JP2001212859A - Injection molding machine and its parallelism adjustment method - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To develop an injection molding machine capable of achieving the parallelism of a molded article with an accuracy of the order of microns. SOLUTION: A fixed die mounting plate (2a), a tail stock (5), and a tie bar (41) to (44) erected between the fixed die mounting plate (2a) and the tail stock (5). And tie bar (41) ~
(44) Reciprocating along the movable mold mounting plate (2b) and the tailstock (5), fixed to the tailstock (5), and reciprocating the movable mold mounting plate (2b) to the fixed mold mounting plate (2a) The fixed mold (1a) attached and the movable mold attached to the movable mold mounting board (2b)
(1b) a mold clamping mechanism (11) for opening and closing the mold and clamping, and a tie bar which is separately attached to the tie bars (41) to (44) and is generated on the tie bars (41) to (44) at the time of mold clamping. It is characterized by comprising tie-bar tension adjusting mechanisms (6A) to (6D) for individually adjusting the tension.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to injection molding capable of realizing extremely high parallelism on opposing mold cavities of fixed and movable dies mounted on a mold mounting plate of an injection molding machine. And a method for adjusting parallelism in the injection molding machine.

[0002]

2. Description of the Related Art In a conventional disk forming method, an infinite number of minute projections (not shown) for forming information formed on a surface of a stamper (52) housed in a mold (51) are formed by a metal mold. In order to accurately transfer to the molding resin (53) injected into the mold (51), FIG.
The steps shown in (1) to (6) are taken. That is,
As shown in (1), the parting surface (54
Stop the movable mold (51b) at a position where b) is slightly away from the parting surface (54a) of the fixed mold (51a), and in this state, inject the resin (53) into the mold cavity (57) (See (2) in the figure). The distance between the two is indicated by (t).

In the injection filling step, the separation distance (t)
A large amount of resin (53) is filled in the mold cavity (57). When the injection filling is completed,
As shown in (3), the gate is cut, and after the gate cut is completed, the mold opening / closing mechanism such as a servo motor driven toggle mechanism is operated again to further mold-tighten, and the filling resin (53)
Is compressed and the holding pressure is cooled ((4) in the same figure). Then, Figure (5)
The mold is opened as shown in (1), and finally the product is taken out as shown in FIG.

According to this method, a much higher pressure is applied to the molded article (55) in the compression / holding / cooling step than at the time of injection and filling. Since the internal pressure of the mold cavity (57) can be kept extremely high as described above, and the cavity shape and the fine projections on the surface of the stamper (52) are good. Therefore, for example, the present invention is often applied to a thin plate-shaped molded product that does not warp and requires high transferability and parallelism, such as a CD, a light guide plate, and an aspherical lens.

However, even in the case of the injection compression molding method capable of mass production of excellent molded articles as described above, much higher precision is required as compared with a CD, such as a DVD or a hard disk. The following problems arise when the method is applied to: That is, when compared to a CD, a DVD has the same diameter of 120 mm but a thickness of half that of a CD when compared to a CD.
It is 0.6 mm, and is used by laminating two disks to increase the amount of stored information.

When reading the information of the upper disk with a laser serving as a pickup, it is difficult to read the information of the laminated lower disk. Since the light is reflected on the information input surface and passed through the upper disk again to be read, the parallelism of the upper disk is required to be unprecedentedly high, for example, high accuracy of the order of microns (10 microns or less). Is done. On the other hand, a CD is used as a single piece without being bonded, so a DVD
It is not required to be as parallel as a disk. Further, when a hard disk is made of resin (conventionally, a glass or aluminum substrate is used), a more severe accuracy of 5 μm or less is required.

Therefore, as an injection molding machine for a product requiring high precision such as a DVD, not only the precision of each part is increased to the utmost, but also the assembling precision, particularly the mold mounting plate (58a) ( Extreme precision is required for the parallelism of 58b). This not only causes a huge increase in cost, but also has a serious problem in terms of reproducibility and reliability and feasibility.

