JP2000271976A - Method for taking out injection molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply, inexpensively take out a molded product and to effectively detect an abnormality in taking out by cutting one end of the molded product in a mold, separating the separated one molding to separate the molded product from the mold, naturally dropping it, taking out it and then taking out the other by a take-out unit. SOLUTION: When a flexible disk 19a of a resin molded product and a resin solidified material 20a are separated, a movable side mold 2 is driven and a mold for injection molding is opened, the material 20a formed at a gate is set to the state separated from the disk 19a. A gate ejecting pin 22a mounted at an ejector plate is ejected to eject the material 20a of the gate and to naturally drop the material 20a. Then, the disk 19a is held by the mold 2. Then, the thin annular disk 29a is ejected by a flexible disk ejecting sleeve 23a, and taken out by a take-out unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an injection-molded article, and more particularly to a method for separating a molded article formed in a mold into two or more pieces by the time the mold is opened.
It relates to a method for removing one or more molded articles.

[0002]

2. Description of the Related Art In an injection molding method, after a cavity formed in a mold is filled with a molten resin and cooled and solidified, the mold is opened, and the formed molded product is ejected from a projecting pin provided in the mold. It is common practice to use a protruding means, such as a protruding sleeve, to protrude and take it out of the mold. Conventionally, as a method of removing a molded product protruding from a mold, a method of free dropping as it is, a method of grasping by a mechanical chuck, a method of vacuum suction by a suction cup, and the like have been used.

In the free-fall method, since a molded product is dropped by gravity, the lighter the weight of the molded product, the more unstable the fall. If the molded product is caught on a mold or the molded product is charged with static electricity, the mold is dropped. May adhere to the surface. In particular, in the injection molding by the hot runner method, unlike the case of the cold runner method, the obtained molded article is not connected to the runner at the gate portion, so the weight of the molded article is lighter than that of the cold runner method. It will be. Therefore, the above-described problem is likely to occur. on the other hand,
In the method of taking out with a take-out machine, the molded product to be taken out has rigidity, and the flatter the shape, the easier it is to take out, and it can be taken out by a method using a mechanical chuck or a vacuum suction method using a suction cup. However, when the molded product to be taken out has a complicated shape or is small, there is no part to be vacuum-adsorbed, and
When the thickness is small, there is a problem in that deformation is caused by a mechanical chuck or vacuum suction, which makes it difficult to take out.

[0004] The problem concerning the removal of the injection molded product from the mold will be described below by taking as an example the case where a flexible disk which is a component of a photographic film cartridge is injection molded. The photographic film cartridge 34 shown in FIG. 4 includes a flexible disk 43a fitted into one end 42a of a spool 42, and another end 4 of the spool 42.
2b and the flexible disk 43 at the other end 42b of the spool 42.
and a VEI ring 44 fitted on the outside of b. The flexible disks 43a and 43b used in this photographic film cartridge have a thickness of 0.1%.
It is very thin (mm to 0.2 mm) and has an opening 45 at the center for fitting the spool 42.
When the flexible disk 43a or 43b is manufactured by injection molding, when the gate portion is set on the surface of the main body of the flexible disk which is a molded product, that is, the gate which is the introduction portion of the molten resin in the injection mold is a molded product. If the opening is formed in the cavity corresponding to the surface, it is difficult to provide a gate drop portion because the formed flexible disk is thin. Also, the molten resin introduced into the cavity from the gate goes around the portion corresponding to the opening,
The flow length of the molten resin flowing to the part opposite to the gate becomes longer, and it is necessary to perform injection at a high resin pressure so that the molten resin is sufficiently filled. However, there is a problem that the molded article cannot be obtained, and furthermore, a weld line is formed in the obtained molded article, resulting in a decrease in strength.

[0005] In order to avoid these problems in injection molding of a flexible disk, it is desirable to perform molding using a mold having a cavity in which a gate portion becomes the center of the flexible disk. However, when injection molding is performed using such a mold, a molten resin is also filled in the central portion corresponding to the opening of the flexible disk, and a molded product having a resin solidified material in a portion corresponding to the opening is obtained. . Therefore, after removing this molded product,
A step of forming a hole in the center and forming an opening is required.

