JP2007230131A - Foamed resin molding machine and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed resin molding machine capable of controlling cracking clearances with high precision during filling of a raw material and mold releasing and its operating method. <P>SOLUTION: The die opening and closing unit of the foamed resin molding machine opens and closes a movable die plate 2 with respect to a fixed die plate 1 and consists of a toggle link 5 arranged between the movable die plate 2 and a clamping housing 8, a cross head 6 expanding and contracting the toggle link 5 and an electric ball screw 7 screwed into the cross head 6 through the clamping housing 8. The die opening and closing unit is equipped with a die thickness adjusting mechanism 9 adjusting the die thickness S when the toggle link 5 is expanded to clamp and a rotation controlling mechanism 20 controlling the rotation of the ball screw so as to control cracking clearances at a constant level. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a foamed resin molding machine for producing a foam molded product and an operation method thereof.

  Conventionally, as disclosed in Patent Document 1, a foamed resin molding machine used in the field of foam molding is configured such that a movable die plate is moved closer to and away from a fixed die plate by driving a piston. There are many things that open and close. Specifically, there is an apparatus provided with a mold opening and closing device as shown in FIG. 5, and this apparatus has a piston 51 attached to a movable die plate 2 having a movable mold 4 attached to the front surface. Is driven by a drive cylinder 52 so that the movable die 4 is moved closer to and away from the fixed die 3 attached to the fixed die plate 1.

  In the foamed resin molding machine as described above, since the mold composed of the fixed mold 3 and the movable mold 4 is replaced and mounted in accordance with the foam molded product, the fixed mold 3 and the movable mold 4 are separated from each other. The die interval (hereinafter referred to as the mold thickness) S when in contact varies widely. Even when the mold thickness S is reduced, the movable mold 4 can be brought into contact with the fixed mold 3 reliably if the stroke of the piston 51 is sufficiently large. However, when the mold thickness S becomes narrower than the stroke of the piston 51, the movable mold 4 cannot be brought into contact with the fixed mold 2, and therefore, as shown in FIG. 53 was installed to compensate for the shortage of strokes. On the other hand, when the mold thickness S is excessively widened by exchanging the mold, it is necessary to remove the distance piece 53 on the contrary. The operation of attaching and detaching the distance piece 53 must be performed in a narrow space, which is very troublesome work such as troublesome work and contamination of the worker with oil.

Further, in the mold opening and closing apparatus as described above, in order to fill the cavities formed in the mold with the foamable resin material (beads) in the process of moving the movable die plate 4 in proximity, it is usually between these A predetermined cracking gap is ensured at once and stopped once, and the mold is clamped by bringing it closer together after the raw material is charged. The cracking gap is important as an air escape path when the raw material is introduced into the mold by the air flow.
However, in the conventional mold opening / closing device using a hydraulic cylinder, the pressing force of the moving die plate 4 varies depending on the viscosity of the oil, the temperature, the speed of the moving die plate 4, and the weight of the moving die 4. There is a problem that the control of the stop position of the die plate 4 is unstable and the cracking gap has an error of ± 0.5 to 1.0 mm with respect to the set value, resulting in variations in molding conditions.

When the molded product is released from the mold, a cracking gap of 5 to 50 mm is set corresponding to the molded product and the movable die plate 4 is opened. At this time, the molded product is floated from the mold. Air is blown into the mold. However, in a conventional hydraulic cylinder type mold opening / closing device, the cracking gap fluctuates due to the increase of the air blowing pressure, and an error of ± 50 to 100 mm often occurs with respect to the set cracking gap. When such a large error occurs, there is a problem that the molded product cannot be transferred to the opposing mold, and the molded product cannot be taken out smoothly. In addition, there is a problem that the molded product is deformed, broken, or pierced by the eject pin.
JP 05-154930 A

  In view of the above-described conventional problems, the present invention eliminates the need for attaching and detaching the distance piece, and further enables a foamed resin molding machine capable of controlling the cracking gap at the time of material filling and mold release with high accuracy, and an operating method thereof. It is an issue to provide.