That is, in a conventional injection molding machine for manufacturing a CD,
Since the required degree of parallelism was on the order of 10 microns (about 15 microns or less), manufacture each part with due care in terms of processing accuracy, assemble it with great care, and finally test injection Molding was performed, and the parallelism of the injection-molded product (55) was measured to confirm whether the accuracy was within the predetermined accuracy.

When the parallelism of the injection molded product (55) is out of the predetermined accuracy, the tie bars (59) to
Screw ends (59a) to (62a) on the fixed mold mounting plate (58a) side of (62)
Rotate any of the nuts (63a) to (66a) screwed to the required amount to individually adjust the tie bar tension at the time of mold clamping of the tie bars (59) to (62). Nuts (63a)-(66
a) Carefully tighten and fix, and perform test injection molding again to measure the parallelism of the injection molded product (55), and measure whether the parallelism of the injection molded product (55) is within the planned accuracy Repeatedly relying on the intuition and skill of the operator to do the work, gradually increasing the accuracy.

The accuracy of parallelism that can be realized by the adjustment work relying on the intuition and skill of the worker is at most 10 micrometers (15 micrometers) required for a conventional injection molding machine for CD manufacturing. (Less than the following) is the limit, and it has not been possible to achieve the accuracy required to be 10 μm or less or 5 μm or less.

For comparison with the present invention, 4
A tension adjustment mechanism installed in the conventional device (B) for adjusting the tension generated in the tie bars (59) to (62) of the book at once.
(67) will be briefly described. The tie bar tension adjusting mechanism (67) is installed on the tail stock (56) side as shown in FIGS. A driven pulley (6) for operating a toggle mechanism (68), which is a part of the tie bar tension adjusting mechanism (67).
The rotating shaft (70) of (9) is rotatably disposed at the center of the tailstock (56), and a bearing coaxial with a bearing (71) that rotatably supports the rotating shaft (70). Large gear through
(72) is rotatably disposed. And the same large gear (72)
Is meshed with a drive gear (75) of a tie bar tension adjusting motor (74) installed on a tail stock (56) via an intermediate gear (73).

On the other hand, tension adjusting nuts (63b) to (66b) mesh with screw ends (59b) to (62b) of the four tie bars (59) to (62) on the tailstock (56) side. And this tension adjustment nut
(63b) to (66b) are further meshed with the large gear (72), and by operating the tie bar tension adjusting motor (74), the large gear is
By rotating simultaneously the tension adjusting nuts (63b) to (66b) meshing with (72), the tension of the four tie bars (59) to (62) is adjusted at one time.

[0013]

The problem to be solved by the present invention is as follows.
An object of the present invention is to develop an injection molding machine capable of achieving the parallelism of a mold mounting plate or a molded product with an accuracy of the order of microns by simply changing the device structure, and a method of adjusting the same.

[0014]

Means for Solving the Problems An injection molding machine (A) according to the first aspect of the present invention comprises a fixed die mounting plate (2a), a tail stock (5), and a fixed die mounting plate (2a). Tie bars (41) to (44) and tie bars (41) to
(44) Reciprocating along the movable mold mounting plate (2b) and the tailstock (5), fixed to the tailstock (5), and reciprocating the movable mold mounting plate (2b) to the fixed mold mounting plate (2a) The fixed mold (1a) attached and the movable mold attached to the movable mold mounting board (2b)
(1b) a mold clamping mechanism (11) for opening and closing the mold and clamping, and a tie bar which is separately attached to the tie bars (41) to (44) and is generated on the tie bars (41) to (44) at the time of mold clamping. And a tie bar tension adjusting mechanism (6A) to (6D) for individually adjusting the tension ". Claim 2 is a driving source of Claim 1. It is specifically limited and is characterized in that "servomotor motors (6a) to (6d) are used as drive sources of tie bar tension adjusting mechanisms (6A) to (6D)".

