JP6683923B2 - Rotary blow molding machine and rotary blow molding method - Google Patents

Description

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

  Conventionally, a rotary blow molding machine for molding a container made of a relatively small resin such as mayonnaise or various beverages by a mold provided on a rotary pedestal is known (for example, Patent Document 1). ).

  The rotary blow molding machine sequentially supplies molten resin members (parisons) by an extruder to a plurality of mold units continuously provided on the outer surface of the rotary pedestal, and gas is supplied to the inside thereof. This is a molding method of 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, actually, when the mold unit is opened, the molded body adheres to an unintended side of the mold unit, and there is a problem that the molded body cannot be taken out smoothly.

  In this respect, Patent Document 1 discloses an invention in which a temporary holding pin provided on one side of the mold unit is inserted in a waste bag portion cut off after molding in parallel with the longitudinal direction of the molded body to temporarily hold the molded body. . However, in Patent Document 1, fine adjustment is difficult because the optimum length of the temporary holding pin varies depending on the material and size of the mold unit and the molded body. There is a problem that it becomes an obstacle to taking out from the mold unit.

Japanese Patent Publication No. 58-40503

  The present invention has been made based on such a circumstance, and its object is to eliminate the need for fine adjustment by changing the material and size of the mold unit or the molded body when the mold unit is opened. 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 can be understood by the following configurations.
(1) A first aspect of the present invention is a rotary blow molding machine, which comprises 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 ejecting means for ejecting the molded body to the side of the first mold.

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

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

(4) In the configuration of any one of (1) to (3) above, the ejecting means may eject the waste bag portion of the molded body.

(5) In the configuration of any one of (1) to (4) above, the second mold has a mirror-finished portion on an inner surface thereof at a position where the molded body is easily attached to the second mold. You may.

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

(7) In the above configuration (5) or (6), the mirror-finished portion 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) above, the first mold has a rough surface finish portion on a position corresponding to the mirror finish portion of the second mold on the inner surface thereof. You may have.

(9) In the configuration of (8) above, 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, comprising: a first mold provided on the surface of a rotary pedestal; and a second mold opened and closed between the first mold and the first mold. A step of supplying a parison to a mold unit constituted by (a), a step of clamping the mold unit to mold a molded body (b), and a step of opening the mold unit (c). ) And a step (d) of taking out the molded body from the mold unit, and in the step (c), the molded body becomes the first mold when the second mold is opened. It is characterized in that the ejecting means provided on the second mold ejects the molded body toward the side of the first mold so as to be held.

(11) In the configuration of (10) above, in step (d), another ejecting means provided in the first mold is configured to move the molded body to the first mold so that the molded body can be smoothly taken out. 2 It may be pushed to the side of the mold.

  According to the present invention, when the mold unit is opened, it is possible to temporarily hold the molded body 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: It is a conceptual diagram which shows the condition which each metal mold | die (upper metal mold | die and lower metal mold | die) provided in the rotary pedestal opened / closed while rotating. Is. FIG. 3 is a side view showing a mechanism for opening and closing the upper mold and the lower mold of FIG. 1. It is a figure which shows an example of the molded object shape | molded by the rotary blow molding machine. FIG. 3 is a plan view showing the inside of the lower mold of FIG. 2. It is a longitudinal cross-sectional view of the lower mold of FIG. FIG. 3 is a plan view showing the inside of the upper mold of FIG. 2. It is a longitudinal cross-sectional view of the upper mold of FIG.

  Hereinafter, modes (hereinafter, embodiments) for carrying out the present invention will be described in detail with reference to the accompanying drawings. The same elements are denoted by the same numbers throughout the description of the embodiments.

(Overall structure 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 that mold the molded body P. It should be noted that, outside the system of the rotary blow molding machine 1, a resin supply device S (right side in the figure, partly shown) for the melted parison M (resin member) and a take-out device for taking out the molded body P (left side in the figure). (Not shown) is provided.

  The rotary pedestal 10 is configured to rotate at a constant speed, and sequentially moves the plurality of mold units 20 provided on the surface. It should be noted that although the case of rotating clockwise is shown here, it may be counterclockwise.

  The mold unit 20 is concentrically arranged on the surface of the rotary base 10. Here, twelve mold units 20 are shown, but the number of arrangements is not limited to this. The mold unit 20 has 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 and the lower mold 30 in a single-opening manner. Hereinafter, a mode in which the lower mold 30 is fixed to the rotary pedestal 10 and the upper mold 40 opens and closes in a one-sided open manner will be described. However, in the present embodiment, the second mold faces the first mold. Even in a mode of moving forward and backward, it can be applied.

