Method for taking out foamed resin molded product

Abstract

To provide a method for taking out a foamed resin molded product, which can suppress take-out failure regardless of the skill level of an operator and can suppress excessive consumption of compressed air.SOLUTION: A method for taking out a foamed resin molded product includes the steps of: introducing compressed air into a fixed-side chamber and adjusting the pressure to a predetermined level; forming a first cracking gap between the two molds after the pressure adjustment in the fixed-side chamber is completed, and placing the foamed resin molded product on a movable mold by lifting it from a fixed mold with the compressed air; slightly protruding an ejector pin into a cavity; introducing compressed air into a movable-side chamber and adjusting the pressure to a predetermined level; forming a second cracking gap between the two molds after the pressure adjustment in the movable-side chamber is completed, and placing the foamed resin molded product on the ejector pin by compressed air from the movable mold side; and opening the mold widely and pushing the foamed resin molded product out of the mold with the ejector pin.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for taking out a foamed resin molded product.

Background Art

[0002] A method of filling pre-expanded particles into a mold, heating and foaming them, and taking out the foamed resin molded product from the mold after cooling is widely used. Among these, in the mold release step of taking out the foamed resin molded product from the mold, a method of introducing compressed air into the contact surface between the mold and the foamed resin molded product to separate the foamed resin molded product from the mold is known.

[0003] The present applicant has conventionally carried out various methods for taking out a foamed resin molded product using compressed air and an ejector pin. Patent Document 1 discloses a mold release method in which, after molding a molded product, a mold release cracking width is formed, compressed air is introduced into the steam chamber of the fixed mold, the molded product is released from the fixed mold and placed in the moving mold, and then compressed air is introduced into the steam chamber of the moving mold to release the molded product from the moving mold, and the mold is opened wide and the molded product is pushed out with an ejector pin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the mold release method described in Patent Document 1, when opening the mold to the mold release cracking width, the movement of the moving mold and the introduction of compressed air were performed simultaneously. However, when introducing compressed air into the chamber while moving the moving mold, the pressure regulation in the chamber became unstable, and the peeling pressure for releasing the molded product was biased and the molded product might not be released uniformly. If the mold release is not performed uniformly, not only will there be a mold release failure, but there is also a risk that the compressed air will be consumed excessively.

[0006] In addition, in a method of taking out a foamed resin molded product using compressed air and an ejector pin, there has been a problem that it is difficult to adjust the timing of the operation of the ejector pin and the protruding amount. For example, if the timing of the operation of the ejector pin is too early or the protruding amount is too large, a pin load is concentrated on the foamed resin molded product that is not yet demolded or is insufficiently demolded, and there may be a problem in taking out such as the foamed molded product being damaged.

[0007] Conventionally, in order to suppress these problems in taking out, operators have made various adjustments. For example, while observing the movement of the ejector pin, the pressure of the compressed air is adjusted, or the operation of the ejector pin is adjusted by operating the tension of a spring that biases the ejector pin in a direction away from the cavity. However, the shapes of the foamed resin molded products to be manufactured are various, and the adjustment of the ejector pin and the compressed air requires the skill of the operator.

[0008] Also, control of the operation timing of the ejector pin and the supply of compressed air has been attempted using a control device such as a programmable logic controller (PLC). However, when the hardware configuration such as the number of ejector pins changes, it may not behave as intended. For example, even if a program is set to operate the ejector pin with a predetermined driving force and timing, the actual behavior of the ejector pin may deviate from the intended timing depending on the number of ejector pins and the like.

[0009] An object of the present invention is to solve the above-described conventional problems, and to provide a method for taking out a foamed resin molded product that can suppress problems in taking out regardless of the skill level of the operator and can suppress excessive consumption of compressed air.