As described above, this occurs when the tie bars (41) to (44) are individually clamped by the tie bar tension adjusting mechanisms (6A) to (6D) when the tie bars (41) to (44) are clamped. Since the tension is adjusted, the parallelism of the injection molded product (3) taken out by test injection molding is measured, and any of the tie bar tension adjustment mechanisms (6A) to ( By operating the required amount of 6D), the parallelism of the injection molded product (3) can be easily adjusted to the expected accuracy. Then, the drive sources of the tie bar tension adjusting mechanisms (6A) to (6D) are changed to servo motors (6a) to
By adopting (6d), the parallelism adjustment can be performed digitally, and unlike the conventional adjustment that relies on the intuition and experience of the operator, the parallelism adjustment can be performed extremely accurately and in a short time. Can be done.

A third aspect of the present invention relates to the method for adjusting the parallelism in the injection molding machine (A) according to the first or second aspect, wherein "the parallelism (H) of the injection molded article (3) is measured. , Injection molded products (3)
If the parallelism (H) of the parallelism (H) is out of the predetermined accuracy, any of the tie-bar tension adjustment mechanisms based on the measured value of the parallelism (H)
Operate (6A) to (6D) to individually adjust the tie bar tension (T41) (T42) (T43) (T44) generated on the tie bars (41) to (44) during mold clamping, and finally injection molding It is adjusted so that the parallelism (H) of the product (3) falls within the predetermined accuracy. "

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Injection compression molding machine according to the present invention
(A) will be described sequentially according to the illustrated embodiment. The device of the present invention
On the machine base (22) of (A), a fixed mold mounting plate (2a) is fixed, and two guide rails (14) are further laid toward the tilt stock (5) side. . Till stock (5)
Is movably mounted on the guide rail (14) via a linear motion mechanism (15a) such as a linear motion bearing. Four tie bars (41) to (44) are provided vertically and horizontally between the fixed mold mounting plate (2a) and the till stock (5). On the tie bars (41) to (44), a movable mold mounting plate (2b) is provided so as to slide along the tie bars (41) to (44).

The movable mold mounting plate (2b) is a mechanism on which necessary mechanisms such as an eject mechanism (E) and a gate cut mechanism (G) for projecting the molded product (3) from the mold cavity (7) are mounted. It consists of a movable die plate part (2b1) on which the part housing (12) and the movable mold (1b) are mounted, and a pressure sensor (13) installed and fixed between the two (12) and (2b1). Have been.

Then, between the tilt stock (5) and the mechanism housing (12), the entire movable mold mounting plate (2b) is reciprocated together with the movable mold (1b) and the mold is clamped. A mold clamping mechanism (11) composed of a mechanism is provided. The moving die plate part (2b1) and a housing for a mechanism part
On the lower surface of (12), linear motion mechanisms (15b) (15c) that move linearly on the running rail (14) are installed, respectively.

The movable mold mounting board (2b) is arranged so as to be close to and away from the fixed mold mounting board (2a), and includes the movable mold mounting board (2b) and the fixed mold mounting board (2a). Since the mold mounting surfaces (2ak) and (2bk), which are opposite surfaces of), serve as mounting reference surfaces for the two dies (1a) and (1b), their flatness is extremely accurately finished. Parallelism is the parallelism (H) of the molded product (3)
Is adjusted to achieve high parallelism.

Next, attachment of the tie bars (41) to (44) will be described. As described in the conventional example, the tie bars (41) to (44) are provided with screw portions at both ends, respectively, and the screw portions on the fixed mold mounting plate (2a) side are fixed side screw portions (41a) to ( 44a), and screw the tail stock (5) side to the adjustment side screw section (41b).
To (44b).

