JPS60178004A - Extrusion molding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an extrusion molding apparatus using a piston type extrusion molding machine capable of degassing under reduced pressure.

Conventional configurations and their problemsCylinders, prismatic nine cylinders, sheets, and even honeycombs,
Extrusion molding is commonly used to mold products with a constant cross-sectional shape. There are two types of molding machines that perform this extrusion molding, one is the rotation of the fusible M There is an extrusion molding machine (hereinafter referred to as a screw set extrusion molding machine) that transfers the plastic raw material by a piston and passes it through a molding die having a desired shape to form the plastic material. This is an extrusion molding machine (hereinafter referred to as a piston type extrusion molding machine) that molds by passing through a molding die.

In addition, in a single-screw extrusion molding machine, the plastic raw material is transferred while being kneaded by the rotation of the screw, so the pressure inside the molding machine is reduced and the plastic raw material can be molded while being degassed, resulting in a molded product with few pores. can get. However, since the plastic raw material is transferred by the rotation of the screw, if an attempt is made to increase the pressure during molding, the raw material may flow over the screw, making it impossible to feed the raw material toward the molding die.

In other words, there is a limit to the amount of pressure that can be applied during molding with a single-screw extrusion molding machine.

On the other hand, in a piston type extrusion molding machine, the plastic raw material is extruded directly by the piston, so extrusion molding can be performed at high pressure. However, on the other hand, the plastic raw material is not kneaded during molding and is extruded as is. However, it has the disadvantage that it cannot be degassed. That is, since the plastic raw material is pressurized in the piston, there is no place for the air contained in the plastic raw material to escape, and the air compressed at high pressure is trapped in the molded body, causing large pores. Furthermore, in the piston type extrusion molding machine, the plastic raw material is not kneaded during molding as described above, and therefore, it is difficult to remove air from the plastic raw material even by degassing.

In addition, high pressure is required to mold the honeycomb molded bodies or cylinders and prisms with large cross-sectional areas, and in screw extrusion molding machines, the plastic raw material is supplied to the mold while rotating. A piston-type extruder is often used for reasons such as the fact that the rotation of the screw leaves curls in the body. However, as mentioned above, although piston type extrusion molding machines are capable of extrusion molding at high pressure, they do not allow vacuum degassing of plastic raw materials, which causes air bubbles in the molded product to degrade product properties. was there. In addition, with piston-type extrusion molding machines, it is necessary to input a certain amount of raw material, extrude it all, then remove the piston from the cylinder, put the raw material in, and extrude again, which is a tedious process, which reduces productivity. It was low.

Purpose of the Invention The present invention eliminates the drawbacks of the piston type extrusion molding machine described above, allows extrusion molding under reduced pressure and degassing, and eliminates the need to remove the piston from the cylinder when charging raw materials, thus providing a piston with high productivity. The present invention aims to provide an extrusion molding device using a type extrusion molding machine.

Structure of the Invention In order to achieve this object, the extrusion molding apparatus of the present invention is provided with an opening and a valve for supplying raw materials on the side surface of the cylinder of a piston type extrusion molding machine, and reduces pressure in the cylinder through this opening and the valve. A screw is provided to supply deaerated raw material for extrusion molding, and extrusion molding is performed using a piston under reduced pressure.

DESCRIPTION OF EMBODIMENTS FIGS. 1 and 2 show an embodiment of the present invention. As shown in the figure, an opening 2 and a valve 3 for supplying raw materials are provided on the side surface of a cylinder 1 constituting a piston-type extrusion molding machine, and a screw 4 is used to knead the raw material 5 for extrusion molding, and while degassing under reduced pressure, It is fed into the cylinder 1 through the opening 2 and the valve 3. FIG. 1 shows this state. Then, when the raw material supply is finished, the screw 4 is reversely rotated to remove the raw material near the opening 2, and then extrusion molding is performed using the piston 6.

FIG. 2 shows this state. In addition, in the figure, 7 is a molding die, 8 is a raw material input hopper, 9 is a vacuum degassing port, 1
o is a perforated plate for maintaining reduced pressure.

In the molded body formed using the apparatus according to the present invention, there are 0.
, no coarse bubbles larger than 0.06 ma were observed.

Effects of the Invention As detailed above, by using the present invention, it is possible to perform vacuum degassing of the extruded raw material, which was difficult with conventional piston type extrusion molding machines, to eliminate coarse air bubbles in the molded product, The density of the molded body can be improved. Furthermore, since there is no need to take out the piston from the cylinder when charging raw materials, the operation becomes easier. Since the piston is not pulled out of the cylinder at the same time, the reduced pressure inside the cylinder is always kept constant, which overcomes the disadvantages of conventional piston-type extrusion molding machines, such as the properties of the molded product changing between the beginning and end of extrusion molding. Therefore, the present invention has great industrial utility value.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a raw material supply state of an extrusion molding apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view similarly showing a state of extrusion molding. 1...Cylinder, 2...Opening, 3
...Valve, 4...Screw, 5...
... Raw material for extrusion molding, 6... Piston.

Claims (1)

[Claims] The original on the side of the cylinder of a piston type extrusion molding machine. An opening and a valve for supplying the raw material are provided, and a screw is provided for supplying the degassed raw material for extrusion molding into the cylinder through the opening and the valve, and extrusion molding is performed by a piston under reduced pressure. Extrusion molding equipment.