second step speed. Since injection was performed, speed control was not accurate.

In this respect, in this embodiment, the speed is always controlled in accordance with the movement stroke distance from the movement start position P based on the movement start position P. Accurate speed control is possible because the reference is made.

In other words, for example, a detection unit for determining a speed change point for detecting the movement position of the movement detection unit 8 is separately provided at a predetermined position between the movement start position P and the stroke end point Q,
Each time the detection unit detects the movement detection unit 8, the filling control unit 5 performs appropriate speed control in the stroke section, so that the speed is simply sequentially changed for each absolute stroke in a conventional manner. As a result, it is possible to make the speed control extremely accurate and appropriate.

[0086]

Since the present invention is constructed as described above, the molten resin that has been measured once is always compressed, and injection control is performed to advance the molten resin by a predetermined stroke based on the position obtained by this compression (movement start position P). Therefore, even if the molten resin contains gas and air, the volume at a constant compression can always be injected by extrusion with a constant stroke. Even so)
The amount of resin actually injected into the mold becomes constant for each molding shot, and a highly precise metering injection is realized as compared with the past.

That is, in the related art, even if the feeding and metering to the front of the injection cylinder is accurate, the actual amount of the resin extruded and injected by applying the injection pressure varies, and the highly accurate metering and injection is not performed. However, according to the present invention, there is provided an injection molding machine and an injection molding method in which measurement accuracy is dramatically improved.

Further, by driving the injection driving body from the memorized starting position to the end point of the stroke, the above-mentioned functions and effects can be surely achieved. It is a molding method.

Further, in the present invention, the filling step and the pressure-holding step are controlled such that the driving state (driving pressure) is switched during the movement of the injection driving body, as compared with the case where the common actuator is used. Is unnecessary, and only one predetermined stroke drive control can be performed by one filling drive device, and only constant pressurization control can be performed by the other pressure-holding drive device. Instead of changing the control output in the middle), a simple structure and simple control are sufficient, and the repetition reproducibility for each molding shot is high. Thus, an epoch-making injection molding machine and an epoch-making method, which can solve the problem and enable high-precision metering injection.

Further, since the control for once compressing and compressing the molten resin is performed by the holding pressure driving device, the control of the filling driving device (filling control section) for performing the constant stroke control does not cause much trouble, and the control is simplified. Can be performed.

Further, in the invention according to the fourth aspect, a starting point storage device for storing a movement start position and a stroke end point,
The end point storage device can be easily realized, and in the invention according to the fifth aspect, particularly, the movement start position can be automatically stored and set by compressing and sucking back the injection molding machine, which is more practical. And an injection molding method.

Further, in the invention according to claim 6, since the speed control of the injection driving body is performed based on the stroke distance based on the movement start position, accurate and appropriate speed control can be realized.

[Brief description of the drawings]

FIG. 1 is an operation explanatory cross-sectional view of a main part at the time of completion of measurement for explaining a basic configuration of the present embodiment.

FIG. 2 is an operation explanatory cross-sectional view of a main part at the time of pressurizing and compressing after completion of measurement for explaining a basic configuration of the present embodiment.

FIG. 3 is an operation explanatory cross-sectional view of a main part at the time of suckback after pressurization and compression (when injection preparation is completed) for explaining the basic configuration of the present embodiment.

FIG. 4 is an operation explanatory cross-sectional view of a main part when injection is completed (filling is completed) for describing a basic configuration of the present embodiment.

FIG. 5 is an operation explanatory sectional view of a main part at the time of pressure holding for explaining a basic configuration of the present embodiment.

FIG. 6 is an operation explanatory cross-sectional view of main parts at the start of weighing again for explaining the basic configuration of the present embodiment.

FIG. 7 is an explanatory cross-sectional view showing a specific configuration employing the in-line method of the present embodiment.

FIG. 8 is an operation explanatory cross-sectional view of a main part in the middle of measurement showing a specific configuration employing the in-line method of the present embodiment.

FIG. 9 is an operation explanatory cross-sectional view of a main part at the time of completion of weighing, showing a specific configuration employing the in-line method of the present embodiment.

