JP3569102B2 - Molding machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a molding machine such as an injection molding machine or a die casting machine, and particularly to a technique relating to eject control of a suitable molding machine is applied when the high-cycle molding is required.
[0002]
[Prior art]
In a molding machine such as an injection molding machine, it is necessary to perform an ejecting operation for separating and ejecting a molded product adhered to a mold from a mold. It is necessary to control the protrusion amount, the forward limit position of the protrusion member, the forward speed of the protrusion member, the retreat speed of the protrusion member, and the retreat limit position (return position) of the protrusion member.
[0003]
FIG. 4 is a control characteristic diagram showing an example of a conventional ejecting operation (operation of a protruding member), in which the vertical axis represents forward speed and backward speed, and the horizontal axis represents time.
[0004]
When the ejecting operation is started, the projecting member enters a pre-progression stage in which the protruding member is driven forward by the eject drive source. In the initial region of the pre-progression process, the protruding member is controlled to be accelerated (progression acceleration region Aa). (The forward constant speed region Ac), the protruding member is decelerated (forward deceleration region Ar). Thereafter, the protruding member is stopped at the forward limit position for a predetermined period (forward limit stop area S), and then enters a retreating stroke in which the ejecting member is driven backward by the eject drive source. In the initial region of the retreat region, the protruding member is acceleration-controlled (retreat acceleration region Ba), and then passes through a region of constant retreat speed (constant reverse speed region Bc), and the protruding member is decelerated (retreat deceleration region Br). When the retreat position (return position) is reached, the eject operation for one cycle ends.
[0005]
The inclination of the speed characteristic line in the forward acceleration region Aa, the forward deceleration region Ar, the backward acceleration region Ba, and the backward deceleration region Br is set so that positional accuracy can be ensured (to prevent overshoot due to excessive acceleration / deceleration. ), Which are set to be moderate to some extent, and are all speed characteristic lines having the same slope.
[0006]
As described above, the accuracy of the forward limit position and the backward limit position (return position) of the protruding member is ensured by making the degree of deceleration in the forward deceleration area Ar somewhat moderate and the degree of deceleration in the reverse deceleration area Br somewhat moderate. it can.
[0007]
[Problems to be solved by the invention]
By the way, the basic purpose of the ejecting operation is to release the molded product from the die. The range of required specifications is wide, such as a configuration in which the protruding member can be shaken down (the forward end position of the protruding member may be slightly varied).
[0008]
For example, in high cycle molding in which one molding cycle is about 10 seconds, the priority task required for the ejecting operation is to shorten the ejection time, and in many cases, the forward end position of the protruding member may be slightly varied. However, even in the high cycle molding, it is necessary to ensure the accuracy of the retreat limit position (return position) of the protruding member, and if the retreat limit position of the protruding member varies, the tip of the eject pin becomes the cavity of the mold. Since it forms a part of the outer shape, it adversely affects the accuracy of the molded product.
[0009]
Considering the control characteristics of the conventional ejecting operation shown in FIG. 4 from this point of view, in order to ensure the accuracy of the retreat limit position (return position) of the protruding member, the degree of deceleration in the retreat deceleration region Br is moderately moderated. Although it is difficult to reduce the time of the backward deceleration region Br, it is difficult to reduce the time of the ejected member as a required eject specification. ), There was room for improvement in shortening the ejection time.
[0010]
The present invention has been made in view of the above points, and an object of the present invention is to make it possible to shorten the ejecting operation time while maintaining the accuracy of the retreat limit position (return position) of the protruding member. .
[0011]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a projecting member for projecting a molded product from a mold, an eject plate to which the projecting member is mounted, an eject drive shaft for driving the eject plate forward and backward, and A drive source for driving the eject drive shaft, and a control unit for controlling the drive source, and the eject plate is connected to the eject drive shaft, so that the projecting member is moved by the eject drive shaft even when the eject member is retracted. In a molding machine that is driven and retracted, a speed characteristic line of deceleration in an end region in a stroke in which the protruding member advances to the forward limit position, and a speed characteristic line of acceleration in an initial region in a stroke in which the ejecting member retreats from the forward limit position. Is the speed characteristic of the deceleration in the end region in the stroke in which the projecting member finally retracts to the retreat limit position. Compared to, controlled to be steeper. Further, drive control is performed by a speed command pattern that does not stop the protruding member at the forward limit position.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an ejection mechanism and an ejection control system in an injection molding machine according to one embodiment of the present invention. In the figure, reference numeral 1 denotes a fixed die plate, 2 denotes a fixed die attached to the fixed die plate 1, 2a denotes a sprue forming member of the fixed die 2, 2a-1 denotes a sprue provided to the sprue forming member 2a. Reference numeral 2a-2 denotes a resin injection port provided in the sprue forming member 2a, and a nozzle of an injection mechanism (not shown) is pressed against the resin injection port 2a-2.