On the fixed mold mounting board (2a) side, the ends of the tie bars (41) to (44) on the fixed mold mounting board (2a) side are four corners of the fixed mold mounting board (2a). The fixing nut (23) is inserted through the fixing hole (41a) to (44a) of the fixing side threaded portion (41a) which is inserted through the through hole (8).
~ (26) are screwed respectively, and the fixed side screw portion (41a) ~
The fixed screw portions (41a) to (44a) are fixed by the fixing tools (27) to (30) provided in each of the (44a). Although various fixing methods are conceivable, here, a plurality of fixing bolts (31) attached to the fixing tools (27) to (30) are tightened, and the fixing tools (27) to (30) are fixed to the fixing side screw portion (41a). ) To (44a), and strongly press the fixing nuts (23) to (26) against the fixed mold mounting plate (2a) to fix the fixed side screw portions (41a) to (44a). And fixing nut
The screws (23) to (26) are firmly brought into contact with each other and fixed.
Thereby, the tie bars (41) to (44) are integrated with the fixed mold mounting plate (2a).

On the tail stock (5) side, the ends of the tie bars (41) to (44) on the tail stock (5) side are inserted into through holes (9) at the four corners of the tail stock (5). The tie bar tension adjusting gear (4) is attached to the adjusting side screw portions (41b) to (44b),
5) to (48) are screwed respectively. The tie bar tension adjusting gears (45) to (48) are the through holes (9) of the tail stock (5).
It is rotatably housed in a housing recess (10) provided coaxially with the camera. Servo motors (6a) to (6d) are individually set for each of the tie bars (41) to (44) beside them, and drive motors attached to the drive shafts of the servo motors (6a) to (6d) are provided. gear
(6a1) to (6d1) mesh with the tie bar tension adjusting gears (45) to (48). Further, the servo motors (6a) to (6d) have pulse generators (6a2) to (6d
2) is installed. In the present embodiment, the tie bar tension adjusting mechanisms (6A) to (6D) include the tie bar tension adjusting gears (45) to (4).
8), servo motors (6a) to (6d), drive gears (6a1) to (6d1), and pulse generators (6a2) to (6d2).

Next, the driving mechanism of the mold clamping mechanism (11) will be briefly described. A servomotor (32) for driving the mold clamping mechanism (11) is installed on the side of the tailstock (5). The drive pulley (34) of the servomotor (32) and the driven pulley (33) rotatably disposed at the center of the tailstock (5) are connected by a transmission belt (35) such as a timing belt. Have been.

A drive nut is provided at the center of the driven pulley (33).
(37) is screwed, and the drive screw (36) is screwed in so as to be able to advance and retreat. The tip of the drive screw (36) is
It is attached to the toggle head (38) of 1) and the drive screw
The toggle arm of the mold clamping mechanism (11) bends and expands in accordance with the advance and retreat of (36).

Next, the present apparatus (A), in particular, both mold mounting boards (2a) (2
The following description focuses on the adjustment for obtaining the required parallelism in b). The mounting surface (22a), which is the upper surface of the machine base (22), is machined to an extremely high degree of flatness, and includes a fixed-side mold mounting plate (2a) and a pair of traveling rails (14) arranged in parallel. Fix it. Next, the tail stock (5), the movable mold mounting plate (2b), the mold clamping mechanism (11), etc. are installed on the traveling rail (14), and the tie bar (6) and other mechanisms are assembled according to the prescribed procedures. Go. What is important here is that the lower surface (2a1) of the fixed mold mounting plate (2a) can secure the required accuracy with only a slight final adjustment.
It is necessary to finish as strict as possible from processing to assembly, including the perpendicularity between the mold and the fixed mold mounting surface (2ak).

When the assembly of the device (A) is completed, the device (A)
Will be shifted to the injection molding operation using. Generally, when the molds (1a) and (1b) are newly installed, or when the old and new molds are exchanged, or when the stamper (7
a) After replacement, etc., perform injection molding on a trial basis before entering the automatic continuous injection molding process, take out the molded product (3), strictly check its parallelism, plate thickness, density, etc., Sufficient adjustments are made until the specifications are completely satisfied, and only then will the automatic injection molding process be switched. Here, the parallelism adjustment for the molded product (3) will be mainly described. First, test injection molding was performed, and the parallelism of the molded product (3) taken out from this was measured to determine the mold cavity.
(7) The inclination of the facing surface (or the error between the facing surfaces) is known.
If the amount of error is known, it is possible to calculate how much tension is applied to which tie bar and the opposing surfaces become parallel to eliminate the error.

