JPS6399916A - Vulcanizing method in injection molding machine and equipment - Google Patents

Abstract

PURPOSE:To improve a quality of a molding by shortening a vulcanizing hour of rubber, by controlling an irradiation dose of a microwave so that the same is increased when an injection quantity is much and on the contrary when the same is little the injection quantity is decreased. CONSTITUTION:A mold 13 is clamped down on a mount 21, a screw 15 is moved backward through turning and a material 19 is accumulated on the tip part in a fixed quantity under a molten state. Then in the case where injection is performed by delaying a speed of a forward movement of a screw 15 gradually like the speeds 1 2 3 4, 'the speed 1' is output through an output signal V by an injection molding controller 50, to begin with. Therefore, although an output control part 57 directs a microwave to an applicator 56 by controlling an aligning instrument 55, the same directs the microwave to the material 19 to be extruded at 'the speed 1' under such an electrical field strength that a temperature of the material 19 is raised up to that of a tower this side of that of vulcanization while the same is being passed through the inside of a tube 27. The inside of the mold 13 can be filled with the material 19 to be injected by raising the temperature of the same up to a fixed value irrespective of an injection quantity per unit time.

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a vulcanization method for an injection molding machine and an apparatus thereof;
In particular, the present invention relates to a method of vulcanizing rubber in an injection molding machine that produces a molded product by injecting and vulcanizing a rubber material into a mold.

Summary of the Invention This invention provides a rubber injection molding machine in which the rubber itself
HF (Ultra High Frequency
) is used to irradiate a portion of the passage with microwaves and control the electric field strength to achieve high-speed vulcanization and quality improvement of rubber.

C. Conventional technology Recently, with the development of industry and advances in material development, the demand for rubber molded products has been increasing.

As shown in FIG. 1, an injection molding machine that manufactures the molded product generally has a nozzle part 1 at the tip for passing the rubber material 9b, and a screw 5 inside for taking in the rubber material 9a. and P4-8b for heating on the outer periphery:
It is composed of a cylinder 6 attached thereto, a mold 3 equipped with a sprue part 2 for passing the material, and a mold heater 7 for thermal vulcanization. The molding process begins with
By rotating the screw 5 in the direction A and moving it backward, the rubber material 9a is taken in from the arrow B and extruded forward to undergo melt plasticization 1-, and a certain amount of the molten material 9b is accumulated at the tip of the screw 5. Thereafter, the material 9b is transferred to the nozzle part 1 and the sprue part 2 by advancing the screw 5.
The material is injected into a mold 3 through the injection molding process, and vulcanized by heating with a mold heater 7 to produce a molded product.

2. Problems to be Solved by the Invention In the above-mentioned molding method, since the mold heater 4-8 is heated to bring it into a molten state and the mold heater 4-7 is heated to vulcanize it, i) it takes a long time for vulcanization. time is required ii)
Due to differences in kneading time using the screw 5, temperature unevenness occurs in the molten state, resulting in flow marks, warpage, distortion, etc.
In addition, if the vulcanization temperature is increased to shorten the vulcanization time, vulcanization reversion may occur, resulting in a decrease in quality. There were other problems.

As an improvement to the above, the present inventor added a microwave dielectric heating section between the nozzle section 1 and the tip of the cylinder 6 in Fig. 1, and irradiated the rubber material 9b to be injected with microwaves. By doing so, a method has been devised in which the rubber itself generates heat internally and is filled into the mold 3 (see Utility Model Application No. 60-074260). However, during the injection operation, the amount of microwave irradiation, that is, the amount of internal heat generated by the rubber itself, is determined in accordance with the amount of rubber to be injected, and the temperature rise value of the rubber is extremely finely controlled. Therefore, there has been a strong desire to develop a method for vulcanizing products of even better quality.

The purpose of the present invention is to provide a vulcanization method for an injection molding machine that can solve these conventional problems and shorten rubber vulcanization time and improve the quality of molded products using a simple and inexpensive method. and equipment.

E. Means for solving the problem In an injection molding machine that irradiates and injects melted plasticized rubber with microwaves in an injection mechanism and heat vulcanizes it in a mold, the amount of microwave irradiation is Characteristic b1 is that control is performed so that when the amount of injection is large per unit time, it is increased, and on the other hand, when the amount of injection is small, it is controlled to be reduced to six.

Effect Generally, when microwaves are irradiated, the heat generation P of rubber becomes P1=, and self F@ECW/c? i? ]・・・・・・・・・
・・・・・・・・・(1) However, F: Frequency (Hz), E
: Electric field strength (V/wound) % k+ : Constant, on the other hand, the energy P for raising the temperature is P
x ”kt” W・ΔT/l (W)...
・・・・・・(2) However, W: Weight of rubber [? ], ΔT
: Temperature increase range ('rt T+ 1 (C), t: Irradiation time (Sec), k, : Indicated by a constant, so when the amount of rubber injected per unit time is large, irradiation is performed with a strong electric field strength E. However, when the rubber passes through the mold for a long time, by irradiating with a weak electric field strength E, the rubber heated to an arbitrary temperature can be fed into the mold and filled.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a microwave dielectric heating section showing an embodiment of the present invention, FIG. 3 is a diagram of an electric program that controls the dielectric heating section of FIG. This is for explaining the operation of FIG. 3.

In FIG. 2, 11 is a nozzle portion that contacts the mounting base 21 and guides the molten material 19 in the cylinder 16 into the mold 13, and 22 is the nozzle portion 11° and the nozzle plate 2.
4. A mounting plate that supports the waveguide 58d and is fixed to the tip of the cylinder 16; 23 is a side cover that fixes the nozzle plate 24 sandwiching the side plate 26 and the chape 27; 25 is the same as the side cover 23; The plate 15, which fixes the nozzle plate 24 and efficiently conveys the microwave from the waveguide 58d into the side plate 26, moves back and forth (or up and down) in the same way as the screw 5 in FIG. 1 described above. A screw (
or plunger).

In FIG. 3, 50 is an injection molding control device that controls the entire rubber injection molding machine, and 51 is a microwave dielectric heating unit that radiation-heats the rubber material, which uses microwaves of 915 MHz or λ450 MHz oscillated by a magnetron. A microwave oscillator 52 that outputs to a waveguide 58a, an isolator 53 that consists of a permanent magnet, a ferrite, and a water load and protects the magnetron by absorbing the reflected power from the applicator side, and measures the incident and reflected power of the microwave. A power monitor 54 monitors the matching state by adjusting the reflected power, a matching device 55 adjusts the reflected power to determine the electric field strength (V/cm ) of the applicator 56, and a matching device 55 receives the output signal V from the injection molding control device t50. Output adjustment section 5 that drives and adjusts
7. The applicator 56 generates heat by irradiating the rubber passing through the tube 27 with microwaves to minimize microwave loss, and the chape 27 is provided with abrasion resistance against the passage of the rubber material 19. I'm making you wait. Moreover, a commercially available magnetron is used for the microwave (1 to 100 GHz).

In the vulcanization method of the present invention, the mold 13 is clamped to the mounting base 21, the screw 15 rotates and retreats, and the material 19 is attached to the tip.
After accumulating (weighing) a certain amount in a molten state, the screw 15 is moved forward at a speed of 1 → 2 → 3 → 4 as shown in Table 1.
When the injection molding control device 50 outputs 1 speed 1 with the output signal V, the output adjustment unit 57 adjusts the matching device 55 and irradiates the applicator 56 with microwaves. This is done by irradiating the material 19 extruded at a speed of 1N with microwaves at such an electric field strength that the material 19 is heated to just below the vulcanization temperature while passing through the tube 2.

In reality, there is a delay time 1+ due to the output adjustment unit 57 and the like until the microwave is irradiated with the desired electric field strength, so the injection molding control device 15G is programmed to adjust the gas velocity by t8 seconds earlier than the start of injection. Output 1〃.

Next, when the output adjustment unit 57 receives the 1st velocity 21, it adjusts the matching device 55 to irradiate the air velocity 21 in the same manner as above, but
v41! so as to irradiate the material 19 extruded in the tube 27 with microwaves at such an electric field strength that it heats up to the same temperature as when the air velocity is 1 while it passes through the tube 27! ! !
,do.

Next, the same adjustment was made for the 1st speed [3#, % speed 4], and the rubber material 19 with the gold heated to the same value was
The applicator 4-56 is filled with microwaves, and the microwave irradiation to the applicator 4-56 is stopped at the same time as the first speed 4 is completed, that is, the injection is completed. As a result, the temperature of the material 19 to be injected is heated to a constant value regardless of the injection amount per potential time, and the mold 1
Since it can be filled into the mold 13, temperature unevenness does not occur within the mold 13, and a molded product without flow marks, warpage, distortion, sink marks, etc. can be manufactured.

