JPH06254952A - Container preparation device - Google Patents

Abstract

PURPOSE:To prevent a die from becoming damaged or a defective molding from generating by stopping die clamping in a next injection step, if even a single lip holding means is determined to be open. CONSTITUTION:When moving a preform from an injection molding station to a following step by intermittent operation of a rotary disc 22, the airtightness state of the split halves 40A, 40B of a lip die 40 is detected using optical sensors 24, 26. If a signal is output from either of these sensors 24, 26, a control part interprets that the lip die 40 is open, and outputs a signal for interrupting injection molding and blow molding in a following cycle to an injection molding drive part. At the same time, the control part outputs a signal for alarming the interruption of molding to a display part. Consequently, it is possible to avoid the collosion between the dies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container manufacturing apparatus, and more particularly to a structure for controlling injection molding of a molded product formed by blow molding.

[0002]

2. Description of the Related Art In general, a synthetic resin thin-walled packaging container called a biaxially stretched blow molded container has a preform obtained by injection molding, for example, located in a blow mold cavity, In addition to the stretching in the direction, the pressure of the gas blown inside expands in the direction perpendicular to the axial direction.

The biaxially stretched blow-molded container described above is formed, for example, by blow-molding preforms in which the number of simultaneous moldings is lined up on a rotary disk that can be intermittently rotated.

Therefore, the preform is molded before the blow molding, and one of the molding methods is injection molding.

FIG. 5 shows a mold clamping state of a mold for injection molding. The preform 100 to be molded is
It is composed of an open lip portion 110 and a bottomed tubular body portion 120 on the lower end side thereof. A lip mold 40, an injection cavity mold 42, and an injection core mold 44 are used to injection-mold such a preform 100. The lip mold 40 has a pair of split molds 40A and 40B that can be opened in the left-right direction in the drawing, and has a cavity surface that defines the outer wall of the lip portion 110 of the preform 100. In addition, the injection cavity mold 42 is a preform 100.
Has a cavity surface 42A that defines the outer wall of the body of the vehicle, and a receiving surface 42B that is continuous with the cavity surface 42A at its lower end.
Has a gate 46 communicating with. The injection cavity 42 has a cooling passage 42B formed therein, and can cool the injection-molded preform 100 to a predetermined temperature. Further, the injection core 44 includes a base end portion 44A and a core pin 44B, and the core pin 44B is the preform 1.
The inner wall of 00 is defined. And this injection core 44
Is also provided with a cooling passage.

[0006] In each of these molds, resin is filled from the gate 46 after the mold is clamped, so that the preform 10 is formed.
Zero injection molding is performed. In the preform 100 obtained by injection molding, since the refrigerant is circulated and supplied in the injection cavity mold 42 and the injection core 44, the preform 100 is cooled to a temperature at which it can be released immediately after the injection molding, and then each mold is cooled. The mold is opened and released.

The above-mentioned lip mold 40 maintains the state in which the lip portion 110 corresponding to the neck portion of the preform 100 or the container is held from the injection molding process to the end of the blow molding. Then, the preform 100 can be released by releasing the holding of the preform 100 by opening the mold in the molding container discharging step after blow molding. Therefore, as shown in FIG. 6, the lip die 40 is normally provided with an elastic body 40C such as a spring to correct the split surface. Then, in the process of discharging the preform 100, the mold is opened by a mold opening means (not shown).

[0008]

When molding a preform with such a mold structure, the following problems may occur.

That is, there is a risk that the mold will be damaged unless the lip mold 40 and the injection cavity mold 42 to be fitted are properly aligned.

That is, as shown in FIG. 5, the lip mold 40 has tapered surfaces on the outer peripheral surface and the inner peripheral surface, and can guide and position when the injection core 44 and the injection cavity mold 42 are inserted. It is like this. But,
When the urging force of the elastic body 40C is weakened due to a change with time, the adhesive force between the split molds of the lip mold 40 is reduced, which may cause the split molds to open. Therefore, when the lip mold 40 is inserted into the injection cavity mold 42, a dimensional difference is generated between the lip mold 40 and the receiving surface 46A of the injection cavity mold 42 due to the opening, whereby the receiving surface of the injection cavity mold 42 is formed. The taper surface 42C reaching 42B will be abutted and the part will be damaged.