Subsequently, the servo motors (6a) to (6a) of the tie bar tension adjusting mechanisms (6A) to (6D) are transmitted from the control unit of the apparatus (A).
d) to send the individual data to each servo motor (6a) to (6
d) operates according to the individual data. Each servo motor (6
The operation amount of a) to (6d) depends on the attached pulse generator (6a2) to (6d2)
Has been confirmed.

When the servo motors (6a) to (6d) operate as instructed, the driving gears (6a1) to (6a1) to (6a) of the servo motors (6a) to (6d)
Tie bar tension adjusting gear (45) individually meshed with (6d1)
~ (48) rotates correspondingly, and the tie bar (41)
Fine adjustment of the tensions (T41) to (T44) generated in (44). The adjustment of the tie bar tensions (T41) to (T44) is generally performed when the mold is opened. Theoretically, approximately one degree of parallelism can be obtained with one adjustment, but if necessary, test injection molding is performed several times.

The thickness of the molded product (3) is adjusted in the same manner so as to be within the specified dimensional accuracy. That is, if the overall thickness of the molded product (3) is insufficient, the tie bar tension adjusting mechanisms (6A) to (6D) operate the servo motors (6a) to (6d) to tie bar tension (T41) to (T44) is slightly loosened, and if the overall thickness of the molded product (3) is excessively large, the tie bar tension adjusting gears (45) to (48) are tightened. Thereby, the thickness of the molded product (3) can be adjusted to the specified size. Of course, the thickness adjustment and the parallelism adjustment of the molded article (3) can be performed simultaneously. Then, when the expected accuracy is obtained for the parallelism, thickness and the like, the process is switched to the automatic injection molding process.
As a result, the adjustment based on the data, not the adjustment depending on the skill or intuition of the operator, is performed so that the molded article (3) having high parallelism, which could not be obtained until now, is extremely simple and with good reproducibility. It can be produced in large quantities.

Next, the tie bar tension adjusting mechanism (6A) to (6D)
The special usage of is explained. The original function of the tie bar tension adjustment mechanism (6A) to (6D) is as described above.
By adjusting the tension (T41) to (T44) generated in (41) to (44) individually, the parallelism (H) of the molded product (3), which is the final product, is high precision like never before However, compression molding can be performed while maintaining the parallelism (H), and compression speed control, pressure control, or position control can be performed in the compression molding. This will be described with reference to FIG.

In order to keep the parallelism (H) of the molded product (3) within the predetermined accuracy, any of the servomotors (6a) to (6)
How to control d) is available as data in the test injection molding immediately before. Therefore, before clamping, the servo motors (6a) to (6d) are activated to
(45) to (48) are slightly retracted, and the mold is clamped in this state. The amount by which the tie bar tension adjusting gears (45) to (48) are retracted
The two dies (1a) and (1b) are separated by (t) (see FIG. 6 (1)).

In this state, the measuring resin is injected into the mold cavity (7) (see FIG. 2B). In the injection filling step,
A large amount of the measuring resin corresponding to the separation distance (t) is filled in the mold cavity (7).

When the injection filling is completed, FIG.
As shown in (4), after the gate cut is completed, the four servo motors (6a) to (6d) are operated simultaneously to advance the tie bar tension adjusting gears (45) to (48) to a predetermined position. Perform additional tightening. The retightening is not performed by the mold clamping mechanism (11) as in the related art, but is performed by operating the tie bar tension adjusting mechanisms (6A) to (6D). Then, while maintaining this position, the filling resin is cooled under pressure (FIG. 4 (4)). Subsequently, the mold is opened as shown in FIG. 5 (5), and finally the product is taken out as shown in FIG. 6 (6).