FIG. 10 is an operation explanatory cross-sectional view of a main part at the time of pressurization and compression after completion of measurement, showing a specific configuration employing the in-line method of the present embodiment.

FIG. 11 is an operation explanatory cross-sectional view of a main part at the time of suckback after pressurized compression showing a specific configuration employing the in-line system of the present embodiment.

FIG. 12 is an operation explanatory cross-sectional view of a main part when injection is completed (filling is completed), showing a specific configuration employing the inline method of the present embodiment.

FIG. 13 is an operation explanatory cross-sectional view of a main part at the time of pressure holding showing a specific configuration employing the in-line method of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection cylinder 2 Injection drive body 3 Molten resin 4 Mold 5 Filling control part 6 Compression weighing control part 8 Movement detection part 9A Detection part 9B Detection part A Start point storage device B End point storage device P Movement start position Q Stroke end point

Claims (6)

[Claims] 1. A molten resin is fed into a front portion of an injection driving body such as an injection screw or an injection plunger in an injection cylinder, and the injection driving body retreated backward is pushed forward by the molten resin fed into the front portion. An injection molding machine configured to inject the molten resin into the mold from the front end of the injection cylinder, and to further pressurize the injection drive body to keep the resin fed into the mold,
After the molten resin is fed to the front of the injection driving body and the weighing is completed, a compression weighing control unit that controls the injection driving body to compress the molten resin in the front part by pressing the injection driving body forward is provided. A position where the injection driving body is compressed and moved forward by the compression weighing control unit is set as a movement start position, and a filling control unit that moves the injection driving body forward by a predetermined stroke based on the movement start position is provided. A start point storage device for storing a position and an end point storage device for storing a stroke end point of the predetermined stroke are provided. The compression weighing control unit and the filling control unit store an end point storage device from the movement start position stored by the start point storage device. An injection molding machine characterized in that a constant-stroke injection driving body is driven at all times up to the stroke end point stored by (1). 2. A molten resin is fed into a front part of an injection driving body such as an injection screw or an injection plunger in an injection cylinder, and the molten driving resin fed into the front part pushes out the injection driving body which has receded rearward to the front. An injection molding method for injecting the molten resin into a mold from a front end of an injection cylinder, and further pressing the injection drive body forward to maintain the pressure of the resin fed into the mold; After the molten resin is fed to the front of the weighing unit and the weighing is completed, the compression driving unit temporarily presses the injection driving body forward to compress the front molten resin, and the compression moves the injection driving body forward. The starting position is stored in the start point storage device as the movement start position, and the injection driving body is moved forward by the filling control unit to the stroke end point stored in the end point storage device based on the movement start position. And injecting the molten resin by moving forward by a predetermined stroke. 3. The filling control unit and the compression weighing control unit are not a common driving device but separate driving devices that are separately driven and controlled, and the filling control unit moves the injection driving body forward by a predetermined stroke. An injection molding machine or an injection molding machine according to any one of claims 1 and 2, characterized in that it is a filling driving device that drives to extrude, and that the compression weighing control unit is a holding pressure driving device that performs the holding pressure control. Forming method. 4. A movement detection unit is provided on the injection driving body or a member that moves with the movement of the injection driving body, and a detection unit that detects a movement position of the movement detection unit is disposed at the predetermined stroke interval. The start point storage device and the end point storage device are configured to hold the position of the detection unit as the movement start position and the position of the stroke end point,
A movement start position and a stroke end point are detected when the movement detection unit comes into contact with or comes close to the detection unit, and drive of the injection driving body is constantly controlled for a predetermined stroke from the movement start position to the stroke end point. The injection molding machine and the injection molding method according to any one of claims 1 to 3. 5. When the injection driving body is once compressed by a compression metering control section, the injection driving body does not move with the movement of the injection driving body while a state where the movement detection section is in contact with or close to the detection section is maintained. The injection molding machine and the injection molding method according to any one of claims 2 to 4, wherein the injection molding machine is configured to move relative to the injection driving body. 6. The apparatus according to claim 1, wherein the driving speed of the injection driving body is controlled by reaching a predetermined stroke distance based on the movement start position. 3. The injection molding machine and the injection molding method according to 1.