JPH01234219A - Injection molding nozzle and injection molding method - Google Patents

Abstract

PURPOSE:To contrive miniaturization of an injection unit, by a method wherein the outside is provided with an ultrasonic oscillator and ultrasonic oscillation to be generated through the ultrasonic oscillator is transmitted to the inside through a nozzle wall. CONSTITUTION:An injection molding nozzle 1 is stuck to the tip of a screw barrel 3 serving a heating cylinder holding an in-line screw 2 as well. The title method is constituted so that an ultrasonic oscillation generated through an ultrasonic oscillator 4 is transmitted to the inside 7 through a nozzle wall 6 from the outside 5 of the nozzle 1 and further to resin 8 in the nozzle 1. Then it is constituted so that the ultrasonic oscillator is actuated by supplying high-frequency electric power only at the time of injection of the resin 8. Therefore, pressure to be applied to the resin 8 at the time of the injection is sufficient with comparatively low pressure and an injection unit including the nozzle 1 may be good with a comparatively small-sized one which can endure low pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an injection molding nozzle and an injection molding method.

[Conventional technology]

-i, the injection molding nozzle installed in the injection molding machine is
The plasticized resin is heated, kneaded, and injected from a large-diameter screw barrel into a small-diameter mold injection port.
It has a constriction part.

In addition, in order to prevent the temperature of the resin from dropping inside the nozzle and causing a decline in its fluidity, a warm oil jacket or electric heater is installed on the outer surface of the nozzle to keep the nozzle temperature constant. The heating temperature is adjusted accordingly.

[Problem to be solved by the invention]

However, in such conventional devices, the flow velocity of the resin at the throttle part during injection is very high, and the flow friction between the inner surface of the nozzle and the resin is large. High pressure must be applied, and therefore the injection unit including the nozzle must be large enough to withstand the high pressure.

Additionally, nozzle heating temperature adjustment should normally only be done during injections when resin fluidity is required; however, oil-filled jackets and electric heaters heat by conduction. However, it is not possible to heat the resin quickly when necessary, and the heating temperature must be constantly adjusted regardless of whether the fluidity of the resin is required, resulting in energy loss.

Furthermore, since the heating temperature of the nozzle is constantly adjusted, the resin that remains in the nozzle without being injected is subjected to unnecessary thermal history, which causes the quality of molded products that are injected with this resin to deteriorate. There were problems such as the possibility of

This invention solves the problems of the conventional ones as described above, and provides an injection unit that can downsize the injection unit, reduce the energy used to heat the resin, and improve the quality of the molded product. The object of the present invention is to provide a molding nozzle and an injection molding method.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes an ultrasonic oscillator on the outer surface, and transmits the ultrasonic vibrations generated from the ultrasonic oscillator through the nozzle wall. , the information is transmitted to the inner surface. This invention also uses an injection molding nozzle equipped with an ultrasonic oscillator on its outer surface, and operates the ultrasonic oscillator only when injecting resin to apply ultrasonic vibrations to the resin flowing inside the nozzle. Injection molding is performed while feeding.

[Effect]

By employing the above-mentioned means, this invention causes the inner surface of the nozzle to cause slight vibrations due to the ultrasonic vibrations generated from the ultrasonic oscillator, thereby reducing the flow friction between the inner surface of the nozzle and the resin. Become.

Further, in this invention, the ultrasonic oscillator is operated only when resin is injected, and is not operated at other times.

〔Example〕

Embodiments of the invention shown in the drawings will be described below.

An embodiment of the injection molding nozzle according to the present invention is shown in FIGS. 1 and 2.
is fixed to the tip of a screw barrel 3 that also serves as a heating cylinder that houses the in-line screw 2.

There are four ultrasonic oscillators 4.4 around the nozzle 1.
．． 4.4 are arranged evenly in the circumferential direction and attached closely to the outer surface 5 of the nozzle l, and these ultrasonic oscillators 4.4.4.4 receive high frequency power from an appropriate high frequency power source (not shown). When supplied, ultrasonic vibrations (elastic compressional waves with a frequency higher than the audible range) are generated toward the center of the nozzle l.

The ultrasonic vibrations generated from the ultrasonic oscillator 4.4.4.4 are transmitted from the outer surface 5 of the nozzle l to the inner surface 7 via the nozzle wall 6, and are further transmitted to the resin 8 inside the nozzle l.
It is now being conveyed to the public.

Also, when performing injection molding using this nozzle l,
By means of an appropriate control means (not shown), high frequency power is supplied to operate the ultrasonic oscillator 4.4.4.4 only when the resin 8 is injected.

Next, the operation of the above will be explained.

First, before injecting the resin 8, the ultrasonic oscillator 4.4
．． 4.4 is not supplied with high frequency power, so that the ultrasound oscillator 4.4.4.4 remains inactive and does not consume any energy.