Further, such a mold opening phenomenon of the lip mold 40 also occurs when an abnormal situation occurs during injection molding and the injection pressure becomes extremely high. That is, the pressure of the injection-molded resin exceeds the mold clamping pressure, and when the mold is opened, the resin enters the gap. Of course, in such a case, the lip mold is opened in the splitting direction, and when the resin also enters the splitting surface and solidifies, it becomes a burr. Furthermore, the receiving surface 4
The extremely high pressure described above may also be generated between 2B and the facing surface of the lip mold 40. In this case, the resin flowing out from the cracking face reaches the cracking face of the lip mold 40 and causes burr. There is. Therefore, if the burr is not discharged from the split mold surface during the process of taking out the molded product and remains in the mold, the lip mold 40 is opened by the thickness of this burr, and as in the case described above. , Injection Cavity 4
There is a risk that the bottom surface of the lip mold 40 abuts the tapered surface 42C reaching the receiving surface 42B of the injection cavity mold 42 when it is inserted into the injection cavity mold 42, and the injection cavity mold 42 is damaged.

Even if the mold opening amount is not so large, when the burr remains in the mold, the lip mold is compressed in the closing direction at the time of mold clamping and foreign matter (burr) causes the lip mold, so-called, The neck of the molded product will be crushed.

Therefore, in view of the above-mentioned problems in the conventional container manufacturing apparatus, the object of the present invention is to prevent damage to the mold or defective molding when molding is performed using a split mold. An object of the present invention is to provide an apparatus for manufacturing a container having a structure capable of performing the above.

[0014]

In order to achieve this object, the invention according to claim 1 uses a lip mold that holds a lip portion of a preform or a molded product, and performs a preform molding step and a blow molding step. In a container manufacturing apparatus having a structure for carrying, at least one or more lip holding means formed by a split mold for holding a neck portion of the preform or a molded product, and at least before injection mold clamping of the preform. In addition, the mold opening detection means for detecting the close contact state of the split mold of the lip holding means, and the lip holding if any of the lip holding means is judged to be open by a signal from the mold opening detection means. Control means for stopping the mold clamping in the next injection step using the means.

According to a second aspect of the present invention, in the apparatus for manufacturing a container according to the first aspect, the mold opening detection means is on both sides in the arrangement direction of the lip holding means and at the boundary of the split surface of the lip holding means. It is characterized in that an optical sensor is provided, which is arranged in the opening direction of the lip holding means.

According to a third aspect of the present invention, in the container manufacturing apparatus according to the first aspect, the mold opening detecting means is in the opening direction of the lip cavity mold formed of split molds formed in the lip holding means. It is characterized by detecting the position of.

[0017]

According to the present invention, when the lip holding means for holding the lip portion of the preform or the neck portion of the container is not in close contact with the mold opening detecting means, the next injection using the non-closed lip holding means. The mold clamping in molding is interrupted. Therefore, when there is a difference in size between the molds, it is possible to prevent collision between the molds and damage due to foreign matter remaining in the molds.

That is, at the time of injection molding, particularly in the case of simultaneous molding of a large number of pieces, when the filling amount of the resin is insufficient in one mold, the total amount of the resin used for injection in the simultaneous molding in another mold. Will be overfilled as the rest of the.
For this reason, the mold filled with excessive resin will open,
The split surface resin in the open state enters and solidifies to form burrs.

If foreign matters such as burrs on the split surface of the mold are not released when the molded product is taken out, when the mold is left open and the mold is clamped in the next injection molding, The molds could not be matched and sometimes damaged. In addition, even when such foreign matter is present in the mold,
A part of the molded product may be compressed and crushed between foreign matters.

Therefore, in the present invention, by detecting such a mold opening, the next injection molding die clamping is not performed, and it is possible to prevent an unexpected accident of the mold or the molded product. .

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. 1 and subsequent drawings, the same components as those shown in FIGS. 5 and 6 are designated by the same reference numerals.

FIG. 1 is a plan view showing an injection stretch blow molding apparatus 10 which is an example of a container manufacturing apparatus according to the present invention.

A turntable 22 is provided on the machine base 20 of the blow molding apparatus 10. The turntable 22 is the machine base 2
It is provided so as to be intermittently rotatable with respect to 0 in the direction of the arrow in the figure. Then, in the process of rotating the turntable 22, the injection molding station 1 for executing the injection molding process of the preform.
2. A temperature control station 14 for performing the temperature control process of the preform, a stretch blow station 16 for performing the biaxial stretch blow molding process of the preform, and an eject station 18 for performing the process of taking out the molded product are provided.