[0013]
Reference numeral 3 denotes a movable die plate, which can be moved back and forth with respect to the fixed die plate 1 by an appropriate mold opening / closing drive source (eg, a mold clamping motor) and a mold opening / closing mechanism (eg, a toggle link mechanism). Reference numeral 4 denotes a movable mold that is attached to the movable die plate 3 via a mold support member 5. Although not shown, the movable mold 4 is in close contact with the fixed mold 2 in a clamped state. The two dies 2 and 4 form a cavity which is a space for forming a molded product.
[0014]
Reference numeral 6 denotes an eject drive shaft mounted on the movable die plate 3 so as to be able to move forward and backward. An eject plate 7 also mounted on the movable die plate 3 so as to be able to move forward and backward is connected to the tip thereof. A plurality of eject pins (projecting members) 8 are implanted in the eject plate 7. In the mold clamping state, the eject pin 8 is located at the retreat limit position (return position), and the tip end surface of the eject pin 8 forms a part of the wall surface of the cavity. After the mold opening is completed or while the mold is being opened, the eject pin 8 is driven forward to eject and release the molded product 9 attached to the movable mold 4.
[0015]
Reference numeral 10 denotes an ejection servomotor (hereinafter, referred to as a servomotor 10) as an ejection drive source mounted on the movable die plate 3, and 11 denotes a rotation-linear motion conversion mechanism (e.g., a well-known mechanism) also provided on the movable die plate 3. ), The rotation of the servo motor 10 is converted to linear motion by a rotation-linear motion conversion mechanism 11, and the linear motion is converted to an eject drive shaft. 6 is transmitted through a connecting member as appropriate.
[0016]
Reference numeral 12 denotes a system controller that controls the entire machine (injection molding machine), and controls the operation of each part of the machine based on various operation control programs and various setting data created in advance. Reference numeral 13 denotes a servo control unit that controls a servo amplifier 14 that drives and controls the servo motor 10. The system controller 12 executes a servo control command based on eject control condition data stored in a set condition value storage unit 12a built therein. The servo control unit 13 controls the drive of the servo motor 10 via the servo amplifier 14 by giving it to the unit 13. Reference numeral 10a denotes an encoder for detecting rotational position information of the servo motor 10. Based on the detection information from the encoder 10a, the servo control unit 13 recognizes the position of the eject pin 8, and servo-controls a speed command value corresponding to the position information. Given to the amplifier 14, the servo amplifier 14 performs speed feedback control of the servo motor 10 by comparing the speed command value with the actually measured speed value based on the detection information from the encoder 10a.
[0017]
Reference numeral 15 denotes an input operation means including a keyboard device or the like. By operating the input operation means 15, the control condition data (setting data) given to the system controller 12 is changed, and the operation start / stop is instructed. It has become.
[0018]
Next, the eject operation of the present embodiment will be described. FIG. 2 is a control characteristic diagram showing an example of the eject operation (the operation of the eject pin 8) of the present embodiment. The vertical axis represents the forward speed and the reverse speed, and the horizontal axis represents time.
[0019]
When the ejecting operation is started, the ejecting pin 8 enters a pre-traveling stage in which the ejecting pin 8 is driven forward by the servomotor 10. The eject pin 8 is controlled to accelerate (forward acceleration region Aa) in the initial region of the forward travel, and then decelerates to control the eject pin 8 through a region of constant forward speed (constant forward speed region Ac) (forward deceleration). Region Ar). As soon as the eject pin 8 reaches the forward limit position, that is, when the forward deceleration region Ar of the eject pin 8 ends, the eject pin 8 enters a retreating stroke in which the eject pin 8 is driven backward by the servo motor 10. In the initial region of the retreat region, the eject pin 8 is controlled to accelerate (retreat acceleration region Ba), and then, through a region of constant retreat (constant reverse region Bc), the eject pin 8 is controlled to decelerate (retreat deceleration region). Br), when reaching the retreat limit position (return position), one cycle of the eject operation is terminated.
