JP2022087647A - Molding device - Google Patents

Abstract

To provide a molding method that can easily take out a molded object from between molds when obstacles are placed in front of or behind the molds.SOLUTION: A method for producing a molded object using first and second molds that can be opened and closed includes: an extrusion step; a mold closing step; and a taking-out step. In the extrusion step, molten resin is extruded between the first and second molds in an open state. In the mold closing step, the first and second molds are closed to form a molded object from the molten resin. The taking-out step includes: an arm insertion step of inserting a taking-out arm between the first and second molds in the open state; a folding step of attaching the molded object to the taking-out arm and folding the molded object; and a pull-back step of pulling back the taking-out arm to which the molded object is attached.SELECTED DRAWING: Figure 14

Description

The present invention relates to a molding apparatus for molding a resin molded product.

Conventionally, as a method of molding a resin molded product, there is a method of hanging a molten resin sheet extruded from an extruder between molds, closing the resin sheet with a mold, and blowing or vacuum forming. (See, for example, Patent Document 1). In this method, since the molten resin sheet extruded from the extruder is placed between the molds and the mold is closed, there are problems such as heating non-uniformity caused by reheating the resin. The resin molded product can be easily molded without causing the problem.

JP-A-2015-168231

By the way, when molding a pair of resin sheets using a pair of molds, an insert member may be inserted between the pair of resin sheets. In such a case, the devices necessary for inserting the insert member may be arranged in front of and behind the mold, and there is a difficulty that it is difficult to take out the molded body.

An object of the present invention is to provide a molding method capable of easily taking out a molded body from between molds when obstacles are arranged in front of and behind the mold.

According to the present invention, it is a method of manufacturing a molded body using the first and second molds that can be opened and closed, and includes an extrusion step, a mold closing step, and a taking-out step. The molten resin is extruded between the first and second molds, and in the mold closing step, the first and second molds are closed to form a molded body from the molten resin, and the taking-out step is opened. An arm insertion step of inserting an take-out arm between the first and second molds in a state, a folding step of attaching the molded body to the take-out arm, and folding the molded body, and the molded body A method is provided that comprises a pull-back step of pulling back the attached take-out arm.

With such a configuration, the molded body can be folded and taken out between the molds, so that the molded body can be easily taken out from between the molds without interfering with obstacles arranged in front of and behind the mold. It becomes possible.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with each other.
Preferably, in the folding step, the molded body is attached by adsorbing to the taking-out arm.
Preferably, in the folding step, the take-out arm is attracted to the side surface of the upper half of the molded body, and the take-out arm is rotated so that the central portion of the molded body is located on the upper side of the take-out arm. By allowing the molded body to be folded.
Preferably, the mold is provided with a protruding portion protruding toward the molten resin at the central portion in the vertical direction, and in the mold closing step, a thin portion is provided at the central portion in the vertical direction of the molded product.

It is a front view which shows typically the molding apparatus 1 which concerns on this embodiment. It is a top view which shows typically the mold closing mechanism 30. It is a perspective view which shows the structure of the take-out arm 50. It is a front view which shows the state which the molds 31 and 32 are closed. It is an enlarged view of the area D1 in FIG. It is a top view which shows the state which the molds 31 and 32 are closed. It is a figure which shows the state which extended the piston 34a. It is a figure which shows the state which the lower burr B2 was dropped. It is a figure which shows the state which the molds 31 and 32 are opened. It is a figure which shows the state which dropped one of the upper burr B1. It is a figure which shows the state which dropped the whole upper burr B1. It is a figure which adsorbed the suction part 53 of the take-out arm 50 to the molded body M. It is a figure which pulled the molded body M away from a mold 32. It is a figure which folded the molded body M.

Hereinafter, embodiments of the present invention will be described. The various features shown in the embodiments shown below can be combined with each other. In addition, the invention is independently established for each characteristic item.

(1. Molding device 1)
A configuration example of the molding apparatus 1 of the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing a configuration example of the molding apparatus 1 of the present embodiment. In this embodiment, the extrusion mechanism 2 will be described in a mode of extruding a resin sheet as a molten resin.

