JP3363952B2 - Injection compression molding method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for injection-compression molding of a foamed resin or the like which is carried out with a mold opened widely. 2. Description of the Related Art FIGS. 2 and 3 show a conventional injection compression molding apparatus.
2 is a horizontal sectional view of the injection compression molding apparatus, and FIG. 3 is a sectional view of the half nut of FIG. In FIG. 2, a mold clamping device in the injection compression molding apparatus includes a fixed platen 4 that holds the fixed mold 2, a movable platen 3 that holds the movable mold 1, and the movable platen 3 being moved back and forth with respect to the fixed platen 4. The die opening / closing cylinder 10 that moves forward, and the movable platen 3 approaches the fixed platen 4 to close the fixed-side mold 2 and the movable-side mold 1, and then the tie bar is fixedly coupled to the fixed platen 4 to perform mold clamping. 13 and a mold clamping cylinder 14.
The tie bar 13 is fixed to the fixed platen 4. The fixed platen 4 and the movable platen 3 are connected and fixed on the opposite side of the mold mounting surface of the movable platen 3, and are opened and closed in a direction substantially perpendicular to the tie bar 13. 2 is engaged by engaging a half nut 9 to be engaged with an engagement groove formed at the tip of the tie bar 13.
3 shows a state in which the half nut 9 is closed, and FIG. 3 shows a state in which the half nut 9 is open. FIG. 4 is a sectional view taken along the line C--C in FIG. 3, and FIG. 5 is a view taken in the direction of the arrow D in FIG. 4. As shown in these figures, the half nut 9 is fixed to the movable platen 3 by a bracket 19. Is slidably hung on the provided guide bar 20,
Further, the ram 18 of the mold clamping cylinder 14 is always
Abuts on the side surface of the flange portion 18a. Reference numeral 22 denotes a guide bar fixed to the bracket 19 and slidably opened and closed by the half nut 9. A screw rod 23 fixed to the movable platen 3 for mold thickness adjustment (adjusting the position of the half nut corresponding to a different mold thickness) and a sprocket 24 screwed to the screw rod 23 are provided. The sprocket 24 can be moved in the axial direction via a chain 25 by a motor (not shown), and its end surface contacts the flange 18a of the ram 18 to serve as a stopper. Reference numeral 15 in FIG. 2 is a position detector for detecting the position of the movable platen 3. Next, the operation of the mold clamping device will be described. FIG. 7 shows a sequence when the injection compression is performed by the mold clamping device. In FIG. 4, the ram 18 of the mold clamping cylinder 14 supplies the pressurized oil to the oil chamber B to be drawn in (moves rightward in the drawing), and the flange 18a is brought into contact with the sprocket 24 and stopped. At this time, the half nut 9 is pushed by the spring 21 and its right side is in contact with the left side of the ram 18. Further, as shown in FIG. 3, the engagement between the meshing groove 9a of the half nut 9 and the meshing groove 13a of the tie bar 13 is released. In FIG. 2, the servo valve 1
1. The pressure oil is sent to the port A of the mold opening / closing cylinder 10 through the switching valve 12, and the movable platen 3 is moved forward (to the right in the figure).
Fixed mold 2 attached to movable mold 1 and fixed platen 4
And match once. In this state, the meshing groove 13a of the tie bar 13 and the meshing groove 13a of the half nut 9 are meshed. At this time, the relative position of the two meshing grooves is a necessary axial gap d so that the peaks of the two grooves do not interfere with each other. (FIG. 6)
The position of the sprocket 24 is adjusted in advance via the chain 25 so that is maintained. Next, the switching valve 12 is switched so that the mold can be opened by supplying hydraulic oil to the port B of the mold opening / closing cylinder 10 and the mold can be clamped by supplying hydraulic oil to the mold closing cylinder 14. After the pressure oil is sent to the oil chamber A of the mold clamping cylinder 14 to perform the mold clamping operation once, the pressure oil is sent to the port B of the mold opening / closing cylinder 10 and the predetermined mold opening e required for injection compression is sent. Open the mold. At this time, the movable mold 1
Is opened by operating the servo valve 11 via the control device 16 and the amplifier 17 while detecting the position by the position detector 15. An injection operation is performed when the mold is opened by an opening amount e of the compression allowance. When the injection is completed, a mold clamping signal is sent from a setting device (not shown) to the servo valve 11,
Pressurized oil is supplied from the servo valve 11 to the mold clamping cylinder 14 to compress (press up) the movable mold 1 and the fixed mold 2 to cool them, thereby performing injection compression of the molded product. In FIG. 2, the example in which the half nut 9 and the mold clamping cylinder 14 are disposed on the movable platen 4 has been described, but the same effect can be obtained by disposing them on the fixed side. [0006] In recent years, the types of molded articles have increased, and the requirements for molding equipment have also increased. In particular, in the case of foam molding, a mold is used to adjust the thickness of the molded article. It is desired to mold the resin more widely than before and inject the resin. However, in the conventional example described above, the distance e of the mold opening performed by the mold opening / closing cylinder after the mold is closed for this purpose is within the range of the gap d for engaging the half nut because the half nut is already closed (at most about 1 mm). Because of the limitations, no further dimensions can be opened. Therefore, the present invention aims to solve the above-mentioned conventional problems by changing the sequence so that the closing operation of the half nut is performed after the mold is opened. Therefore, the present invention provides a fixed plate holding a fixed mold, a movable plate holding a movable mold, and moving the movable