[0020]
Here, in the present embodiment, the inclination angle θ1 of the speed characteristic line in the forward deceleration region Ar and the inclination angle θ1 of the speed characteristic line in the reverse acceleration region Ba are determined by the reverse deceleration region Br (when the eject pin 8 It is set to be steeper (θ1> θ2) than the inclination angle θ2 of the speed characteristic line in the retraction stroke (finally in the retraction stroke for returning to the retraction limit position in preparation for the cycle). 4, the forward deceleration and the reverse acceleration are performed more rapidly than in the prior art shown in FIG. Therefore, the time T _Ar of the forward deceleration region Ar of the present embodiment is shorter than the time T _Ar ′ of the forward deceleration region Ar in the prior art shown in FIG. 4, and the time T _Ar of the backward acceleration region Ba of the present embodiment is shorter. _Ba is also shorter than the time _TBa ′ of the backward acceleration region Ba in the conventional technique shown in FIG. Further, in the present embodiment, since the drive control is performed by a speed command pattern that does not stop the eject pin 8 at the forward limit position, the forward limit stop area S in the related art shown in FIG. time T _S of the forward limit stop area S is also adapted to eliminate.
[0021]
That is, when the control method shown in FIG. 2 is employed, one cycle time of the eject operation is reduced as compared with the conventional technique shown in FIG.
{(T _Ar '-T _Ar ) + (T _Ba ' -T _Ba ) + T _S }
, Which greatly contributes to shortening of the eject operation time.
[0022]
However, when the control described above is performed, the forward end position of the eject pin 8 varies, but in high cycle molding, in most cases, it is sufficient to simply shake off the molded product. Variations in the forward end position of the pin 8 are practically acceptable. Note that the slope of the speed characteristic line in the reverse deceleration region Br (final region in the reverse stroke for the eject pin 8 to return to the retreat limit position (finally) in preparation for the next molding cycle) is the same as the conventional one. Therefore, the position accuracy of the retreat limit position (return position) of the eject pin 8 is sufficiently ensured.
[0023]
Here, the inclination of the speed characteristic line in the forward acceleration region Aa shown in FIG. 2 (that is, the degree of forward acceleration) is selected to be an appropriate value according to the mechanism and the type of molding, and is shown in FIG. Although it is assumed to be equivalent to the prior art, a speed characteristic line steeper than this may be used in some cases.
[0024]
FIG. 3 is a control characteristic diagram showing another example of the eject operation (the operation of the eject pin 8) of the present embodiment, in which the vertical axis represents the forward speed and the reverse speed, and the horizontal axis represents time. In the present example shown in FIG. 3, the eject pin 8 is reciprocated a plurality of times in one cycle of the eject operation so that the eject pin 8 reaches the forward limit position a plurality of times.
[0025]
That is, when the ejecting operation is started, the ejecting pin 8 enters a forward traveling step (1) in which the ejecting pin 8 is driven forward, and in the initial region of the preceding traveling step (1), the ejecting pin 8 is acceleration-controlled (forward acceleration area Aa-1). Then, the eject pin 8 is controlled to decelerate (a forward deceleration region Ar-1) through a region of a constant forward speed (constant forward speed region Ac-1). As soon as the eject pin 8 reaches the forward limit position, the eject pin 8 enters a retreat stroke (1) in which the eject pin 8 is driven to retreat. In the initial region of the backward stroke (1), the eject pin 8 is controlled to accelerate (reverse acceleration region Ba-1), and then passes through a region of constant reverse speed (constant reverse region Bc-1). Deceleration control is performed (reverse deceleration area Br-1).
[0026]
In the retraction stroke (1), the eject pin 8 does not return to the retreat limit position, but returns to just before the retreat limit position. When the eject pin 8 retreats to a predetermined position just before the retreat limit position (when the retreat deceleration area Br-1 ends), the process immediately proceeds to the step (2) before the eject pin 8 is driven forward. In the initial region of the preceding traveling process (2), the eject pin 8 is controlled to accelerate (forward acceleration region Aa-2), and then passes through a region of constant forward speed (constant forward region Ac-2). The deceleration is controlled (forward deceleration area Ar-2).
[0027]
Then, as soon as the eject pin 8 reaches the forward limit position, the eject pin 8 enters a backward stroke (2) in which the eject pin 8 is driven backward. In the initial region of the reverse stroke (2), the eject pin 8 is acceleration-controlled (reverse acceleration region Ba-2), and then passes through the region of constant reverse speed (constant reverse speed region Bc-2). Deceleration control is performed (reverse deceleration area Br-2). This retreat stroke (2) is exactly the same operation as the previous retreat stroke (1), and the eject pin 8 does not return to the retreat limit position, but returns just before the retreat limit position. As soon as the eject pin 8 retreats to a predetermined position before the retreat limit position (when the retreat deceleration area Br-2 ends), the process immediately proceeds to the step (3) before the eject pin 8 is driven forward. In the initial region of the forward traveling step (3), the ejection pin 8 is acceleration-controlled (forward acceleration region Aa-3), and then passes through the region of constant forward speed (constant forward region Ac-3). The deceleration is controlled (forward deceleration area Ar-3). The preceding process (3) is exactly the same as the previous process (2).