Therefore, after injection molding and before opening the mold, the gate is cut off from the molded product in the mold to form an opening. As described above, since the opening is formed in the mold, a step of forming the opening again after taking out from the mold becomes unnecessary, which is effective in reducing the cost in the molding process. Therefore, regardless of the cold runner method or hot runner method, after filling the cavity with molten resin and cooling and solidifying, cut a part of the molded product formed in the cavity inside the mold before opening the mold A method of projecting two or more parts by separating them into two or more parts has been proposed as a method of molding an annular part or a compact disk (CD) having an opening in a part (for example, 55-15834
JP, JP-A-1-99821, JP-B-6-75
892) and various other methods have been proposed.
It has been implemented.

[0007] However, the flexible disk is a very thin molded article having a weight of less than 0.1 g as described above. In addition, since it is a thin molded product, it is formed by filling the cavity with molten resin at a high speed (injection speed is 500 mm / s or more) at the time of injection molding. It is easy to do. Therefore, when the flexible disk is removed by free fall after molding the flexible disk, a problem that the flexible disk does not separate from the mold or adheres to the mold due to static electricity or the like charged in the middle of the fall even if it falls easily occurs. . As described above, if the mold is closed to perform the next injection molding while the molded article is attached to the mold, the mold may be damaged by the attached molded article. On the other hand, in the method of taking out a molded product by an unloader instead of free fall, when the flexible disk and the gate are separated in the mold, two molded products must be taken out, and the flexible disk is As shown in FIG. 3, since it is complicated and has a shape with a small number of flat portions, vacuum suction is very difficult depending on a suction cup or the like. Moreover, since the rigidity of the flexible disk is extremely low, the flexible disk may be deformed if it is strongly sucked by a suction cup or the like or if it is gripped by a mechanical chuck.

When a molded article is taken out by such a take-out machine, some kind of detecting means is usually employed to confirm whether or not the molded article has been completely taken out. For example, in the method of removing a molded product by vacuum suction, it is detected whether the degree of pressure reduction of the suction device when the molded product is sucked has reached a set value, and it has been confirmed that the removal operation of the molded product has been completed. In this method, for example, the protrusion of the molded product from the mold is defective, or as a result of failure in delivery, if the suction is not sufficient, because the degree of decompression of the suction device does not reach the set value,
It is determined that an abnormality has occurred, and the mold closing operation in the next step is stopped.

However, when the two separated molded articles are taken out by vacuum suction together and an abnormality is detected, since the gate portion has a flat portion which can be easily sucked, it is necessary to take out the two molded products with a strong suction force. However, since the flexible disk has few flat parts and low rigidity,
Unable to take out with strong adsorption power. Therefore, even if the gate portion could be sucked, but the flexible disk could not be sucked, the suction of the gate portion would increase the degree of decompression of the suction device, and no abnormality might be detected. Furthermore, in order to adsorb two molded products,
There is also a disadvantage that the structure of the suction unit of the unloader becomes very complicated. When the structure becomes complicated, for example, when the number of cavities increases (for example, four or more), the size and weight of the take-out plate provided with the suction head for taking out the product increases, and the rigidity of the take-out plate increases. The problem of securing and vibration increases.

As described above, in injection molding, when two or more separated molded articles are taken out of the mold after opening the mold, and when all the separated two or more molded articles are taken out by free fall, In addition, there is a problem that separation of each molded product after dropping is complicated. Further, when the molded product is lightweight, the molded product may stick to the mold due to static electricity or the like and may not drop. On the other hand, lightweight, small molded products that are hard to fall naturally
There are problems that it is difficult to take out by a method such as vacuum suction or mechanical chuck. Furthermore, when a molded article is cut into two or more pieces in a mold, the gap between the separated molded articles is substantially zero, and sometimes it is entangled when taking out the article. In addition, it is difficult to take out the film by vacuum suction and mechanical chuck at the same time. Further, when two or more separated molded articles are simultaneously taken out by an unloader and accumulated in the same container or the like, there is a problem that subsequent separation becomes difficult.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to take out a molded product divided into two or more in a mold easily and at low cost before opening the mold. In addition, when there is an abnormality in the removal, it is possible to reliably detect the abnormality, and it is particularly suitable as a method for injecting a thin and lightweight molded product and removing the thin and lightweight molded product. To provide a simple method.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method in which a molten resin is filled in a mold by an injection molding method, cooled and solidified to form a molded product. Before opening, a part of the molded product formed in the mold is cut in the mold and separated into at least two or more molded products. After the mold is opened, each separated molded product is formed into a mold. When separately protruding and removing from the mold by the provided protruding means, one of the molded products is protruded, separated from the mold, naturally dropped and taken out, and then the other molded product is taken out by a take-out machine. And a method for taking out an injection molded product.