plate back and forth with respect to the fixed plate. A mold opening / closing cylinder to be moved, a tie bar for closing the movable plate or fixed plate after the movable plate approaches the fixed plate and the movable die and the fixed die are closed, and the tie bar is movable. A half nut to be locked to a board or a fixed board, a mold clamping cylinder arranged on the movable board or the fixed board for applying a tension to the tie bar to perform mold clamping, and a position for detecting a position of the movable board. A control device including a detector, a unit for setting a desired mold opening amount, and a unit for calculating an appropriate meshing position of the half nut for an arbitrary mold thickness and moving the half nut to the position; In the injection compression molding machine, For the mold opening amount and any mold thickness, the half nut is adjusted in advance to stop at the proper meshing position, and then the movable platen is advanced by the mold opening / closing cylinder to temporarily close the mold, The movable platen is moved backward to open the mold by the set opening amount, and then the half nut is engaged with the tie bar to couple the movable platen or the fixed platen to the tie bar, and then the resin is injected and compressed by the mold clamping cylinder. This is a means for solving the problem. According to the present invention, after the mold is closed by the mold opening / closing cylinder and the mold is pressed once, the mold opening operation is continuously performed without engaging the half nut to open the mold by an opening amount e (large amount). This is characterized in that the half nut is engaged with the tie bar. The position of the half nut is determined by moving the sprocket of the stopper so as to maintain a gap d necessary to avoid interference between the half nut and the tie bar. For this purpose, the control device is provided with a means capable of setting the mold opening amount e and the sprocket is moved by the mold thickness t, the mold opening amount e, and the gap d, and the appropriate meshing position of the half nut (the required moving distance f of the sprocket) is calculated. Have a means to do it. In operation, first, a desired mold opening amount e is set in the control device. Next, when the mold thickness is determined, the control device calculates the required movement distance f of the sprocket, and moves the sprocket by this distance. Move the movable platen forward with the mold opening / closing cylinder, close and press the two dies once, check the mold thickness with the position detector, and then retreat the movable plate with the mold opening / closing cylinder while monitoring with the position detector. The mold is opened and stopped by the mold opening amount e set in the above. Here, the half nut is engaged with the tie bar. A necessary gap d is naturally maintained in the engagement groove portion. Next, after the resin is injected, compression is performed by a mold clamping cylinder, and after cooling, the mold is opened by a mold opening / closing cylinder. Thus, the molding is completed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. The injection compression molding apparatus used in the present invention is:
Since the same device as the above-described conventional device is used, the detailed detailed structure of the device is omitted here, but the device used in the present invention is provided in the control device 16 with the mold opening control as described in detail below. The feature is that the means for incorporating is incorporated. The control device 16 can set the mold opening amount e, and the thickness t = t _{1 of the} mold sent from the position detector 15.
Means for calculating the required movement amount f of the sprocket 24 to an appropriate position by using + t ₂ , the mold opening amount e, and the gap d between the engagement groove portions of the tie bar 13 and the half nut 9.
The following mold opening control is performed. First, a desired mold opening amount e is set in the control device 16. Further, a gap d required for the engagement groove between the tie bar and the half nut is also given to the control device and stored. Next, the pressurized oil is sent to the oil chamber A of the mold clamping cylinder 14 shown in FIG. 2 to move the ram 18 backward (left side in the figure) to release the contact with the sprocket 24, and then the sprocket 24 is moved to the reference position by the chain 25. Let it. The reference position uses an appropriate position in the case of the minimum mold thickness that can be used by the mold clamping device. The position is detected by a limit switch (not shown) provided on the driving side of the chain 24. Further, pressure oil is sent to the oil chamber A of the mold opening / closing cylinder 10 to move the movable platen 3 forward (to the right in the drawing) to close and press both molds. Next, position detector 1
5 Information mold thickness t = t ₁ + t ₂ shown in FIG. 6 is sent to the controller unit 16 from the controller die thickness as described above t
Sprocket 2 using ₁ + t ₂ , mold opening e and gap d
The required moving distance f to the appropriate position of No. 4 is calculated. Next, the sprocket 24 is moved by the chain 25 by the moving distance f. This movement distance is measured by measuring the number of rotations of the drive sprocket of the chain 25 (not shown). Further, pressure oil is sent to the oil chamber B of the mold clamping cylinder 14 to advance the ram 18 together with the half nut 9 (to the right in the figure),
When the contact is stopped, the preparation for the production process is completed. The above preparation operation can be automatically performed by the sequencer of the control device. Next, the operation at the time of production will be described with reference to FIG. 1. FIG. 1 shows a sequence of a production process. First, the half nut 9 is disengaged from the tie bar 13. Next, pressure oil is sent to the port A of the mold opening / closing cylinder 10, the movable platen 3 is advanced, and the movable mold 1 and the fixed mold 2 are closed and pressed once. Next, the position detector 15 detects the mold thickness t ₁ + t.