Next, when injecting the resin 8, high frequency power is supplied to operate the ultrasonic oscillator 4.4.4.4.

Then, ultrasonic vibration is immediately generated from the ultrasonic oscillator 4.4.4.4, and this ultrasonic vibration is applied to the outer surface 5 of the nozzle l.
from the nozzle wall 6 to the inner surface 7.

For this reason, the inner surface 7 of the nozzle 1 causes slight vibrations in the radial direction, and this slight vibration reduces the frictional force between the inner surface 7 of the nozzle 1 and the resin 8 flowing inside the nozzle 1.

Therefore, it is sufficient to apply a relatively small pressure to the resin 8 during injection, and as a result, the injection unit including the nozzle 1 can be relatively small and can withstand small pressure.

In addition, a part of the ultrasonic vibration transmitted from the ultrasonic oscillator 4.4.4.4 to the inner surface 7 of the nozzle l is transmitted to the resin 8 inside the nozzle 1, and is attenuated internally by the viscoelasticity of the resin 8. As a result, the energy of ultrasonic vibrations is converted into thermal energy.

For this reason, the temperature of the resin 8 increases and the viscosity decreases, so
Resin 8 has good fluidity.

Moreover, since this energy conversion occurs rapidly, it is sufficient to generate ultrasonic vibrations only during injection, and as a result, it is sufficient to generate ultrasonic vibrations only during injection. Energy loss is completely (unnecessary).

Furthermore, since the ultrasonic oscillator 4.4.4.4 is not activated except during injection, even if there is resin 8 that remains in the nozzle l without being injected, that resin 8 will cause unnecessary thermal history. As a result, even if this resin 8 is subsequently injected and molded, the quality of the molded product will be no different from other molded products.

Then, by controlling the high frequency power supplied to the ultrasonic oscillator 4.4.4.4, the ultrasonic oscillator 4.4.4
．． By changing the phase, energy amount, etc. of the ultrasonic vibrations generated from 4, arbitrary values can be obtained for the temperature distribution and frictional resistance of the resin 8. As a result, the resin 8 can be adjusted to suit the molded product. This means that it can be ejected in this condition.

FIG. 3 shows another embodiment of the injection molding nozzle according to the present invention, and this injection molding nozzle 11 includes four ultrasonic oscillators 14, 14 evenly arranged in the circumferential direction.
．． 14 and 14 (of which only two are shown) are mounted obliquely upward, and the rest are the same as the injection molding nozzle 1 shown in FIGS. 1 and 2.

This injection molding nozzle 11 also operates in the same manner as the injection molding nozzle 1 shown in FIGS. 1 and 2, so a description of its operation will be omitted.

In the above embodiments, the number of ultrasonic oscillators 4.14 was four, but it is not limited to this, and any number can be used.
It goes without saying that the mounting position is not limited to the illustrated position, but can be mounted at any arbitrary position.

〔Effect of the invention〕

By configuring this invention as described above, the inner surface of the nozzle can be slightly vibrated by the ultrasonic vibrations generated from the ultrasonic oscillator, and this fine vibration can cause the inner surface of the nozzle and the inside of the nozzle to flow. The frictional force with the resin can be reduced, so the injection pressure of the resin can be reduced, and as a result, the injection unit including the nozzle can be downsized. In addition, since the ultrasonic oscillator is activated only during resin injection to raise the temperature of the resin, it is possible to reduce the energy used to heat the resin.Furthermore, since the resin is not subjected to unnecessary thermal history, the molding It has unique effects such as being able to improve the quality of products.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the injection molding nozzle according to the present invention, FIG. 2 is a bottom view of the one shown in FIG. 1, and FIG. 3 is a cross-sectional view showing another embodiment of the injection molding nozzle according to the present invention. FIG. 1.11 Injection molding nozzle 2
Inline screw 3... Screw barrel 4.14... Ultrasonic oscillator 5.15... Outer surface 6.16... Nozzle wall 7.17. ...Inner surface 8.18... Resin Fig. 1 Inside Fig. 2

Claims (1)

[Claims] (1) Ultrasonic oscillators (4) (14) are provided on the outer surface, and ultrasonic vibrations generated from the ultrasonic oscillators (4) (14) are transmitted to the nozzle wall (6) ( 16) through the inner surface (7) (
17) An injection molding nozzle characterized by transmitting the following information. (2) Use an injection molding nozzle (1) (11) equipped with an ultrasonic oscillator (4) (14) on the outer surface, and use the ultrasonic oscillator (4) (14) only when injecting the resin. An injection molding method characterized in that injection molding is performed while operating the nozzle (1) (11) to apply ultrasonic vibration to the resin flowing within the nozzle (11).