At this time, by controlling the tightening speed, the molded product
(3) Quality (for example, improvement of transferability) can be achieved (compression speed control), and four servo motors (6a) to (6d) are controlled based on a pressure signal from a pressure sensor (13). By controlling the pressure, it is also possible to control the four servo motors (6a) to (6d) to stop the moving mold (1b) according to the stop position of the moving mold (1b). Can be used to control the position, and the thickness of the molded product (3) can be controlled. Also in the above case, the stop positions of the individual tie bar tension adjusting gears (45) to (48) by the four servo motors (6a) to (6d) are controlled based on the data selected by the test injection molding. Therefore, the parallelism (H), plate thickness, and other dimensions are kept within the planned accuracy.

[0036]

According to the present invention, the tension generated when the tie bar is clamped is individually adjusted by the tie bar tension adjusting mechanism individually disposed on the tie bar. The parallelism of the injection molded product can be easily adjusted to the predetermined accuracy simply by operating any one of the tie bar tension adjustment mechanisms in accordance with the measurement result of the parallelism of the injection molded product. By using a servo motor as the drive source of the tie-bar tension adjusting mechanism, the parallelism can be adjusted extremely accurately and in a short time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the mold mechanism of the present invention taken along the line XX shown in FIG.

FIG. 2 is a plan sectional view of a tailstock of the device of the present invention.

FIG. 3 is an arrow view from the tail stock side of the device of the present invention.

FIG. 4 is a sectional view of a conventional die mechanism taken along line YY shown in FIG. 5;

FIG. 5 is an arrow view from the tail stock side of a conventional example.

FIG. 6 is a process procedure diagram of compression molding in injection molding.

[Explanation of symbols]

 (A) This machine (1a) Fixed die (1b) Moving die (2a) Fixed die mounting plate (2b) Moving die mounting plate (3) Molded product (41) (42) (43) (44) Tie bar (5) Tail stock (6A) (6B) (6C) (6D) Tie bar tension adjustment mechanism (6a) (6b) (6c) (6d) Servo motor (7) Mold cavity

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshiaki Hara 1-4-4 Yatacho, Shinjuku-ku, Tokyo Inside Sony Music Entertainment Inc. (72) Shinji Kobayashi 1-4-4 Yatamachi, Shinjuku-ku, Tokyo F-term in Sony Music Entertainment Inc. (reference) 4F202 AH38 AP02 CA11 CB01 CL01 CL22 CL32 CL38 CL43 CL44 CL50 4F206 AH38 AP024 JA07 JL09 JN31 JT05 JT33 JT38

Claims (3)

[Claims] 1. A fixed mold mounting board, a tail stock, a tie bar provided between the fixed mold mounting board and the tail stock, a movable mold mounting board reciprocating along the tie bar, and a tail. A mold that is fixed to the stock and that opens and closes and clamps the mold between the fixed mold attached to the fixed mold fixture and the movable mold attached to the movable mold fixture by reciprocating the movable mold fixture. An injection molding machine comprising: a clamping mechanism; and a tie bar tension adjusting mechanism that is individually attached to the tie bar and individually adjusts a tie bar tension generated in the tie bar during mold clamping. 2. The injection molding machine according to claim 1, wherein a servomotor is used as a drive source of the tie bar tension adjusting mechanism. 3. The parallelism adjusting method for an injection molding machine according to claim 1, wherein the measured value of the parallelism is obtained when the parallelism of the injection-molded article whose parallelism is measured is out of a predetermined accuracy. The tie bar tension generated on the tie bar at the time of mold clamping is individually adjusted by operating any of the tie bar tension adjustment mechanisms based on the reference, and finally the parallelism of the injection molded product is adjusted to be within the predetermined accuracy. A parallelism adjustment method in an injection molding machine, characterized in that: