JP2016064567A - Extrusion blow molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion blow molding machine, capable of accurately supplying high quality parison into a mold, and producing a molded article which is high quality with high productivity.SOLUTION: An extrusion blow molding machine 1 comprises: a parison supply device 3 for restraining parison which is discharged vertically downward from a die head 2D of an extruder 2, and supplying the parison to a parison supply position P1 separated from the die head 2D; a mold transport/opening and closing device 4 for transporting plural molds M, installed to a horizontal plane, to a take-out position P2 from the parison supply position P1 continuously and sequentially, performing closing operation of the molds M sandwiching the parison, and then performing open operation of the mold M for taking out a molded article; and a blow device 5 for blowing blow air into the parison sandwiched in each mold M during transport of the molds M reaching the take-out position P2 from the parison supply position P1. The parison supply device 3 has a pick-up mechanism 30 for gripping the parison by moving in a horizontal direction during moving downward.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an extrusion blow molding machine.

  An extrusion blow molding machine melts a thermoplastic resin with an extruder, discharges the melted resin from the die head of the extruder to form a hollow parison, sandwiches the parison with a pair of blow molds, It is a molding machine that blows blow air into a sandwiched parison to form a hollow body.

  Such an extrusion blow molding machine generally employs a method in which a parison discharged vertically downward is directly sandwiched between molds, but is continuously discharged from a die head when continuously producing a molded product. It is necessary to sandwich the parison with the mold one after another. In this case, as a mold transfer method, a vertical rotary type in which a mold support (blow wheel) is rotated in a vertical plane so that the mold is transferred vertically according to the direction in which the parison descends, or a parison There is known a horizontal rotary type in which a mold support body in which molds are arranged in a horizontal plane perpendicular to the descent direction of the mold is rotated around a vertical axis, and the molds are sequentially conveyed to a descent position of the parison.

  Further, in the prior art described in Patent Document 1 below, the extruded parison is sandwiched by a pair of sandwiching means, the sandwiched parison portion is cut and separated from the parison body, and both the sandwiching means are separated from each other. A biaxial stretch blow molding machine is described in which a parison portion is stretched in the longitudinal direction and is further inserted into a mold with the parison portion sandwiched.

JP-A-52-1005626

  The above-described vertical rotary extrusion blow molding machine moves the mold sandwiching the parison in the downward direction of the parison, and always supplies the parison into the mold by constantly restraining the parison with the mold. However, in this case, the mold height (upper limit of the mold height) is limited by the circumferential length / number of molds of the mold support, and the mold has a height lower than the circumferential length / number of molds. In the case of using a mold, the distance between the mold and the mold becomes wide, and the rate of occurrence of burrs (unformed parison parts) increases, and smooth continuous operation becomes difficult due to the operation of removing burrs. For this reason, the vertical rotary extrusion blow molding machine is not suitable for the production of molded products of various types and small lots. In addition, the vertical rotary system employs a needle blow that blows by inserting a needle from the side of the mold because the adjacent mold is close to the upper end of the mold. There are also problems that cannot be done.

  In contrast, a horizontal rotary extrusion blow molding machine sandwiches a vertically descending parison with a horizontally moving mold, so there is no restriction on the mold height, the upper part of the mold is opened, and the upper opening is opened. Efficient blowing can be used. However, when the downward movement direction of the parison and the moving direction of the mold are orthogonal to each other and the parison is continuously supplied to the mold, it becomes difficult to place the parison at an appropriate position in the mold. On the other hand, there is an intermittent type molding machine that temporarily stops the mold and sandwiches the continuously descending parison, but in this case, not only the operating efficiency of the machine is lowered, but also in the mold. In order to relatively stop the parison movement, it is necessary to move the die head and the extruder upward, which requires a large drive system for moving heavy objects, and makes it difficult to perform continuous operation quickly. Become. Furthermore, if it is attempted to increase the productivity of the molded product by speeding up the conveyance of the mold, it is necessary to increase the discharge speed of the parison, which causes melt fracture and the like, and the quality of the parison deteriorates, resulting in high quality molding. There arises a problem that it becomes impossible to obtain things.