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

  Then, the molded body P is molded by blowing air and cooling from the fifth mold unit 205 to the ninth 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). Then, the molded body P is sequentially taken out from the eleventh mold unit 211 by a take-out device (not shown) (step (d) of the rotary blow molding method). After the molded body P is taken out, the upper mold 40 moves from the twelfth mold unit 212 to the first mold unit 201 in a state where the upper mold 40 is fully opened.

  Here, as will be described later in detail, the upper die 40 of the die unit 20 is provided with ejecting means (pushing down pin 433), and when the upper die 40 is opened in step (c). The ejecting means (ejecting pin 433) ejects (pushes) the molded body P toward the lower mold 30 so that the molded body P is held by the lower mold 30. Further, the lower die 30 is provided with another push-out means (push-up pin 333), and in step (d), another push-out means (push-up pin 333) is provided so that the molded body P can be smoothly taken out. The molded body P is ejected (pushed up) toward the upper mold 40. The term "toward the upper die 40" is used broadly to mean "upward as viewed from the lower die 30". Similarly, "to the side of the lower mold 30" is widely used to mean "downward when 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 drawing, the molded body P is sequentially taken out from the state in which it is held on the lower die 30 side. The molded body P taken out is deburred and finished as a product.

  Here, the point that the upper mold 40 opens and closes in a one-sided 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 has a first base portion 31, a second base portion 32, and a lower cavity portion 33, and the first base portion 31 is provided with a shaft portion 311. The first base portion 31 and the second base portion 32 are fixed to the rotary pedestal 10. The upper mold 40 has a first base portion 41, a second base portion 42, and an upper cavity portion 43, and the first base portion 41 is provided with a receiving portion 411 that receives the shaft portion 311. As a result, the upper mold 40 is hinged to the lower mold 30 and opens and closes in a one-sided open shape as shown by the arrow. The mold unit 20 of this aspect may be called a book type.

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

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

(Molded body P and burr portion 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, a case is shown here as the molded body P, and the molded body P is molded with the burr portions B on the head side and the bottom side. The head side burr portion Ba and the discard bag portion Bc are connected to the head side, and the bottom side burr portion Bb is connected to the bottom side. A blowing port Bb1 for blowing air is provided in part of the bottom-side burr portion Bb. The leading bottom burr Bb and the trailing head burr Ba are taken out from the mold unit 20 in a state of being connected to each other, and then the leading bottom burr Bb is taken by a take-out device (not shown). And the trailing head side burr portion Ba are cut. In the molded body P, there is a shoulder portion PS immediately below the head Ph into which the cap is fitted, and a certain range of the lowermost portion is called a bottom portion PBt. A body portion PBd is between the shoulder portion PS and the bottom portion PBt. The recess C on the upper portion of the discard bag portion Bc will be described later. The molded body P and the burr portion B are not limited to those shown here.

(Lower mold 30)
The lower die 30 will be described. 4 is a plan view of the inside of the lower mold 30, and FIG. 5 is a sectional view taken along the 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 arranged between them. The first base portion 31 and the second base portion 32 are fixed to the rotary pedestal 10. The first base portion 31 is provided with a shaft portion 311 for hinge-connecting an upper mold 40, which will be 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. The second concave portion 332 is a head of the molded body P. Head-side second recessed portion 332a formed corresponding to the head-side burr portion Ba on the part side, and bottom-side second recessed portion 332b formed corresponding to the bottom-side burr portion Bb on the bottom side of the molded body P. And the second recess 332c for the discard bag portion formed corresponding to the discard bag portion Bc. The bottom-side burr Bb is provided with an air nozzle 34 for blowing air into the molded body P. The first rough surface finishing portion 334a and the second rough surface finishing portion 334b will be described later again.

  A push-up means (push-out means) push-up pin 333 for pushing up (leaving) the discard bag portion Bc is provided in the second recess portion 332c for the discard bag portion. As shown in FIG. 5, the push-up pin 333 is configured to be driven to be retractable by an air cylinder. As described above, the molded bodies P connected through the burr portion B are sequentially taken out by the take-out device, but in order to assist in taking them out smoothly, the push-up pin 333 pushes up the discard bag portion Bc, The molded body 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 this embodiment, the molded body P is released from the lower cavity portion 33 and then the lower mold 30 in order from the bottom portion to the head portion. Therefore, in the step of the eleventh mold unit 211, the push-up pin 333 pushes up the waste bag portion Bc of the molded body P to smooth the mold release.

