JPS60242013A - High-kneading screw - Google Patents

Abstract

PURPOSE:To provide the title screw in which breakup of solids is accelerated and plasticizing capability is enhanced, by providing discontinuous cutouts in the flight of a specified screw thread in a barrier-type screw having a pressure-reducing groove between a plurality of screw threads and a specified thread. CONSTITUTION:The second screw thread 12 and the third screw thread 13 branched from a screw thread 11 in the vicinity of a melting section (b) and united at a metering section (c) are provided in the screw 10 having a feed section (a), the melting section (c) and the metering section (c), whereby a solid section groove 14 and a molten section groove 15 are partitioned from each other, and a shallow pressure-reducing groove 16 is provided between the screw threads 12, 13. The flight of the second screw thread is provided with discontinuous cutouts (d) to obtain the objective screw in which the spacing between a cylinder barrel 17 and the thread 12 is larger (h1) at the parts (d) and smaller (h1a) at parts (e).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high kneading screw that can be applied to injection molding machines and extrusion molding machines.

(Prior art) The conventional barrier screw 1 shown in FIGS. 1 to 3 starts from a thread 2 (main flight) near the fusion part, and then a second thread 3 (main flight) that joins the thread 2 in the metering part. This is a two-groove type screw in which the dam fly) is branched and the screw groove defined by the threads is divided into a solid section groove 4 and a melt section groove 5.

Now, in FIGS. 1 and 2, the solid f is blocked by the screw thread 3, and only the molten resin g passes over the second thread 3 and is transferred to the melt section groove 5, but in this case, the cylinder barrel 6 and If the dam clearance h with the second screw thread 3 is small, the processing capacity will be reduced, and if it is large, unmelted resin will flow in, resulting in a reduction in quality.

(Problems to be Solved by the Invention) Conventional injection molding machines have had many complaints due to the screws, and therefore there has been a demand for the development of higher performance screws.

(Means for Solving the Problems) The present invention was proposed in response to the above-mentioned demand, and consists of branching the second and third threads of the thread near the melting part, and , in a screw having a barrier type three-groove groove in which a third thread is combined and a pressure reducing groove is provided between the second and third threads, flights of the second thread are intermittently made; It has a notched configuration.

(Function) Now, the second screw thread, that is, the flight of the solid section in full bloom, is alternately connected with the wide gap part and the narrow gap part, and the third screw thread, that is, the molten section. The gap on the groove side is narrower. Therefore, pressure turbulence occurs in the solid section groove in a direction parallel to the flights, promoting breakup of the solid.

(Example) An example of the present invention will be described below with reference to the drawings. Fig. 4 is a side view of a screw showing an example of the present invention. In the figure, the screw 10 is divided into a supply part a, a melting part b, and a metering part C. A second screw thread 12 and a third screw thread branch from a screw thread 11 near the melting part and join in the metering part C. It has a thread 13 of.

The solid section groove 14 and the melt section groove 15 are divided by the thread 12.13, and a shallow vacuum groove 16 is formed in the middle of the thread 12.13. Also cylinder barrel 17
The relationship between the gaps hl and hla between the cylinder barrel 17 and the thread 12, and the gap h2 between the cylinder barrel 17 and the thread 13 is hl>hla.
> h2 (Fig. 7).

Figure 8 shows a developed view of the molten part, and the screw thread I2 has flights in which large gaps h1 and small gaps hla are connected alternately, and the flights in part (A) in the figure are large. There is a gap hi, and the flight portion (b) has a small gap hla.

Next, an example configured as described above will be explained.
The raw material supplied from a hopper (not shown) to the supply section a receives thermal energy from a heater (not shown) and shear energy due to the rotation of the screwer 0, and is gradually melted and transferred forward.

In addition, in the molten part, as shown in Fig. 5, the solid r is
As the screw 10 rotates, a molten film g is formed between the cylinder barrel 17 and the solid f due to its strong shearing action, and the shear force of the molten film g causes the surface of the solid f to Melting is rapidly accelerated. The molten body j is screw thread J2 and thread thread 1.
3 and is transferred to the melt section groove 15. When passing through the gaps h1 and hla and the gap h2, it is subjected to a strong shearing action and is uniformly melted.

Also, the small solid j that passed through the gaps h1 and hla is
It is captured by the third screw thread 13 and is subjected to even stronger shearing force as shown in FIG. 7, thereby completely melting it. The molten material is extruded from a gouer (not shown) by the pumping action of the screw 10.

Furthermore, since the second thread 12 is a stepped flight with a gap hl>hla, pressure disturbance occurs in the direction parallel to the flight in the solid section groove 14, promoting breakup of the solid.

FIG. 10 is a sectional view taken along the line DD in FIG. 8 of an embodiment different from FIG. 9, in which the notches of the flights of the screw thread 12 are connected in an elongated manner.

(Effect of the invention) FIG. 6 shows the cylinder internal pressure corresponding to FIG. 5, where the solid line is the pressure waveform of the portion passing through the gap hla of the second thread 12, and the dotted line is the pressure waveform passing through the gap h1. This is the partial pressure waveform. The pressure shown in this figure is acting on the resin in the process of melting, and the solid f is captured by the second thread and is prevented from flowing into the melt section groove. The partially unmelted solid j that flowed out together with the molten film g is subjected to high shear when passing over the second screw thread, and is depressurized in the vacuum groove, resulting in a break-up, resulting in a disjointed state m as shown in Figure 7. become.

The solid m thus separated is captured by the third screw out, and when passing through the gap h2, it is subjected to an even stronger shearing force and is completely and homogeneously melted. At this time, since the solid m receives shearing energy and heat transfer energy when passing through the gaps hl and hla, the resin temperature is rising and it is in a state where it is extremely easy to melt. Therefore, unlike the conventional method shown in FIG. 1, the plasticizing ability can be increased without exhibiting quality deterioration, which is a disadvantage of barrier screws.

[Brief explanation of drawings]

Fig. 1 is a side view showing a part of a conventional barrier screw, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a side view of the entire screw, and Fig. 4 is an embodiment of the present invention. FIG. 5 is an enlarged sectional view taken from B to B in FIG. 4, FIG. 6 is a diagram showing the relationship between the position and cylinder pressure corresponding to FIG. 5, and FIG. Detailed view of C part in Figure 5, Figure 8 is a developed view of the flight of the kneading section (melting zone b), Figure 9 is a detailed view of the flight in Figure 8.
The sectional view, FIG. 10, is a sectional view taken along the line DD in FIG. 8, and is a sectional view showing an embodiment different from that in FIG. 9. Description of the main parts of the figures 10 - Screw 11 - Thread 12 - = second thread 13 - Third thread 14 Solid section groove 15 - Melt section groove 16 - Vacuum groove 17 Cylinder barrel h1. hla, h2-gap a-supply section - melting section C
- Needle section patent applicant: Mitsubishi Heavy Industries, Ltd. Location: Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] Branching the second and third threads from the thread near the melted part, and combining the second and third threads at the needle length part,
1. A high kneading screw having a barrier type three thread thread having a vacuum groove between the second and third threads, characterized in that the flights of the second thread are intermittently cut out.