[0028]
Then, as soon as the eject pin 8 reaches the forward limit position, the eject pin 8 enters a retreat stroke (3) in which the eject pin 8 is driven to retreat. In the initial region of the reverse stroke (3), the eject pin 8 is controlled to accelerate (reverse acceleration region Ba-3), and then passes through the region of constant reverse speed (constant reverse speed region Bc-3). When the deceleration control is performed (reverse deceleration region Br-3) and the vehicle reaches the retreat limit position (return position), the eject operation for one cycle is completed. The backward stroke (3) is the same operation as the backward stroke shown in FIG.
[0029]
In the example shown in FIG. 3 described above, the forward deceleration area Ar-1 in the forward travel step (1), the reverse acceleration area Ba-1 and the reverse travel deceleration area Br-1 in the reverse travel step (1), and the forward travel step (2). Forward acceleration area Aa-2 and forward deceleration area Ar-2, reverse travel area (2), reverse acceleration area Ba-2 and reverse deceleration area Br-2, forward travel area (3), forward acceleration area Aa-3 and forward deceleration The inclination angle θ1 of the velocity characteristic line in each of the region Ar-3 and the retreating acceleration region Ba-3 in the retreating stroke (3) is determined by the retreating deceleration region Br-3 (in the case where the eject pin 8 is It is set to be steeper (θ1> θ2) than the inclination angle θ2 of the velocity characteristic line in the retreating stroke (final region in the retreating stroke for returning to the retreat limit position) in preparation for the cycle. Therefore, in the present embodiment shown in FIG. 3, that is, even when the eject pin 8 is reciprocated a plurality of times, the time for the eject operation can be reduced, and the eject pin 8 is at the retreat limit position (return position). Accuracy can be maintained.
[0030]
【The invention's effect】
As described above, according to the present invention, it is possible to shorten the ejecting operation time while maintaining the accuracy of the retreat limit position (return position) of the protruding member. It can be applied to cases where it is sufficient to contribute to shortening the molding cycle.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an ejection mechanism and an ejection control system in an injection molding machine according to an embodiment of the present invention.
FIG. 2 is a control characteristic diagram showing one example of an eject operation in the injection molding machine according to one embodiment of the present invention.
FIG. 3 is a control characteristic diagram showing another example of an eject operation in the injection molding machine according to one embodiment of the present invention.
FIG. 4 is a control characteristic diagram showing an example of a conventional eject operation.
[Explanation of symbols]
Reference Signs List 1 fixed die plate 2 fixed mold 2a sprue forming member 2a-1 sprue 2a-2 resin injection port 3 movable die plate 4 movable mold 5 mold support member 6 eject drive shaft 7 eject plate 8 eject pin (projecting member) )
9 Molded product 10 Eject servo motor (servo motor)
10a Encoder 11 Rotation-linear motion conversion mechanism 12 System controller 12a Set condition value storage unit 13 Servo control unit 14 Servo amplifier 15 Input operation means

Claims (4)

A projecting member for projecting a molded product from a mold, an eject plate on which the projecting member is mounted, an eject drive shaft for driving the eject plate to move forward and backward, a drive source for driving the eject drive shaft, Control means for controlling a drive source, and the eject plate is connected to the eject drive shaft, the projecting member is also driven by the eject drive shaft even when retracted in a molding machine that retreats ,
The speed characteristic line of deceleration in the final region in the stroke in which the projecting member advances to the forward limit position, and the speed characteristic line of acceleration in the initial region in the stroke in which the projecting member retreats from the forward limit position, are determined by the projecting member. A molding machine having means for controlling so as to be steeper than a speed characteristic line of deceleration in an end region in a stroke of retreating to a retreat limit position. In claim 1,
A molding machine characterized in that drive control is performed by a speed command pattern that does not stop the protruding member at the forward limit position. In claim 1,
A molding machine characterized in that the ejecting member is reciprocated a plurality of times so as to reach the forward limit position a plurality of times in one cycle of the ejecting operation. In claim 3,
The speed characteristic line of the acceleration in the initial region in the stroke in which the projecting member advances to the forward limit position after the second time, and the speed characteristic line of the deceleration in the terminal region in the stroke in which the projecting member retreats other than the last time, A molding machine characterized in that control is performed so as to be steeper than a speed characteristic line of deceleration in an end region in a stroke in which a projecting member finally retreats to a retreat limit position.

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