Hereinafter, the method for removing an injection-molded article of the present invention (hereinafter, referred to as “method of the present invention”) will be described in detail.

According to the method of the present invention, after a part of the molded article formed in the mold by injection molding is cut off in the mold, and after the mold is opened, at least two of the molded articles are separated.
This is a method in which one is taken out by natural fall and the other is taken out by a take-out machine. Of the molded articles separated into two or more, the molded article taken out by natural fall is appropriately selected, and is appropriately selected according to the shape, dimensions, and the like of the molded article.
Basically, a material that can be reliably dropped, a portion that does not become a product, and a material that does not cause quality deterioration such as breakage even when dropped are appropriate. For example, in the injection molding of a flexible disk which is a thin part constituting the photographic film cartridge shown in FIG. 4, a gate portion formed at a portion corresponding to the center opening and separated from the flexible disk main body in the mold is naturally formed. If the gate is removed by dropping, the gate portion and the flexible disk, which is a product, can be separated and taken out, and the flexible disk can be reliably taken out by the take-out machine, which is effective. In particular, the method of the present invention is effective when a molded product having a thickness of 1 mm or less is taken out by a take-out machine. In the method of the present invention, the molded articles that have fallen naturally are accumulated in an accumulation container arranged at a drop position below the mold.

In the method of the present invention, a take-out machine for taking out the other molded product is not particularly limited, and a take-out device using suction by vacuum suction, a take-out device using a mechanical chuck, and a method of sucking a molded product are used. Any type of unloader, such as the unloader, may be selected as appropriate according to the shape, weight, dimensions, mechanical strength, and the like of the molded product to be unloaded. For example, in the case of removing the flexible disk shown in FIG.
It is preferable to use an unloader by vacuum suction.

The method of the present invention can be applied to injection molding using a mold having a gate of either a cold runner system or a hot runner system. In particular,
According to the method of the present invention, when forming a molded product having a portion such as an opening and a cutout portion in a gate portion in injection molding using a mold having a hot runner type gate, the gate portion and the molded product are integrated. This is effective when the gate portion is cut off from the molded product in the mold after the molding, the gate portion is taken out by natural fall after the mold is opened, and the molded product is taken out by the unloader.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thin annular flexible disk shown in FIG. 4 is injection-molded as a molded product by a hot runner type two-piece mold using a valve gate system shown in FIGS. How to explain,
The method of the present invention will be described.

In the injection molding method using the injection mold 1 having a hot runner structure shown in FIG. 1, first, the movable mold 2 is driven so that the fixed mold 3 and the movable mold 2 are driven. Is closed to form cavities 4a and 4b and gate portions 6a and 6b communicating with cavities 4a and 4b via communication portions 5a and 5b.
Next, the injection nozzle 9 of the injection molding machine is brought into contact with the introduction hole 8 formed in the sprue bush 7 provided on the fixed-side mounting plate 3a, and the molten resin material is injected. The injected molten resin material flows through the runner 10 and is introduced into the hot runners 11a and 11b. At this time,
The needle pins 13a and 13b are driven upward by the needle pin drive cylinders 12a and 12b to open the gates 14a and 14b, and the molten resin material is supplied to the gate portions 6a and 6b and the connection portions 5a and 5b. Are introduced into the cavities 4a and 4b and filled. Gate portions 6a and 6b, communication portions 5a and 5b, and cavities 4a and 4b
Is cooled and solidified by cooling means appropriately disposed in the fixed mold 3 and the movable mold 2, for example, cooling water flowing through a cooling water flow passage.

