JP2001062553A - Screw and cylinder cleaning method in metal injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw and cylinder cleaning method which can easily eliminate a sticking element such as un-dissolution element stuck to a screw groove and inside a cylinder of a metal injection molding machine. SOLUTION: When a molding material or its high melting point component (a sticking element) 3 is stuck to a screw groove bottom at a low temperature part of an injection molding machine cylinder 1 and a cylinder inner face, a metal-to-metal compound purging material 4, melting point of which is lower than that of the molding material, is inputted into the cylinder 1. By doing so, the purging material 4 is melted at a low temperature part so that the molding material is dissolutionary diffused to the melted purging material 4 or is mechanically scrap off with the purging material 4, rigidity of which is higher than that of the molding material, resulting in elimination of the sticking element 3 being stuck to the screw groove bottom and a cylinder inner wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a screw and a cylinder in a metal injection molding machine, and more particularly to a method for removing undissolved matter such as undissolved matter in a screw groove and a cylinder. .

[0002]

2. Description of the Related Art Conventionally, as a method for cleaning a screw groove or a cylinder in a metal injection molding machine, generally, after purging a molding material in a cylinder at a molding temperature, a cylinder head and a screw are removed, and the screw groove and the inside of the cylinder are removed. The removal of the molding material adhered to the surface is mechanically removed by a grinding tool such as a grinder, or the removal is performed by using a chemical such as an acid that dissolves the molding material.

When only a high melting point alloy component (hereinafter, referred to as a high melting point component) of a molding material adheres to a screw groove or a cylinder, a cylinder temperature is set in accordance with the melting point of the high melting point component. That is, a method is employed in which purging is performed at a cylinder temperature higher than the molding temperature to dissolve and remove the high melting point component, and in some cases, the screw is pulled out from the cylinder and cleaned.

[0004]

As described above, when a high melting point component adheres to a screw groove or a cylinder, the cylinder must be heated to purge the molding material in order to remove it. During the heating, purging, and cooling operations,
There is a problem that molding cannot be performed and production is interrupted.

If the high melting point component adheres to the bottom of the screw groove, the high melting point component is not in close contact with the cylinder, so that it is difficult to be heated. One of the operations of putting the molding material in and peeling it off little by little is required, which consumes a lot of time and energy. Further, there is a problem that heating the cylinder above the molding temperature leads to deterioration of the cylinder material.

Further, when the screw is removed and immersed in a thin acid solution to remove the magnesium alloy, if the immersion is performed for a long time, the screw is corroded simultaneously with the magnesium alloy.

If a high melting point component adheres to the inner surface of the cylinder, it is necessary to perform machining such as removal of the cylinder and polishing of the inner surface, or removal by immersion in an acid solution. There is a problem of being interrupted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to easily remove deposits such as undissolved deposits in screw grooves and cylinders in a metal injection molding machine. An object of the present invention is to provide a screw and cylinder cleaning method that can be performed.

[0009]

The present invention solves the above-mentioned problems as follows. That is, a purge material made of an intermetallic compound or an alloy close to an intermetallic compound made of a main component of a molding material and other elements is put into a cylinder of a metal injection molding machine, and adheres to a screw groove or a cylinder. Remove any undissolved material. The purge material preferably has a lower melting point than the molding material.

[0010]

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

FIG. 1 shows a state in which a deposit 3 made of a molding material or its high melting point component adheres to the bottom of a screw groove or the inner surface of a cylinder in a low-temperature portion of a cylinder 1 of a metal injection molding machine. In the present invention, in order to remove the deposit 3, as shown in FIG. 2, a barge material 4 of an intermetallic compound having a lower melting point than the molding material is charged into the cylinder 1. Since the injected purge material 4 has a higher hardness than the molding material,
The molding compound is mechanically scraped off. In addition, purge material 4
Dissolves in the low temperature part, so that the molding material dissolves and diffuses in the purge material 4 which has dissolved. Thereby, the deposit 3 attached to the inner surface of the cylinder or the bottom of the screw groove is removed.

If the purging material 4 is introduced before the screw 2 is removed, the molding material does not solidify and the screw 2 does not move, and the intermetallic compound purging material 4 attached to the screw 2 is removed. Since it is more brittle than the molding material, it can be easily removed mechanically. In addition, the purging material is in a non-equilibrium state, and the main component of the molding material and its intermetallic compound are mixed in two.
It is preferable to contain 0% or more.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention, the liquidus temperature is about 5 ° C.
A case where the AZ91D magnesium alloy at 95 ° C. is injection-molded will be described.

As shown in FIG. 1, AZ91D or its high melting point component having a melting temperature of about 660 ° C. is formed on the bottom of the screw groove or the inner surface of the cylinder in the low temperature portion of the cylinder 1.
If the deposit 3 such as (α phase) adheres, the feed ability of the raw material supplied from the hopper is reduced, and the measurement becomes unstable.

Therefore, as the purge material 4, the liquidus temperature containing about 20% of AI, which is the β phase of AZ91D, is about 550 ° C.
Is charged into the cylinder 1 via a hopper. Preferably, the purge material 4 contains 10% or more of AI.

The set temperature of the cylinder heater closest to the hopper of the cylinder 1 is set at 560 ° C., and the melting point of the purge material 4 charged into the cylinder 1 is about 550 ° C. Therefore, as shown in FIG. 4 starts dissolving immediately after being charged into the cylinder 1, and removes the attached matter 3 by solid solution. If the purge material 4 is sent to the front of the cylinder 1 before the deposit 3 dissolves, the screw 2 is rotated after the purge material 4 is put from the hopper, and the purge material 4 is continuously fed. To remove the deposit 3.

Since the purge material 4 has a high aluminum content, in other words, there is little magnesium component having high flammability, so that there is an advantage that the purged material is hard to burn. After purging using the purge material 4, the screw 2 was pulled out, and a small amount of the purge material 4 adhered to the screw flight. Thus, the screw 2 could be incorporated into the cylinder 1 again without pickling.

[0018]

As described above, the present invention has the following advantages. (A) Deposits such as high melting point components adhering to screws etc.
It can be removed without increasing the temperature of the cylinder. (B) Undissolved matter attached to the screw near the hopper side where the cylinder temperature does not rise to the melting point of the molding material can also be removed. (C) The time for screw removal and the work of consuming a large amount of energy have been eliminated. Also, when removing the screw, the attached purge material can be easily peeled off,
The need for pickling has almost disappeared.

[Brief description of the drawings]

FIG. 1 is a view showing a state in which a deposit is attached to a screw groove bottom.

FIG. 2 is a conceptual diagram showing a state in which an adhered substance is dissolved in a purge material.

[Explanation of symbols]

 1 Cylinder 2 Screw 3 Deposit 4 Purge material

Claims (4)

[Claims] In a cylinder (1) of a metal injection molding machine,
A purge material (4) composed of an intermetallic compound or an alloy close to the intermetallic compound made of the main component of the molding material and other elements is charged, and the undissolved material (3 A method for cleaning a screw and a cylinder in a metal injection molding machine, wherein 2. The method for cleaning a screw and a cylinder in a metal injection molding machine according to claim 1, wherein the melting point of the purge material is lower than the melting point of the molding material. 3. The purging material (4) is in a non-equilibrium state,
3. The method for cleaning a screw and a cylinder in a metal injection molding machine according to claim 1, wherein the method comprises at least 20% of a main component of the molding material and an intermetallic compound thereof. 4. The screw and cylinder in a metal injection molding machine according to claim 1, wherein when the molding material is a magnesium alloy, a magnesium alloy containing 10% or more of AI is used as the purge material (4). Cleaning method.