Patent Application
20190039278
The present invention relates to a blow molding apparatus and a blow molding method for performing blow molding by supplying a parison discharged from a die head to a blow mold.
As blow molding by which a hollow container and the like are molded, a molding method (a direct blow molding method) is known in which a thermoplastic molten discharged material (hereinafter, referred to as a parison) having a hollow pipe shape which is discharged from a die head is clamped between blow molds and blow air is blown into the parison inside the molds.
Blow molding apparatuses which perform such blow molding can be broadly classified according to types of movement of a mold into: a rotary type in which a plurality of molds are sequentially moved to a parison supplying position along an annular path; and a shuttle type in which one or a plurality of molds are linearly moved to the parison supplying position. A rotary type blow molding apparatus is suitable for mass-producing one type of a hollow container due to a large number of molds arranged on an annular path, but a shuttle type blow molding apparatus is suitable for high-mix, low-volume production which requires a small number of molds to be frequently replaced.
With a shuttle type blow molding apparatus, although die heads are arranged in plurality and simultaneous molding is performed using a plurality of molds in order to improve productivity, the use of a plurality of die heads creates a variation in quality of discharged parisons themselves, which makes it difficult to secure uniform quality of molded products. In contrast, the conventional art described in PTL 1 below proposes improving productivity of a shuttle type blow molding apparatus by moving a plurality of molds to a parison supplying position in an efficient manner. PTL 1 describes a blow molding apparatus which supplies a parison into molds by arranging, to the right and left of a single parison, two each of four stages which move in an X-Y direction perpendicular to a central axis (a vertical axis) of the single parison and sequentially moving molds installed on each stage to a parison discharging position.
In a single rotary type blow molding apparatus, during a period of time required by one of a large number of molds arranged on an annular path to make one revolution and return to its original position, step times such as a time required for supplying a parison to molds, a blow time, and a time required for extracting a molded product from the molds are allocated at a fixed ratio. Therefore, for example, in order to extend the blow time, a speed of movement of molds must he reduced, which causes productivity to decline. In addition, an optimal mold size may be subjected to restrictions based on the number of molds and a turning radius. Furthermore, when replacing molds in order to accommodate a wide variety of molded products, since a large number of molds constitute a single set, replacing the molds requires a significant amount of time. Accordingly, rotary type blow molding apparatuses are not suitable for high-mix, low-volume production.
In contrast, since a shuttle type blow molding apparatus enables a blow time to be adjusted regardless of operation times of other steps and only requires a short period of time for replacing molds due to the small number of used molds, shuttle type blow molding apparatuses are suitable for high-mix, low-volume production. However, as in the case of the conventional art described earlier, improving productivity by sequentially moving a plurality of molds to a parison supplying position problematically prevents sufficiently high productivity from being attained because there is a limit to how fast heavy molds can be moved along a complex path.
In addition, in conventional art in which a parison discharged from a die head is directly clamped between molds, since a discharge speed of the parison also restricts productivity, there is a further problem in that it is difficult to supply a good-quality parison to the molds due to an occurrence of a drawdown in the parison from the die head or an occurrence of an accumulation of a parison above the molds immediately after the parison is clamped between the molds.
The present invention has been proposed in order to address such problems, and an object of the present invention is to improve productivity in blow molding while being suitable for high-mix, low-volume production, to obtain a high-quality molded product by supplying a good-quality parison to molds, and the like.
In order to solve the problems described above, a blow molding apparatus according to the present invention is configured as follows.
A blow molding apparatus including: a die head which discharges a parison; a parison supplying part which cuts the discharged parison at a preset length and conveys the cut parison; and a blow molding part in which the supplied parison is clamped between blow molds so as to perform blow molding, wherein the parison supplying part has a pickup chuck which conveys the cut parison alternately to a first supplying position set on one of right and left sides with respect to a discharge center of the die head and a second supplying position set on the other of right and left sides with respect to the discharge center, and in the blow molding part, the supplied parison is clamped between the blow molds that are arranged at the first supplying position and the second supplying position, respectively.
In addition, a blow molding method according to the present invention is configured as follows.
A blow molding method including: a parison supplying step of cutting, at a preset length, a parison discharged from a die head and conveying the cut parison; and a blow molding step of performing blow molding by the supplied parison being clamped between blow molds, wherein the parison supplying step conveys the parison discharged from the die head alternately to a first supplying position set on one of right and left sides with respect to a discharge center of the die head and a second supplying position set on the other of right and left sides with respect to the discharge center, and the blow molding step is performed by the supplied parison being clamped between the blow molds that are arranged at the first supplying position and the second supplying position, respectively.