  On the other hand, it has been proposed that the parison discharged from the die head is sandwiched by the clamping means and supplied to the mold as in the prior art described above, but the parison continuously discharged from the die head is improved in quality. The present condition is that the concrete and effective means supplied to the metal mold | die clamped in the state and conveyed continuously is not proposed.

  This invention makes it an example of a subject to cope with such a problem. In other words, the mold height is not restricted, the machine can be operated smoothly and continuously to increase the operating efficiency of the machine, the blow can be performed efficiently, and a high-quality parison is supplied accurately in the mold. It is an object of the present invention to provide an extrusion blow molding machine capable of producing a molded product with high quality and high productivity.

In order to achieve such an object, an extrusion blow molding machine according to the present invention has the following configuration.
A parison supply device that constrains the parison discharged vertically downward from the die head of the extruder and supplies the parison to a parison supply position away from the die head, and a plurality of molds installed in a horizontal plane sequentially and continuously supply the parison. A mold conveying / opening / closing device for conveying the mold from the position toward the removal position of the molded article, performing a closing operation of the mold sandwiching the parison and opening the mold for removing the molded article, and from the parison supply position A pick-up device that blows blow air into a parison sandwiched between the molds during conveyance of the mold to the take-out position, and the parison supply device moves horizontally and picks up the parison while moving downward An extrusion blow molding machine comprising a mechanism.

  Since such an extrusion blow molding machine has the above-mentioned characteristics, the mold height is not regulated, smooth continuous operation is enabled to improve the operation efficiency of the machine, and efficient blow molding is performed. It is possible to provide an extrusion blow molding machine that supplies a high-quality parison with high accuracy and produces a molded product with high quality and high productivity.

It is the schematic plan view which showed the whole structure of the extrusion blow molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which showed operation | movement of the pick-up mechanism (pickup chuck) in the parison supply apparatus of the extrusion blow molding machine which concerns on embodiment of this invention. It is explanatory drawing which showed operation | movement of the restraint chuck with which the parison supply apparatus of the extrusion blow molding machine which concerns on embodiment of this invention is provided. It is explanatory drawing (operation curve figure of a restraint chuck) which showed operation | movement of the restraint chuck with which the parison supply apparatus of the extrusion blow molding machine which concerns on embodiment of this invention is provided. It is the schematic plan view which showed the whole structure of the extrusion blow molding machine which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing the overall configuration of an extrusion blow molding machine according to an embodiment of the present invention. The extrusion blow molding machine 1 stores a parison discharged vertically downward from a die head 2D of the extruder 2 in a mold M and blows blow air into the parison sandwiched between the molds M to produce a molded product. , A parison supply device 3, a mold conveying / opening / closing device 4, a blow device 5, and the like.

  The parison supply device 3 restrains the parison discharged vertically downward from the die head 2D of the extruder 2 and supplies the parison to the parison supply position P1 away from the parison center P0 in the die head 2D. A restraining / cutting mechanism 31 is provided. In the illustrated example, the pickup mechanism 30 is provided for each of the plurality of molds M, and the parison restraining / cutting mechanism 31 is provided in the vicinity of the die head 2D. The pickup mechanism 30 includes a pair of upper and lower pickup chucks described later, and the parison constraint / cutting mechanism 31 includes a constraint chuck described later.

  The mold conveying / opening / closing device 4 includes a mold conveying unit 4A that sequentially and continuously conveys a plurality of molds M installed in a horizontal plane from the parison supply position P1 to the take-out position P2. A mold opening / closing operation unit 4B is provided for performing the closing operation of the mold M sandwiching the parison at the supply position P1 and opening the mold at the take-out position P2. Here, the mold conveying unit 4A has the mold positions 4C arranged on a circumference 4R centered on the vertical axis O, and the mold positions 4C continuously rotate around the vertical axis O. The mold opening / closing operation unit 4B opens and closes the mold M in the tangential direction of the circumference 4R.

