JP4214121B2 - Resin molding machine - Google Patents

Description

  The present invention relates to a resin molding machine, and is an apparatus capable of performing a series of processes from injection molding to stretch blow molding of a molded product, and a process from an injection molding process to a stretch blow molding process. The invention relates to an apparatus that prevents the deformation of the preform and adjusts the temperature of the preform to increase the molding accuracy.

  In the resin molding technique, when a blow molded product is finally produced, a technique is known in which a preform is first molded by injection molding and stretch blow molded in order to increase molding accuracy. The applicant has also developed an apparatus for achieving this series of techniques and has filed an application as shown in Patent Document 1.

Japanese Patent Laid-Open No. 2004-276527

  By the way, in the case of the resin molding machine mentioned above, the preform receiving core for carrying the preform from the injection molding process to the stretch blow molding process plays an important role. As shown in FIG. 5, for example, a conventional receiving core is schematically shown in which a support protrusion 42 having a predetermined length is provided at the center of a base 41, and the base end of the preform (P) is fitted to the support protrusion. It was something like that. That is, the support protrusion 42 is configured to have a diameter substantially the same as the inner diameter of the base end portion of the preform (P), which is inserted into the base end portion of the preform, and is sucked by, for example, vacuum, mechanical configuration or adhesive The preform (P) was prevented from falling off by being held with a substance or the like, and was transported to the stretch blow molding process. In this case, the length of the support protrusion 42 is shorter than the length of the preform (P), and the inner diameter of the preform was not supported up to the innermost end, so the preform was received in the horizontal direction. In such a case, there is a problem in that the preform in which the inside is melted hangs down by its own weight and is deformed, and the center position cannot be maintained. Therefore, when carrying out stretch blow molding in the vertical direction after transporting, there is a possibility that the center position is shifted and distortion occurs in the molding.

  In this type of resin molding machine, the temperature control of the preform is also very important. In other words, if there is a partial variation in the temperature of the preform, or if a temperature deviation appears regardless of the thickness of the preform, the product that has undergone the subsequent stretch blow molding process will have a problem in molding accuracy and high quality. It cannot be guaranteed.

  Furthermore, when carrying the preform, it is necessary to avoid interference with other equipment. That is, as the molding process proceeds, the male and female molds reciprocate, and the transfer arm and the preform receiving core rotate. In order to prevent the preform from being damaged due to interference with other devices, it is necessary to accurately convey the preform to the stretch blow molding process.

  The present invention is intended to solve the various problems described above, and in a resin molding machine, while preventing deformation of the preform, performing accurate temperature control, and further ensuring that it is in place. It is intended to be conveyed.

In order to solve the above-described problems, the present invention includes an injection molding block and a blow molding block, and transfers a preform molded in the injection molding block to a preform receiving core provided at the tip of the transfer arm. In a resin molding machine that performs blow molding by transferring a preform to the blow molding block by rotation, the preform receiving core has a shape substantially similar to the inner shape of the preform, and the preform receiving core A heater for maintaining the predetermined temperature by heating the preform from the inside is provided inside, and the preform receiving core is slidably inserted into a base provided at the tip of the transfer arm. A bar receiving plate at the rear end of the receiving core, and a return bar between the bar receiving plate and the base. The interposed therebetween to urge the preform receiving core transfer arm side, has to press the rod receiving plate at a draw bar to advance the preform receiving core employs the that to perform blow molding.

  In the present invention, the shape of the preform receiving core is substantially the same as the inner shape of the preform. That is, since the skin layer is formed on the surface of the preform and the inside is in a molten state, for example, when receiving the preform in a horizontal state, the preform is prevented from sagging and deforming due to its own weight. Since the preform can be supported from the inside of the preform over the entire length of the preform, the preform can be reliably prevented from being deformed by its own weight, and can be transferred to the stretch blow molding process while maintaining the center position. Therefore, it became possible to mold with high accuracy.

  In addition, since a heater is built inside the preform receiving core, the temperature of the preform can be raised from the inside to a predetermined temperature, and the temperature can be adjusted, and the occurrence of distortion during blow molding can be prevented. .