Means for Solving the Problems

[0010] A method for taking out a foamed resin molded product in a foam molding machine including a fixed mold, a movable mold, and an ejector pin attached to the fixed mold, the method comprising: introducing compressed air into a chamber of the fixed mold and adjusting the pressure to a predetermined pressure; after the pressure adjustment of the chamber of the fixed mold is completed, forming a first cracking interval between the two molds, and floating the foamed resin molded product from the fixed mold by the compressed air and placing it in the movable mold; slightly protruding the ejector pin into the cavity; introducing compressed air into a chamber of the movable mold and adjusting the pressure to a predetermined pressure; after the pressure adjustment of the chamber of the movable mold is completed, forming a second cracking interval larger than the first cracking interval between the two molds, and placing the foamed resin molded product on the ejector pin by the compressed air from the movable mold side; opening the mold widely, and pushing out the foamed resin molded product out of the mold by the ejector pin.

[0011] Further, the ejector pin is slid by being pressed by an ejector plate that can approach and separate from the fixed mold, and it is preferable to detect the position of the ejector plate and control the protruding amount of the ejector pin based on the position information.

[0012] Further, a play width is provided between the pressing surface of the ejector plate and the pressed surface of the ejector pin, and it is preferable to advance the ejector plate to a position where the pressing surface contacts the pressed surface and stop it before the step of slightly protruding the ejector pin into the cavity.

Effect of the Invention

[0013] In the present invention, it is possible to provide a method for taking out a foamed resin molded product that can suppress defective taking out regardless of the operator's skill level and suppress excessive consumption of compressed air.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] Embodiments for carrying out the invention are shown below.

[0016] (Manufacturing Apparatus for Foamed Resin Molded Product) The manufacturing apparatus 10 for a foamed resin molded product in the embodiment will be described. As shown in FIG. 1, the manufacturing apparatus 10 of the embodiment includes a fixed mold 20 and a movable mold 30. A cavity C is formed by these fixed mold 20 and movable mold 30. In this specification, as shown in FIG. 1 and the like, the movable mold 30 side is taken as the front side of the manufacturing apparatus 10, and the fixed mold 20 side is taken as the rear side of the manufacturing apparatus 10. Further, in this specification, the mold opening direction is taken as the forward direction of the ejector pin 40 described later, and the mold closing direction is taken as the backward direction of the ejector pin 40.

[0017] The fixed mold 20 of the embodiment is provided with a fixed-side chamber 21 at the back, and the fixed-side cavity surface 22 is provided with vent holes (not shown) capable of supplying the steam supplied into the fixed-side chamber 21 to the cavity C. Further, a feeder (not shown) for filling the cavity C with pre-expanded particles is connected to the fixed mold 20 of the embodiment.

[0018] The movable mold 30 of the embodiment includes a moving-side chamber 31 at the back, and the moving-side cavity surface 32 is provided with vent holes (not shown) through which the vapor supplied into the moving-side chamber 31 can be supplied to the cavity C. The movable mold 30 is opened and closed with respect to the fixed mold 20 by a driving means such as a cylinder (not shown).

[0019] The manufacturing apparatus 10 includes an ejector pin 40 that extrudes the foamed resin molded product from the cavity C. As shown in FIG. 1, the ejector pin 40 of the embodiment includes a shaft portion 40 made of metal and a pin head 411 provided at the front end of the shaft portion 40, and is attached to the fixed mold 20 such that the front end surface of the pin head 411 is flush with the fixed-side cavity surface 22. The configuration of the ejector pin 40 of the embodiment will be described in detail later.

[0020] The manufacturing apparatus 10 of the embodiment includes an ejector plate 50 that presses the ejector pin 40 to move it closer to and away from the fixed mold 20. The ejector plate 50 of the embodiment is provided on the back side of the fixed mold 20. As shown in FIGS. 1 and 2, the ejector plate 50 of the embodiment includes a rectangular frame-shaped ejector frame 51 and a plurality of horizontally bar-shaped pressing members 52 provided inside the ejector frame 51. Although FIG. 2 shows a state in which one ejector pin 40 is engaged with the ejector plate 50, in actuality, a plurality of ejector pins 40 are often attached to the ejector plate 50 according to the shape and quantity of the foamed resin molded product.

[0021] As shown in FIG. 1, the ejector plate 50 of the embodiment is connected to an air cylinder 60 which is a driving means, and is movable closer to and away from the fixed mold 20. Note that the driving means of the ejector plate 50 is not limited to the air cylinder 60, and other driving means may be used.

[0022] The air cylinder 60 of the embodiment is connected to an air supply source (not shown). A solenoid valve 61 is provided between the air cylinder 60 and the air supply source. By opening the solenoid valve 61, compressed air is supplied to the air cylinder 60, and by closing the solenoid valve 61, the supply of compressed air to the air cylinder 60 is stopped.

[0023] Further, the manufacturing apparatus 10 includes means for supplying compressed air for releasing the foamed resin molded product in the cavity C. In the manufacturing apparatus 10 of the embodiment, each of the fixed mold 20 and the movable mold 31 is connected to an air supply source (not shown), and compressed air can be separately supplied to the fixed-side chamber 21 and the movable-side chamber 31. Note that the air supply source of the compressed air may be the same as the air supply source of the air cylinder 60 or may be separate.

[0024] The compressed air supplied into the fixed-side chamber 21 jets out from the vent hole formed in the fixed-side cavity surface 22 toward the cavity C, and the foamed resin molded product in the cavity C can be released from the fixed mold 20. Similarly, the compressed air supplied into the movable-side chamber 31 jets out from the vent hole formed in the movable-side cavity surface 32 toward the cavity C, and the foamed resin molded product in the cavity C can be released from the movable mold 30.

[0025] A fixed-side compressed air supply valve 70 is provided between the fixed mold 20 of the embodiment and the air supply source. In the embodiment, by opening the fixed-side compressed air supply valve 70, compressed air is supplied into the fixed-side chamber 21, and by closing the fixed-side compressed air supply valve 70, the supply of compressed air into the fixed-side chamber 21 is stopped.

[0026] Also, a movable-side compressed air supply valve 71 is provided in the movable mold 30 of the embodiment in the same manner as in the fixed mold 20. By opening the movable-side compressed air supply valve 71, compressed air is supplied into the movable-side chamber 31, and by closing the movable-side compressed air supply valve 71, the supply of compressed air into the movable-side chamber 31 is stopped.

[0027] The manufacturing apparatus 10 includes control means 80 for controlling the supply of compressed air. The control means 80 of the embodiment controls the entire manufacturing apparatus 10 including the solenoid valve 61, each compressed air supply valve, etc.

[0028] (Ejector pin and ejector plate) As described above, the ejector pin 40 of the embodiment slides while being pressed by an ejector plate 50 that can approach and separate from the fixed mold 20. Hereinafter, the structures of the ejector pin 40 and the ejector plate 50 of the embodiment will be described.

[0029] As described above, the ejector pin 40 of the embodiment includes a metal shaft portion 40 and a pin head 411 provided at the front end of the shaft portion 40, and is attached to the fixed mold 20 such that the front end surface of the pin head 411 is flush with the fixed-side cavity surface 22 (hereinafter, the position of the ejector pin 40 at this time is referred to as the "retracted position").

[0030] As shown in FIGS. 2 and 3, a metal sleeve 42 is attached to the shaft portion 41 of the ejector pin 40 of the embodiment. The sleeve 42 of the embodiment is a cylindrical member having a through hole with an inner diameter slightly larger than the outer diameter of the shaft portion 41.

[0031] The sleeve 42 of the embodiment has a rearward U-shaped receiving portion 421 that is open at the rear in a side view at its front end. The receiving portion 421 of the embodiment is formed in a U shape from a front plate and a pair of upper and lower plates, and is fixed to the sleeve 42 by welding.

[0032] A circular movable flange portion 422 is attached to the middle portion of the sleeve 42 so as to be movable in the front-rear direction. A spring retaining member 423 having a diameter larger than the outer diameter of the sleeve 42 is provided at the rear end of the sleeve 42. As shown in FIG. 3, screw holes are formed in the spring retaining member 423 and the sleeve 42. The sleeve 42 is fixed to the shaft portion 41 by tightening a fastening member 424 into this screw hole. The fastening member 424 in the example shown in FIG. 2 is a wing bolt, and can be tightened or loosened by an operator by hand.

[0033] A spring 425 is provided between the movable flange portion 422 and the spring retaining member 423. The spring 425 is a compression spring, and as will be described later, it cooperates with the movable flange portion 422 and the pressing member 52 to bias the ejector pin 40 in the direction of retraction. Conventionally, the forward momentum of the ejector pin 40 has been adjusted by adjusting the position of the sleeve 42 to adjust the stroke of the spring 425.

[0034] As shown in FIGS. 1 to 3, the front end side of the ejector pin 40 is attached to the fixed mold 20, and the rear end is a free end. In the embodiment, as shown in FIGS. 2 and 3, the middle portion of the ejector pin 40 is inserted between the pressing members 52, 52 adjacent to each other vertically, and the front end side and the rear end side of the two upper and lower pressing members 52 are arranged so as to be sandwiched between the receiving portion 421 and the movable flange portion 422.

[0035] As shown in FIGS. 2 and 3(a), the ejector plate 50 in the non-operating state before the mold release process is stationary at a position where the pressing member 52 presses the movable flange portion 422 rearward, and always holds the ejector pin 40 in the retracted position. In the embodiment, the spring 425 is biased in the direction of always retracting the ejector pin 40 by being pushed rearward and compressed by the movable flange portion 422. Hereinafter, the position of the pressing surface 52a, which is the front end surface of the pressing member 52, in the non-operating state before the mold release process shown in FIG. 3(a) is defined as the initial position P1.

[0036] When the pressing surface 52a of the ejector plate 50 is at the initial position P1 (that is, when the ejector pin 40 is at the retracted position), the front end surface of the pin head 411 maintains a flush state with the fixed-side cavity surface 22 of the fixed mold 20. Further, in the embodiment, a seal member such as an O-ring (not shown) is provided between the rear end surface of the pin head 411 and the fixed mold 20, and the fixed mold 20 and the pin head 411 are in close contact and sealed by the ejector pin 40 being biased in the direction of always retracting.

[0037] In the embodiment, as shown in Fig. 3(a), a play width Dp is provided between the pressing surface 52a when in the initial position P1 and the surface 421a to be pressed, which is the back surface of the front plate of the receiving portion 421.

[0038] When the air cylinder 60 is driven to move the ejector plate 50 forward, as shown in Fig. 3(b), when the pressing member 52 has advanced a distance corresponding to the play width Dp, the pressing surface 52a of the pressing member 52 comes into contact with the surface 421a to be pressed of the receiving portion 421. Hereinafter, the position of the pressing surface 52a at this time is defined as the pressing effective position P2.

[0039] When the ejector plate 50 further advances, the pressing member 52 presses the receiving portion 421 forward beyond the pressing effective position P2, and the ejector pin 40 begins to slide forward. In the embodiment, in this way, a slight time difference occurs between the start of sliding of the ejector plate 50 and the start of sliding of the ejector pin 40. When the ejector pin 40 advances, the pin head 411 projects forward from the fixed side cavity surface 22 of the fixed mold 20.

[0040] When the pressing member 52 further presses the receiving portion 421 forward, as shown in Fig. 3(c), the ejector pin 40 further advances. As a result, the pin head 411 projects further forward from the cavity surface 22, and the foamed resin molded product in the cavity C can be pushed out of the mold.

[0041] (Position detecting means) In the present invention, it is preferable to detect the position of the ejector plate 50 and control the protruding amount of the ejector pin 40 based on the information of the position.

[0042] The manufacturing apparatus 10 of the embodiment includes position detecting means (not shown) for detecting the position of the ejector plate 50. The position detecting means of the embodiment detects the position of the pressing surface 52a of the ejector plate 50, and for example, a linear encoder or a limit switch can be used.

[0043] The position detection means in the embodiment detects that the pressing surface 52a of the ejector plate 50 has reached the effective pressing position P2, and sends a signal to the control means 80. Based on the signal, the control means 80 determines that the ejector plate 50 has reached a position where it can press the ejector pin 40 and the ejector pin 40 can start to move.

[0044] With such a configuration, since the forward distance from the pressable position of the ejector plate 50 and the protruding amount from the fixed-side cavity surface 22 of the ejector pin 40 are substantially the same, the control means 80 can control the forward distance of the ejector plate 50 to accurately control the protruding amount of the ejector pin 40 from the fixed-side cavity surface 22.