The operation of the gate portion 6a, the connecting portion 5a and the cavity 4a will be described below as an example. The same applies to the operation in the gate portion 6b, the communication portion 5b, and the cavity 4b.

0.3 to 1.5 seconds after the completion of filling the cavity with the molten resin material, the movable back plates 2c and 2d are moved by the cut punch drive hydraulic cylinder 16a against the urging force of the spring 15a. The attached cut punch 17 a is moved from the movable mold 2 to the fixed mold 3. The driven cut punch 17a moves toward the fixed side template 3c, and the connecting portion 5a is closed by the side surface 18a of the cut punch 17a, and the cavity 4 is closed.
a flexible disk which is a resin molded product in a.
The solidified resin formed on the gate portion 6a is connected to the connecting portion 5a.
Is separated at

Next, after the cut punch 17a is moved, the position of.
After 2 to 0.5 seconds, the needle pin 13a is driven downward in FIG. 1 to close the gate 14a, and the cavity 4a
Further, the resin material of the gate 6a is cooled and solidified, a flexible disk is formed as a resin molded product in the cavity 4a, and a solidified resin is formed in the gate 6a. Next, as shown in FIG. 2, the movable mold 2 is driven to open the injection mold. At this time, the resin solidified product 20a formed on the gate portion is
a. Next, first, a projecting plate 21a is driven by a projecting drive hydraulic cylinder (not shown).
Gate protruding pin 22 attached to
a is protruded, and as shown in FIG. 3, the resin solidified products 20a and 20b of the gate portion protrude and fall naturally.
The resin solids 20a and 20b that have fallen naturally are accumulated in an accumulation container (not shown) arranged at the drop position. At this time, the flexible disks 19a and 19
b is held by the movable mold 2. Next, the thin annular flexible disks 19a and 19b are protruded by the flexible disk protruding sleeve 23a, and the protruded flexible disks 19a and 19b are taken out by an unloader. The unloader may be an unloader using a vacuum chuck such as a suction cup, an unloader using a mechanical chuck, or an unloader using a suction method.

According to the above removal method, the gate portion unnecessary as a product is first released from the mold, and only the flexible disk as the product is removed by the removal machine. With a simple structure,
This is advantageous because it can be handled with inexpensive equipment.
In addition, the thickness of the flexible disk, which is a product, needs to be about 0.2 mm due to the required function. However, the thickness of the gate, which is not a product, can be designed to be thicker (because 0.3 to 0.8 mm), so that the weight can be increased by that much, so that it is easy to drop freely and the danger of adhering to the mold during the drop can be greatly reduced. further,
When taking out the gate and the flexible disk at the same time, in order to avoid the mixture of the flexible disk and the gate, two collecting parts are also provided, and two parts are not moved from the chuck part of the unloader to each collecting part. However, according to the method of the present invention, the accumulation unit is
Only at a single location, the equipment is inexpensive, and the cycle of the unloading operation by the unloader can be accelerated. Furthermore, when the flexible disk is taken out, there is no gate at the center, so a hole is formed in the center of the flexible disk. Therefore, when chucking the flexible disk, this hole can be used for positioning or for guiding, and it is very easy to take out the flexible disk, and at the same time, the flexible disk is removed from the mold to the unloader. Can be reliably delivered.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, 6,6 nylon PP
E (manufactured by Sumitomo Chemical Co., Ltd., Arturi Y19A) as a resin raw material, using a two-cavity hot runner type mold having a structure shown in FIG. 1 and an injection speed: 500 mm / s by a high-speed injection molding machine. Under the following conditions, the flexible disk shown in FIG. 4 was continuously molded for 10,000 shots, and the stability of dropping the gate portion and the stability of removing the flexible disk were examined. Molding condition Molding machine cylinder temperature 310 ° C Sprue, manifold temperature 310 ° C Valve gate temperature 310 ° C Mold temperature 80 ° C Injection and cooling conditions: Filling time 0.05 seconds or less Gate cut pin rise time: 0.3 to after injection 2.0 seconds Valve pin closing time: 0.2 seconds to 1.
5 seconds Cooling time: 0.45 to 2.45 when the cycle is 6 seconds
Second Mold opening / closing and flexible disk removal time: 3 seconds Cycle 6.0 to 8.0 seconds Center gate, flexible disk protrusion time Center gate protrusion time: 0.3 seconds after mold opening starts Flexible disk protrusion time: mold opening 0.2 after completion
Seconds (approx. 1 second from mold opening to completion)

