JPH0669701B2 - Injection molding machine and injection molding method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine (or a die casting machine; the same applies hereinafter) used for injection molding of synthetic resins and an injection molding method using this injection molding machine. More particularly, the present invention relates to an injection molding machine and an injection molding method that are preferably used as those that facilitate mold replacement in the field of injection molding that requires frequent mold replacement.

2. Description of the Related Art In recent years, in the field of injection molding, there is an increasing demand for high-mix low-volume production. For example, it is not uncommon for one injection molding machine to be forced to change molds about five times a day. Therefore, regarding the injection molding machine, facilitation of die replacement work and its automation and shortening of required time,
Cost reduction is a major development issue.

Therefore, conventionally, in order to achieve such a problem, for example, in the injection molding machine described in JP-A-60-82309, the moving side die plate is completely separated and released from the tie bar attached to the fixed side die plate. It is configured to move wide open. A locking means such as a half nut that locks the moving side die plate and the tie bar is provided immediately before the moving side die plate approaches the fixed side die plate and both molds are closed. It is designed to be tightenable. Therefore, by moving the die plate of the moving side completely released from the tie bar to open the die plate sufficiently and sufficiently, the die can be horizontally changed without being disturbed by the tie bar.

In the injection molding machine described in Japanese Patent Publication No. 41-6794, a moving die plate is opened and closed by a high speed hydraulic cylinder.
The movable die plate can be engaged with and disengaged from the tie bar by a half nut, and a mold clamping cylinder is formed at a connecting portion between the tie bar and the fixed die plate.

In the injection molding machine described in Japanese Patent Publication No. 50-28974, the moving die plate is also opened and closed by a high-speed hydraulic cylinder. The movable die plate is configured so that it can be engaged with and disengaged from a tie bar by a half nut, and a mold clamping cylinder is attached to the movable die plate.

All of the above injection molding machines have a configuration in which the molds are changed only in the lateral direction of the molding machine.

In the mold exchanging device described in Japanese Patent Laid-Open No. 50-117077, C-shaped channel type steel-like mold holding mechanisms are provided on the moving side and stationary side die plates so as to face each other in the horizontal direction. The die holding mechanism is provided with a hydraulically driven lock mechanism that is a so-called wedge mechanism that fixes the die attached to each die at a predetermined position. In the vicinity of the side of the molding machine, a preset next-order mold is prepared or a mold moving mechanism is installed to carry away the removed first-order mold, and the molding machine and the mold moving mechanism are connected to each other. It is configured to have a metal mold loading / unloading mechanism for horizontally loading / unloading the metal mold between the two.

The mold exchanging devices described in JP-A-58-222827 and JP-A-60-137516 are also configured such that the molds of the injection molding machine are moved in and out in the horizontal direction.

Next, the injection molding machine described in Japanese Patent Application No. 63-132082 and the drawings includes a fixed die plate for holding a fixed die, a moving die plate for holding a moving die, and a moving die. A mold opening / closing mechanism that moves the plate closer to or farther from the fixed die plate, a mold clamping mechanism that clamps the closed mold with high thrust, and an injection device, at least 90 ° The movable die plate is installed on a swivel base provided with a guide for moving the movable die plate. A swivel drive mechanism is installed on the swivel base. The movable die plate is equipped with a locking device that is detachably attached to the tie bar attached to the fixed die plate. A mold opening / closing mechanism for moving the moving-side die plate closer to or farther from the fixed-side die plate is installed on the swivel base, and the die standby device is configured to facilitate die exchange.

Problems to be Solved by the Present Invention I) The conventional injection molding machine and mold exchanging device described above have the old die attached to the die plate and the new die to be attached next when the die is replaced. It is an indispensable condition to safely and horizontally take in and out by, for example, a die loading / unloading mechanism or a transfer device, with a highly accurate and reliable content. Therefore, the structure and operation of the mold exchanging device are complicated, and automation is difficult. And, since the structure has no choice but to perform the mold replacement work in the horizontal direction of the injection molding machine, the interval between the adjacent molding machines is too narrow depending on the arrangement of the injection molding machines in the injection molding factory, so that the mold replacement cart etc. However, there were some drawbacks and problems such as some cases that could not be implemented and could not be implemented.