  The blow device 5 blows blow air into the parison sandwiched between the molds M during conveyance of the mold M from the parison supply position P1 to the take-out position P2, and is disposed above the mold M here. A blow pin (not shown) is inserted from the upper end opening of the mold M. Further, the extrusion blow molding machine 1 includes a take-out turret 6, and the take-out turret 6 takes out the molded product from the mold M opened at the take-out position P <b> 2 and conveys it to the take-out conveyance port 7.

  The basic operation of such an extrusion blow molding machine 1 will be described. A parison is ejected vertically downward from the die head 2D. In contrast to this, the die conveying / opening / closing device 4 continuously rotates the die position 4C around the vertical axis O, and a pickup mechanism 30 provided for each die position 4C. The parison supply device 3 having the function performs the operation of storing the parison for each mold M.

  When the parison is discharged from the die head 2D, the pickup mechanism 30 (pickup chuck) in the parison supply device 3 moves under the die head 2D in advance in a state of being moved outside the circumference 4R as the mold position 4C rotates. At this time, the parison discharged from the die head 2D is grasped and conveyed to the parison supply position P1 on the circumference 4R. The pickup mechanism 30 is provided so as to be movable in the radial direction of the circumference 4R. The pick-up mechanism 30 moves to the outside of the circumference 4R before the mold position 4C is closest to the die head 2D, and the parison discharged from the die head 2D is discharged. After grasping, it moves in the direction of the vertical axis O, and conveys the grasped barison to the parison supply position P2.

  At the parison supply position P1, the mold opening / closing operation unit 4B of the mold conveying / opening / closing device 4 closes the opened mold M to sandwich the supplied parison. Thereafter, the mold M sandwiching the parison is transported to the take-out position P2 by the mold transport section 4A of the mold transport / opening / closing device 4. Then, blow air is blown into the parison sandwiched between the molds M by the blow device 5 during the conveyance.

  At the take-out position P2, the mold opening / closing operation part 4B of the mold conveying / opening / closing device 4 opens the closed mold M, and the blow-molded molded product is released from the mold M. At that time, since the pickup mechanism 30 always holds the parison while being conveyed on the upper and lower sides of the mold M, the molded product is held by the pickup mechanism 30. Then, the pickup mechanism 30 (pickup chuck) moves outside the circumference 4R at the take-out position P2, takes out the molded product from the mold M, and delivers it to the take-out turret 6. The take-out turret 6 includes a carrying chuck 6A, rotates the carrying chuck 6A in synchronization with the rotation of the mold position 4C, receives the molded product at the taking-out position P2, and opens it at the take-out carrying port 7. Then, the pickup mechanism 30 moved to the outside performs an operation of approaching the die head 2D and grasping the next parison in that state.

  FIG. 2 shows the operation of the pickup chucks 3 </ b> A and 3 </ b> B provided in the pickup mechanism 30 in the parison supply device 3. The pickup mechanism 30 includes a pair of upper and lower pickup chucks 3A and 3B. The interval T between the two pickup chucks 3A and 3B is constant and is set to be slightly wider than the height of the mold M, and holds the parison P sandwiched between the molds M on the upper and lower sides of the mold M. The pickup chucks 3A and 3B move in the horizontal direction while moving vertically downward, and perform an operation of grasping the parison P.

  FIG. 2 shows operations of the pickup chucks 3A and 3B accompanying the horizontal movement of the mold position 4C. (A) is a state before the mold position 4C is closest to the die head 2D, and (b) is a mold position 4C. Is the state closest to the die head 2D, (c) is the state before the mold position 4C is separated from the die head 2D and reaches the parison supply position P1, and (d) is the state where the mold position 4C has reached the parison supply position P1. Is shown. The pickup chucks 3A and 3B are installed in the mold position 4C for each mold M, and move in the horizontal direction indicated by the arrow H as the mold position 4C is moved by the mold transport unit 4A. Further, as shown in (a) to (d), the pickup chucks 3A and 3B move downward in the vertical direction indicated by the arrow V while the mold position 4C approaches and separates from the die head 2D. At this time, the moving speed in the vertically downward direction can be set to a speed equivalent to or close to the descending speed of the parison P discharged from the die head 2D. As will be described later, when the parison P discharged from the die head 2D is always restrained by the restraining chuck, the lowering speed of the pickup chucks 3A and 3B is set in accordance with the moving speed of the restraining chuck.