(Upper mold 40)
Next, the upper die 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 arranged between them. The first base portion 41 is provided with a receiving portion 411 for receiving the shaft portion 311 of the lower mold 30 in order to hinge the lower mold 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. The second concave portion 432 is a head of the molded body P. Head-side second recessed portion 432a formed corresponding to the head-side burr portion Ba on the part side and bottom-side second recessed portion 432b formed corresponding to the bottom-side burr portion Bb on the bottom side of the molded body P. And a second recess 432c for the waste bag portion formed corresponding to the waste bag portion Bc. The first mirror surface finishing portion 434a and the second mirror surface finishing portion 434b will be described later in more detail.

  The second recess 432c for the sacrificial bag portion is provided with a push-down pin 433 as a push-down means (push-out means) for pushing down (pushing) the discard bag Bc toward the lower mold 30 side. The push-down pin 433 is configured to be retractable by an air cylinder as shown in FIG. 7. As described above, the molded articles P connected through the burr portion B are sequentially taken out by the take-out device. However, in order to take them out smoothly, when the upper mold 40 is opened, the molded articles P are It is desirable that the lower cavity portion 33 and the lower die 30 are held. The push-down pin 433 pushes down the waste bag portion Bc and prevents the upper mold 40 from opening with the molded body P 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 opens, Immediately before shifting from the mold unit 209 to the tenth mold unit 210, the throw-down pin 433 pushes down the waste bag portion Bc of the molded body P toward the lower mold 30. At this time, even if the molded body P bites into the lower cavity portion 33 by pushing down the push-down pin 433, it is pushed up by the push-up pin 333 described above, so the molded body P should be taken out smoothly. You can The depression C on the upper portion of the waste bag portion Bc shown in FIG. 3 is formed when the push-down pin 433 pushes it down. Since the recess 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 die 40 is provided with the push-down pin 433 so that the molded body P does not follow when the upper die 40 is opened. In order to make this function more effective, as shown in FIGS. 6 and 7, the inner surface of the upper cavity portion 43 may be mirror-finished at a portion where the molded body P is easily attached. Here, the place where the molded body P is likely to adhere refers to a place within a range of ± 10 degrees, with the direction in which the molded product P is released from being 0 degree. For example, when the molded body P is a container, the ranges including the portions corresponding to the shoulder portion PS and the bottom portion PBt of the molded body P are the first mirror surface finishing portion 434a and the second mirror surface finishing portion 434b, respectively.

  The shoulder portion PS of the molded body P generally has a stepped shape in a side view because a cap is fitted over the shoulder portion PS. Further, the bottom portion PBt naturally hits the end portion, and thus has a stepped shape. Regarding the portion formed in the stepped shape, when the upper mold 40 is opened in a one-sided manner, the corresponding portion of the upper cavity portion 43 and the molded body P are likely to adhere to each other and have a rubbing relationship. Therefore, by making the range including the portions corresponding to these areas mirror-finished, it is possible to smoothly release the upper cavity portion 43 without causing scratches due to rubbing at the portions.

  6 and 7, a range including a portion corresponding to the shoulder portion PS of the molded body P as a portion to which the molded body P is likely to adhere is a range including a portion corresponding to the first mirror-finished portion 434a and the bottom portion PBt. Although the second mirror-finished portion 434b is shown, of course, it is not necessary to limit to these portions. Depending on the shape of the molded body P, the body portion PBd, which is an intermediate region between the shoulder portion PS and the bottom portion PBt, may be provided with a stepped shape, and thus 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 0.01 μm to 0.10 μm arithmetic average roughness Ra, and 0.01 μm to 0.03 μm arithmetic average roughness Ra. Ra is more preferable. The upper cavity portion 43 is generally set to have an arithmetic average roughness Ra of 1.00 μm to 2.00 μm in consideration of the degree required for the molded body P, and thus should be a mirror surface not rougher than this. Thereby, it becomes easier to release from the upper cavity portion 43 and further the upper mold 40.

(Lower cavity part 33)
In order to make it easier for the molded body P to remain in the lower mold 30, that is, the lower cavity portion 33 when the upper mold 40 is opened from the lower mold 30, as shown in FIGS. Corresponding to providing the mirror-finished portion in the upper cavity portion 43 of FIG. 3, a rough-finished portion may be provided in the lower cavity portion 33 of the lower mold 30. As a result, the molded body P can be easily released from the upper cavity portion 43 and hard to be released from the lower cavity portion 33.