The molding apparatus 1 includes a pair of extrusion mechanisms 2 and a mold closing mechanism 30. The extrusion mechanism 2 includes a hopper 12, an extruder 13, an accumulator 17, a T-die 18, and a drawing roller 28. The extruder 13 and the accumulator 17 are connected via a connecting pipe 25. The accumulator 17 and the T-die 18 are connected via a connecting pipe 27. Hereinafter, each configuration will be described in detail.

<Hopper 12, extruder 13>
The hopper 12 is used to charge the raw material resin 11 into the cylinder 13a of the extruder 13. The form of the raw material resin 11 is not particularly limited, but is usually in the form of pellets. The raw material resin is, for example, a thermoplastic resin such as a polyolefin, and examples of the polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, an ethylene-propylene copolymer and a mixture thereof. The raw material resin 11 is charged into the cylinder 13a from the hopper 12 and then heated in the cylinder 13a to be melted into a molten resin. Further, it is conveyed toward the tip of the cylinder 13a by the rotation of the screw arranged in the cylinder 13a. The screw is arranged in the cylinder 13a, and the molten resin is kneaded and conveyed by its rotation. A gear device is provided at the base end of the screw, and the screw is rotationally driven by the gear device. The number of screws arranged in the cylinder 13a may be one or two or more.

<Accumulator 17, T-die 18>
The molten resin is extruded from the resin extrusion port of the cylinder 13a and injected into the accumulator 17 through the connecting pipe 25. The accumulator 17 includes a cylinder 17a and a piston 17b slidable inside the cylinder 17a, and the molten resin can be stored in the cylinder 17a. Then, by moving the piston 17b after a predetermined amount of the molten resin is stored in the cylinder 17a, the molten resin is pushed out from the extrusion slit 18a provided at the lowermost end of the T-die 18 through the connecting pipe 27 and hung down to be melted. The resin sheets 22 and 23 in the state are formed.

<Stretching roller 28>
The extrusion mechanism 2 has a stretching roller 28 for stretching the molten resin sheets 22 and 23 extruded from the extrusion slit 18a. As shown in FIG. 2, the stretching roller 28 is composed of a pair of adjusting rollers 28a and 28b and an auxiliary roller 28c. The pair of adjusting rollers 28a and 28b are arranged at predetermined positions below the T-die 18. The auxiliary rollers 28c are arranged at predetermined positions below the pair of adjusting rollers 28a and 28b.

The extrusion mechanism 2 sandwiches the resin sheets 22 and 23 extruded from the extrusion slit 18a between the pair of adjusting rollers 28a and 28b, and causes the resin sheets 22 and 23 to be sent downward by the rotation of the adjusting rollers 28a and 28b. The resin sheets 22 and 23 are stretched and thinned. Here, by adjusting the relationship between the extrusion speed of the resin sheets 22 and 23 extruded from the extrusion slit 18a and the delivery speed of the resin sheets 22 and 23 by the adjusting rollers 28a and 28b, the occurrence of drawdown or neck-in can be generated. Can be prevented. As a result, restrictions on the type of resin, particularly the MFR and melt tension values, or the extrusion rate per unit time can be reduced.

<Mold closing mechanism 30>
The mold closing mechanism 30 includes a pair of openable and closable molds 31 and 32 for molding the resin sheets 22 and 23, a blower 38, an insert device 63 for inserting an insert member, and a molded product. The taking-out arm 50 (see FIG. 2) is provided. A slide member 33 configured to be slidable in the width direction of the resin sheet is provided on the upper surface and the lower surface of the mold 32.

The molds 31 and 32 have cavities 31a and 32a, and pinch-off portions 31b and 32b are provided so as to surround the cavities 31a and 32a. At the center of the molds 31 and 32 in the vertical direction, protrusions 31c and 32c protruding toward the resin sheet are provided. Decompression suction holes (not shown) are provided in the cavities 31a and 32a, and the resin sheets 22 and 23 are decompressed and sucked through the decompression suction holes along the inner surfaces of the cavities 31a and 32a of the molds 31 and 32. It is possible to shape it into a different shape. The decompression suction hole is a very small hole, one end of which is communicated to the inner surface of the cavities 31a and 32a through the inside of the molds 31 and 32, and the other end is connected to the decompression device. Outer frames 61 and 62 are attached to the outside of the molds 31 and 32.