II) In the case of the injection molding machine described in the above-mentioned prior application, there is an advantage that the method of directly transferring the mold to and from the mold standby device by using the swivel base can be implemented. However, if a pair of movable and fixed dies are combined into one set for cantilever support on the moving die plate for die replacement, the die guide pin 22 and the pin to which it fits as shown in Figs. 2 and 3. Due to the gap with the hole 23, the fixed mold 8 tends to slightly lower than the moving mold 8 ′, and when the mold is transferred to and from the mold standby device 15, the fixed mold 8 is molded. Mold standby device 15
Or, it may not be able to transfer well by touching (contacting) the mold storage. Further, the injection molding machine according to the invention of the prior application employs a configuration in which the fixed die plate and the tie bar are retracted to a position where they do not interfere with the turning of the moving die plate for the purpose of reducing the overall length thereof. However, not only the mechanism is too large and the structure is complicated, but also a complicated means is required for positioning and fixing the stationary die plate. . In addition, since it often occurs that a movable die standby device cannot be installed in a production factory in terms of price and operation method of the factory, these points are problems to be solved.

Means for Solving the Problems (First and Second Inventions) As a means for solving the problems of the above-mentioned conventional techniques, an injection molding machine according to the present invention, as shown in the drawings, is a fixed mold 8 A fixed side die plate 1 for holding the moving die 8 ', a moving side die plate 2 for holding the moving die 8', and a mold opening / closing mechanism A for moving the moving side die plate 2 and the fixed side die plate 1 closer to or farther from each other. In the injection molding machine comprising the mold clamping mechanism B for clamping the mold closed with a high thrust and the injection device 4, a) at least 90 ° can be swiveled and the swivel drive mechanism C can be used.
The moving guide 18 for the moving die plate 2 was provided on the swivel base 6 on which the moving die plate 2 was installed.

(B) The movable die plate 2 is provided with a detachable locking device D on the tie bar 7 attached to the fixed die plate 1.

C) A mold opening / closing mechanism A for moving the moving die plate 2 closer to or farther from the fixed die plate 1 is installed on the swivel base 6.

D) The swivel lifting device E is installed under the swivel 6, respectively.

The injection molding machine of the present invention is also provided with a mold clamping piston 17 at the base end portion of the tie bar 7 attached to the stationary die plate 1, and the mold clamping piston 17 is installed in the mold clamping cylinder 16 to perform the mold clamping. Mechanism B was configured. The mold clamping cylinder 16 is also characterized in that the mold clamping piston 17 is formed in a size (length) that allows the backward stroke L required for the tie bar 7.

Action The locking device D is released from the tie bar 7, and the mold opening / closing mechanism A moves the moving die plate 2 backward by a predetermined stroke to perform the mold opening process.

When the moving side die plate 2 is moved forward by the mold opening / closing mechanism A, the tie bar 7 moves through the through hole of the moving side die plate 2.
It is inserted into 2a. When the tie bar 7 is locked by the locking device D immediately before the mold is closed, the mold clamping reaction force can be obtained. Therefore, the mold is clamped by the mold clamping mechanism B after the mold is closed, and the injection molding process can be started.

In order to replace the molds 8 and 8 ′, first, the movable mold 8 is closed and the fixed mold 8 is released from the fixed side die plate 1, and the pair of molds 8 and 8 ′ are moved to the movable side die plate 2. Held in. Then, the die plate 2 on the moving side is opened and moved,
Simultaneously with or after the operation in which the movable die plate 2 is released from the tie bar 7 to open the mold up to a predetermined stroke, the mold clamping mechanism B is driven to allow the tie bar 7 to escape by the backward stroke L. After that, when the swivel base 6 is swung by 180 °, for example, the movable die plate 2 and the molds 8 and 8 ′ are outwardly oriented so as to face the mold standby device (or mold exchanging base) 15. Therefore, if necessary, the mold opening / closing mechanism A is driven to move the movable die plate 2 so as to approach the mold standby device 15. In addition, the swivel lifting device E is used to rotate the swivel 6
When the mold is raised properly, the lower surfaces of the molds 8 and 8'which are inclined downward as shown in Figs. 2 and 3 become higher than the receiving surface of the mold standby device 15, and the moving die plate 2 and the metal mold It is possible to smoothly transfer (exchange) the molds 8 and 8'to and from the mold standby device 15.

By selectively controlling the swivel angle of the swivel base 6 in accordance with the position of the mold standby device 15, the molds 8 and 8'can be exchanged widely not only in the horizontal direction of the injection molding machine but also in the rearward direction.

(Third invention) In the injection molding method using the above injection molding machine, a plurality of preset molds 9 _{1 to} 9 ₄ are arranged around the swivel base 6 as shown in FIG. The mold subjected to the injection process by the molding machine is put down at a predetermined position by using the swivel base 6 to perform the cooling process. Then, the next-order mold is mounted on a molding machine, the mold is exchanged, and the next-order mold is taken out of the molded product by opening the mold and the injection process is performed.

Function For example, in the case of a molded product that requires a long cooling time, such as a foamed molded product, by placing the molding mold on the mold standby device 15 after the injection process, cooling for a necessary and sufficient time Can be done. During that time, you can take out the molded product with a different molding die and perform the injection process.In other words, you can perform molding with a rotary system that shortens the actual molding cycle, improving the operating efficiency and productivity of the molding machine. Can be planned.

Example Next, an example of the present invention shown in the drawings will be described.

FIG. 1 shows a state in which the moving die plate 2 is opened by the injection molding machine according to the present invention. This injection molding machine includes a fixed die plate 1 that holds a fixed die (female die) 8 by a die clamp device 3 and a moving side that holds a movable die (male) 8 ′ by a die clamp device 3. And a die plate 2. The fixed die 8 is fixed to the fixed die plate 1.
Is attached to the injection device 4 (however, most of them are not shown). The fixed die plate 1 and the movable die plate 2 were installed on the rear surface of the movable die plate 2 by inserting the tie bar 7 attached to the fixed die plate 1 into the through hole 2a of the movable die plate 2. For example, by locking the locking device D using the hydraulically driven half nut 5 at the tip portion (screw portion) of the tie bar 7 inserted into the through hole 2a, a reaction force sufficient to withstand the mold clamping pressure during the molding process. To get The stationary die plate 1 is provided with a hydraulic mold clamping mechanism B including a mold clamping cylinder 16 having a large-diameter mold clamping piston 17 provided at the right end (base end) of the tie bar 7.

Therefore, the locking device D closes the mold with the tie bar 7 locked, and the hydraulic pressure is sent to the mold clamping cylinder 16 during the mold clamping process, so that a strong mold clamping pressure sufficient to withstand the injection molding pressure is applied to the pair of molds 8,8. ′ Can be added. The mold clamping cylinder 16 is formed with a size (length) that allows a retreat stroke L for allowing the tie bar 7 to escape to a position where the tie bar 7 does not interfere with the turning of the moving die plate 2 and the molds 8, 8 '. Has been done. The fixed die plate 1 is the molding machine base
It is fixed to the left end in the above figure.

The swivel base 6 is installed on the swivel lift device E.
The swivel lifting device E has a configuration in which a vertically upward hydraulic jack 21 is installed on a base 20. A non-rotating large gear 13 is supported by the output shaft of the hydraulic jack 21, and a swivel base 6 is installed inside the large gear 13 via a ball bearing 25 so as to freely swivel 360 °. The movable die plate 2 is installed on the swivel base 6. Moving slide guides (beds) 18, 18 are provided on the upper surface of the swivel 6 (FIG. 4), and the moving die plate 2 is installed so as to linearly slide on it. A swivel motor 12 that rotationally drives a pinion 12a that meshes with the large gear 13 is fixed to a lower portion of the swivel 6, and a swivel drive mechanism C that swivels the swivel 6 to an arbitrary angle is configured.

A ball screw shaft 11 for opening and closing the mold is installed rotatably on the upper part of the swivel 6 in parallel with the sliding guide 18 for moving, and a parent nut meshing with the ball screw shaft 11 is mounted on the moving side die plate. It is provided in 2. The ball screw shaft 11
Is rotated by the mold opening / closing motor 10 fixed at 6 when turning,
A mold opening / closing mechanism A for moving the moving die plate 2 closer to or farther from the fixed die plate 1 is configured.

In the mold opening for taking out the molded product after the injection molding and the cooling process, first, the mold clamping mechanism B is loosened and the locking device D is released from the tie bar 7. Next, when the mold opening / closing motor 10 is started in the normal direction, the moving side die plate 2 is separated from the tie bar 7 and moves backward to the left in the figure to largely open the die, resulting in the die open state shown in FIG. The product is taken out. When the mold opening / closing motor 10 is reversely activated after the molded product is taken out, the movable die plate 2 moves forward to the right in the drawing toward the mold closing, and the tie bar 7 is again inserted into the through hole 2a. Then, the tie bar 7 is locked again by the locking device D immediately before the mold is closed, and the mold clamping process by the mold clamping mechanism B is started.