  When the upper cavity portion 43 is provided with the first mirror surface finishing portion 434a and the second mirror surface finishing portion 434b, the first rough surface finishing portion 334a and the second rough surface finishing portion are provided at the 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. Therefore, a mirror-finished portion is provided in the range including the place of the upper cavity portion 43. When provided, the lower cavity portion 33 may also be provided with a rough surface finishing portion at the corresponding position. Note that, here, although an example in which the shoulder portion PS of the molded body P is vertically symmetrically formed is shown, the first rough surface finishing portion 334a of the lower cavity portion 33 is formed in the upper cavity portion 43 at the first. It may be formed to have an asymmetrical contour with respect to the mirror-finished portion 434a.

  The degree of finishing of the first rough surface finishing portion 334a and the second rough surface finishing 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. The roughness Ra is more preferable. The lower cavity portion 33 is generally set to have an arithmetic average roughness Ra of 1.00 μm to 2.00 μm in consideration of the degree required for the molded body P, but the first rough surface finishing portion 334 a and the second rough surface finishing portion 334 a. By making the surface finishing portion 334b a relatively rougher surface than the other portions (excluding the first mirror finishing portion 434a and the second mirror finishing portion 434b), the lower cavity portion 33 and thus the lower die 30 can be further It becomes difficult to release.

  Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be added to the above-described embodiment. It is also apparent from the scope of the claims that the embodiments added with such changes or improvements can 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 opens and closes 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 two-die type mold unit 20 in which the upper mold 40 is opposed to the first mold to open and close and the second mold is opened and closed, and the push-down pin 433 as push-down means is a push-out pin as push-out means. Can also be applied.

DESCRIPTION OF SYMBOLS 1 ... Rotary blow molding machine 10 ... Rotation base 20 ... Mold units 201-212 ... 1st mold unit-12th mold unit 30 ... Lower mold (1st mold)
31 ... 1st base part 311 ... Shaft part 32 ... 2nd base part 33 ... Lower cavity part 331 ... 1st recessed part 332 ... 2nd recessed part 332a ... Head side 2nd recessed part 332b ... Bottom side 2nd recessed part 332c ... Waste bag part Second concave portion 333 ... push-up pin 334a ... first rough surface finishing portion 334b ... second rough surface finishing 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 side 2nd recessed part 432c ... Waste bag part Second recess 433 for use ... push-down pin (release pin)
434a ... 1st mirror finishing part 434b ... 2nd mirror finishing part M ... Resin member (parison)
P ... Molded body Ph ... Head PS ... Shoulder PBt ... Bottom PBd ... Body B ... Burr Ba ... Head burr Bb ... Bottom burr Bc ... Waste bag S ... Resin supply device D ... Die

Claims (11)

A rotary blow molding machine,
A rotating pedestal,
A mold unit provided on the surface of the rotary pedestal for molding a molded body,
The mold unit has a first mold and a second mold that opens and closes between the first mold and
The second mold has ejecting means for ejecting the molded body to the side of 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.   The die unit has a lower die as the first die and an upper die as the second die that opens and closes in a one-sided manner between the lower die and the ejecting means. 2. The rotary blow molding machine according to claim 1, wherein is a pushing-down unit that pushes down the molded body toward the lower mold.   3. The rotary blow molding machine according to claim 1, wherein the ejecting means is an ejecting pin driven by an air cylinder.   The rotary blow molding machine according to any one of claims 1 to 3, wherein the ejecting means ejects the waste bag portion of the molded body.   5. The rotary according to claim 1, wherein the second mold has a mirror-finished portion on an inner surface of the second mold at a position where the molded body is easily attached to the second mold. Blow molding machine.   The rotary blow molding machine according to claim 5, wherein the mirror-finished 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, 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-finishing part of the said 2nd metal mold | die on the inner surface, The any one of Claim 5 to 7 characterized by the above-mentioned. 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,
Provided on the surface of the rotary base, and the first mold, and clamping the Rukin type unit is composed of a second mold which opens and closes between the first mold, supplying a parison step (a) When,
A step (b) of forming a molded body by blowing air and cooling the mold unit;
Step (c) of opening the mold unit,
And (d) removing the molded body from the mold unit,
In step (c), ejecting means provided in the second mold causes the molded body to move to the first mold so that the molded body is held by the first mold when the second mold is opened. (1) A rotary blow molding method characterized in that it is pushed to the mold side. In step (d), another ejecting means provided in the first mold ejects the molded body to the second mold side so that the molded body can be smoothly taken out. Item 10. The rotary blow molding method according to Item 10.

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