JP3527872B2 - Injection molding machine and its parallelism adjustment method - Google Patents

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 achieving extremely high parallelism on the mold cavity surfaces of fixed and moving molds mounted on a mold mounting plate of an injection molding machine, which face each other. Machine and a method for adjusting parallelism in the injection molding machine.

[0002]

2. Description of the Related Art In a conventional disk molding method, a myriad of minute projections (not shown) for forming information are formed on the surface of a stamper (52) housed in a mold (51). In order to accurately transfer to the molding resin (53) injected into the mold (51), as shown in FIG.
The steps shown in (1) to (6) are taken. That is, the figure
As shown in (1), the moving mold (51b) parting surface (54
The moving mold (51b) is stopped at a position where b) is slightly apart from the parting surface (54a) of the fixed mold (51a), and in this state, the resin (53) is injected 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) corresponding to is filled in the mold cavity (57). When injection filling is completed,
Gate cutting is performed as shown in (3), and after the gate cutting is completed, the mold opening / closing mechanism such as the servo motor-driven toggle mechanism is operated again to perform further mold clamping, and the filling resin (53)
The compression and cooling with holding pressure are performed ((4) in the same figure). Then, the same figure (5)
The mold opening is performed as shown in FIG. 3, and finally the product is taken out as shown in FIG.

According to this method, since a much larger pressure is applied to the molded product (55) in the compression holding pressure cooling step than in injection filling, the directivity due to the flow of the filling resin (53) is different from the ordinary injection molding. Since the internal pressure of the mold cavity (57) can be kept extremely high as described above, there is no unevenness in the strain, and the shape of the cavity and the transfer of fine projections on the surface of the stamper (52) are good. Therefore, for example, it is often applied to a thin plate-shaped molded product such as a CD, a light guide plate, and an aspherical lens, which does not warp and which requires high transferability and parallelism.

However, even if it is an injection compression molding method capable of mass-producing excellent molded products as described above, it is required to have much higher precision than a CD, such as a DVD or a hard disk. However, the following problems arise. That is, even if a DVD is the same disc as a CD, the diameter is 120 mm and the same, but the thickness is half.
It is 0.6 mm, and two disks are stuck together to increase the amount of information stored.

When the information on the upper disc is read by a laser serving as a pickup, when reading the information on the lower disc which is attached, the upper disc is transmitted and the information on the lower disc is read. Since it is reflected on the information input surface and read again by passing through the upper disc, parallelism of the upper disc is required to have a high precision that has never been achieved, for example, high precision on the order of microns (10 microns or less). To be done. On the other hand, a CD is used as a single disc without being stuck together,
It does not require as high a parallelism as a disc. Further, even if the 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 products requiring high precision such as a DVD, it goes without saying that the precision of each part is raised to the utmost limit, and the assembling precision thereof, especially the die mounting board (58a) ( Extreme precision is required for the parallelism of 58b). This not only causes enormous cost increase, but also has a big problem in terms of feasibility in terms of reproducibility and reliability.

That is, in the conventional injection molding machine for CD manufacturing,
The required parallelism was on the order of 10 μm (about 15 μm or less) .Therefore, carefully manufacture the parts, carefully assemble them, and assemble them carefully. Molding was performed, and the parallelism of the injection-molded product (55) was measured, and it was confirmed whether or not it was within the expected accuracy.

If the parallelism of the injection-molded product (55) is out of the expected accuracy, the tie bar (59)-
(62) Fixed mold mounting board (58a) side screw end (59a) ~ (62a)
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 each tie bar (59) to (62). Nut (63a) ~ (66
Carefully tighten and fix a), and then 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 expected accuracy. The accuracy of the work was gradually driven by repeating the work of relying on the intuition and skill of the worker.

The precision of parallelism that can be realized by the adjustment work that depends on the intuition and skill of the operator is at most 10 micron meters (15 micron meters) required for the conventional injection molding machine for CD manufacturing. However, it was impossible to achieve the accuracy required to be 10 μm or less or 5 μm or less.