A blow molding apparatus and a blow molding method configured as described above are capable of improving productivity while being suitable for high-mix, low-volume production. In addition, by supplying a good-quality parison to molds, a high-quality molded product can be obtained.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A same reference sign in different drawings in the following description indicates a common portion and redundant descriptions will be omitted as appropriate. As shown in
The die head 2 has a vertically downward discharge port and discharges the extruded parison P having a hollow cylindrical shape vertically downward at a prescribed discharge speed. P0 in
The parison supplying part 3 is provided with a pickup chuck 10 which grasps and conveys the parison P1 cut at a prescribed length from a single discharged parison P. The pickup chuck 10 conveys the cut parison P1 alternately to a first supplying position S1 set on one of right and left sides with respect to the discharge center P0 of the die head 2 and a second supplying position S2 set on the other of right and left sides with respect to the discharge center P0. While the first supplying position S1 and the second supplying position S2 are each set at one location on the left or right side in this case, this configuration is not restrictive, and a plurality of supplying positions may be set at a plurality of locations on one of the right and left sides and a plurality of supplying positions may be set at a plurality of locations on the other of the right and left sides.
The pickup chuck 10 shown in
As a conveyance route of the parison P1 from the discharge center P0 to the first supplying position S1 or the second supplying position S2, the parison P1 may be conveyed by sliding the rotation center 10P of the pickup chuck 10 to 10P′ so that the chuck part 10A traces a linear path after tracing a circular path or the parison P1 may be conveyed solely along a circular path. In addition, the parison P1 may he conveyed by sliding the rotation center 10P of the pickup chuck 10 to 10P′ while a circular path is being traced, or the pickup chuck 10 may be rotated while the rotation center 10P of the pickup chuck 10 is being slid and the parison P1 may be conveyed by stopping the slide at 10P′ after the rotation ends. Moreover, when supplying positions are provided in plurality on right and left sides of the discharge center, respectively, the conveyance route of the pickup chuck 10 is to be appropriately set in accordance with the supplying positions.
While the pickup chuck 10 rotates around the rotation center 10P by 180 degrees in the example shown in
In addition, as shown in
In this case, as shown in
The blow molding part 4 is provided with the blow molds 40 at each of the first supplying position S1 and the second supplying position S2, and performs blow molding by the parison P1 supplied to each supplying position being clamped between the blow molds 40. In the illustrated example, first blow molds 40(A) are installed at the first supplying position S1 and second blow molds 40(B) are installed at the second supplying position S2. Each blow mold 40 does not move and only performs opening/closing operations at a fixed position.
In contrast, at the blow molding part 4 that is arranged at the first supplying position S1 and the second supplying position S2, respectively, a parison supplying step T1 of supplying the parison P1 conveyed by the pickup chuck 10 to the blow molds 40 and a blow molding step T2 are independently repeated.
In the parison supplying step T1, an operation of the supplied parison P1 being damped between molds by mold clamping is performed, and in the blow molding step T2, a series of operations including starting air blow to the parison P1 clamped between the molds, ending the air blow, cooling, mold opening, and extracting a molded product is performed.
In this case, by appropriately modifying operation timings of the pickup chuck 10 at the blow molding part 4 on one side, since a period of time between a given parison supplying step T1 and a next parison supplying step T1 can be appropriately set and the respective steps of the blow molding step T2 can be appropriately set within the period of time, settings of a blow time and the like can be appropriately modified in accordance with high-mix, low-volume production.
In addition, each blow melding part 4 can start the blow molding step T2 of the first blow molds 40(A) (start air blow to the first blow molds 40(A)) during a period from supplying the parison P1 to the first blow molds 40(A) at the first supplying position S1 to supplying the parison P1 to the second blow molds 40(B) at the second supplying position S2, and start the blow molding step T2 of the second blow molds 40(B) (start air blow to the second blow molds 40(B)) during a period from supplying the parison P1 to the second blow molds 40(B) at the second supplying position S2 to supplying the parison P1 to the first blow molds 40(A) at the first supplying position S1.
Accordingly, since step times of the blow molding step T2 of a plurality of blow molding parts 4 can be advanced so as to partially overlap each other, the plurality of blow molding parts 4 can be operated in an efficient manner and high productivity can be obtained. In doing so, since the example shown in
In addition, according to the blow molding apparatus 1, since the parison P1 cut at a prescribed length from the parison P discharged from the die head 2 is grasped by the pickup chuck 10 and supplied to each blow mold 40, the accumulation of a parison above molds and the like can be eliminated as compared to a case where the discharged parison P is directly clamped between molds, and a parison with good quality can be supplied. As a result, the quality of a molded product can be improved.
Specifically, in the example shown in
With respect to the first supplying position S1, the mold moving mechanism 5 moves the first blow molds 40(A) to the first supplying position S1 while simultaneously causing the third blow molds 40(C) to move (retreat) from the first supplying position S1, and causes the first blow molds 40(A) to move (retreat) from the first supplying position S1 while simultaneously moving the third blow molds 40(C) to the first supplying position S1. In addition, with respect to the second supplying position S2, the mold moving mechanism 5 moves the second blow molds 40(B) to the second supplying position S2 while simultaneously causing the fourth blow molds 40(D) to move (retreat) from the second supplying position S2, and causes the second blow molds 40(B) to move (retreat) from the second supplying position S2 while simultaneously moving the fourth blow molds 40(D) to the second supplying position S2.
At each blow molding part 4, the parison supplying step T1 and the blow molding step T2 are performed, and mold movement which involves operating the mold moving mechanism 5 described above is performed in parallel with the blow molding step T2. A parison is supplied to each blow mold 40 by combining an operation of the pickup chuck 10 and an operation of the mold moving mechanism 5, and in the example shown in
Mold movement and mold stoppage are performed during a period from supplying the parison P1 to the first blow molds 40(A) at the first supplying position S1 to supplying the parison P1 to the second blow molds 40(B) at the second supplying position S2 and supplying the parison P1 to the fourth blow molds 40(D) at the second supplying position S2.
In addition, the third blow molds 40(C) at the first supplying position S1 moves to the first supplying position S1 simultaneously with the movement (retreat) of the first blow molds 40(A). Furthermore, the parison supplying step T1 to the third blow molds 40(C) simultaneously stops at a timing where the first blow molds 40(A) stop during the blow molding step T2, and is performed during a movement (retreat) of the second blow molds 40(B) from the second supplying position S2 and a movement of the fourth blow molds 40(D) to the second supplying position S2. Subsequently, the respective steps are performed in a similar manner to the first blow molds 40(A) described earlier.
On the other hand, the parison supplying step T1 of the second blow molds 40(B) on the side of the second supplying position S2 is performed during a movement (retreat) of the first blow molds 40(A) from the first supplying position S1 and a movement of the third blow molds 40(C) to the first supplying position S2 and, subsequently, the respective steps are performed in a similar manner to the first blow molds 40(A) described earlier.
In addition, the fourth blow molds 40(D) at the second supplying position S2 move to the first supplying position S1 simultaneously with the movement (retreat) of the second blow molds 40(B). Furthermore, the parison supplying step T1 to the fourth blow molds 40(D) simultaneously stops at a timing where the second blow molds 40(B) stop during the blow molding step T2, and is performed during a movement of the first blow molds 40(A) to the first supplying position S1 and a movement (retreat) of the third blow molds 40(C) to the first supplying position S1. Subsequently, the respective steps are performed in a similar manner to the first blow molds 40(A) described earlier.
While movement of the blow molds 40 is required in the example shown in
In addition, even in this example, since the parison P1 cut at a prescribed length from the parison P discharged from the die head 2 is grasped by the pickup chuck 10 and conveyed to each blow mold 40, the accumulation of a parison above molds and the like can be eliminated as compared to a case where the discharged parison P is directly clamped between molds, and a parison with good quality can be supplied. As a result, the quality of a molded product can be improved.
In addition, in order to ensure that a blow pin is inserted into a parison, the insides of the chuck parts 11A and 12A of the upper side pickup chuck 10(U) have a concave shape so that a parison can be grasped in an opened state. In contrast, the insides of the chuck parts 11B and 12B of the lower side pickup chuck 10(D) have a linear shape so that a parison can be grasped in a state where the parison is crushed. Furthermore, the upper side pickup chuck 10(U) and the lower side pickup chuck 10(D) are respectively supported by a lifting mechanism 13 so as to be ascendible and descendible upward and downward in the vertical direction, and rotations of the upper side pickup chuck 10(U) and the lower side pickup chuck 10(D) are controlled by a driving part 14.
The parison supplying part 3 shown in
An operation example of the pickup chuck 10 and the pinch mechanism 20 will be described using
In addition, the pinch mechanism 20 applies tension to the parison P while moving downward after the pinch part 21 holds the parison P at the first position I. In other words, a movement speed of the pinch part 21 which moves from the first position I to the second position II is set higher than a speed of descent of the parison P. Due to a subsequent pinch part 21 holding the parison P while a preceding pinch part 21 moves downward, the parison P with the preset length is held by a pair of pinch parts 21 (See
In contrast, the upper side pickup chuck 10(U) and the lower side pickup chuck 10(D) are held at a certain interval and operate so as to approach the parison P held by the pair of pinch parts 21 while moving downward in accordance with the movement of the pinch parts 21 (See
Next, a specific apparatus and operations for extracting a molded product (a bottle) from blow molds will be described. As shown in
As shown in
The gripping hand 31 is driven by an actuator 31A and grips a part (a gripped part W1) of the bottle W protruding from the blow molds 40. In the bottle W which is blow-molded by the blow molds 40, a part of the parison clamped between the blow molds 40 protrudes to the outside (upper side) of the blow molds 40 to form the gripped part W1 outside of the blow molds 40. By gripping the gripped part W1, the gripping hand 31 can grip the bottle W before the blow molds 40 open.
The support arm 32 supports the gripping hand 31 and also supports the label holding part 50. The support arm 32 is moved linearly by the moving mechanism 33 and approaches to and separates from the blow molds 40. The moving mechanism 33 is provided with a slide guide 33A which extends linearly and an actuator 33B which moves the support arm 32 along the slide guide 33A.
In order to insert a label to be attached to the bottle W into the blow molds 40, the label holding part 50 supported by the support arm 32 respectively sucks and holds one label L1a and one label L1b from label bundles La and Lb, and the label holding part 50 is provided with a suction pad 51 and a telescopic cylinder 52.
An operation of the extracting apparatus 30 will be described with reference to
As shown in
The state shown in
Subsequently, as shown in
Subsequently, as shown in
Subsequently, as shown in
Subsequently, as shown in
In such operations, by setting the timing T2 at which the gripping hand 31 of the extracting apparatus 30 grips the bottle W so as to occur before the start timing T3 of mold opening, an operation time after the mold opening can be shortened as compared to a conventional case in which mold opening is performed in a state where a bottle is supported by a blow pin and the bottle is subsequently gripped. In addition, by moving the support arm 32 from the first position to the second position, since the label holding part 50 can be brought close to the blow molds 40, a label attaching operation can be performed in an efficient manner even when a holding position of the label bundles La and Lb is set at a position separated from the blow molds 40.
Furthermore, since the operation of moving the support arm 32 to the third position (the attaching position) is an extension of the operation of moving the support arm 32 to the second position (the gripping position), a moving operation of the gripping hand 31 and a moving operation of the label holding part 50 can be performed by one moving mechanism 30. Therefore, a moving mechanism for individually moving the label holding part cart be omitted and, at the same time, installation space efficiency of the equipment can be improved.
As described above, with the blow molding apparatus 1 or a blow molding method using the blow molding apparatus 1 according to an embodiment of the present invention, the parison supplying step T1 is performed in which the parison P1 cut at a prescribed length from one parison P discharged downward from the die head 2 is distributed and conveyed by a movement of the pickup chuck 10 in the parison supplying part 3 to the first supplying position S1 and the second supplying position S2 respectively provided to the right and left of the discharge center P0, and independent blow molding steps T2 are performed by blow molding parts 4 respectively provided at the first supplying position S1 and the second supplying position S2.
Accordingly, blow molding steps of various modes accommodating high-mix, low-volume production can be performed with a small number of blow molds 40 and, at the same time, a movement of the heavy blow molds 40 can be minimized by adopting the pickup chuck 10, and highly efficient blow molding can be executed by causing step times of the blow molding steps T2 performed at the first supplying position S1 and the second supplying position S2, respectively, to advance so as to partially overlap each other. Therefore, highly productive blow molding can be performed despite having an equipment configuration suitable for high-mix, low-volume production.
In addition, with the blow molding apparatus 1 and the blow molding method according to an embodiment of the present invention, since the discharged parison P is cut at a preset length and supplied to the blow molds 40 by the parison supplying part 3, the parison P1 with reduced deformation and good quality can be supplied to the blow molds 40 arid a high-quality molded product can be obtained by blow molding. In particular, as shown in
As described above, the blow molding apparatus 1 and the blow molding method according to an embodiment of the present invention are capable of improving productivity in blow molding while being suitable for high-mix, low-volume production and are capable of obtaining a high-quality molded product by supplying a good-quality parison to molds.
While embodiments of the present invention have been described in detail with reference to the drawings, it is to be understood that specific configurations of the present invention are not limited to the embodiments and that various design modifications and the like may be made without departing from the spirit and scope of the invention. In addition, the embodiments described above may be implemented so as to combine respective techniques thereof as long as there are no contradictions, problems, and the like in an object, a configuration, and the like of such implementations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-019965 | Feb 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/003384 | 1/31/2017 | WO | 00 |