  The operations of the pickup chucks 3A and 3B are as follows. The pickup chucks 3A and 3B move in the horizontal direction while moving vertically downward, approach the die head 2D, and lower the parison P at the parison center P0 in the die head 2D. Is transferred to the parison supply position P1 where the mold M is closed. By such conveyance, when the pickup chucks 3A, 3B come into contact with the parison P, the speed difference between the descending pickup chucks 3A, 3B and the descending parison P is reduced, and the outer surface of the parison P and the pickup chucks 3A, 3B are reduced. It is possible to avoid the phenomenon that the inner surface of 3B is rubbed and the phenomenon that the pool of parison P is formed on the chuck immediately after the pickup chucks 3A and 3B grasp the parison. As a result, a high-quality parison P can be supplied to the mold M.

  3 and 4 show operations of the restraining chucks 3C and 3D provided in the parison restraining / cutting mechanism 31. FIG. As shown in FIG. 3, the parison restraining / cutting mechanism 31 of the parison supply device 3 includes a plurality of restraining chucks 3C and 3D and a restraining chuck operating unit 3E. Although two restraining chucks 3C and 3D are shown in the same time zone to hold the top and bottom of the parison P, a plurality of the restraining chucks 3C and 3D can be provided so as to be fed out in sequence.

  The restraining chucks 3C and 3D always restrain the parison P so that the pick-up chucks 3A and 3B grasp the parison P in a stable state. The restraining chucks 3C and 3D hold the parison P at the first position (I) close to the die head 2D and move to the second position (II) farther from the die head 2D than the first position (I). At that time, the other restraint chuck 3D grips the parison P at the first position (I) before the one restraint chuck 3C reaches the second position (II). Then, while the pair of restraining chucks 3C and 3D are holding the parison P, the pickup chucks 3A and 3B hold the parison P. At this time, the moving speed of the restraining chucks 3C and 3D from the first position (I) to the second position (II) is made faster than the descending speed of the parison P discharged from the die head 2D, and the parison P is moved between the die head 2D. Pull on.

  The restraint chuck operation unit 3E that operates the restraint chucks 3C and 3D repeatedly operates the restraint chucks 3C and 3D at a predetermined cycle, constantly restrains the parison P discharged from the die head 2D and continues its pulling state. Let The downward movement of the restraining chucks 3C, 3D is a movement for restraining the parison P and applying a pull. However, the upward movement of the restraining chucks 3C, 3D is as follows. This is a return operation for preparing for the restraint operation.

  3A to 3E show the change in the discharge state of the parison P and the operation of the restraining chucks 3C and 3D in chronological order. 3 (a) and 3 (b), the restraining chuck 3C moves downward while gripping the parison P, and the restraining chuck 3D moves without gripping the parison P in the reverse return direction. . In FIG. 3C, the preceding restraint chuck 3C restrains the parison P, and the subsequent restraint chuck 3D grips the parison P at the first position (I). After the state of FIG. 3C, as shown in FIG. 3D, the parison P is gripped by the pair of restraining chucks 3C and 3D. Thus, the parison P is held by the restraining chucks 3C and 3D. In the gripped state, the above-described pair of pickup chucks 3A and 3B performs an operation of grasping the parison P.

  FIG. 4 is an operation curve of the restraint chucks 3C and 3D shown in FIG. 3. The horizontal axis is the time T, the vertical axis is the distance Z from the die head 2D, the solid line is the operation curve of the restraint chuck 3C, and the broken line is a broken line. Shows the operation curve of the restraint chuck 3D. Note that the states at times [1] to [5] in FIG. 4 correspond to the states (a) to (e) in FIG.