The turntable 22 is provided with a structure for holding the neck portion of the molded product or the lip portion 110 of the preform 100 during the movement to each station. This structure is the same as that described in FIG. A mold 40 is used. Therefore, the lip die 40 is provided so as to be interlocked with the turntable 22 side, and in the present embodiment, the split dies 40A and 40B of the lip die 40 are supported and attached to the turntable. It is provided with a lip plate 40D. The lip die 40 is provided along the circumferential direction of the turntable 22 so that four blocks can be simultaneously molded into one block.

On the other hand, mold opening detection means is provided at a position corresponding to at least before mold clamping is performed in the injection molding process. That is, the mold opening detection means is the lip mold 4
It is for detecting the close contact state of the split molds 40A and 40B of 0, and in the case of the present embodiment, it is composed of a plurality of optical sensors 24 and 26 composed of a transmission type. The optical sensors 24 and 26 are always fixed to a fixed position regardless of the rotation of the turntable 22 in the injection molding station 12 that executes the injection molding process of the preform 100. In the case of the present embodiment, It is provided so as to face the annular taper surface 40E (see FIG. 2) of the lip die 40 that projects toward the receiving surface 42B side of the injection cavity 42. The optical sensors 24 and 26 are, as shown in FIG. 2, on both sides of the lip plate 40C in the arrangement direction of the lip mold 40,
The split mold opening direction (see FIG. 2) with the split surface of the lip mold 40 as a boundary.
(Inside, in the direction indicated by the arrow).

The optical sensors 24 and 26 arranged in the split mold opening direction with the split surface of the lip mold 40 as a boundary,
As the facing distance in the opening direction of the split mold, the injection cavity 4
2 when the lip mold 40 is inserted into the injection cavity 4
The second taper surface 42C is set at an interval at which an opening amount that cannot be corrected can be detected.

Therefore, when any one of the lip molds 40 blocks the optical path of any of the optical sensors 24 and 26, it is detected that the split mold of the lip mold 40 has an opening larger than the allowable amount. it can.

The optical sensors 24 and 26 are adapted to output to the control unit 30 a signal which detects this state when either optical path is blocked.

The control unit 30 is provided for sequence control of the molding process in the blow molding apparatus 10 including the injection molding process, and its configuration is shown in FIG.

That is, the control unit 30 has a ROM 30B in which a molding sequence program and basic data necessary for sequence control are registered, and a microcomputer 30A having a RAM 30C in which various data can be written.
The main part is composed of. The optical sensors 24 and 26 are connected to the input side of the microcomputer 30A, and the blow molding drive section 32, the injection mold clamping drive section 34 and the display section 36 are connected to the output side. It is connected via the / O interface 30D.

The control unit 30 determines that the split molds 40A and 40B of the lip mold 40 holding the preform are in close contact with each other based on the signal output from either the optical sensor 24 or 26. In this case, a signal for continuously executing the injection molding sequence including the mold clamping is output to the injection molding driving unit 34.

When the abnormality warning is given, the split molds 40A, 4A are provided after the molding product take-out step and before the injection molding.
0B is open without being in close contact, and the cause thereof is, as described above, that foreign matters such as burrs remain and the initial habit of the lip mold 40 itself is deteriorated. In this case, the lip mold 40 is replaced by the injection cavity mold 4
If inserted into 6, there is a risk that both will collide with a place other than the proper fitting position and be damaged.

Next, the operation will be described.

FIG. 4 is a flow chart for explaining the operation of the control unit 30, and this flow chart is set in the program for molding sequence control.

The preform 100 formed by injection molding is held by the lip mold 40 at the injection molding station 12 and moves together with the turntable 22.
Injection molding station 12 with intermittent rotation of turntable 22
When the preform moves from the next step to the next step, the split die 40 of the lip die 40 is moved by the optical sensors 24 and 26.
The close contact state of A and 40B is detected.

On the other hand, in the control unit 30, the optical sensor 24,
When the output signal from any one of 26 is discriminated and the signals are output from both, the split mold 40A of the lip mold 40, 4
It is determined that all 0B are in close contact with each other, and a signal for executing injection molding mold clamping in the molding cycle is output to the injection mold clamping drive unit 34. Therefore, even if the lip mold 40 is inserted into the injection cavity 42 and clamped, the split molds 40A and 40B do not collide with the injection cavity mold 42.