In order to replace the molds 8 and 8 ′, a mold standby device (stand) 15 for transferring the molds is installed at the back position (or side position is acceptable) of the swivel base 6 of the injection molding machine. (See Figure 4). The mold standby device 15 is a table having substantially the same height as the lower surfaces of the pair of molds 8 and 8'held by the movable die plate 2, and is a preset standby mold (preset die) in the next order. Place 9 and wait for mold change.

As a procedure for mold replacement, first, a pair of molds 8 and 8'is closed. Then, the guide pin 22 which is projected in advance from the moving die plate 8'in parallel with the tie bar 7 is fitted into the guide hole 23 of the fixed die. Therefore, the mold clamping device 3 is released to move the fixed mold 8 from the fixed side die plate 1.
, The pair of molds 8 and 8'will be separated from the guide pin 2
It is held on the moving die plate 2 in the combined state of being integrated into one via 2 (Figs. 2 and 3). At this time, in order to positively separate the fixed die 8 from the fixed die plate 1, a plurality of release springs 24 are provided on the fixed die mounting surface of the fixed die plate 1.

The moving side die plate 2 holding the pair of molds 8 and 8'is
The mold opening / closing mechanism A opens the mold to a position approximately above the center of rotation. Simultaneously with or before or after this movement, the mold clamping piston 17 of the mold clamping mechanism B is moved to the rightward limit as shown in FIG. 2, and the tie bar 7 is escaped rightward in the drawing by the stroke L. Therefore, the movable die plate 2 and the pair of molds 8 and 8 ′ held by the movable die plate 2 are moved to the second position on the swivel base 6 by the stroke L that the tie bar 7 retracts and escapes to the right in the drawing. It is possible to make a turn at a position closer to the right side in the figure and reduce the die opening stroke of the moving side die plate 2. Moreover, 18
When rotated by 0 °, the movable die plate 2 and the molds 8 and 8'are conveniently located closer to the mold standby device 15 (Fig. 3).

The motor 12 of the swivel drive mechanism C is started to move the swivel base 6 180
° When swiveled, moving die plate 2 and mold 8,8 '
3 has a posture and a direction facing the mold standby device 15 as shown in FIG. At this point, the mold opening / closing motor 10 of the mold opening / closing mechanism A is started again to move the moving die plate 2 to the mold converting device.
Move toward 15. Simultaneously with or after this movement, the swivel raising / lowering device E is driven, and the lower surfaces of the pair of molds 8 and 8 ′ held by the moving side die plate 2 are slightly higher than the receiving surface of the mold standby device 15. After adjusting to
Further, the pair of molds 8 and 8 ′ are carried to a position right above the mold standby device 15. Then, when the mold clamping device 3 is released and the moving mold 8'is separated from the moving die plate 2, the pair of old molds 8 and 8'is passed to the mold standby device 15. The pair of molds 8 and 8'are separated from each other as indicated by arrows a and b in FIG. At this time, in order to positively separate the moving die 8 ′ from the moving die plate 2, a plurality of release springs 24 are also installed on the die mounting surface of the moving die plate 2. On the other hand, the next preset standby die 9 prepared in advance on the die standby device 15 is advanced as shown by the arrow C (FIG. 4), and the die clamping device 3 is moved to the moving side die plate 2. You can hold it.

After that, the mold opening / closing motor 10 is started and the moving side die plate 2 is moved backward to the position of the turning center (FIG. 3). Then, the swivel lifting device E lowers the swivel 6 to the original level. Next, the turning motor 12 is started, and the turning base 6 is turned 180 ° so that the movable die plate 2 and the fixed die plate 1 face each other (second relation).
Figure). The motor 10 of the die opening / closing mechanism A is started again to move the die plate 2 on the moving side to close the die, and the fixed die 8 is brought into contact with the die plate 1 on the fixed side. The die replacement work is completed by holding it on the plate 1.