At the same time, since the range of temperature rise up to the vulcanization temperature in the mold is extremely small, it is possible to vulcanize in a short time.

In this way, the amount of microwave irradiation is varied according to the speed, that is, the amount of injection, and the temperature is raised to a value close to a uniform vulcanization temperature before vulcanization, resulting in high-quality and low-cost molded products. be able to.

In this example, i) injection was performed by changing the speed into four stages; however, the number of stages may be determined arbitrarily, and it is also easy to speed up or slow down, or perform continuous control. realizable. it) Although speed information (oil flow rate) was used for the output signal V of the injection molding control device 50, it is clear that the other pressure information determining the forward movement of the screw (or plunger) 15 can also be used. ii)
The applicator 4-56 was provided between the nozzle part 11 and the cylinder 16, and it was provided between the nozzle part 11 and the cavity of the mold 13, that is, in a part of the sprue, to control the electric field strength of the microwave as described above. The injection material 19 can be controlled to generate heat.

The dotted line in Table 1 shows the control details when the material 19 is injected while gradually lowering its temperature.
For the change from 2 to 3 to 4, the matching box 55 is adjusted so that the microwave irradiation power is weakened over time even if the output signal V is constant. Conversely, by controlling the electric field strength to increase over time, it is possible to eject the material 19 while gradually increasing its temperature.

The amount of microwave irradiation, that is, the electric field strength value, is determined by the amount of injection, the structure such as the length of the tube 27, and the material conditions such as the type and amount of polarity, non-polar rubber or carbon black, and the amount added.

We have described a method in which the amount of microwave irradiation is changed according to changes in the speed (or pressure), but by changing the injection speed (or injection pressure) while keeping the irradiation amount constant, it is possible to irradiate material 19. Similarly, by changing the time, material 1
9 can be heated.

Furthermore, although a rubber injection molding machine has been described, the method of the present invention can also be employed for heating an injection molding machine that injection molds a resin material.

H. As described in the detailed description of the invention, in an injection molding machine that injects a molten material and vulcanizes it in a mold, the material to be injected is irradiated with microwaves to generate heat, and then the material is filled into the mold. Since it is vulcanized and molded, the vulcanization time is shortened and the quality of the molded product is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional injection molding machine, and FIG. 2 is a configuration diagram of a microwave dielectric heating section showing an embodiment of the present invention.
FIG. 3 is an electrical block diagram of the microwave dielectric heating section. 1.11... Nozzle part 2... Sprue part 3.13
... Mold 4... Molded product 5,15... Screw (or plunger) 6.16... Cylinder
7...Mold heater 8...Heater 9a,
9b, 19...Material 21...Mounting stand 22.
...Mounting plate 23...Side cover 24...Nozzle plate 25...Plate 26...Side plate 27...Chape 50...Injection molding control device 51...Microwave dielectric heating section 52 ...Microwave oscillator 53...
・Isolator 54...Power monitor 55...
- Matching device 56... Applicator 57... Output adjustment section 58a-58d... Waveguide patent applicant Matsuda Seisakusho Co., Ltd. Table 1 Drawing No. 10 Fig. 3

Claims (5)

[Claims] (1) In an injection molding machine that irradiates and injects melted plasticized rubber with microwaves in an injection mechanism and heat vulcanizes it in a mold, the amount of microwave irradiation is adjusted when the amount of injection is large. A vulcanizing method for an injection molding machine characterized by controlling the amount of injection to be increased and, conversely, to decrease when the amount of injection is small. (2) The injection molding machine according to claim 1, characterized in that the amount of microwave irradiation is changed depending on the injection movement speed of an injection mechanism that injects the molten plasticized rubber. Sulfur method. (3) A vulcanizing method for an injection molding machine according to claims 1 and 2, characterized in that the amount of microwave irradiation is changed when the amount of injection is the same. (4) When the amount of microwave irradiation is kept constant,
A vulcanizing method for an injection molding machine according to claim 1, characterized in that the injection is performed by changing the injection movement speed of the injection mechanism. (5) In an injection molding machine that irradiates and injects melted and plasticized rubber in an injection mechanism and heat-vulcanizes it in a mold, an output means that outputs an injection movement speed of the injection mechanism; Injection molding characterized by comprising an adjustment means for adjusting the amount of microwave irradiation based on the output, and a member that transmits the adjusted microwave and passes through the rubber that generates heat due to the microwave. machine vulcanization equipment.