JPH01160628A - Injection molding machine - Google Patents

Abstract

PURPOSE:To improve the fluidity of a molten resin, inject it into a mold in an optimum condition, while passing it smoothly through the inside of a nozzle and perform molding of disk-shaped medium with high precision, high productivity, high reliability and advanced quality, by arranging separately and individually a plurality of heaters being different temperature ranges in the nozzle portion of a screw cylinder and providing respectively a temperature sensor at each heater. CONSTITUTION:Molding material is fed from a feed zone 11, heated and molten by heaters 17 and 18 of a screw cylinder 12, pressed and sent to a nozzle portion 14. In the nozzle portion 14, uniformly kneaded and fluidized molten resin is controllably heated with two units of heaters 15 and 16 at nozzle rand part 142 and nozzle gate part 141 while passing through each part 142 and 141. Temperature sensors 19 and 20 are embedded in the nozzle and detect a temperature closer to that of resin, and keep an optimum state in which the resin passes through the nozzle part 14 to perform a stable molding and a precise molding. Thus, it is possible to minimize the occurrence of flow-mark, etc., and mass- produce high-precision and high-quality items.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an injection molding machine for optical disks, etc., for injection molding disk-shaped media such as optical disks and magneto-optical disks.

[Conventional technology]

In general, information disks such as optical disks or magneto-optical disks used as information recording carriers are molded products that are injection molded in a disk mold. Conventionally, this type of injection molding machine uses a nozzle in the head of a screw cylinder. A molded product is manufactured by joining the sprue and supplying fluid molding raw material to the cavity via a runner.

In a conventional screw injection molding machine, as shown in the example in Fig. 5, the material sent from the supply section C is melted by the screw b in the heating cylinder a as it moves forward, and is compressed and kneaded to be homogenized. and is injected into the mold e through the nozzle d. This heating cylinder a constitutes a heating zone in which the material inside is directly heated by several sets of pando heaters h, h+, and ht equipped on the outer periphery, and each thermocouple is used to maintain a temperature suitable for the material used. known to be controlled.

[Problem that the invention seeks to solve]

However, in this type of conventional example, the temperature of the heating zone in the heating cylinder is controlled by a plurality of heaters h, h, ,h, extending from the nozzle d to the material supply section C, as shown in Fig. 4.
, but in the nozzle d, which is an important part that directly affects the molten state of the material that is injected into the mold cavity, the molten resin in the heating cylinder is heated by a single heater h. Because of the distance between the heater h and the sensor i, it was not possible to accurately control the resin temperature at the nozzle. Despite the need for high-level control, the control of the nozzle gate and nozzle land areas was not sufficient, resulting in negative effects on the disk molded substrate, such as flow marks on the disk surface. or silver (silver vapor stain)
Alternatively, variations in birefringence between shots frequently occur, and delicate temperature control is also difficult, leading to product defects and problems in processing accuracy and reliability.

The present invention aims to accurately eliminate these conventional drawbacks, and provides optical disks, etc., which can improve the productivity of forming disk-shaped media with high accuracy and greatly improve reliability and quality. The purpose is to provide an injection molding machine with a simple configuration and at low cost.

[Means for solving problems]

The present invention configures an injection unit by including a rotatable and slidable screw 13 in a screw cylinder 12 that communicates with a molding material supply section 11, and supplies the material from the tip nozzle section 14 of the screw cylinder 12. Supply section 1
Heaters 16, 17, 18 for multiple heating on 1 side...
In an injection molding machine equipped with ...--, a plurality of heaters 15.16 having different temperature bands are individually arranged and arranged in the nozzle portion 14 of the screw cylinder 12, and each heater 15.16 This injection molding machine is characterized by being equipped with temperature sensors 19 and 20 for temperature adjustment, respectively.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 1 to 3. A fixed mold l and a movable mold 2 for molding a disk-shaped information medium
A sprue 8 on the mold side is connected to a nozzle section 14 for supplying molten resin into the cavity formed by the ring member 3 which is interposed between both molds 1.2 and molds the outer peripheral part of the disk. An injection unit is constructed by having a rotatable and slidable screw 13 in a cylinder 12 that communicates with a molding material supply section 11 in a molding machine that is arranged so as to be able to join the molding material at the tip of the screw cylinder 12. A plurality of heating heaters 16, 17, 18, . A plurality of heaters 15, 16 are individually arranged and each heater 15, 16 is provided with a temperature sensor 19, 20 for temperature adjustment, thereby forming an injection molding machine.

The nozzle portion 14 of the screw cylinder 12 includes:
Nozzle gate part 14I and nozzle land part 14! The band heater 15 is divided into both parts.
, 16, and their temperature sensors 19, 20, such as thermocouples, are also embedded in the nozzle section 14 and connected to the control system.

That is, the temperature sensors 19 and 20 are installed in an operation panel 25, that is, a computer 23 that includes an input section 21 and an output section 22 in the control system of the injection molding machine, and are compared with a setter 24 of fixed data to calculate the resin temperature. It is designed to perform temperature control, automatic metering control, injection speed control, and other necessary controls such as pressure control. It should be noted that the input section 21 also includes the detected values of a temperature sensor 26 and a pressure sensor 27 provided on the mold 1.2 side, so as to provide optimum conditions for incorporation.

The screw 13 is equipped with a needle at its tip for opening and closing the injection port as needed, and from the tip, the screw cylinder 12 is sequentially connected to a metering section and a compression section.

It is preferable that the temperature zone of this compression section is higher than the other temperature zones.

In the figure, 28 is an injection drive unit for a hydraulic cylinder including a ram, and 29 is a motor.

The spool 81 communicates with the runner 8□, but it may be formed directly on the stationary mold 1 or the sprue bush 8
In any case, the molding raw material can be introduced into the cavity molded by the mold, and the nozzle part 14 joined to the sprue 81 is a hollow cylinder, and the The raw material flow path has a nozzle gate section 141 which is narrowed down to a small diameter on the injection port side at the tip, and if necessary, a titanium ion brating layer is formed on the entire circumference of the raw material flow path or only on the nozzle gate section. Good to use.

The mold for forming the cavity is equipped with an outer stumbling bar 4 as shown in FIG.
A stubber holder consisting of an outer stamper holder 4 and an inner stamper holder 5 for fixing the gate cut punch 9 and the stubber 10 is provided, and the stationary mold 1 is provided with a ring member 3 and a sprue bush 8, respectively. A sleeve 6 for ejecting the molded product is fitted into the center of the inner stamper presser 5, and a gate cut punch 9 and a runner ejecting pin 7 are slidably inserted into the sleeve 6. We are preparing for

Therefore, during molding, after the movable mold 2 is moved and fitted to the fixed mold 1, the mold is clamped by applying pressure, and then vacuum is applied to the cavities in both molds 1.2 before material is supplied. After suctioning, the molten resin is injected from the nozzle part 14 in the head of the screw cylinder for supplying the raw material, guided into the cavity via the runner 8z, compressed and molded while maintaining pressure, and after cooling, the gate cut punch 9 is moved. Remove the sprue runner and
The mold can be opened to take out the product.The molding material is input from the supply section 11, heated by the heaters 17 and 18 of the screw cylinder 12, and compressed while melting.
Sent to 4. Nozzle part 14 for injecting the molten resin in this screw cylinder 12 into the cavity of the mold
In this case, while the uniformly kneaded and fluid molten resin passes through the nozzle land part 14g and the nozzle gate part 141, the nozzle land part 14g and the nozzle gate part 141 can be controlled by two systems of heaters, and the temperature sensor 19.20 is also used. Embedded in the nozzle to sense the temperature closer to the molten resin,
Stable molding and precision molding are possible by maintaining the optimum condition for passage through the nozzle part 14, and even if polycarbonate resin is used as a product, injection from the nozzle part can be performed smoothly and the occurrence of flow marks can be minimized. This makes it possible to mass-produce products with high precision and good quality.

〔Effect of the invention〕

The present invention provides a nozzle for supplying raw materials for disc-shaped information media, in which a plurality of heaters with different temperature bands are individually arranged and arranged in the nozzle part of a screw cylinder, and each heater is equipped with a temperature sensor for adjusting the temperature. This makes it possible to control the nozzle section by dividing it into multiple temperature zones, making it possible to control the resin temperature according to the type of flowing resin used, improving the fluidity of the molten resin and allowing it to flow smoothly inside the nozzle. As a result, injection into the mold is performed under optimal conditions, and there are no adverse phenomena such as flow marks or silver on the product surface or variations between birefringence shots, allowing for production with good processing accuracy, significantly improving quality and reliability. In addition to significantly improving temperature control through the specific placement of heaters and temperature sensors, there is no risk of defects or deterioration that would adversely affect the disk, and the molding process is easy to handle and productivity is extremely high. There are effects such as

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the system of the embodiment of the present invention, Fig. 2 is an enlarged vertical sectional view of a part, Fig. 3 is a longitudinal sectional view of the mold, Fig. 4 is an explanatory diagram of the conventional example, and Fig. 5 is a vertical sectional view of the device in use. DESCRIPTION OF SYMBOLS 1... Fixed side mold, 2... Movable side mold, 3... Ring member, 4... Outer stamper holder, 5... Inner stamper holder, 6... Projection sleeve, 7...
- Ejector pin, 8... Sprue bush, 8. ...
Sprue, 8...Runner, 9...Gate cut punch, 10...Stamper 111...Supply section, 12
...Screw cylinder, 13...Screw, 1
4... Nozzle part, 15.16.17.18... Heater, 19.20... A degree sensor, 23... Computer, 25... Operation panel. Patent applicant: Minoru Pharmacist, patent attorney, TDC Co., Ltd. Figures 2, 4, and 5

Claims (2)

[Claims] (1) A cylinder (
12) A screw (13) is rotatably and slidably provided in the injection unit to constitute an injection unit, and extends from the tip nozzle part (14) side of the screw cylinder (12) to the material supply part (11) side. Multiple heaters (16
)(17)(18)... In an injection molding machine equipped with
) (16) are individually separated and arranged, each heater (
15) Temperature sensor (1) that adjusts the temperature in (16) respectively.
9) An injection molding machine characterized by being equipped with (20). (2) The nozzle part (14) of the screw cylinder is
Nozzle gate part (14_1) and nozzle land part (14_
2), and the band heater (15) (16) and its temperature sensor (19) are divided into both parts.
(20) An injection molding machine according to claim 1, which is equipped with (20).