  Furthermore, since the preform receiving core is slidable back and forth via the return spring and the protruding portion is reduced during the transfer, interference with other devices can be prevented and damage to the preform can be prevented.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 3 are side sectional views showing an outline of a molding apparatus to which the present invention is applied, and basically have the same configuration as the resin molding machine described in Patent Document 1 according to the applicant's application. is there. The molding machine as a whole shows a series of cycle processes in which the molding process proceeds from FIG. 1 to FIG. 3 and returns from FIG. 3 to FIG. Here, A represents an injection molding block in the apparatus of the present invention, and B represents a blow molding block. Reference numeral 1 denotes a fixed side of the apparatus, and reference numeral 2 denotes a moving side. The moving side 2 performs a reciprocating motion so that a series of steps from injection molding to blow molding is continuously performed.

  As a structure of the fixed side 1, 3 is a hot runner adopting a known structure, 4 is a nozzle for introducing a molten resin such as PET into the hot runner 3, and 5 is a gate for injecting the molten resin into a mold. , 6 is a female die, 7 is a mouth mold for placing a preform (preform) after injection molding on the female die 6 side or undercutting the molded product, and 8 is a female. It is a fixed side plate storing the mold 6. Here, as is apparent from the drawings, in the apparatus of the present invention, the female die 6 and the mouth portion die 7 are not assembled from the nozzle 4 side, but the hot runner 3 is left as it is from the moving side 2 to the female die 6 and the mouth portion. The mold 7 is assembled in the order. Reference numeral 9 denotes a gate cutting machine for cutting protrusions remaining on the gate portion of the preform.

  Next, the structure of the moving side 2 will be described. 10 is a male mold for injection molding a preform, and 11 is a moving side plate on which the male mold 10 is provided. Then, the moving side 2 repeats reciprocating movement with respect to the fixed side 1, and the molten resin introduced from the nozzle 4 is passed through the gate 5 by the hot runner 3 in a state where the male die 10 is securely accommodated in the female die 6. In this way, preforms are sequentially manufactured, and unnecessary gate portion protrusions are cut out by the gate cutting machine 9. As described above, the injection molding of the preform is performed in accordance with the reciprocation of the moving side 2 with respect to the fixed side 1.

  Subsequently, a configuration in which a preform manufactured by the above-described procedure is conveyed and a final product is manufactured by blow molding will be described. In the figure, reference numeral 12 denotes a preform transfer arm. When this transfer arm rotates by a predetermined angle, the preform receiving core 13 installed at the tip thereof receives the preform from the injection mold, and the blow molding machine receives the preform. Transport. As for the blow molding block B, one side 14 of the split hollow molds 14 and 15 is provided on the fixed side 1 and the other side 15 is provided on the moving side 2. Are arranged so as to be combined as a molding die at the same time as they are in close contact with the fixed side 1. FIG. 1 shows the case where the transfer arm 12 moves downward and the preform receiving core 13 is located on the blow molding block B side, and FIG. 2 is the opposite, FIG. 2 shows the preform receiving core 13 on the injection molding block A side. The case where it is located is shown. In the present embodiment, the transfer arm 12 is configured to deliver the preform by rotating 90 degrees downward from the horizontal direction, but the rotation angle is not limited. Reference numeral 16 denotes a nest of the preform receiving core 13, which prevents the preform received by the preform receiving core 13 from dropping during transfer by applying vacuum. Note that this configuration is an example, and it is also within the scope of the present invention to adopt a configuration in which the insert 16 is prevented from falling off by mechanical contact with the preform or a configuration in which falling off is prevented by light adhesion. included.

  Reference numeral 17 denotes a stretching rod, and 18 is a tip of a stretching rod, and has a configuration in which air is blown through a molding die during blow molding. In addition, the extending | stretching rod front-end | tip tip 18 can be removed and replaced | exchanged, and a dissimilar molded product can be shape | molded by exchanging this.