The foamed resin molding machine according to the present invention made to solve the above problems is
In a foamed resin molding machine comprising a fixed die plate having a fixed mold, a movable die plate having a movable mold, and a mold opening and closing device for opening and closing the movable die plate with respect to the fixed die plate.
The mold opening / closing device is screwed into the crosshead through the mold clamping housing, the toggle link disposed oppositely between the movable die plate and the mold clamping housing, the crosshead for bending and extending the toggle link. As an electric ball screw,
A mold thickness adjusting means for adjusting the mold thickness of the mold clamped by moving the mold clamping housing to the mold opening and closing device;
And a ball screw rotation control means for performing constant control of the cracking gap by stopping the movable mold at the cracking position during mold clamping and mold opening.

In the above-described foamed resin molding machine, the mold thickness adjusting means comprises a mold thickness adjusting motor for moving the mold clamping housing, a rotary encoder for detecting the position of the moving die plate, and a controller for driving the mold thickness adjusting motor. And can
The ball screw rotation control means may comprise an electric motor that rotates the ball screw, a rotary encoder that detects the rotation speed of the electric motor, and a controller that drives the electric motor.

The operation method of the foamed resin molding machine of the present invention is an operation method of a foamed resin molding machine that performs mold clamping using the foamed resin molding machine according to any one of claims 1 to 3,
Corresponding to the mold thickness of the replaced mold, after moving the mold clamping housing by the mold thickness adjusting means and presetting the mold thickness,
After obtaining the mold clamping force at the mold clamping limit and finely adjusting the mold thickness by the mold thickness adjusting means based on the measurement result,
When the mold is opened once and then clamped, the extension of the toggle link is controlled by the ball screw rotation control means to control the cracking gap at the time of filling the raw material constant.

Moreover, the operation method of the foamed resin molding machine of the present invention is an operation method of the foamed resin molding machine that performs mold release using the foamed resin molding machine according to any one of claims 1 to 3,
After molding the molded product, control the bending of the toggle link with the ball screw rotation control means while putting air into the fixed mold, open the movable mold to the mold release cracking position, and move the molded product by air to move Deposit in a mold,
Next, while controlling the extension of the toggle link by the ball screw rotation control means while putting air into the movable mold, the movable mold was clamped to the mold clamping clamp position, and the molded product was floated with air and deposited in the fixed mold. later,
Subsequently, the molded product is pushed out and dropped with an eject pin while opening the mold.

  In the invention according to claim 1, since the moving die plate is moved by a toggle link bent and stretched by an electric ball screw, the cracking gap at the time of filling the material and at the time of releasing is larger than that of the conventional hydraulic cylinder type. It can be controlled with high accuracy.

  In the invention according to claim 2, by operating the mold thickness adjusting motor, the mold clamping housing can be moved in the front-rear direction to adjust the mold thickness when the mold is replaced.

  The invention according to claim 3 can detect the load torque at the time of mold clamping and adjust the mold thickness to a set value based on the result. Since the controller controls the position of the crosshead by detecting the rotation speed of the electric motor with the rotary encoder, the cracking position can be correctly controlled.

  In the invention according to claim 4, since the position of the mold clamping housing is adjusted by the mold thickness adjusting means, excessive or insufficient mold clamping force does not occur. Since the toggle link is extended by the rotation of the ball screw and the ball screw rotation control means, it is possible to prevent the fluctuation of the raw material filling condition by controlling the cracking gap during the raw material filling to be constant.

  In the invention according to claim 5, since the toggle link is bent and extended at the time of mold release by the rotation of the ball screw and the ball screw rotation control means, the cracking gap in mold release and mold clamping can be controlled to be constant. Thus, the blown air as in the conventional hydraulic cylinder system does not cause a significant fluctuation in the cracking gap, and the molded product can be taken out smoothly.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is a schematic configuration diagram showing a foamed resin molding machine provided with a mold opening / closing device according to the present invention. In FIG. 1, a movable die plate 2 is disposed to face the fixed die plate 1, and a mold clamping housing 8 is disposed on the right side of the movable die plate 2 in the drawing.

  A fixed die 3 is attached to the fixed die plate 1, and a movable die 4 is attached to the movable die plate 2. A cavity 13 is formed between the fixed die 3 and the movable die 4. The fixed die 3 is provided with a raw material supply device 16 and an eject pin 17 for extruding a molded product through the fixed die plate 1. Furthermore, the fixed mold 3 and the movable mold 4 are provided with pipes 18 for introducing water, steam, air, and the like.