The slide member 33 has an air cylinder 34 as a stretched portion that can be stretched in a direction perpendicular to the width direction of the resin sheets 22 and 23 in a plan view, and a bracket as a cutting portion for cutting the resin sheets 22 and 23. 35 is provided.

As shown in FIG. 2, a front spring 64 is attached to the front of the molds 31 and 32, and a rear spring 65 is attached to the rear of the molds 31 and 32 so as to connect the outer frames 61 and 62. An insert device 63 is arranged in the center of the front spring 64. A take-out arm 50 is arranged further behind the rear spring 65. The take-out arm 50 is configured to be movable in the front-rear direction of the molds 31 and 32.

<Removal arm 50>
As shown in FIG. 3, the take-out arm 50 includes an arm body 51 connected to a robot arm (not shown) and a folding plate 52. The folding plate 52 is formed in a flat plate shape, and one or more (four in the example shown in FIG. 3) suction portions 53 are provided on one side thereof. The shape of the folding plate 52 and the number of the suction portions 53 are not limited to this example, and may be appropriately set according to the size and shape of the molded body M. The arm body 51 is configured to be rotatable about its longitudinal direction as a rotation axis.

(2. Manufacturing method of resin sheet)
A method for manufacturing the resin molded product P using the molding apparatus 1 will be described with reference to FIGS. 4 to 14.

First, a predetermined amount of the melt-kneaded thermoplastic resin is stored in the accumulator 17, and a predetermined amount of the thermoplastic resin stored in the accumulator 17 is extruded from the extrusion slits 18a provided at the T-die 18 at predetermined intervals. Extrude intermittently. As a result, the molten resin sheets 22 and 23 are extruded from the extrusion slit 18a at a predetermined extrusion speed.

The extrusion mechanism 2 widens the distance between the adjusting rollers 28a and 28b arranged below the extrusion slit 18a from the thickness of the resin sheets 22 and 23. As a result, the lowermost portions of the molten resin sheets 22 and 23 extruded downward from the extrusion slit 18a can be smoothly supplied between the pair of adjusting rollers 28a and 28b. The timing at which the distance between the pair of adjusting rollers 28a and 28b is wider than the thickness of the resin sheets 22 and 23 may be set not after the start of extrusion but at the end of secondary molding for each shot.

Next, the extrusion mechanism 2 narrows the distance between the pair of adjusting rollers 28a and 28b, sandwiches the resin sheets 22 and 23, and sends the resin sheets 22 and 23 downward by the rotation of the pair of adjusting rollers 28a and 28b. At this time, the rotation speed of the pair of adjusting rollers 28a and 28b is decreased with the passage of time, and the feeding speed is adjusted so as to be close to the extrusion speed of the resin sheets 22 and 23.

In this way, with the passage of time, the resin is reduced by reducing the relative speed difference between the downward feeding speed of the resin sheets 22 and 23 due to the rotation of the pair of adjusting rollers 28a and 28b and the extrusion speed of the resin sheets 22 and 23. The downward pulling force of the pair of adjusting rollers 28a and 28b decreases toward the upper part of the sheets 22 and 23, and the stretching thinning due to such pulling force is relatively reduced, and the thinning due to drawdown or neck-in is relatively reduced. Can be canceled out, drawdown or neck-in can be effectively prevented, and a uniform thickness can be formed in the extrusion direction.

Next, the pair of resin sheets 22 and 23 sent out from the pair of extrusion mechanisms 2 are arranged between the molds 31 and 32 in the open state. When the positioning of the resin sheets 22 and 23 is completed, the rotation of the pair of adjusting rollers 28a and 28b and the auxiliary rollers 28c of the extrusion mechanism 2 is temporarily stopped, and the resin sheets 22 and 23 are sandwiched between the pair of adjusting rollers 28a and 28b. To.

