JPH06254951A - Container preparation device - Google Patents

Abstract

PURPOSE:To prevent an injection die from being damaged by a preform which remains inside the die by detecting the number of performs held after separation from the die at an injection molding station, and clamping the die for a next round of injection using a lip holding means which holds the preform, if the number of preforms is found equal to a predetermined number. CONSTITUTION:A preform which is molded by injection moves being held by a lip die on a rotary disc 22 side. A control part 28 counts an output signal from an optical sensor 26 and compares the count with the number of simultaneously molded preforms which is set by a number input switch 30. If the number of simultaneously molded preforms coincides with the number of preforms held by the lip die by comparison, a signal is output to an injection molding drive part 36 so that the preform is molded by injection in a next cycle using the lip holding means. Thus it is possible to avoid the generation of an abnormal load to the die.

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 an injection molding control structure for 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.

As a molding apparatus for the above-mentioned container, for example,
Attach the lip cavity type to the rotating disk that can be rotated intermittently,
There is one that performs one cycle of molding at an injection molding station, a temperature control station, a blow molding station, and an eject station. This method is called a hot parison method or a one-stage method.

By the way, a preform is molded before blow molding, and one of the molding methods is injection molding.

FIG. 4 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 44A 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 lip die 40 described above is maintained in a state of holding the preform 100 or the lip portion 110 corresponding to the neck portion of the container from the injection molding process to the end of the blow molding, and at the time of ejecting after the blow molding. When the mold is opened, the holding of the preform 100 is released and the preform 100 is discharged. Therefore, the lip type 4
In the case of 0, correction is usually given to bring the split surface into close contact with the elastic body 40C such as a spring. And preform 1
In the discharging step of 00, the mold is opened by a mold opening means (not shown).

[0008]

In the one-stage system as described above, injection molding is performed in the next cycle on the premise that there are no residues or foreign matters in the mold shown in FIG. The molded preform may remain in the mold. Therefore, when the mold is clamped in the next cycle, the mold is clamped while the foreign matter in the mold is sandwiched, and there is a risk of damaging the mold.

That is, in the structure of the mold shown in FIG. 4, if the mold and the preform are not properly separated after injection molding, for example, the preform 100 may fall into the injection cavity mold 42, Alternatively, the preform 10
0 may remain in close contact with the injection core 44. One of the reasons why the preform 100 is left in the injection cavity 42 is that the injection amount of the resin at the time of injection molding is not a predetermined amount and the so-called short shot occurs and the resin does not reach the neck. And preform 1
The body part other than the neck part of 00 easily falls into the injection cavity 42. Further, one of the reasons why the preform 100 remains in intimate contact with the injection core mold 44 is that, due to a short shot, the threaded portion remains unfinished and is not retained by the lip, and intimately adheres to the incore in the shrink direction of the preform. It is to be lifted while doing.

Therefore, when the injection mold is clamped in the next molding cycle while the preform remains in the injection cavity mold 42 or the injection core mold 44, the preform remaining in the solidified state is clamped. When it collides with the mold due to force, a load such as crushing or bending the mold is generated and the mold is damaged, or a normal injection molded product cannot be obtained.

Therefore, an object of the present invention is to prevent damage to the mold in advance even when the preform remains in the mold in view of the problems in the conventional container manufacturing apparatus described above. An object of the present invention is to provide an apparatus for manufacturing a container having a structure capable of achieving the above.

[0012]

In order to achieve this object, the invention according to claim 1 has a structure in which a preform molded at an injection molding station is held by lip holding means and conveyed to the next step. In a container manufacturing apparatus, means for detecting the number of preforms separated at the injection molding station and held by the lip holding means, and the number of preforms at a predetermined value based on a signal from the detecting means. It is characterized in that it is provided with a control means for carrying out the next injection mold clamping using a lip holding means holding the preform only in a case.

According to a second aspect of the present invention, in the container manufacturing apparatus according to the first aspect, the detection means is provided between the time when the injection-molded preform is opened and the time before the next injection-molding die is clamped. It is characterized by a detection operation.

According to a third aspect of the present invention, in the container manufacturing apparatus according to the first aspect, the detecting means optically detects the passage of the preform while the injection-molded preform is being conveyed to the next step. It is characterized by being configured by an optical sensor for detecting.