  Four tie bars 14 are disposed through the movable die plate 2 and the mold clamping housing 8, and the mold clamping housing 8 is positioned by an adjusting nut 10 screwed into an end portion of the tie bar 14. A small gear 31 is provided coaxially with the adjustment nut 10, and the small gears 31 of the four tie bars 14 mesh with the large gear 35. A chain can be used instead of the gear.

  A mold thickness adjusting means 9 is disposed in the vicinity of the clamping housing 8. The mold thickness adjusting means 9 includes a mold thickness adjusting motor 93 and a rotary encoder 92 that detects the position of the movable die plate 2, and a drive gear 91 mounted on the rotating shaft of the adjusting motor 93 is large via the intermediate gear 34. It meshes with the gear 35. With the above configuration, when the mold thickness adjusting motor 93 is operated, the rotation of the drive gear 91 is transmitted to the large gear 35, and the small gears 31 are integrally rotated simultaneously. Since each adjustment nut 10 moves forward and backward along the threaded portion of each tie bar 14, the movable die plate 2 also moves forward and backward, and the position in the front-rear direction can be adjusted. The rotary encoder 92 can detect the position of the movable die plate 2 by detecting the rotational speed of the mold thickness adjusting motor 93. Alternatively, the position of the movable die plate 2 can be detected by attaching the rotary encoder 92 to the movable die plate 2 and rotating the rotary encoder 92 in the form of a rack and pinion.

  As the mold of the foamed resin molding machine, an aluminum mold is used, unlike iron in the case of an injection molding machine or a die casting machine. This is because iron causes corrosion problems due to the use of steam, and it is necessary to use aluminum having good heat conductivity in order to shorten the cooling time after molding and before mold opening. However, since it is made of aluminum, wear and sag are larger than those of iron, so it is necessary to adjust the die thickness at the time of clamping. If this is neglected, steam will spout from the parting surface or the dimensional accuracy of the molded product will be inferior. For these reasons, it is necessary to carefully adjust the mold thickness S using the mold thickness adjusting means 9 in small increments.

  The mold clamping housing 8 and the movable die plate 2 are arranged with the toggle links 5 facing each other, and these toggle links 5 are connected to the crosshead 6. The toggle link 5 includes a link A connected to the movable die plate 2, a link B connected to the link A and the mold clamping housing 8, and a link C connected to the link B and the crosshead 6.

  A ball nut 15 is fixed to the cross head 6, and a ball screw 7 is screwed into the ball nut 15. The ball screw 7 is screwed through the clamping housing 8 in a rotatable state. An electric motor 12 for rotating the ball screw is connected to the end of the ball screw 7 opposite to the cross head 6 via a coupling 11.

  The toggle link 5 is provided with a ball screw rotation control means 20 for controlling the cracking gap to be constant by stopping the movable mold 4 at the cracking position when the mold is clamped and opened. The ball screw rotation control means 20 includes an electric motor 12 that bends and stretches the toggle link 5 by moving the crosshead 6 back and forth, a rotary encoder 32 that is attached to the electric motor 12 and can detect the position of the crosshead 6; The controller 33 is connected to the rotary encoder 32 and controls the position of the crosshead 6. The electric motor 12 can also detect a load torque as a mold clamping force.

  By configuring the ball screw rotation control means 20 as described above, the load torque at the time of mold clamping can be measured as the mold clamping force, and the mold clamping housing 8 is positioned forward and backward by the mold thickness adjusting means 9 based on the result. Fine adjustments can be made. Further, since the bending and stretching of the toggle link 5 is controlled by the ball screw rotation control means 20, the cracking position can be set correctly. Further, the cracking position can be correctly held by the position holding function of the ball screw 7.

Below, the operating method of an above-mentioned foamed resin molding machine is demonstrated.
FIG. 4 is a flowchart of the process. FIG. 2 is a view showing a state in which the toggle link 5 is bent and the movable die plate 2 is maximally separated from the solid die plate 1, and the mold is exchanged corresponding to the molded product to be manufactured in this state. Attached.