[0045] In the embodiment, the position detection means directly detects the position of the pressing surface 52a, but the present invention is not limited to this configuration. For example, the position detection means may detect the position of a portion other than the pressing surface 52a of the ejector plate 50, and the control means 80 may estimate whether the pressing surface 52a has reached the extrusion effective position P2 in consideration of the difference between the detected position of the portion and the position of the pressing surface 52a.

[0046] (Method for taking out foamed resin molded product) Next, with reference to FIGS. 4 to 6, a method for taking out the foamed resin molded product W in the embodiment will be described. The foamed resin molded product W in this example has a thickness of about 240 mm.

[0047] (Step 1) When heating steam is supplied to the cavity C filled with pre-expanded particles, the pre-expanded particles inside the cavity C are heated and foamed, and the volume expands and they fuse with each other. After the cavity C is heated for a predetermined time and then cooled, the foamed resin molded product W becomes in a state where it can be taken out. In the embodiment, at the end of Step 1, both the fixed-side chamber 21 and the moving-side chamber 31 are in a substantially vacuum state with reduced pressure.

[0048] (Step S2) Introduce air into the fixed-side chamber 21 in a decompressed state to make it in a normal pressure state.

[0049] (Step S3) Open the fixed-side compression air supply valve 70 to supply compressed air to the fixed-side chamber 21, and adjust the pressure of the fixed-side chamber 21 to a predetermined pressure.

[0050] At this time, the position of the pressing surface 52a of the pressing member 52 of the ejector plate 50 is the initial position P1 shown in Fig. 5(a). At this stage, the ejector pin 40 of the embodiment is stationary at the retracted position, and the pin head 411 is flush with the fixed-side cavity surface 22 of the fixed mold 20.

[0051] (Step S4) Open the solenoid valve 61 of the air cylinder 60 to advance the piston rod of the air cylinder 60. The ejector plate 50 pushed by the piston rod starts to advance from the initial position P1. When the ejector plate 50 advances a distance equal to the play width Dp and reaches the pressing effective position P2 where the pressing surface 52a can press the ejector pin 40 as shown in Fig. 5(b), stop the ejector plate 50.

[0052] In the embodiment, the position of the ejector plate 50 is detected by a position detection means (not shown), and the control means 80 receives the signal from the position detection means and stops the ejector plate 50. Note that the method of stopping the ejector plate 50 at the above-described position is not limited to this. For example, the initial position of the ejector plate 50 may be positioned so that the play width Dp becomes a predetermined value (for example, 10 mm), and the ejector plate 50 may be advanced and stopped by the same distance as the play width Dp.

[0053] (Step S5) After it is confirmed that the pressure regulation of the fixed-side chamber 21 is completed, move the movable mold 30 in the mold-opening direction at a low speed, and form a first cracking interval Dm1 between the fixed mold 20 and the movable mold 30 as shown in Fig. 5(c). At this time, compressed air is introduced from the fixed-side chamber 21 between the fixed-side cavity surface 22 and the foamed resin molded product W, so that the foamed resin molded product W can be lifted from the fixed mold 20 and entrusted to the movable mold. Note that the first cracking interval Dm1 in the embodiment is 10 mm, but the value is not limited to this.

[0054] (Step S6) Advance the ejector plate 50 slightly forward, and as shown in Fig. 5(d), project the ejector pin 40 slightly into the cavity C. In the example of the embodiment, the ejector plate 50 is advanced 10 mm so that the protruding amount L1 of the ejector pin 40 from the fixed-side cavity surface 22 is 10 mm. Hereinafter, the position when the tip of the ejector pin 40 protrudes slightly from the fixed-side cavity surface 22 in Step S7 is defined as the first extrusion position of the ejector pin 40.

[0055] When the ejector pin 40 stops at the first extrusion position, stop the supply of compressed air to the fixed-side chamber 21.

[0056] (Step S7) After confirming that the low-speed movement of the movable mold 30 in the mold-opening direction has surely stopped, introduce air into the decompressed moving-side chamber 31 to make it in the normal pressure state.

[0057] (Step S8) As shown in Fig. 6(a), open the moving-side compressed air supply valve 71 to supply compressed air to the moving-side chamber 31 and adjust the pressure of the moving-side chamber 31 to a predetermined pressure.