  In FIG. 4, the restraining chucks 3C and 3D are moved downward at a constant speed, and the following is performed at a timing T1 that is earlier by the time Ts from the timing T2 at which one restraining chuck 3C (3D) reaches the second position (II). The restraining chuck 3D (3C) grips the parison P at the first position (I), and then the two restraining chucks 3C and 3D move while holding the parison P for the time Ts. Part or all of the above-described time Ts is set in a process of holding the parison P by the pair of pickup chucks 3A and 3B, and separating and transporting the parison P to the mold M. The pair of pickup chucks 3A and 3B move in synchronization with the restraining chucks 3C and 3D, and as described above, move horizontally to grab the parison P while moving downward.

  The extrusion blow molding machine 1 provided with such a parison supply device 3 operates a plurality of restraining chucks 3C and 3D to constantly restrain the parison P discharged from the die head 2D and apply linear tension. As a result, uneven thickness due to draw-down of the parison P discharged vertically downward is suppressed, and an appropriate tension that does not change the direction and speed is applied to the pickup chucks 3A and 3B while maintaining this tension state. Delivered. As a result, a high-quality parison P having high thickness uniformity and excellent molecular orientation can be supplied to the mold M.

  FIG. 5 shows an extrusion blow molding machine according to another embodiment of the present invention. Here, the same parts as those of the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted. In the extrusion blow molding machine 1A according to this embodiment, the configuration of the pickup mechanism is changed from the above-described embodiment.

  In FIG. 5, the extrusion blow molding machine 1A employs a transport turret type pickup mechanism 30A. The pickup mechanism 30A rotates horizontally around a vertical axis O1 different from the vertical axis O of the mold conveying / opening / closing device 4 and includes a plurality of pickup chucks 3A and 3B arranged at equidistant positions from the vertical axis O1. Move horizontally. Similar to the above-described embodiment, also in this pickup mechanism 30A, the pair of upper and lower pickup chucks 3A, 3B rotate horizontally and grab the parison while moving downward in the process toward the parison center P0 in the die head 2D. I do. The opening and closing operations of the pickup chucks 3A and 3B are opened before the parison center P0, closed at the parison center P0, grabbed by the parison, rotated and supplied to the mold M, and then opened again. Become.

  The mold conveying / opening / closing device 4 rotates horizontally around the vertical axis O in synchronization with the pickup mechanism 30A, and horizontally moves a plurality of molds M arranged at equal distances from the vertical axis O. In the mold M, the position in contact with the rotation trajectory of the pickup chucks 3A and 3B is a parison supply position P1, which is closed with the parison interposed therebetween, and then blown with an air blow by a blow device (not shown) while rotating in the direction of the arrow. Is done. Then, the mold M is opened at the take-out position P <b> 2 in contact with the conveyance chuck 6 </ b> A of the take-out turret 6. The take-out turret 6 rotates in the direction of the arrow, and at a position where the take-out turret 6 is in contact with the mold M (take-out position P2), the transport chuck 6A holds the molded product and transports it in the direction of the arrow.

  In such an extrusion blow molding machine 1, 1 A according to the embodiment of the present invention, a plurality of molds M installed in the mold conveying / opening / closing device 4 are arranged in a horizontal plane so as to be installed vertically. The height of the mold can be set freely regardless of the number of molds, and the mold height is not restricted. Further, unlike the vertical rotary type, since continuous operation is not hindered by the occurrence of burrs, smooth continuous operation is possible, and the operating efficiency of the machine can be increased. Further, by providing the parison supply device 3 having the pickup chucks 3A and 3B and the restraining chucks 3C and 3D, when the conveyance speed of the mold M is increased to increase the productivity, the descending speed of the parison is increased. Without change, it can be handled by pulling the parison. For this reason, productivity can be improved without lowering the quality of the parison due to melt fracture or the like. Further, even for continuous operation, the parison can be accurately supplied to the individual molds M by the pickup chucks 3A and 3B, and both improvement in productivity and improvement in the quality of the molded product can be achieved. Further, the position of the pickup chucks 3A and 3B with respect to the mold M can be arbitrarily adjusted to cope with the thickness adjustment of the asymmetric bottle.