  Reference numeral 19 denotes a bottom plate attachment plate, and a bottom mold 20 for blow molding is provided on the top thereof. The bottom mold mounting plate 19 is supported by a bottom mold mounting presser plate 21 in a state where the moving side 2 is closed. The bottom mold mounting presser plate 21 branches and applies pressurized air used at the time of injection molding. Thus, the bottom plate mounting plate 19 is urged upward so that the bottom mold 20 does not move even during blow molding. The bottom plate mounting plate 19 may be structured to move in the horizontal direction or the rotational direction when the support of the bottom mold mounting presser plate 21 is removed, so that the final molded product can be easily taken out.

  In such a configuration, a series of steps from injection molding to blow molding will be described. First, the fixed mold 1 and the movable mold 2 are combined, and the male mold 10 is fitted to the female mold 6 to provide the hot runner system 3 and the like. Install the injection molding machine. Then, an arbitrarily selected resin such as molten PET resin, polyethylene resin, or polypropylene resin is injected into the nozzle 4. In this case, in this embodiment, the gate 5 is set longer than usual. In the case of PET resin, since it may be crystallized by injection molding, the purpose is to leave this crystallized part in the gate 5 part, and improve the quality and yield of the final molded product. Because. Subsequently, the moving side 2 is moved in the direction of arrow C to expand the mold. In this embodiment, the shape of the mouth mold 7 is set so that at least some undercut occurs. By doing so, it is possible to avoid the preform coming into close contact with the male mold 10 and moving to the male mold 10 when the mold is opened, and to ensure the subsequent steps. In this way, the injection molding process is completed. During the injection molding process, the transfer arm 12 is positioned so as to face vertically downward, and the preform receiving core 13 is positioned on the blow molding block B side.

  Subsequent to the injection molding process, a preform transfer process is started. As the mold is opened, the transfer arm 12 rotates in the direction of arrow D to reach the state shown in FIG. 2, and then the mouth mold 7 advances toward the preform receiving core 13 while holding the preform. A preform receiving core 13 is provided at the tip of the transfer arm 12. Since the core has the same shape as the male mold 10, the preform receiving core 13 is covered with the preform. At this time, the mouth mold 7 is divided into two parts in the direction of arrow E in FIG. 3 and expands, and even when an undercut or the like is provided, the part does not interfere. The mouth mold 7 then moves backward and returns to the state shown in FIG. 1, but the preform moves to the receiving core 13 side because vacuum or the like is working in the insert 16 provided in the receiving core 13. Subsequently, the protrusion remaining on the gate 5 is cut by the gate cutting machine 9 attached to the fixed side 1. Then, the transfer arm 12 rotates in the return direction (the direction opposite to the arrow C) to transfer the preform to the blow molding block B. In order to prevent damage to the preform, it is necessary that the preform receiving core 13 and the center of the mouth mold 7 coincide with each other. Although not shown, it goes without saying that the male mold 10 and the transfer arm 12 or the preform receiving core 13 are offset so as not to interfere with each other due to the rotation thereof.

  After being transferred to the blow molding block B, the moving side 2 moves in the mold closing direction, and the drawing rod 17 installed on the moving side 2 passes through the inside of the moving side plate 11 while drawing the preform. Compressed air is blown from the tip 18 side of this to perform stretched hollow molding. In the injection molding block A, the preform injection molding process is in progress at the same time.

  In the blow molding process, since the bottom mold mounting plate 19 is supported by the pressurized air branched from the bottom mold mounting presser plate 21 as described above, the molding mold such as the bottom mold 20 is not displaced in the molding process. Absent. When the mold clamping of the injection molding machine is changed from high pressure to low pressure, the hollow molds 14 and 15 move downward with the mold closed to release the interference with the insert 16 and prevent damage to the molded product. I am doing so. In this case, the suction by the vacuum in the insert 16 is stopped.

  As a final process, a process for taking out a molded product will be described. When the moving side 2 is expanded again as shown in FIG. 2 or FIG. 3, the bottom mold 20 in the blow molding block B is provided on the fixed side 1, so that the molded product is placed on the bottom mold 20 in the fixed side. 1 remains. From this state, the molded product is dropped onto an appropriate conveyor (not shown) or the like by its own weight by rotating or translating the bottom mold mounting plate 19 and transporting it outside the apparatus. Note that the molded product can be taken out by a known molded product take-out machine or the like instead of being dropped onto the conveyor.

  Next, details of the transfer arm and the preform receiving core in the present invention will be described with reference to FIG. FIG. 4 shows a state in which the preform receiving core 13 holds the preform (P) after injection molding. In the figure, reference numeral 31 denotes a base provided at the tip of the transfer arm 12, and a receiving core 32 is slidably fitted into the receiving core 32, and a preform receiving core 13 is attached to the tip of the receiving core 32. The preform receiving core 13 has substantially the same shape as the inner shape of the preform (P) molded in the injection molding process (that is, the shape of the male mold), up to the inner inner end of the preform (P). Inserted without gaps. Here, almost the same shape means that a skin layer is formed on the surface of the preform and the inside is in a molten state. For example, when receiving the preform in a horizontal state, the preform hangs down due to its own weight and deforms. This means that any shape that can be supported from the inside of the preform over the entire length of the preform may be used. In addition, the preform is securely held by a known means such as vacuum. Thereby, even if the preform (P) is received in a horizontal state, the preform (P) in which the inside is in a molten state is not deformed by its own weight, and can be transferred while maintaining the center position. In addition, an appropriate heater (not shown) is provided inside the preform receiving core 13, and the temperature of the preform (P) is raised from the inside to a predetermined temperature to adjust the temperature by appropriately controlling the heater. ing. The type of heater is not particularly limited, and various known heaters can be applied. By these, the generation | occurrence | production of the distortion at the time of performing stretch blow molding after conveyance can be prevented, and it can shape | mold with high precision.

  Further, a rod receiving plate 33 is attached to the rear end of the receiving core 32, and a return spring 34 is interposed between the rod receiving plate 33 and the base 31, and the preform receiving core 13 is moved to the transfer arm side ( Energized in the direction of the arrow). In this case, when the transfer arm 12 is moved, the protruding portion from the transfer arm 12 is reduced as much as possible to prevent interference with other devices and prevent the preform from being damaged.

  The preform (P) held in this way is transferred from the horizontal direction to the vertical direction by the rotation of the transfer arm 12, and proceeds to the stretch blow molding process. As described above, since the deformation of the preform is prevented at the time of transfer, the preform is accurately positioned in the mold. In the stretching blow process, the stretching rod 17 presses the rod receiving plate 33 at the rear end of the receiving core 32 and advances the preform receiving core 13 while compressing the return spring 34. The preform (P) is subjected to stretch blow molding by blowing pressurized air from the tip of the preform receiving core 13 through a high-pressure air flow path 35 provided in the base 31 of the transfer arm 12. At this time, the injection molding block is proceeding with the next preform injection molding process at the same time. Thereafter, the molded product is taken out in the final process, the series of processes is completed, and the same process is repeated again.

It is the schematic which showed an example of the resin molding machine with which this invention is applied. Similarly, it is the schematic which shows the operation | movement in the middle. Similarly, it is the schematic which shows the operation | movement in the middle further. It is the schematic which shows operation | movement of a preform receiving core. It is sectional drawing which shows an example of the conventional preform receiving core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed side 2 Moving side 6 Female type 7 Mouth type 10 Male type 12 Transfer arm 13 Preform receiving core 17 Extending rod 31 Base 32 Receiving core 33 Rod receiving plate 34 Return spring 35 High pressure air flow path

Claims (1)

An injection molding block and a blow molding block are provided, the preform molded in the injection molding block is transferred to a preform receiving core provided at the tip of the transfer arm, and the preform is transferred to the blow molding block by the rotation of the transfer arm. In the resin molding machine that performs blow molding, the preform receiving core has a shape substantially similar to the inner shape of the preform, and the preform is heated from the inside to the inside of the preform receiving core. A heater for maintaining a predetermined temperature is provided, and the preform receiving core is provided on a receiving core slidably fitted on a base provided at the tip of the transfer arm, and a rod receiving plate is provided at the rear end of the receiving core. A preform receiving core with a return spring interposed between the rod support plate and the base. Feed biases the arm side, a resin molding machine, characterized in that to perform the blow molding by pressing the rod receiving plate at a stretching rod to advance the preform receiving core.

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