For the purpose of comparison with the present invention, 4
Tension adjusting mechanism installed in the conventional device (B) for adjusting the tension generated in the book tie bars (59) to (62) at once
I will briefly explain about (67). The tie bar tension adjusting mechanism (67) is installed on the tailstock (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 arranged in the central portion of the tailstock (56), and the bearing is coaxial with the bearing (71) that rotatably supports the rotating shaft (70). Large gear through
(72) is rotatably arranged. And the same gear (72)
Engages with the drive gear (75) of the tie bar tension adjusting motor (74) installed in the tailstock (56) via the intermediate gear (73).

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

[0013]

The problems to be solved by the present invention are as follows.
The objective is to develop an injection molding machine and its adjustment method that can achieve parallelism of a mold mounting board or molded products with an accuracy of the order of micron meters simply by changing the equipment structure.

[0014]

[Means for Solving the Problems] The injection molding machine (A) according to claim 1 has a "fixed mold mounting plate (2a), a tailstock (5), and the fixed mold mounting plate (2a)". ) And tailstock (5)
And the tie bars (41) to (44) installed between
A moving mold mounting board (2b) that reciprocates along 1) to (44),
The fixed mold (1a) and the movable mold mounting plate (2b) fixed to the tailstock (5) and reciprocally moved on the movable mold mounting plate (2b) are mounted on the fixed mold mounting plate (2a). A mold clamping mechanism (11) for opening and closing the mold with the movable mold (1b) attached and for clamping.
Tie bar tension adjusting mechanism (6A) to (6D) individually attached to the tie bars (41) to (44) for individually adjusting the tie bar tensions generated in the tie bars (41) to (44) during mold clamping. An injection molding machine (A) having a tie bar tension adjusting mechanism.
Parts (6A) to (6D) are tail stocks for each tie bar (41) to (44).
Adjustment screws (41b) to (44b) engraved on the
It is screwed and stored freely in the tailstock (5).
A tie bar tension adjustment gear that is (45) - (48), tie bar
-Drive teeth individually meshing with the tension adjusting gears (45) to (48)
Cars (6a1) to (6d1) are installed in the tailstock (5).
Attached and parallel to the molded product obtained by test injection
Parallelism is controlled individually based on the degree data, and is expected during mold clamping.
Servo motors (6a) to (6d) that achieve parallelism of
It is composed of " .

As described above, the tie bars (41 ) to (6d) are individually arranged by the servo motors (6a) to (6d) individually arranged on the tie bars (41) to (44).
Since the tension generated during mold clamping of (44) is adjusted, the parallelism of the injection-molded product (3) taken out by the test injection molding is measured, and one of the services is measured according to the measurement result.
It is possible to easily adjust the parallelism of the injection-molded product (3 ) to the desired accuracy by operating the required amounts of the Bomotors (6a)-(6d) . In this way, by setting the servomotors (6a) to (6d) as the drive sources of the tie bar tension adjusting mechanism (6A) to (6D), the parallelism can be digitally adjusted. Unlike the adjustment that relied on the intuition and experience of the operator, the parallelism can be adjusted extremely accurately and in a short time.

" Claim 2 " is a method for adjusting the parallelism in the injection molding machine (A) according to claim 1 , wherein "when the parallelism (H) of the injection-molded product (3) is measured, the injection is performed. When the parallelism (H) of the molded product (3) is out of the expected accuracy, one of the servo motors (6a) to (6d) is operated based on the measured value of the parallelism (H) to clamp the mold. The tie bar tensions (T41) (T42) (T43) (T44) that sometimes occur on the tie bars (41) to (44) are adjusted individually, and finally the parallelism (H) of the injection molded product (3) is the expected accuracy. "Adjust to fit inside."

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An injection compression molding machine according to the present invention.
(A) will be sequentially described according to the illustrated embodiment. Device of the present invention
On the machine base (22) of (A), the fixed mold mounting board (2a) is fixed, and further two guide rails (14) are laid toward the till stock (5) side. . Tillstock (5)
Is movably mounted on the guide rail (14) through a linear motion mechanism (15a) such as a linear motion bearing. Then, four tie bars (41) to (44) are installed vertically and horizontally between the fixed mold mounting plate (2a) and the till stock (5). On the tie bars (41) to (44), a movable die mounting plate (2b) is arranged so as to slide along the tie bars (41) to (44).

The movable mold mounting plate (2b) is a mechanism equipped with necessary mechanisms such as an eject mechanism (E) for ejecting the molded product (3) from the mold cavity (7) and a gate cut mechanism (G). Consists of a moving die plate part (2b1) on which the part housing (12) and moving mold (1b) are mounted, and a pressure sensor (13) installed / fixed between both parts (12) (2b1). Has been done.

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

The movable die mounting board (2b) is arranged so as to be close to and away from the fixed die mounting board (2a), and the movable die mounting board (2b) and the fixed die mounting board (2a) The mold mounting surface (2ak) (2bk) that is the opposing surface of () is the mounting reference surface of both molds (1a) (1b), so its flatness is extremely accurately finished, and as described later, The parallelism is the parallelism (H) of the molded product (3)
Assembled and adjusted to achieve a high degree of parallelism.

Next, the 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 threaded portions on both ends, respectively, and the fixed die mounting board (2a) side threaded portion is fixed side screwed portion (41a) to ( 44a) and adjust the thread on the tailstock (5) side to the thread on the adjustment side (41b)
~ (44b).

On the fixed mold mounting board (2a) side, the end portions of the tie bars (41) to (44) on the fixed mold mounting board (2a) side are the four corners of the fixed mold mounting board (2a). Through the through hole (8) of the fixing nut (23) to the fixed side screw part (41a) ~ (44a)
~ (26) are respectively screwed, and fixed side screw part (41a) ~
The fixing side screw parts (41a) to (44a) are fixed by the fixing tools (27) to (30) provided on each of the (44a). Although various fixing methods can be considered, here, the plurality of fixing bolts (31) attached to the fixing members (27) to (30) are tightened to fix the fixing members (27) to (30) to the fixing side screw portion (41a). ) ~ (44a) is strongly pressed against the ends of the fixing nuts (23) ~ (26) against the fixed mold mounting plate (2a), and the fixed side screw parts (41a) ~ (44a). And fixing nut
The screws of (23) to (26) are firmly contacted and fixed.
As a result, the tie bars (41) to (44) are integrated with the fixed mold mounting board (2a).

On the tailstock (5) side, the ends of the tie bars (41) to (44) on the tailstock (5) side are inserted into the through holes (9) at the four corners of the tailstock (5). , The tie bar tension adjusting gear (4) on the adjusting side screw parts (41b) to (44b)
5) to (48) are screwed together. The tie bar tension adjusting gears (45) to (48) are the through holes (9) of the tailstock (5).
It is rotatably housed in a housing recess (10) provided coaxially with. Then, next to it, servo motors (6a) to (6d) are individually installed for each of the tie bars (41) to (44), and drive attached to the drive shafts of the servo motors (6a) to (6d). 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) such as rotary encoders.
2) is installed. In this embodiment, the tie bar tension adjusting mechanism (6A) ~ (6D), the tie bar tension adjusting gears (45) ~ (4.
8), servo motors (6a) to (6d), drive gears (6a1) to (6d1), and pulse generators (6a2) to (6d2).

Next, the drive 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 surface of the tailstock (5). The drive pulley (34) of the servo motor (32) and the driven pulley (33) rotatably arranged at the center of the tailstock (5) are connected by a transmission belt (35) such as a timing belt. Has been done.

At the center of the driven pulley (33) is a drive nut.
(37) is screwed, and the drive screw (36) is screwed so that it can move forward and backward. The tip of the drive screw (36) is attached to the mold clamping mechanism (1
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 stretches as the (36) moves back and forth.

Next, this apparatus (A), especially both mold mounting boards (2a) (2
An explanation will be given focusing on the adjustment for obtaining the required parallelism of b). The mounting surface (22a), which is the upper surface of the machine base (22), is processed to have extremely high flatness, and includes the fixed-side mold mounting board (2a) and a pair of traveling rails (14) arranged in parallel. Fix it. Next, install the tailstock (5), moving mold mounting board (2b), mold clamping mechanism (11), etc. on the running rail (14), and assemble the tie bar (6) and other mechanisms in the prescribed procedure. Go. What is important here is that the bottom surface (2a1) of the fixed side mold mounting plate (2a) is secured so that the required accuracy can be secured with only a slight final adjustment.
It is necessary to finish as strictly as possible from processing to assembly, including the squareness between the fixed mold mounting surface (2ak) and.

When the assembly of this device (A) is completed, this device (A)
Will be moved to the injection molding work using. Generally, when a new die (1a) (1b) is installed, or when the old and new dies are replaced, or the stamper (7
a) After replacement, injection molding is performed on a trial basis before entering the automatic continuous injection molding process, and the molded product (3) is taken out and its parallelism, plate thickness, density, etc. are strictly checked, It will be adjusted enough to completely meet the specifications, and only then will the automatic injection molding process be switched to. Here, the adjustment of parallelism to the molded product (3) will be mainly described. First, test injection molding is performed, the parallelism of the molded product (3) taken out from this is measured, and the mold cavity is measured.
Know the inclination of the facing surface (or the error between the facing surfaces) in (7).
If the amount of error is known, it is possible to calculate how much tension should be applied to which tie bar so that the facing surfaces become parallel and the error is eliminated.

Next, the servo motors (6a) to (6) of the tie bar tension adjusting mechanism units (6A) to (6D) are controlled by the control unit of the apparatus (A).
Individual data is sent to (d) and each servo motor (6a) to (6
Activate d) according to the individual data. Each servo motor (6
a) ~ (6d) actuation amount is the attached pulse generator (6a2) ~ (6d2)
Have been confirmed in.

When the servo motors (6a) to (6d) operate as instructed, the drive gears (6a1) to (6a1) to the servo motors (6a) to (6d)
Tie bar tension adjustment gear (45) individually meshing with (6d1)
~ (48) correspondingly rotates, and the tie bar (41) during mold clamping.
Finely adjust the tension (T41) to (T44) generated in (44) to (44) individually. The adjustment of the tie bar tensions (T41) to (T44) is generally performed when the mold is opened. Theoretically, almost one degree of parallelism can be obtained with one adjustment, but if necessary, multiple test injection moldings are performed.

The thickness of the molded product (3) is adjusted by the same method so as to be within the specified dimensional accuracy. That is, when the thickness of the entire molded product (3) is insufficient, the tie bar tension (T41) is activated by operating the servo motors (6a) to (6d) of the tie bar tension adjusting mechanism (6A) to (6D). (T44) is loosened slightly, and conversely, when the thickness of the molded product (3) is too large, the tie bar tension adjusting gears (45) to (48) are tightened. This allows the thickness of the molded product (3) to be adjusted to the specified dimensions. Of course, the thickness adjustment and the parallelism adjustment of the molded product (3) can be simultaneously performed. Then, when the expected accuracy of the parallelism, the thickness, etc. is obtained, the process is switched to the automatic injection molding process.
As a result, the adjustment is based on the data, not the adjustment depending on the skill and intuition of the operator.Therefore, it is extremely easy and reproducible to produce a highly parallel molded product (3) that could not be obtained until now. It became possible to produce in large quantities.

Next, the tie bar tension adjusting mechanism (6A) to (6D)
I will explain about the special usage of. The original function of the tie bar tension adjusting mechanism (6A) to (6D) is as described above.
The tension (T41) to (T44) generated in (41) to (44) is adjusted individually, and the parallelism (H) of the final product, the molded product (3), is as high as 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 make the parallelism (H) of the molded product (3) within the predetermined accuracy, which servo motor (6a) to (6
How to control d) is available as data from the test injection molding just before. Therefore, before clamping the mold, operate the servo motors (6a) to (6d) to tighten the tie bar tension adjustment gear.
(45) to (48) are slightly retracted, and the mold is clamped in this state. The amount by which the tie bar tension adjustment gears (45) to (48) are retracted.
Both molds (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 (2) in the figure). In the injection filling step,
The mold cavity (7) is overfilled with an amount of measuring resin corresponding to the distance (t).

When the injection filling is completed, (3) in FIG.
Gate cut is performed as shown in, and after the gate cut is completed, the four servo motors (6a) to (6d) are operated simultaneously to move the tie bar tension adjusting gears (45) to (48) forward to a predetermined position. Tighten. The retightening is not performed by the mold clamping mechanism (11) as in the conventional case, but is performed by operating the tie bar tension adjusting mechanism sections (6A) to (6D). Then, while maintaining this position, the filled resin is cooled with holding pressure ((4) in the same figure). Subsequently, the mold opening is performed as shown in FIG. 5 (5), and finally the product is taken out as shown in FIG. 6 (6).

At this time, the molded product is controlled by controlling the tightening speed.
The quality of (3) (for example, improvement of transferability) can be achieved (compression speed control), and the four servo motors (6a) to (6d) are controlled based on the pressure signal from the pressure sensor (13). By doing so, it is possible to control the pressure, and to control the four servo motors (6a) to (6d) so as to stop the moving mold (1b) according to the stop position of the moving mold (1b). It is also possible to control the position with, and it is possible to control the thickness of the molded product (3). Even 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 will be kept within the expected accuracy.

[0036]

According to the present invention, the tie bar tension adjusting mechanism section individually arranged on the tie bar individually adjusts the tension generated at the time of mold clamping of the tie bar. It is possible to easily adjust the parallelism of the injection-molded product to the intended accuracy simply by operating any one of the tie bar tension adjusting mechanisms according to 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, parallelism can be adjusted extremely accurately and in a short time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along line XX shown in FIG. 3 of a mold mechanism portion of the device of the present invention.

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

FIG. 3 is a view of the device of the present invention as seen from the side of the tailstock.

FIG. 4 is a cross-sectional view taken along the line YY shown in FIG.

FIG. 5 is an arrow view from the side of the tailstock of the conventional example.

FIG. 6 is a process flow chart of compression molding in injection molding.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshiaki Hara, 1-4 Yata-cho, Shinjuku-ku, Tokyo Inside Sony Music Entertainment Inc. (72) Shinji Kobayashi 1-chome, Yata-cho, Shinjuku-ku, Tokyo No. 4 Inside Sony Music Entertainment Inc. (56) References JP-A-7-148805 (JP, A) JP-A-56-131059 (JP, A) JP-B 1-42814 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/76

Claims (2)

(57) [Claims] 1. A fixed mold mounting plate, a tail stock, a tie bar installed between the fixed mold mounting plate and the tail stock, a movable mold mounting plate that reciprocates along the tie bar, and a tail. A mold that is fixed to the stock and reciprocates the moving mold mounting plate to open and close the mold between the fixed mold mounted on the fixed mold mounting plate and the moving mold mounted on the moving mold mounting plate, and to perform mold clamping. In an injection molding machine having a tightening mechanism and a tie bar tension adjusting mechanism section that is individually attached to the tie bar and individually adjusts the tie bar tension generated in the tie bar at the time of mold clamping , the tie bar tension adjusting mechanism section includes each tie bar tension adjusting mechanism section. The adjustment nut engraved on the tailstock end of the
The tailstock is screwed onto each of the
The tie bar tension adjusting gear currently stored and the drive gear individually meshing with the tie bar tension adjusting gear
Have, attached to the tailstock, for test injection
Based on the parallelism data for the molded product obtained from
Parallelism is controlled separately to achieve the desired parallelism during mold clamping.
An injection molding machine characterized by being configured with a servo motor . 2. The parallelism adjusting method for an injection molding machine according to claim 1 , wherein the parallelism of the injection-molded product whose parallelism is measured is out of a predetermined accuracy, the measured value of the parallelism is used as a reference. in to one of the service
The parallelism in the injection molding machine is characterized by individually adjusting the tie bar tension generated in the tie bar during mold clamping by operating the servo motor , and finally adjusting the parallelism of the injection molded product so that it falls within the planned accuracy. Adjustment method.