Second Embodiment FIG. 5 shows, as a preferred method of using the injection molding machine having the above-described structure, four mold yard (or the mold standby device 15 is provided at four positions at positions where the periphery of the swivel base 6 is divided into approximately four equal parts. It is supposed to be installed in each case (including the case. The same applies hereinafter), and a maximum of four preset molds 9 _{1 to} 9 ₄ are placed so that the molds can be exchanged. In FIG. 5, the mold is 9 ₁ → 9
₄ shall be used in the rotary system. Mold 9
₁ has just started on the mold standby unit cooling step is finished injection step, being received in the mobile die plate 2 as next mold 9 ₂ ends of the cooling process. Then, the fixed mold 8 is held on the fixed side die plate 1 in the above-described manner, and the process of taking out the molded product in the mold opening process and the subsequent injection process proceed. During that time, the other molds 9 ₃ , 9 ₄ and 9 ₁ are given a necessary and sufficient cooling period, which is convenient for high quality molding of a molded product that requires a long time, such as a foamed molded product. The actual operating efficiency of the machine can be increased.

Not only this method of use is convenient for efficient and rational die exchange in a molding factory where frequent die changes are required.

Advantageous Effects of the Present Invention As described above in detail with reference to the embodiments, in the injection molding machine according to the present invention, a pair of molds 8 and 8'is replaced by a mold opening / closing mechanism of the molding machine. Since the function of A can be effectively used to directly transfer the molds 8 and 8 to and from the mold standby device 15, the molds can be exchanged easily, quickly, and safely as an almost automated work. It reduces the burden of frequent mold replacement work and shortens the required time, contributing to productivity improvement.

Moreover, by utilizing the swivel base 6, the molds 8 and 8'can be exchanged not only in the horizontal direction of the injection molding machine but also in the backward direction. Regardless of the layout of the injection molding machine, find a vacant space and place the mold waiting device 15 there.
By installing, there is the flexibility to change the mold and it has excellent adaptability.

Not only that, by placing a plurality of molds around the swivel base where molds can be changed, a mold standby device that can be operated can be omitted, and it is possible to automatically replace a plurality of molds at low cost. Moreover, in the case of molds for molded products that require a long cooling time, such as foamed molded products, it is possible to perform molding with a different mold during the cooling process after injection, which is very economical. It is possible to use machines with high operating efficiency.

[Brief description of drawings]

1 to 3 are plan views showing a mold closing and mold clamping state in which the injection device portion of the injection molding machine according to the present invention is omitted, and FIG. 4 is a plan view showing the mold opening state. FIG. 5 is a plan view showing the mold opening state of another embodiment. 8 ... Fixed mold, 1 ... Fixed die plate 8 '... Moving die, 2 ... Moving die plate A ... Mold opening / closing mechanism, B ... Mold clamping mechanism 4 ... Injection device, 18 …… Movement sliding guide 6 …… Swivel device, C …… Swivel drive mechanism 7 …… Tie bar, D …… Locking device E …… Swivel base lifting device, 17 …… Clamping piston 16 …… Clamping cylinder , 9 _{1 to} 9 ₄ ... Hydraulic cylinder

Claims (3)

[Claims] 1. A fixed die plate for holding a fixed die, a movable die plate for holding a movable die, and a mold opening / closing means for moving the movable die plate closer to or farther from the fixed die plate. In the injection molding machine consisting of a mechanism, a mold clamping mechanism for clamping the closed mold with high thrust, and an injection device, a) At least 90 ° swivel is possible and the swivel drive mechanism is installed. A guide for moving the moving die plate is provided on the swivel base, and the moving die plate is installed. (B) The moving die plate is equipped with a detachable locking device for the tie bar attached to the fixed die plate. C) The swivel is equipped with a mold opening / closing mechanism that moves the moving die plate closer to or farther from the fixed die plate, and d) the swivel lifting device is installed under the swivel. The It, an injection molding machine, wherein, respectively. 2. A mold clamping piston is provided at a base end of a tie bar attached to a fixed die plate, and the mold clamping piston is installed in a mold clamping cylinder to form a mold clamping mechanism. The injection molding machine according to claim 1, wherein the mold clamping cylinder is sized so that the mold clamping piston allows a backward stroke required for the tie bar. 3. A plurality of preset molds are arranged around the swivel base, and after the injection process by the molding machine, the molds are lowered to a predetermined position by using the swivel base to perform the cooling process. The method according to claim 1 or 2, characterized in that the molds are placed and the next-order mold is mounted on the molding machine, and the molds are exchanged, and the molded product is taken out and injected by opening the mold for the next-order mold. An injection molding method using the injection molding machine described in the item 2.