  After the mold replacement, the position of the mold clamping housing 8 is adjusted in advance by driving the mold thickness adjusting motor 93 so as to meet the replaced mold thickness S. Then, the toggle link 5 is extended to perform mold clamping to the mold clamping limit, and the mold clamping force is measured by the mold clamping force measuring means. For example, the load torque of the electric motor 12 accompanying the mold clamping is measured as the mold clamping force. Thereafter, the mold opening is performed once. At this time, the controller 33 determines whether or not the mold clamping force is the set value. When the clamping force is excessive or insufficient, the position of the clamping housing 8 is finely adjusted back and forth to adjust the clamping force to a set value. The clamping force can be measured by detecting the extension of the tie bar 14 with a strain gauge attached to the tie bar 14 or directly by detecting the extension of the tie bar 14. .

  When the mold clamping force is a set value, the mold clamping is started by the extension of the toggle link 5, and the mold clamping is stopped at the position where the cracking interval L is left (FIG. 3). Usually, the cracking position is about 0.1 to 10 mm before the mold clamping limit. In the present invention, since the mold clamping is performed by the toggle link 5, the moving speed of the moving die plate 2 is naturally reduced in the vicinity of the cracking position, so that the moving die plate 2 can be moved at a high speed as a whole. Since the ball screw rotation control means 20 controls the bending and stretching of the toggle link 5, the cracking position can be set correctly. Further, since the electric ball screw 7 is employed, the cracking position can be correctly held by the position holding function of the ball screw 7.

  After the movable mold 4 is stopped at the cracking position, the raw material supply device 16 starts filling the raw material into the cavity 13, and the raw material filling is finished by counting out a timer provided in the raw material supply device 16.

  Next, after re-clamping to the mold clamping limit (FIG. 1), steam is introduced into the fixed mold 3 and the movable mold 4 from the steam pipe. Then, the introduction of the steam is stopped by counting out the timer for introducing the steam. The raw material in the cavity 13 is expanded and fused. Thereafter, cooling water is injected into the fixed mold 3 and the movable mold 4 from the water supply pipe, and the injection is stopped when the water injection timer counts out. The expanded raw material is cooled and fixed to complete the molding.

  After molding, mold opening starts at low initial speed due to the characteristics of toggle link 5 and shifts to a slightly faster medium speed mold opening at the position where the mold is opened 2 to 3 mm from the mold clamping limit, but at the same time as mold opening starts or mold opening The mold is opened while air is introduced into the fixed mold 3 before the start, the mold opening is stopped at the cracking position of the mold release, and the molded product is floated with air and deposited on the movable mold 4 side. Next, the medium-speed mold clamping is performed to the cracking position of the mold clamping while putting air into the movable mold 4, the mold clamping is stopped, and the molded product is deposited in the fixed mold 3. Thereafter, the molded product can be dropped and removed by extruding the molded product with the eject pin 16 while opening the mold at a high speed.

  When opening the mold, the cracking position is not set in advance, and the pressure of the air entering the cavity 13 is detected. It is also possible to employ a method of stopping at a suitable position. Further, by setting the cracking position in advance, it is possible to change the air pressure and the mold opening / closing speed using the mold opening position as a parameter. The three points of position, air pressure, and acceleration / deceleration of the opening / closing speed are repeatedly applied to each molding cycle by the ball screw rotation control means 20 according to the preferable release conditions according to the depth, shape, and release characteristics of the molded product. it can. Therefore, the molded product can be taken out stably, and mold release defects can be greatly reduced. The effect that the amount of mold release / take-out air used can be halved is produced.

  As described above, the molding of the molded product of one cycle is completed. When subsequently molding the same molded product, the mold opening is performed to the mold opening limit or halfway, and then mold clamping for filling the raw material is started.

  When exchanging the mold, after opening the mold to the mold opening limit, the mold thickness adjusting motor 9 is driven to retract the mold clamping housing 8 to the mold exchanging position. By this operation, the mold can be exchanged.

As described above, the foamed resin molding machine of the present invention has the following characteristics.
(1) Since the mold clamping is performed by the electric motor connected to the toggle link, the cracking position at the time of filling the raw material can be controlled with higher accuracy than the conventional hydraulic cylinder system. By adopting the toggle link, the moving die plate can be automatically reduced in speed before the mold closing limit, and the stopping accuracy of the moving die plate can be increased. Therefore, the cracking position can be always set to be constant to prevent the raw material filling failure.