As a comparative example, after forming a flexible disk in the same manner as in the above-described embodiment, the protruding and removing steps of the gate portion and the flexible disk were changed as follows, and the stability of the gate portion falling was changed. The stability of taking out the flexible disk was examined. Comparative Example 1: At 0.2 seconds after the mold opening was completed, both the center gate portion and the flexible disk were simultaneously projected and allowed to fall naturally. Comparative Example 2: At 0.2 seconds after the mold opening was completed, both the central gate portion and the flexible disk were simultaneously projected, and were taken out by vacuum suction with a suction cup.

[0025]

[0026]

As described above, according to the method of the present invention,
Unnecessary parts of the product are first released from the mold, and only the molded product to be taken out is taken out by a take-out machine, so that the chuck portion has a simple structure and the equipment can be inexpensive. In addition, when a portion unnecessary as a product is taken out by natural fall first, the thickness, weight, etc. can be increased so that the product can easily fall naturally without obeying the conditions imposed on the molded product as a product, Free fall is easy, and the risk of adhering to the mold can be greatly reduced. Conventionally, when removing both parts, two collecting parts were provided in order to avoid mixing of both molded products, and two parts had to be moved from the chuck part of the unloader to each collecting part. According to the method of the invention, only one accumulating section is required, the equipment is inexpensive, and the cycle of taking out the molded product by the unloader can be accelerated. Furthermore, when removing a molded product, since there is no unnecessary portion as a product, the portion where the unnecessary portion is cut off is used for positioning to be chucked at the time of removal by the removal machine. It can be used for inviting, and it is very easy to take out the molded product, and it is possible to reliably transfer the molded product from the mold to the take-out machine.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating injection molding of a flexible disk using a hot runner type mold.

FIG. 2 is a view for explaining a method of taking out a flexible disk by a method of the present invention in injection molding of a flexible disk by a hot runner type mold.

FIG. 3 is a diagram illustrating removal of a flexible disk according to the method of the present invention.

FIG. 4 is a perspective view showing a flexible disk which is a component of the photographic film cartridge.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 injection molding die 2 movable die 3 fixed die 4a, 4b cavity 5a, 5b communication portion 6a, 6b gate portion 7 sprue bush 8 introduction hole 9 injection nozzle 10 runner 11a, 11b hot runner 12a, 12b needle Pin drive cylinder 13a, 13b Needle pin 14a, 14b Gate 15a Spring 16a Cut punch drive hydraulic cylinder 17a Cut punch 18a Side surface of cut punch 17a 19a Flexible disk 20a Resin solidified 21a, 21b Projection plate 22a Gate protrusion pin 23a Flexible disk protrusion Sleeve 41 Photographic film cartridge 42 Spool 42a One end of spool 42b The other end of spool 43a, 43b Flexible disk 44 VEI ring 45 Opening

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naoyoshi Chino 2-12-1, Ogimachi, Odawara-shi, Kanagawa Prefecture F-Film Co., Ltd. F-term (reference) 4F202 CA11 CB01 CK35 CK84 CK89 CM02 CM14 CM18 CN05

Claims (1)

[Claims] A mold is filled with a molten resin by an injection molding method, cooled and solidified to form a molded product, and a part of the molded product formed in the mold before opening the mold. Is separated into at least two or more molded articles in a mold, and after the mold is opened, each separated molded article is separately projected by a projecting means provided on the mold and taken out from the mold. A method for removing an injection-molded article, wherein one of the molded articles is protruded, separated from a mold, dropped naturally, and then removed, and then the other molded article is removed by a removal machine.