JPS6164422A - Vacuum extrusion forming machine - Google Patents

Abstract

PURPOSE:To effect the deaeration of material sufficiently, eliminate generation of bubbles in a formed piece and improve the strength of the formed piece by a method wherein evacuation is effected through an air discharging port provided a cap or immediately before the cap. CONSTITUTION:An air discharging port 18 is provided immediately before a cap 5 at the terminal section of a barrel 4 and evacuation of the inside of barrel is effected through the discharge port 18. The air discharging port may be provided on the cap itself. In order not to enter a material into the aid discharge port 18, a spring plate 19, having an area larger than the area of the air discharging port, is provided at the entrance of the air discharging pot 18 and when the material does not arrive at the position of the spring plate, the spring plate is separated from the air discharging port and evacuation may be effected through the air discharging port. When the material has passed the position of the spring plate 19, the spring plate is pushed by he material and the air discharging port may be blockaded by the spring plate.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a vacuum extrusion molding machine used in the process of manufacturing products such as bricks, roof tiles, and pipes using ceramics, plastics, etc. [Background Art] Conventional vacuum Extrusion molding machines generally had a structure as shown in FIG. That is, as shown in FIG. 1, this vacuum extrusion molding machine has a hopper 2 above the pug mill 1, a vacuum chamber 3 on the side of the end of the pug mill 1,
A barrel 4 is disposed below each, and a base 5 is provided at the end of the barrel 4. A shaft 7 having a propeller 6 formed around it passes through the pug mill 1, and one end of the shaft is connected to a drive device 8, so that the material 9 is kneaded by the rotation of the propeller 6. The vacuum chamber 3 is provided with two exhaust ports 10 at the upper part, and these exhaust ports are connected to a vacuum pump (not shown in the figure) to evacuate the air in the vacuum chamber 3 and the barrel 4. There is. The barrel 4 is provided with an auger screw 11, and one end of the shaft 12 is connected to a drive device 13 to rotate the auger screw 11.

The material 9 supplied to the hopper 2 is kneaded by the propeller 6 of the pug mill 1, and the material 9 is mixed between the pug mill 1 and the vacuum chamber 3.
and is pushed out into the vacuum chamber 3 through a large number of small holes 15 formed in the partition plate.

Then, it is degassed in the vacuum chamber 3, enters the barrel 4, and is sent toward the mouthpiece 5 by the auger screw 11. A tapered compression column ring 1 is provided between the auger screw and the mouthpiece.
6, and is discharged from the nozzle-shaped extrusion port 17 of the mouthpiece 5.

However, this vacuum extrusion molding machine had the following problems. In other words, when the crosstalk material fills up to part A of the barrel, it becomes impossible to evacuate the air in the barrel from that position to the mouthpiece 5, so the air inside the barrel is drawn into the material by the auger screw, which may cause defects in the initial stage. The problem is that the material is discharged from the extrusion port 17. This state continues until the material that has been sufficiently deaerated begins to be discharged (most of the material in which air is drawn in by the auger screw in this way is initially discharged from the extrusion port 17, Some of the material remains in the barrel, mixes with the material that has been sufficiently degassed, and is sometimes discharged.If the defective material discharged from the extrusion port is used as described above, air bubbles will occur in the molded product. However, this caused a decrease in the strength of the molded product.

[Purpose of the invention]

In view of the above points, an object of the present invention is to provide a vacuum extrusion molding machine that can prevent the generation of air bubbles in a molded product and improve the strength of the molded product.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides a vacuum extrusion molding machine that is equipped with a hopper above a pag mill for kneading materials, a vacuum chamber for degassing the materials on the side of the end, and a barrel below this vacuum chamber. The gist is a vacuum extrusion molding machine characterized in that an exhaust port for evacuating the inside of the barrel is provided at the end of the barrel.

That is, as shown in the embodiment shown in FIG. 2, an exhaust port 18 is provided at the end of the barrel 4 (just before the mouthpiece 5 in this embodiment), and the vacuum inside the barrel is removed from this point. The only difference from the conventional example is that
Therefore, in FIG. 2, the same numbers as in FIG. 1 are given to the parts corresponding to the same parts as in the conventional example. In addition,
The exhaust port may be provided in the cap itself.

In order to prevent air from leaking from the extrusion port 17 during vacuuming, the extrusion port is covered with duct tape, which is peeled off when the material comes just before the extrusion port.

In order to prevent material from entering the exhaust port 18, for example, it is recommended to do the following. That is, the exhaust port 18
As shown in FIG. 3, a spring plate 19 having an area larger than the area of the exhaust port is provided at the inlet of the exhaust port, and when the material does not reach this position, this spring plate is separated from the exhaust port and Vacuum can be drawn from the mouth, but as the material passes through the spring plate 19, the spring plate is pushed by the material, gradually reducing the gap with the exhaust port, and finally blocking the exhaust port. That's how you do it. Next, as shown in FIG. 4, a limit switch 2 is attached to the compression column ring 16.
0 is set so that when the material pushes the spring plate 19, the tip of the spring plate activates this limit switch, and the limit switch 20 can confirm that the material has reached this position. It becomes like this. Thereby, by checking the limit switch 20, a vacuum pump (not shown in the figure) that draws a vacuum from the exhaust port 18 can be stopped, and the above-mentioned adhesive tape or the like blocking the extrusion port can be peeled off. Furthermore, in order to automate the work of pasting adhesive tape, etc.
As shown in FIG. 4, a lid 21 that opens and closes the extrusion port 17 is attached to the tip of the mouthpiece 5, and when the plunger of the limit switch 20 is pressed, a device that drives the lid 21 is activated, and the lid 21 is opened. It is okay to do so.

By installing an exhaust port in the nozzle or just before the nozzle in this way, air can be removed from the barrel even after the material fills up to part A. This prevents air from being drawn into the material by the auger screw, ensuring that there is sufficient material. This makes it possible to obtain degassed molded products.

〔Effect of the invention〕

The vacuum extrusion molding machine according to the present invention also draws vacuum from the mouthpiece or the exhaust port provided just before the mouthpiece, so that the material can be sufficiently degassed and no air bubbles will be generated in the molded product. , the strength of molded products can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional example, and FIG. 2 is a sectional view of an embodiment of a vacuum extrusion molding machine according to the present invention.
FIG. 3 is a detailed sectional view of the exhaust port portion of the same as above, and FIG. 4 is a detailed sectional view of the base portion of another embodiment.

Claims (2)

[Claims] (1) In a vacuum extrusion molding machine equipped with a hopper above the pag mill for kneading materials, a vacuum chamber for degassing the materials on the side of the end, and a barrel below this vacuum chamber, A vacuum extrusion molding machine characterized by being provided with an exhaust port for vacuuming. (2) The vacuum extrusion molding machine according to claim 1, wherein the exhaust port is provided in the mouthpiece.