JP2017177592A - Rotary blow molding machine and rotary blow molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary blow molding machine and a rotary blow molding method, which are capable of temporarily holding a molded article on one side of a molding unit when opening the mold unit, without requiring fine adjustment for corresponding to changes in materials and sizes of the molding units and molded articles.SOLUTION: A rotary blow molding machine 1 includes a rotary pedestal 10 and a molding unit 20 which is provided on a surface of the rotary pedestal 10 for molding a molded article P. The molding unit 20 includes a first molding die 30 and a second molding die 40 that is opened and closed with respect to the first molding die 30. The second molding die 40 has thrust-off means 433 for thrusting off the molded article P toward the first molding die 30 side so that the molded article P is held at the first molding die 30 when the second molding die 40 is opened.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotary blow molding machine and a rotary blow molding method.

  2. Description of the Related Art Conventionally, for producing relatively small resin containers such as mayonnaise and various beverages, a rotary blow molding machine that molds the containers with a mold provided on a rotating base is known (for example, Patent Document 1). ).

  A rotary blow molding machine sequentially supplies molten resin members (parisons) to a plurality of mold units provided continuously on the outer surface of a rotating pedestal by an extruder, and gas is supplied to the inside thereof. This is a molding method for continuously molding a hollow molded body by blowing. In this blow molding, it is desirable from the viewpoint of taking out the molded body that the molded body is always held in the same direction of the mold unit when the mold is opened. However, when the mold unit is actually opened, there is a problem that the molded body adheres to an unintended side of the mold unit and the molded body cannot be taken out smoothly.

  Patent Document 1 discloses an invention in which a temporary holding pin provided on one side of a mold unit is temporarily held parallel to the longitudinal direction of a molded body in a discarded bag portion cut out after molding. . However, in Patent Document 1, since the optimal length of the temporary holding pin varies depending on the material and size of the mold unit and the molded body, fine adjustment is difficult. There was a problem that it became an obstacle to taking out from the mold unit.

Japanese Patent Publication No.58-40503

  The present invention has been made based on such circumstances, and its purpose is that when the mold unit is opened, fine adjustment by changing the material and size of the mold unit and the molded body is not required. Another object of the present invention is to provide a rotary blow molding machine and a rotary blow molding method capable of temporarily holding a molded body on one side of a mold unit.

The present invention is grasped by the following composition.
(1) A first aspect of the present invention is a rotary blow molding machine, comprising: a rotary pedestal; and a mold unit that is provided on a surface of the rotary pedestal and molds a molded body. Has a first mold and a second mold that opens and closes between the first mold, and the molded body is held by the first mold when the second mold is opened. As described above, the second mold has a projecting means for projecting the molded body toward the first mold.

(2) In the configuration of (1), the mold unit is a second mold that opens and closes in a single-opening manner between a lower mold as the first mold and the lower mold. An upper die may be provided, and the push-out means may be a push-down means that pushes down the molded body toward the lower mold.

(3) In the configuration of (1) or 2, the projecting means may be a projecting pin driven by an air cylinder.

(4) In any one configuration of the above (1) to (3), the protruding means may protrude the discarded bag portion of the molded body.

(5) In any one of the constitutions (1) to (4), the second mold has a mirror finish on the inner surface at a position where the molded body is likely to adhere to the second mold. May be.

(6) In the configuration of (5), the mirror finish portion may include a range corresponding to a shoulder portion and a bottom portion of the molded body.

(7) In the configuration of (5) or (6), the mirror finish may have an arithmetic average roughness Ra of 0.01 μm to 0.10 μm.

(8) In the configuration of any one of (5) to (7), the first mold has a rough surface finish portion on the inner surface at a position corresponding to the mirror finish portion of the second mold. You may have.

(9) In the configuration of the above (8), the rough surface finish portion may have an arithmetic average roughness Ra of 1.50 μm to 2.50 μm.

(10) A second aspect of the present invention is a rotary blow molding method, which is provided on a surface of a rotary pedestal and is opened and closed between a first mold and the first mold. A step (a) for supplying a parison to a mold unit comprising: a step (c) for clamping the mold unit and molding a molded body; and a step (c) for opening the mold unit. And the step (d) of taking out the molded body from the mold unit, and when the second mold is opened during the step (c), the molded body becomes the first mold. The holding means provided in the second mold so as to be held protrudes the molded body to the first mold side.

(11) In the configuration of the above (10), another protruding means provided in the first mold causes the molded body to be removed from the first mold so that the molded body can be smoothly taken out in the step (d). You may project to the side of 2 molds.

  According to the present invention, when the mold unit is opened, the molded body is temporarily held on one side of the mold unit without requiring fine adjustment by changing the material and size of the mold unit and the molded body. It is possible to provide a rotary blow molding machine and a rotary blow molding method.

It is a figure which shows the rotary blow molding machine which concerns on embodiment of this invention, Comprising: The conceptual diagram which shows the condition where each metal mold | die (upper metal mold | die and lower metal mold | die) provided in the rotation base was opened and closed, rotating. It is. It is a side view which shows the mechanism of opening and closing of the upper metal mold | die and lower metal mold | die of FIG. It is a figure which shows an example of the molded object shape | molded with a rotary blow molding machine. It is a top view which shows the inner side of the lower metal mold | die of FIG. It is a longitudinal cross-sectional view of the lower mold of FIG. It is a top view which shows the inner side of the upper metal mold | die of FIG. It is a longitudinal cross-sectional view of the upper metal mold | die of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.

(Overall configuration of rotary blow molding machine 1 and rotary blow molding method)
As shown in FIG. 1, the rotary blow molding machine 1 includes a rotary pedestal 10 and a plurality of mold units 20 that are provided on the surface of the rotary pedestal 10 and mold the molded body P. In addition, outside the system of the rotary blow molding machine 1, a molten parison M (resin member) resin supply device S (right side in the figure, partially shown) and a take-out device for taking out the molded body P (left side in the figure). (Not shown) is provided.

  The rotating pedestal 10 is configured to rotate at a constant speed, and sequentially moves a plurality of mold units 20 provided on the surface. In addition, although the case where it rotates clockwise here is shown, it may be counterclockwise.

  The mold unit 20 is disposed concentrically on the surface of the rotary base 10. Here, twelve mold units 20 are illustrated, but the number of arrangements is not limited to this. The mold unit 20 includes a lower mold 30 as a first mold and an upper mold 40 as a second mold that opens and closes between the lower mold 30 in a single-opening manner. In the following, a mode in which the lower mold 30 is fixed to the rotary base 10 and the upper mold 40 opens and closes in a single-opening manner will be described. In this embodiment, the second mold faces the first mold. Thus, the present invention can be applied even if the vehicle moves forward and backward.

  The plurality of mold units 20 open and close as follows from the first mold unit 201 located at 12:00 to the twelfth mold unit 212 immediately before the first mold unit 201. In the first mold unit 201, the upper mold 40 is fully opened with respect to the lower mold 30. From this state, the upper mold 40 is sequentially closed from the second mold unit 202 to the third mold unit 203, and the fourth mold unit 204 to which the parison M is supplied from the die D of the resin supply device S. The stage is completely closed, that is, the mold is clamped (step (a) of the rotary blow molding method).

  And the molded object P is shape | molded by blowing and cooling air from the 5th mold unit 205 to the 9th mold unit 209 (step (b) of the rotary blow molding method). The upper mold 40 is opened at the stage of the tenth mold unit 210, and the upper mold 40 is fully opened at the stage of the eleventh mold unit 211 (step (c) of the rotary blow molding method). And the molded object P is taken out one by one by the taking-out apparatus which is not illustrated from the 11th metal mold | die unit 211 (step (d) of a rotary blow molding method). After the molded product P is taken out, the upper mold 40 is moved from the twelfth mold unit 212 to the first mold unit 201 with the upper mold 40 fully opened.

  Here, as will be described in detail later, the upper mold 40 of the mold unit 20 is provided with a pushing means (push-down pin 433), and when the upper mold 40 is opened in step (c). The pushing means (push-down pin 433) pushes the molded body P toward the lower mold 30 (pushes down) so that the molded body P is held by the lower mold 30. Further, the lower mold 30 is provided with another push-out means (push-up pin 333). In step (d), another push-out means (push-up pin 333) is provided so that the molded product P can be smoothly taken out. The molded body P is pushed out toward the upper mold 40 side (push up). It should be noted that “to the upper mold 40 side” is widely used to mean “upward when viewed from the lower mold 30”. Similarly, “to the lower mold 30 side” is also widely used to mean “downward as viewed from the upper mold 40”.

  As shown in FIG. 1, the molded body P is taken out from the eleventh mold unit 211 in a state of being connected by the burr portion B. At that time, as shown in the figure, the molded body P is sequentially taken out from the state of being held on the lower mold 30 side. The removed molded body P is deburred and finished as a product.

  Here, the point that the upper mold 40 opens and closes in a single-open manner will be described. As shown in FIG. 2, the mold unit 20 includes a lower mold 30 and an upper mold 40. The lower mold 30 includes a first base portion 31, a second base portion 32, and a lower cavity portion 33, and a shaft portion 311 is provided on the first base portion 31. The first base 31 and the second base 32 are fixed to the rotary base 10. The upper mold 40 includes a first base 41, a second base 42, and an upper cavity portion 43, and the first base 41 is provided with a receiving portion 411 that receives the shaft portion 311. As a result, the upper mold 40 is hinge-coupled to the lower mold 30 and opens and closes in a single-opening manner as indicated by the arrows. The mold unit 20 of this aspect may be referred to as a book type.

  In the case of this book type, after the upper mold 40 is fully opened, the molded product P is taken out by the take-out device while being held in the lower mold 30. If the molded product P is attached to the upper mold 40, it cannot be taken out by the take-out device, and the molded product P is attached to the upper mold 40 from the twelfth mold unit 212 to the fourth. The state moves to the mold unit 204 and a state (double shot) occurs in which a new parison M is supplied on the molded product P in an overlapping manner and defective products are generated.

  In order to avoid such a state, in this embodiment, the lower mold 30 and the upper mold 40 constituting the mold unit 20 are configured as follows.

(Molded product P and burr part B)
Here, an example of the aspect of the molded body P molded by the mold unit 20 will be described in advance. As shown in FIG. 3, here, a case of a container is shown as the molded body P, and the molded body P is molded with burr portions B on the head side and the bottom side. The head side burr part Ba and the disposal bag part Bc are connected to the head part side, and the bottom part side burr part Bb is connected to the bottom part side. A part of the bottom burr part Bb has an air inlet Bb1 for blowing air. The preceding bottom side burr part Bb and the following head side burr part Ba are taken out from the mold unit 20 in a connected state, and thereafter, the preceding bottom side burr part Bb is removed by a take-out device (not shown). And the following head side burr | flash part Ba is cut | disconnected. In the molded body P, there is a shoulder portion PS immediately below the head portion Ph into which the cap is inserted, and a certain range at the bottom is referred to as a bottom portion PBt. Between the shoulder portion PS and the bottom portion PBt is a body portion PBd. The dent C at the top of the discard bag portion Bc will be described later. In addition, the molded object P and the burr | flash part B are not restricted to the aspect shown here.

(Lower mold 30)
The lower mold 30 will be described. 4 is a plan view of the inside of the lower mold 30, and FIG. 5 is a cross-sectional view taken along line AA of FIG. The lower mold 30 includes a first base portion 31, a second base portion 32, and a lower cavity portion 33 disposed therebetween. The first base 31 and the second base 32 are fixed to the rotary base 10. The first base portion 31 is provided with a shaft portion 311 for hinge-joining an upper mold 40 described later.

  The lower cavity portion 33 has a first concave portion 331 corresponding to the molded body P and a second concave portion 332 molded so as to correspond to the burr portion B, and the second concave portion 332 is the head of the molded body P. The head-side second recess 332a formed corresponding to the head-side burr portion Ba on the part side, and the bottom-side second recess 332b formed corresponding to the bottom-side burr portion Bb on the bottom side of the molded body P And a second recessed portion 332c for the discarded bag portion formed corresponding to the discarded bag portion Bc. An air nozzle 34 for blowing air into the molded body P is provided on the bottom burr portion Bb. The first rough surface finishing portion 334a and the second rough surface finishing portion 334b will be described later with renewed terms.

  The second recess 332c for the discard bag portion is provided with a push-up means (push-out means) push-up pin 333 for pushing up (push out) the discard bag portion Bc. As shown in FIG. 5, the push-up pin 333 is configured to be driven by an air cylinder so as to be protruded and retracted. As described above, the molded body P connected through the burr part B is sequentially taken out by the take-out device, but in order to assist in taking it out smoothly, the push-up pin 333 pushes up the disposal bag part Bc, The molded product P is easily released from the lower cavity portion 33.

  Specifically, as shown in FIG. 1, in the rotary blow molding machine 1 according to the present embodiment, the mold is released from the lower cavity portion 33 and then the lower mold 30 in order from the bottom to the head of the molded body P. Therefore, the mold release is made smooth by pushing up the discarded bag portion Bc of the molded product P by the push-up pin 333 at the stage of the eleventh mold unit 211.

(Upper mold 40)
Next, the upper mold 40 will be described. 6 is a plan view of the inside of the upper mold 40, and FIG. 7 is a cross-sectional view taken along the line BB of FIG. The upper mold 40 includes a first base portion 41, a second base portion 42, and an upper cavity portion 43 disposed therebetween. The first base portion 41 is provided with a receiving portion 411 that receives the shaft portion 311 of the lower die 30 in order to hinge-couple the lower die 30 described above.

  The upper cavity portion 43 has a first concave portion 431 corresponding to the molded body P and a second concave portion 432 molded so as to correspond to the burr portion B, and the second concave portion 432 is the head of the molded body P. The head-side second recess 432a formed corresponding to the head-side burr portion Ba on the part side, and the bottom-side second recess 432b formed corresponding to the bottom-side burr portion Bb on the bottom side of the molded body P. And a second recessed portion 432c for the discarded bag portion formed corresponding to the discarded bag portion Bc. The first mirror-finished portion 434a and the second mirror-finished portion 434b will be described later again with terms.

  A push-down pin 433 is provided as a push-down means (push-out means) for pushing down (push-out) the waste bag part Bc toward the lower mold 30 side in the second recess part 432c for the throw-away bag part. As shown in FIG. 7, the push-down pin 433 is configured to be able to protrude and retract with an air cylinder. As described above, the molded body P connected through the burr portion B is sequentially taken out by the take-out device. However, in order to smoothly take out the molded body P, when the upper mold 40 is opened, It is desirable that the lower cavity portion 33 and thus the lower mold 30 be held. The push-down pin 433 pushes down the discarded bag portion Bc to prevent the upper mold 40 from being opened in a state where the molded product P is attached to the upper cavity portion 43.

  Specifically, as shown in FIG. 1, in the rotary blow molding machine 1 according to the present embodiment, in order to prevent the molded body P from following when the upper mold 40 is opened, the ninth metal Immediately before the transition from the mold unit 209 to the tenth mold unit 210, the throwing pin 433 pushes the discarded bag portion Bc of the molded product P toward the lower mold 30 side. At this time, even if the molded product P bites into the lower cavity portion 33 by the push-down of the push-down pin 433, it is later pushed up by the push-up pin 333, so that the molded product P can be taken out smoothly. Can do. The dent C at the top of the discarded bag portion Bc shown in FIG. 3 is formed when pushed down by the push-down pin 433. Since the dent C is formed in the discarded bag portion Bc, the appearance of the molded product P is not affected.

(Upper cavity part 43)
As described above, the upper mold 40 is provided with the push-down pins 433 so that the molded body P does not follow when the upper mold 40 is opened. In order to make this function more effective, as shown in FIGS. 6 and 7, a mirror finish may be applied to the inner surface of the upper cavity portion 43 where the molded product P is likely to adhere. Here, the location where the molded product P is likely to adhere refers to a location that is within a range of ± 10 degrees, with the direction in which the molded product P is released as 0 degrees. For example, when the molded product P is a container, the ranges including locations corresponding to the shoulder portion PS and the bottom portion PBt of the molded product P are defined as a first mirror-finished portion 434a and a second mirror-finished portion 434b, respectively.

  The shoulder portion PS of the molded body P is generally stepped in a side view because a cap is inserted above the shoulder portion PS. Further, since the bottom PBt naturally hits the end, it has a stepped shape. About the part currently formed in this level | step difference, when the upper metal mold | die 40 opens in a single-opening shape, the location corresponding to the upper cavity part 43 and the molded object P will adhere easily, and it will become a rubbing relationship. In view of this, by providing a mirror-finished range including the locations corresponding to these, it is possible to release the upper cavity portion 43 smoothly without causing scratches due to rubbing at the locations.

  6 and 7, the range including the portion corresponding to the shoulder portion PS of the molded body P as the portion where the molded body P is likely to adhere is the range including the portion corresponding to the first mirror-finished portion 434a and the bottom portion PBt. Although the 2nd mirror surface finishing part 434b is shown, of course, it is not necessary to limit to these places. Depending on the shape of the molded body P, a stepped shape may be given to the body portion PBd, which is an intermediate region between the shoulder portion PS and the bottom portion PBt, and therefore the range including the portion may be mirror-finished.

  The degree of finishing of the first mirror-finished portion 434a and the second mirror-finished portion 434b is preferably an arithmetic average roughness Ra of 0.01 μm to 0.10 μm, and an arithmetic average roughness of 0.01 μm to 0.03 μm. Ra is more preferable. In consideration of the degree required for the molded product P, the upper cavity portion 43 is generally set to an arithmetic average roughness Ra of 1.00 μm to 2.00 μm. This makes it easier to release the mold from the upper cavity portion 43 and thus the upper mold 40.

(Lower cavity part 33)
When the upper mold 40 is opened from the lower mold 30, the molded body P is more easily placed in the lower mold 30, that is, the lower cavity portion 33, and as shown in FIGS. Corresponding to the provision of the mirror finish portion in the upper cavity portion 43, the rough finish portion may be provided in the lower cavity portion 33 of the lower mold 30. As a result, the molded product P can be easily released from the upper cavity portion 43 and difficult to release from the lower cavity portion 33.

  When the first mirror surface finishing portion 434a and the second mirror surface finishing portion 434b are provided in the upper cavity portion 43, the first rough surface finishing portion 334a and the second rough surface finishing portion are provided at corresponding positions of the lower cavity portion 33. 334b will be provided. Depending on the shape of the molded body P, a stepped shape may be given to the body portion PBd, which is an intermediate region between the shoulder portion PS and the bottom portion PBt, so that the mirror finish portion is included in the range including that portion of the upper cavity portion 43. When provided, the lower cavity portion 33 may also be provided with a rough surface finish portion at a corresponding position. Here, an example is shown in which the shoulder portion PS of the molded body P is formed symmetrically in the vertical direction, but the first rough surface finish portion 334 a of the lower cavity portion 33 is first in the upper cavity portion 43. It may be formed so as to have an asymmetrical formation with the mirror finish 434a.

  The degree of finishing of the first rough surface finish portion 334a and the second rough surface finish portion 334b is preferably an arithmetic average roughness Ra of 1.50 μm to 2.50 μm, and an arithmetic average of 1.80 μm to 2.00 μm. More preferably, the roughness Ra is used. The lower cavity portion 33 is generally set to an arithmetic average roughness Ra of 1.00 μm to 2.00 μm in consideration of the degree required for the molded body P. However, the first rough surface finished portion 334a and the second rough surface portion 334a are used. By making the surface finish portion 334b a rough surface that is relatively rougher than other portions (excluding the first mirror finish portion 434a and the second mirror finish portion 434b), the surface finish portion 334b is further removed from the lower cavity portion 33 and the lower mold 30. It becomes difficult to release.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. Further, it is apparent from the description of the scope of claims that embodiments with such changes or improvements can also be included in the technical scope of the present invention. For example, in the above-described embodiment, the book-type mold unit 20 in which the upper mold 40 is opened and closed in a single-opening manner from the lower mold 30 has been described. However, in the present embodiment, the lower mold 30 is the first mold, A split mold unit 20 in which the upper mold 40 is a second mold that opens and closes opposite to the first mold, and a push-down pin 433 as a push-down means is a push-out pin as a push-out means. Can also be applied.