[0015]

According to the present invention, after the preform is molded, the number of preforms held by the lip holding means is detected, and the detected number is compared with a predetermined value, that is, the number of simultaneous moldings. It Therefore, if the number of preforms held by the lip holding means does not match the number of simultaneous moldings, it is determined that the preforms remain on the mold side used at this molding station. You can As a result, the next injection molding process using the lip holding means in the state where the number of preforms is insufficient can be stopped, so the mold clamping of the mold used for the next preform molding is stopped. By preventing an abnormal load from being applied to the die, damage to the die can be prevented.

[0016]

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 FIG. 4 are designated by the same reference numerals.

FIG. 1 is a plan view showing a machine base 20 of a blow molding apparatus 10 which is an example of a container manufacturing apparatus according to the present invention. The blow molding apparatus 10 uses a hot parison method capable of molding a preform on a rotary orbit by an injection molding mechanism, which will not be described in detail.

A turntable 22 is provided on the machine base 20. The turntable 22 is provided so as to be intermittently rotatable with respect to the machine base 20 in the direction of the arrow shown in the drawing. The station 16 that executes the blow molding process and the eject station 18 that executes the molded product take-out process are moved.

On the turntable 22, while the injection-molded preform 100 is going from the injection molding station 12 to the eject station 18, the lip portion 1 of the preform 1 is formed.
A holding means for holding 10 is provided, and in this embodiment, this holding means is the lip mold 40 shown in FIG.
It is composed by. The lip type 40 is the turntable 22.
The number of simultaneous moldings is set so that four blocks form one block along the circumferential direction.

On the other hand, in the direction of rotation of the turntable 22, from the injection station 12 to the temperature control station 14, which is the next step, for detecting the number of preforms 100 held by the lip holding means 40. A detection means is arranged. In the case of this embodiment, the detection means is
On the way from the injection molding station 12 to the temperature control station 14, the reflection type diffusion optical sensor 26 facing the preform held by the lip mold 40 on the turntable 22 side.
(Hereinafter referred to as an optical sensor 26), the presence of the preform is detected when the light from the light source enters the light receiving portion.

The optical sensor 26 outputs a detection signal to the control unit 28.

The control unit 28 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 28 has a ROM 28B in which a molding sequence program and basic data necessary for sequence control are registered, and a microcomputer 28A having a RAM 28C in which various data can be written.
The main part is composed of. The optical sensor 26 and the number input switch 30 are provided on the output side of the microcomputer 28A, and the temperature adjustment drive unit 32 is provided on the output side.
The blow molding drive unit 34, the injection molding drive unit 36, and the display unit 38 are connected via the I / O interface 28D. The quantity input switch 32 is, for example, a switch for inputting the simultaneous molding quantity for each production lot of the container, and the quantity is inputted by the operator.

In the control section 28, the number of preforms per block held in the lip mold 40 output from the optical sensor 26 is determined based on the simultaneous preform molding number set by the number input switch 32. If the same number of preforms as the reference preforms that are counted and held in the lip mold 40, a normal molding drive sequence is set for the temperature adjustment drive unit 32 and the blow molding drive unit 34. In addition to outputting a signal for execution, a signal for executing a regular injection molding sequence for the next cycle is similarly output to the injection molding drive unit 36.

On the other hand, when the number of preforms held by the lip die 40 does not match the number of preforms simultaneously formed, that is, the number of preforms 100 held by the lip die 40 is insufficient. If you are
A signal for displaying an abnormality warning is output to the display unit 38, and the blow molding drive unit 34 and the injection molding drive unit 36 are supplied to the next cycle using the lip mold 40, that is, at least the next injection. A signal is output to stop the mold clamping operation. In this case, all the next steps may be stopped.

When an abnormal warning is given, at least one of the injection molded preforms is at least one of the simultaneously molded preforms, the injection cavity mold 42 or the injection core 4.
This is the case that the 4th side remains. In this case, if the mold is clamped at the next injection molding and remains in the mold, the mold and the preform collide with each other due to the mold clamping force, and a load such as crushing or bending the mold occurs. There is a risk of damaging the mold.