Next, the resin sheets 22 and 23 are shaped along the cavities 31a and 32a of the molds 31 and 32, respectively. This step can be performed by performing vacuum suction of the resin sheets 22 and 23 with the dies 31 and 32.

Next, as shown in FIGS. 4 to 6, the molds 31 and 32 are closed. At this time, the insert product 67 attached to the insert jig 66 of the insert device 63 is inserted into the end face of the molded body M. As a result, the resin sheets 22 and 23 are welded to each other along the pinch-off portions 31b and 32b, and a molded body M having a shape along the inner surface of the cavity formed by the pair of molds 31 and 32 is obtained. Here, since the protrusions 31c and 32c are provided on the molds 31 and 32, the thin portion M1 is formed at the central portion in the vertical direction of the molded body M. Specifically, as shown in FIG. 5, the thickness T1 of the thin portion M1 has a relationship of T1 <2T with respect to the thickness T of the molded body M other than the thin portion. When the molds 31 and 32 are closed in this way, burrs are formed on the top and bottom of the molds 31 and 32 by the resin sheets 22 and 23. Hereinafter, the burr formed above the molds 31 and 32 is referred to as an upper burr B1, and the burr formed below the molds 31 and 32 is referred to as a lower burr B2.

Next, as shown in FIG. 7, the piston 34a of the air cylinder 34 provided on the upper side and the lower side of the mold 32 is extended in the direction of the upper burr B1 and the lower burr B2.

Next, the slide member 33 is slid along the width direction of the resin sheets 22 and 23. As a result, the horizontal surface 35b of the bracket 35 provided at the tip of the piston 34a cuts the upper burr B1 and the lower burr B2. As a result, as shown in FIG. 8, the lower burr B2 formed on the lower side of the molds 31 and 32 is dropped onto the belt conveyor 40 and conveyed.

Next, as shown in FIG. 9, the piston 34a and the slide member 33 of the air cylinder 34 are returned to their original positions, and the molds 31 and 32 are opened. In the present embodiment, the molded body M is opened in a state of being adsorbed on the mold 32 by suction from the decompression suction hole inside the mold 32 provided on the blower 38 side.

Next, as shown in FIG. 10, while blowing air F from the blower 38, the pair of adjusting rollers 28a and 28b and the auxiliary rollers 28c on the blower 38 side were rotated and sandwiched by the stretching rollers 28. Release one of B1.

Next, as shown in FIG. 11, the pair of adjusting rollers 28a and 28b and the auxiliary rollers 28c on the opposite side of the blower 38 are rotated to open the other of the upper burrs B1 held by one of the stretching rollers 28. As a result, the upper burr B1 falls on the belt conveyor 40 and is conveyed.

Next, as shown in FIG. 12, by operating the robot arm, the take-out arm 50 is inserted between the molds 31 and 32 so as to pass above the rear spring 65 from the rear of the molds 31 and 32. , The suction portion 53 is attached to the molded body M by adsorbing it.

Next, as shown in FIG. 13, the molded body M is separated from the mold 32 by operating the robot arm. Next, the arm body 51 is rotated about the longitudinal direction as a rotation axis. Specifically, the molded body M is rotated so as to be located above the folding plate 52 (in the direction of arrow A in FIG. 13). As a result, as shown in FIG. 14, the molded body M is folded so as to be wrapped around the folding plate 52.

Next, the robot arm is pulled back to the rear of the molds 31 and 32, and the molded body M is taken out from between the molds 31 and 32 so as to pass above the rear spring 65. After that, the resin molded product P is manufactured by removing the peripheral burrs formed on the peripheral portion of the molded body M. The folding plate 52 attached to the tip of the take-out arm 50 is removed by a robot (not shown), and the insert jig 66 for attaching the insert product 67 to the insert device 63 is attached to the take-out arm 50. ..

As described above, in the manufacturing process of the present embodiment, there is an arm insertion step of inserting the take-out arm 50 between the open molds 31 and 32, and an arm insertion step of attaching the molded body M to the take-out arm 50 and folding the molded body M. It includes a folding step and a step of pulling back the take-out arm to which the molded body is attached. Therefore, even when devices such as an insert device 63, a front spring 64, and a rear spring 65 are arranged before and after the dies 31 and 32, it is possible to easily take out the molded body formed between the dies. It will be possible.