DESCRIPTION OF SYMBOLS 1 ... Rotary blow molding machine 10 ... Rotating base 20 ... Mold unit 201-212 ... 1st mold unit-12th mold unit 30 ... Lower mold (1st mold)
31 ... 1st base 311 ... Shaft part 32 ... 2nd base 33 ... Lower cavity part 331 ... 1st recessed part 332 ... 2nd recessed part 332a ... Head side 2nd recessed part 332b ... Bottom part side 2nd recessed part 332c ... Disposal bag part Second concave portion 333 ... Push-up pin 334a ... First rough surface finish portion 334b ... Second rough surface finish portion 34 ... Air nozzle 40 ... Upper die (second die)
41 ... 1st base part 411 ... receiving part 42 ... 2nd base part 43 ... upper cavity part 431 ... 1st recessed part 432 ... 2nd recessed part 432a ... head side 2nd recessed part 432b ... bottom part side 2nd recessed part 432c ... disposal bag part Second concave portion 433 ... push-down pin (extrusion pin)
434a ... 1st mirror surface finishing part 434b ... 2nd mirror surface finishing part M ... Resin member (parison)
P ... Molded body Ph ... Head PS ... Shoulder PBt ... Bottom PBd ... Body B ... Burr part Ba ... Head side burr part Bb ... Bottom burr part Bc ... Waste bag part S ... Resin supply device D ... Die

Claims (11)

A rotary blow molding machine,
A rotating pedestal,
A mold unit that is provided on the surface of the rotating pedestal and molds a molded body;
The mold unit includes a first mold and a second mold that opens and closes between the first mold;
The second mold has a projecting means for projecting the molded body toward the first mold so that the molded body is held by the first mold when the second mold is opened. Rotary blow molding machine characterized by   The mold unit includes a lower mold as the first mold and an upper mold as the second mold that opens and closes in a single-opening manner between the lower mold and the protruding means. 2. The rotary blow molding machine according to claim 1, wherein the rotary blow molding machine is a push-down means that pushes down the molded body toward the lower mold.   The rotary blow molding machine according to claim 1 or 2, wherein the protruding means is a protruding pin driven by an air cylinder.   The rotary blow molding machine according to any one of claims 1 to 3, wherein the push-out means pushes out a discarded bag portion of the molded body.   The rotary according to any one of claims 1 to 4, wherein the second mold has a mirror finish portion at a position where the molded body easily adheres to the second mold. Blow molding machine.   The rotary blow molding machine according to claim 5, wherein the mirror finish portion includes a range corresponding to a shoulder portion and a bottom portion of the molded body.   The rotary blow molding machine according to claim 5 or 6, wherein the mirror-finished portion has an arithmetic average roughness Ra of 0.01 µm to 0.10 µm.   The said 1st metal mold | die has a rough surface finishing part in the position corresponding to the said mirror surface finishing part of the said 2nd metal mold | die in the inner surface. Rotary blow molding machine.   The rotary blow molding machine according to claim 8, wherein the rough surface finish portion has an arithmetic average roughness Ra of 1.50 μm to 2.50 μm. A rotary blow molding method,
A step of clamping a mold unit, which is provided on the surface of the rotating base and includes a first mold and a second mold opened and closed between the first mold and supplying a parison (a )When,
Step (b) of blowing air into the mold unit and cooling to form a molded body;
Opening the mold unit (c);
Removing the molded body from the mold unit (d),
In step (c), a protruding means provided in the second mold causes the molded body to be held in the first mold so that the molded body is held by the first mold when the second mold is opened. A rotary blow molding machine characterized by protruding to the side of one mold. In the step (d), another protruding means provided in the first mold projects the molded body toward the second mold so that the molded body can be smoothly taken out. Item 11. The rotary blow molding method according to Item 10.

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