(2) Since the mold opening after molding is performed by an electric motor connected to the toggle link, the cracking position can be optimally controlled corresponding to molds having different cavity shapes, depths, drafts, etc. . Therefore, there is no possibility of causing a mold release failure due to excessive air removal.
In addition, by adopting a toggle link, the molded product can be released at a low speed until it is released from the fixed mold, and after it is released, the mold can be opened at a high speed, thus shortening the cycle time. be able to.

(3) By adopting a toggle link method for opening and closing the mold, the opening and closing of the movable die plate can be supported by four tie bars. When releasing the mold, the movable die plate is opened while swinging, not parallel to the fixed die plate, due to the difference in frictional force between the molded product and the mold and the contact surface between the fixed die and the movable die. Sometimes. Even in such a case, since the attachment portion of the link A is close to each tie bar, the mold can be opened while preventing shaking. Therefore, there is a great advantage that the swing can be made smaller than the opening and closing by a single hydraulic cylinder provided at the center of the movable die plate as in the prior art, and the mold can be released without causing defects such as deformation of the molded product.

It is a schematic block diagram of the foaming resin molding machine provided with the metal mold | die opening / closing apparatus which concerns on this invention. It is a schematic block diagram of the foamed resin molding machine opened to the mold opening limit. It is a schematic block diagram of the foaming resin molding machine of the state by which the movable mold | type was stopped in the cracking position at the time of raw material addition. It is a process flow figure which manufactures a foaming molded product. It is a schematic block diagram of the foaming resin molding machine provided with the conventional metal mold | die opening / closing apparatus.

Explanation of symbols

1 fixed die plate, 2 moving die plate, 3 fixed type, 4 moving type, 5 toggle link, 6 cross head, 7 ball screw, 8 mold clamping housing, 9 mold thickness adjusting means, 10 adjusting nut, 11 coupling, 12 electric Motor, 13 cavity, 14 tie bar, 15 ball nut, 16 raw material supply device, 17 eject pin, 18 piping, 20 ball screw rotation control means, 32 rotary encoder, 33 controller, 92 rotary encoder, 93 mold thickness adjustment motor

Claims (5)

In a foamed resin molding machine comprising a fixed die plate having a fixed mold, a movable die plate having a movable mold, and a mold opening / closing device for opening and closing the movable die plate with respect to the solid die plate,
The mold opening / closing device is screwed into the crosshead through the mold clamping housing, the toggle link disposed oppositely between the movable die plate and the mold clamping housing, the crosshead for bending and extending the toggle link. As an electric ball screw,
A mold thickness adjusting means for adjusting the mold thickness of the mold clamped by moving the mold clamping housing to the mold opening and closing device;
A foamed resin molding machine, comprising: a ball screw rotation control means for performing constant control of the cracking gap by stopping the movable mold at the cracking position during mold clamping and mold opening.   2. The mold thickness adjusting means comprises a mold thickness adjusting motor for moving the mold clamping housing, a rotary encoder for detecting the position of the moving die plate, and a controller for driving the mold thickness adjusting motor. The foamed resin molding machine described in 1.   The ball screw rotation control means comprises an electric motor that rotates the ball screw, a rotary encoder that detects the rotation speed of the electric motor, and a controller that drives the electric motor. Foamed resin molding machine. A method for operating a foamed resin molding machine that performs mold clamping using the foamed resin molding machine according to claim 1,
Corresponding to the mold thickness of the replaced mold, after moving the mold clamping housing by the mold thickness adjusting means and presetting the mold thickness,
After obtaining the mold clamping force at the mold clamping limit and finely adjusting the mold thickness by the mold thickness adjusting means based on the measurement result,
A method for operating a foamed resin molding machine characterized in that when a mold is opened once and then clamped, the extension of the toggle link is controlled by a ball screw rotation control means to control the cracking gap at the time of filling the raw material constant. A method for operating a foamed resin molding machine that performs mold release using the foamed resin molding machine according to claim 1,
After molding the molded product, control the bending of the toggle link with the ball screw rotation control means while putting air into the fixed mold, open the movable mold to the mold release cracking position, and move the molded product by air to move Deposit in a mold,
Next, while controlling the extension of the toggle link by the ball screw rotation control means while putting air into the movable mold, the movable mold was clamped to the mold clamping clamp position, and the molded product was floated with air and deposited in the fixed mold. later,
Subsequently, a method for operating a foamed resin molding machine, wherein the molded product is extruded and dropped with an eject pin while the mold is opened.

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