On the other hand, when a signal is output from either of the optical sensors 24 and 26, it is determined that the lip mold 40 is open, and the injection in the next blow molding and the next molding cycle is performed. A signal for interrupting molding is output to the injection molding drive unit 34, and a signal for warning that molding interrupt has occurred is output to the display unit 36. Therefore, the split molds 40A and 40B of the lip mold 40 are not clamped together, and collision between the molds is avoided.

According to this embodiment, the opening of the mold can be detected by using a simple optical sensor without requiring a special structure.

According to this embodiment, the optical sensor 24,
26 is provided so as to face the annular tapered surface 40E (see FIG. 2) of the lip die 40 that projects toward the receiving surface 42B side of the injection cavity 42. Therefore, this position is
Because there is nothing other than preforms,
It is possible to detect the close contact state of the mold without being disturbed by the devices installed around the lip mold 40.

Further, according to this embodiment, the optical sensor 2
Since the Nos. 4 and 26 are provided so as to face the annular taper surface 40E of the lip die 40, the sensitivity for detecting the opening amount of the lip die 40 is the same as that of the taper surface 40E only by moving the lip die 40 in the longitudinal direction. You can adjust the spacing between. Therefore, as compared with the case where the opening amount is adjusted for the vertical piece, the area occupied in the lateral direction for the movement of the optical sensor is not required, and the enlargement of the device can be prevented.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the gist of the invention. For example, not only a one-stage system or a hot parison system in which injection molding to blow molding are performed on the same rotating disk while being rotated, but also a one-stage system without a temperature control process It is also possible. In any case, it is particularly applicable to a container manufacturing apparatus that uses a split mold of a type capable of opening and closing molds having relative shapes.

Further, as the type of the mold opening detecting means, either a non-contact type or a contact type can be used. Specific examples of these types include photoelectric sensors including transmissive and reflective types, sensors using laser light, proximity switches, push button structure switches called so-called touch sensors, pressure switches, and the like. is there. Of these detection means, the contact type may be embedded in the lip type, and each time the lip type reaches the injection position,
The contact status may be confirmed.

[0043]

As described above, according to the present invention, the degree of opening of the mold to be clamped is detected and the molding process is controlled at a time corresponding to before molding using a mold having a structure for clamping. can do. Therefore, when the split mold used for molding is opened more than a predetermined amount, it is possible to prevent the mold from being clamped in the molding process. It is possible to prevent collision and prevent the mold from being damaged.

[Brief description of drawings]

FIG. 1 is a plan view for explaining the overall structure of a blow stage used in a container manufacturing apparatus according to the present invention.

FIG. 2 is a perspective view for explaining a relationship between a lip holding unit and a mold opening detection unit in the blow stage shown in FIG.

FIG. 3 is a block diagram for explaining a configuration of a control unit used in the container manufacturing apparatus according to the present invention.

4 is a flowchart for explaining the operation of the control unit shown in FIG.

FIG. 5 is a cross-sectional view showing an example of a mold structure used in injection molding.

FIG. 6 is a perspective view showing a structure of a lip cavity mold which constitutes a lip holding means in the mold structure shown in FIG.

[Explanation of symbols]

 10 Manufacturing Equipment 12 Injection Molding Station 22 Rotating Disk 24, 26 Optical Sensor 30 Control Unit 32 Blow Molding Drive Unit 34 Injection Molding Drive Unit 36 Display Unit

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Claims (3)

[Claims] 1. A container manufacturing apparatus having a structure for carrying a preform molding step and a blow molding step by using a lip mold for holding a lip portion of the preform or the molded article, wherein the preform or the molded article is provided. At least one lip holding means formed of a split die for holding the neck portion of the mold, and at least a mold opening detection means for detecting a close contact state of the split die of the lip holding means before the injection molding die clamping of the preform. And a control means for stopping the mold clamping in the next injection process using the lip holding means when it is determined by the signal from the mold opening detection means that even one of the lip holding means is open. An apparatus for manufacturing a container, which is characterized by being provided. 2. The container manufacturing apparatus according to claim 1, wherein the mold opening detection means is on both sides in the arrangement direction of the lip holding means and in a direction in which the lip holding means opens with the split surface of the lip holding means as a boundary. An apparatus for manufacturing a container, which is provided with an optical sensor disposed in each of the above. 3. The container manufacturing apparatus according to claim 1, wherein the mold opening detection means detects a position in a opening direction of a lip cavity mold made of a split mold, which is formed in the lip holding means. An apparatus for manufacturing containers.