₂ is measured and sent to the controller, and the controller 16 confirms that the mold thickness is correct. Further, the valve is switched to send pressure oil to the port B of the mold opening / closing cylinder 10, and the movable platen 3 is moved backward by the set mold opening amount e and stopped while monitoring the movable platen 3 with a position detector. Next, the half nut 9 is closed and engaged with the tie bar 13. The half nut 9 meshes with a necessary gap d. Next, the resin is injected, and when the injection is completed, pressure oil is sent to the oil chamber A of the mold clamping cylinder 14 to move the movable mold 1.
Then, the fixed mold 2 is compressed (pressurized) and cooled, and the oil pressure of the mold clamping cylinder 14 is reduced. Then, the mold is opened by the mold opening / closing cylinder 10 to complete the molding. Next, pressurized oil is sent to the oil chamber B of the mold clamping cylinder 14, and the ram 18 is retracted to a position where it contacts the sprocket 24, thereby returning to the initial state. The operation of the above production process can be automatically performed by the sequencer of the control device 16. The required travel distance f of the sprocket
May be replaced by the apparent thickness t ₁ + t ₂ + e of the mold thickness t = t ₁ + t ₂ during the calculation performed when the mold is replaced by the above-described conventional apparatus. That is, the method of calculating the required travel distance f of the sprocket will be described with reference to FIG. 6 (indicated by a two-dot chain line 9 'in FIG. 6 indicates a half nut at an appropriate position). Distance from the first peak of the nut to the mold mounting surface of movable platen t ₁ : Thickness of movable mold t ₂ : Thickness of fixed mold e: Mold opening d: Mesh between half nut and tie bar Mountain gap b at the time: Assuming the distance from the first mountain of the tie bar to the die mounting surface of the fixed platen 4, the required moving distance f is calculated by the following equation. F = b + np- (t ₁ + t ₂ + a + e + d) where n is a positive integer and is selected so that 0 ≦ f <p. Although the adjustment of the proper meshing position of the half nut has been described above using the sprocket, which moves in the axial direction by rotation, as a stopper, the injection compression molding method according to the present invention uses the half nut position adjusting means. The present invention is applicable to all devices provided with. For example, as a method of adjusting the position of the half nut, a method of inserting a spacer corresponding to each mold thickness between the movable platen and the half nut, or moving the ram a required distance from a reference position and applying the half nut to the ram. Although contacting methods and the like have been proposed, the present invention is also applicable to devices using these methods. As described above in detail, according to the present invention, since the closing operation of the half nut is performed after opening the mold, the thickness of the molded product is adjusted by the opening amount of the mold by foam molding or the like. In such a case, an excellent effect is obtained such that the range of the adjustment amount, which was conventionally small, can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sequence diagram of an injection compression molding apparatus for implementing the method of the present invention. FIG. 2 is a plan sectional view of an injection compression molding apparatus according to an embodiment of the present invention and a conventional technique. FIG. 3 is a cross-sectional view of the state in which the half nut of FIG. 2 is disengaged. FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3; FIG. 5 is a view taken in the direction of arrow D in FIG. 4; FIG. 6 is an explanatory diagram showing a relationship between a tie bar and a half nut of each part. FIG. 7 is a sequence diagram of a conventional injection compression molding apparatus. [Description of Signs] 1 movable mold 2 fixed mold 3 movable plate 4 fixed plate 9 half nut 10 mold opening / closing cylinder 13 tie bar 14 mold clamping cylinder 24 sprocket

Claims (1)

(57) [Claims] [Claim 1] A fixed plate holding a fixed mold, a movable plate holding a movable mold, and a mold opening / closing cylinder for moving the movable plate back and forth with respect to the fixed plate. And a tie bar for closing the movable platen or the fixed platen after the movable platen approaches the fixed platen and closing the movable die and the fixed die, and the tiebar is moved to the movable platen or the fixed platen. A half nut to be locked to, a mold clamping cylinder disposed on the movable platen or fixed platen for applying a tension to the tie bar to perform mold clamping, and a position detector for detecting a position of the movable platen, An injection compression molding apparatus having a control device including means for setting a desired mold opening amount and means for calculating an appropriate meshing position of a half nut for an arbitrary mold thickness and moving the half nut to the position. In the set mold opening amount and arbitrary mold thickness Then, the half nut is adjusted in advance so as to stop at the proper meshing position, and then the movable platen is advanced by the mold opening / closing cylinder to temporarily close the mold. An injection compression molding method, comprising opening a mold by an opening amount, then engaging a half nut with a tie bar to couple a movable plate or a fixed plate with the tie bar, injecting resin, and compressing the resin with a mold clamping cylinder.