[0058] (Step S9) After confirming that the pressure adjustment of the moving-side chamber 31 is completed, move the movable mold 30 in the mold-opening direction at a low speed. As shown in Fig. 6(b), form a second cracking gap Dm2 larger than the first cracking gap Dm1 between the fixed mold 20 and the movable mold 30, and use the compressed air ejected into the cavity C from the movable mold 30 side to place the foamed resin molded product W that was in close contact with the movable mold 30 on the ejector pin 40. Note that the second cracking gap Dm2 in the embodiment is 30 mm, but it is not limited to this value.

[0059] Thereby, the ejector pin 40 that has protruded to the first extrusion position can receive the foamed resin molded product W, maintain the state where the foamed resin molded product W floats slightly from the fixed-side cavity surface 22, and prevent it from adhering to the fixed mold 30 again.

[0060] (Step S10) After stopping the supply of compressed air to the moving chamber 31, the moving mold 30 is rapidly moved, and as shown in Fig. 6(b), it is widely opened.

[0061] (Step S11) Simultaneously with the mold opening, the ejector pin 40 is advanced to push out the foamed resin molded product W from the mold. In the example of the embodiment, the ejector plate 50 is advanced by 280 mm so that the protruding amount L2 from the fixed-side cavity surface 22 of the ejector pin 40 is 280 mm. When the position of the ejector pin 40 in Step S12 is set as the second extrusion position, the protruding amount L2 at the second extrusion position is set to an amount that can push out the foamed resin molded product W from the mold.

[0062] (Step S12) The foamed resin molded product W pushed out by the ejector pin 40 falls onto a predetermined recovery means, and the taking-out process is completed.

[0063] With the above-described taking-out method, it is possible to suppress defective taking-out of the foamed resin molded product W regardless of the skill level of the operator, and to suppress excessive consumption of compressed air.

[0064] As described above, the present invention has been described by taking the embodiment as an example, but the present invention is not limited to the above embodiment, and various aspects are possible. For example, the structures of the ejector pin 40 and the ejector plate 50 are not limited to this embodiment, and it is also possible to adopt a configuration in which the ejector plate 50 presses the rear end of the ejector pin 40.

Description of Reference Numerals

[0065] 10 Manufacturing apparatus 20 Fixed mold 21 Fixed-side chamber 30 Moving mold 31 Moving-side chamber 40 Ejector pin 42 Sleeve 421 Receiving portion 421a Pressed surface 50 Ejector plate 52 Pressing member 52a Pressing surface Dp Play width P1 Initial position P2 Effective pressing position 60 Air cylinder 70 Fixed-side compressed air supply valve 71 Moving-side compressed air supply valve 80 Control means Dm1 First cracking interval Dm2 Second cracking interval

Claims

1. A method for removing a foamed resin molded product from a foam molding machine including a fixed mold, a movable mold, and an ejector pin attached to the fixed mold, comprising: introducing compressed air into the chamber of the fixed mold and adjusting the pressure to a predetermined pressure; after the pressure adjustment of the chamber of the fixed mold is completed, forming a first cracking interval between the two molds, floating the foamed resin molded product from the fixed mold by compressed air and placing it in the movable mold; slightly protruding the ejector pin into the cavity; introducing compressed air into the chamber of the movable mold and adjusting the pressure to a predetermined pressure; after the pressure adjustment of the chamber of the movable mold is completed, forming a second cracking interval larger than the first cracking interval between the two molds, and placing the foamed resin molded product on the ejector pin by compressed air from the movable mold side; and a method for removing a foamed resin molded product including a step of opening the mold widely and pushing out the foamed resin molded product out of the mold by the ejector pin.

2. The ejector pin is slid by being pressed by an ejector plate that can approach and separate from the fixed mold, The method for removing a foamed resin molded product according to claim 1, wherein the position of the ejector plate is detected and the protruding amount of the ejector pin is controlled based on the position information.

3. A play width is provided between the pressing surface of the ejector plate and the pressed surface of the ejector pin, before the step of slightly protruding the ejector pin into the cavity, The method for removing a foamed resin molded product according to claim 2, wherein the ejector plate is advanced and stopped until the pressing surface contacts the pressed surface.

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