  Furthermore, the parison discharged from the die head 2D can be constantly restrained and a constant tension can be applied, and the influence of drawdown or parison shaking can be eliminated, and a constant high quality parison can be supplied at all times. . In addition, since the pickup chucks 3A and 3B move in the vertical direction while moving in the vertical direction to grab the parison, the outer surface of the parison and the inner surface of the pickup chucks 3A and 3B are rubbed, or the pickup chucks 3A and 3B are Immediately after grabbing, it is possible to avoid a phenomenon in which a pool of parisons is formed on the chuck. As a result, a high-quality parison can be supplied to the mold M, and the size and thickness of the molded product can be stabilized.

  If the structural advantage of the extrusion blow molding machines 1 and 1A is given, the blow device 5 can be disposed on the upper part of the mold M, so that the blow efficiency can be improved and the cooling performance can be improved by increasing the air flow rate. Further, since the parison center P0 and the parison supply position P1 in the die head 2D are different from each other, the mold M does not pass under the die head 2D. As a result, even if the blow device 5 is arranged on the upper part of the mold, the avoidance operation of the blow device 5 with respect to the die head 2D becomes unnecessary. Further, since the mold M can be attached from the normal direction on the circumference 4R of the mold transport / opening / closing device 4, the mold changing operation is facilitated. Thus, an extrusion blow molding machine suitable for multi-product small-lot production can be obtained.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention. In addition, the above-described embodiments can be combined by utilizing each other's technology as long as there is no particular contradiction or problem in the purpose and configuration.

1, 1A: extrusion blow molding machine, 2: extrusion machine, 2D: die head,
3: Parison supply device, 3A, 3B: Pickup chuck,
3C, 3D: Restraint chuck, 3E: Restraint chuck operation unit,
30, 30A: pickup mechanism, 31: parison restraint / cutting mechanism,
4: Mold transfer / opening / closing device,
4A: Mold conveying section, 4B: Mold opening / closing operation section, 4C: Mold position,
5: Blow device,
6: take-out turret, 6A: transfer chuck, 7: take-out transfer port,
M: mold, P: parison,
P0: Parison center, P1: Parison supply position, P2: Removal position,
O, O1: Vertical axis, 4R: Circumference

Claims (5)

A parison supply device that restrains the parison discharged vertically downward from the die head of the extruder and supplies the parison to a parison supply position away from the die head;
A plurality of molds installed in a horizontal plane are sequentially and continuously conveyed from the parison supply position toward the molded product take-out position to perform a closing operation of the mold sandwiching the parison and take out the molded product. Mold transfer / opening / closing device for opening mold,
A blower that blows blow air into a parison sandwiched between molds during conveyance of the mold from the parison supply position to the removal position;
The extrusion blow molding machine is characterized in that the parison supply device includes a pickup mechanism that moves in the horizontal direction while moving downward and grabs the parison. The mold conveying / opening / closing device continuously rotates the mold position on the circumference around the vertical axis around the vertical axis, and opens and closes the mold in the tangential direction of the circumference,
2. The extrusion blow molding machine according to claim 1, wherein the pickup mechanism grasps a parison discharged from the die head located outside the circumference and conveys the parison to the parison supply position on the circumference.   The pick-up mechanism is disposed at each mold position in the mold transport / opening / closing device, and is provided so as to be movable in the radial direction of the circumference, and moves to the outside of the circumference at the take-out position. 3. The extrusion blow molding machine according to claim 2, wherein the molded product inside is taken out, and the parison is grasped by approaching the die head in a state where the molded product is moved outward.   The parison supply device includes a restraining chuck that grips a parison discharged from the die head at a first position close to the die head and moves to a second position farther from the die head than the first position. The pick-up mechanism while one of the restraining chucks grips the parison and the pair of restraining chucks grips the parison before the one restraining chuck reaches the second position. The extrusion blow molding machine according to any one of claims 1 to 3, wherein the gripper holds a parison.   5. The extrusion blow molding machine according to claim 4, wherein a speed at which the restraining chuck moves from the first position to the second position is made faster than a descending speed of a parison discharged from the die head. .

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