Next, the operation will be described.

FIG. 3 is a flow chart for explaining the operation of the control unit 28, and this flow chart is set in the program for controlling the molding sequence.

Then, the injection-molded preform is
It moves while being held by the lip mold 40 on the turntable 22 side. When the preform moves due to the intermittent rotation of the turntable 22, the presence of the preform is detected by the optical sensor 26.

On the other hand, the control unit 28 counts the output signal from the optical sensor 26 and compares it with the simultaneous molding number set by the number input switch 30. Then, by this comparison, it is judged whether or not the number of simultaneous moldings and the number of preforms held by the lip mold 40 match, and if they match, the next cycle using the lip holding means. A signal is output to the injection molding drive unit 36 in order to perform the injection molding in 1. At this time,
A signal for continuing the operation is also output to the temperature adjustment drive unit 32 and the blow molding drive unit 34.

On the other hand, when it is determined that the set number of simultaneous moldings and the number of preforms held by the lip mold 40 after the mold release do not match, the injection molding drive unit 36 is pressed. Lip type 4 with insufficient number of reforms
A signal for interrupting the injection molding in the next cycle using 0 is output, and then a signal for issuing an abnormality occurrence warning is output to the display unit 38. At this time, a signal for interrupting the operation is also output to the blow molding drive unit 34.

According to this embodiment, normally, in addition to detection of abnormal molding during injection molding, detection of the carry-in status of the preform can accurately detect the residual of the preform in the injection molding die. Can be detected. That is, the abnormal molding during injection molding is detected by detecting the injection time, the injection pressure, and the moving position of the plunger, and if these do not satisfy the predetermined conditions, it is determined that the abnormal molding has occurred. ing. However, the detection of such abnormal molding is detection at the time of molding, and does not target the actually molded product. Therefore, by making it possible to determine the state of the preform that has actually been molded and released by using a simple configuration such as the optical sensor shown in the present embodiment, targeting the actual molded product in addition to the time of molding. It is possible to detect abnormal molding, and thereby double check the damage prevention of the molding die in the next molding cycle.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the invention. For example, not only targeting a one-stage system or hot parison system in which injection molding to blow molding are performed on the same rotating table, but also a one-stage system without a temperature control process. It is also possible to do so.

The quantity input switch is not always provided, and may be replaced with, for example, the simultaneous molding quantity for each lot registered in the molding sequence program.

[0035]

As described above, according to the present invention, the number of released preforms is compared with the number to be molded in the injection molding process. Then, when the number of released preforms is not a predetermined value, it can be determined that the preforms remain in the mold used in the injection molding process. This makes it possible to stop the injection molding process of the next preform using the lip holding means in which the number of preforms is insufficient, so the mold clamping for the next preform is stopped. By avoiding abnormal load on the mold, damage to the mold is prevented.

[Brief description of drawings]

FIG. 1 is a plan view for explaining an overall configuration of a machine base used in a container manufacturing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a control unit used in the container manufacturing apparatus according to the present invention.

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

FIG. 4 is a cross-sectional view for explaining a clamped state of a mold used for injection molding.

[Explanation of Codes] 10 Manufacturing Equipment 12 Injection Molding Station 22 Rotating Disk 26 Optical Sensor 28 Control Unit 32 Number Input Switch 34 Blow Molding Drive Unit 36 Injection Molding Drive Unit 38 Display Unit

Claims (3)

[Claims] 1. A container manufacturing apparatus having a structure for holding a preform molded in an injection molding step by a lip holding means and carrying it to the next step, wherein the lip holding means is released at the injection molding station. Next, using the means for detecting the number of preforms held by, and the lip holding means holding the preforms only when the number of preforms is at a predetermined value by the signal from the above detection means. And a control unit for performing the injection mold clamping of the container. 2. The container manufacturing apparatus according to claim 1, wherein the detection means detects the injection-molded preform from the time the injection mold is opened to the time before the next injection-mold clamping. Characteristic container manufacturing equipment. 3. The container manufacturing apparatus according to claim 1, wherein the detection means is constituted by an optical sensor that optically detects passage of the preform while the injection-molded preform is being conveyed to the next step. An apparatus for manufacturing a container, which is characterized in that