Further, since the folding plate 52 and the insert jig can be exchanged and attached to the tip of the arm body of the take-out arm 50, the space before and after the mold closing mechanism 30 can be efficiently used. can.

(3. Other embodiments)
It should be noted that the above-described embodiment is a preferred embodiment of the present invention, and the present invention is not limited to this, and can be variously modified and carried out based on the technical idea of the present invention.

For example, in the above embodiment, the molded body M is attached to the take-out arm 50 by using the suction portion 53, but the present invention is not limited to this embodiment. For example, the molded body M may be gripped by a grip portion provided at the tip of the take-out arm 50.

Further, in the above embodiment, the take-out arm 50 is attracted to the side surface of the upper half of the molded body M, and the take-out arm 50 is rotated so that the central portion of the molded body M is located above the take-out arm 50. Thereby, the molded body M is folded, but the present invention is not limited to this aspect. For example, the molded body M may be folded by adsorbing the folding plate 52 of the take-out arm 50 to the side surface of the lower half of the molded body M and moving the folding plate 52 in parallel between the molds 31 and 32.

Further, in the above embodiment, the thin portion M1 is formed in the vertical central portion of the molded body M by providing the protruding portion protruding toward the resin sheets 22 and 23 in the central portion of the molds 31 and 32. .. This makes it possible to easily bend the molded body M in the folding step, but the present invention is not limited to this aspect. For example, by adopting a soft material as the resin sheets 22 and 23, the molded body M may be easily bent.

Further, in the above embodiment, the molten resin sheets 22 and 23 are extruded by the extrusion mechanism 2, and the molds are closed and sucked by the openable and closable dies 31 and 32 to form the resin molded body. Not limited to. For example, blow molding may be performed in which the parison is extruded into a cylindrical shape by the extrusion mechanism 2 and air is blown into the parison. Alternatively, the resin sheet may be in a mode in which the mold is closed by the mold and the air is blown in combination.

1: Molding device 2: Extrusion mechanism 11: Raw material resin 12: Hopper 13: Extruder 13a: Cylinder 17: Accumulator 17a: Cylinder 17b: Piston 18: T die 18a: Extrusion slit 22: Resin sheet 23: Resin sheet 25: Connection Tube 27: Connecting tube 28: Stretching roller 28a: Adjusting roller 28b: Adjusting roller 28c: Auxiliary roller 30: Mold closing mechanism 31: Mold 31a: Cavity 31b: Pinch-off part 31c: Protruding part 32: Mold 32a: Cavity 32b: Pinch-off part 32c: Protruding part 33: Slide member 34: Air cylinder 34a: Piston 35: Bracket 35b: Horizontal plane 38: Blower 40: Belt conveyor 50: Take-out arm 51: Arm body 52: Folding plate 53: Suction part 61: Outside Frame 62: Outer frame 63: Insert device 64: Front spring 65: Rear spring 66: Insert jig 67: Insert product

Claims (4)

It is a method of manufacturing a molded product using the first and second molds that can be opened and closed.
Equipped with extrusion process, mold closing process, and taking-out process,
In the extrusion process, the molten resin is extruded between the first and second molds in the open state.
In the mold closing step, a molded body is formed from the molten resin by closing the first and second molds.
The taking-out step is
An arm insertion step of inserting a take-out arm between the first and second molds in the open state, and
A folding step of attaching the molded body to the taking-out arm and folding the molded body,
A method comprising a pull-back step of pulling back a take-out arm to which the molded body is attached. The method according to claim 1.
In the folding step, a method of adsorbing the molded body to the taking-out arm. The method according to claim 2.
In the folding step, the take-out arm is attracted to the side surface of the upper half of the molded product.
A method of folding a molded body by rotating the take-out arm so that a central portion of the molded body is located above the take-out arm. The method according to any one of claims 1 to 3.
The mold has a protruding portion protruding toward the molten resin at a central portion in the vertical direction.
In the mold closing step, a method of providing a thin portion in the central portion in the vertical direction of the molded product.

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