JP2002254151A - Heating cylinder cleaning device for metal injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device for a heating cylinder capable of easily and safely removing a resolidified matter stuck to the inner hole face of a heating cylinder. SOLUTION: The device comprises a movable support stand A for holding a heating cylinder 2, and a cleaning liquid circulating device B for circulating a cleaning liquid in the inner hole face 11 of the heating cylinder 2. The movable support stand A compresses a stand 21 and a pan 22 provided on the upper face of the stand 21, and the heating cylinder 2 is held in the pan 22. The bottom face of the pan is tilted, and into a recovering hole 34 provided on the lower most part thereof, a filter 35 is inserted, and an opening/closing valve 37 is fit on the lower part of the recovering hole 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cylinder cleaning apparatus for removing a residue adhered to a hole inside a heating cylinder of a metal injection molding apparatus for injection molding a metal material such as a magnesium alloy, an aluminum alloy, and a zinc alloy. It is.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a metal injection molding apparatus.

As shown in FIG. 1, a heating cylinder 2 is attached to a front part of an injection unit 1, and a rotary motor 4 is attached to a rear part. A heating heater 6 is attached to the outer periphery of the heating cylinder 2, and a material hopper 5 is attached to a rear part of the heating cylinder 2. A screw 3 having a spiral groove (hereinafter referred to as a screw groove) on an outer surface is formed in an inner surface hole 11 of the heating cylinder 2.
Are inserted rotatably and slidably in the axial direction.
The screw 3 is driven forward and backward by an injection cylinder (not shown) built in the injection unit 1, and is rotationally driven by a rotary motor 4.

[0004] At the rear of the heating cylinder 2 is provided a material inlet 9 for connecting the inner surface hole 11 and the lower part of the material hopper.

Next, the operation of the metal injection molding apparatus will be described.

[0006] In the measuring step, a metal material (hereinafter, referred to as a material chip) such as granules, cut pieces, and crushed pieces is put into a material hopper 5. The material chips fall from the material hopper 5 through the material inlet 9 into the inner surface hole 11 of the heating cylinder 2, and when the rotation of the rotary motor 4 is transmitted to the screw 3,
It is heated and stirred while being sent to the front of the heating cylinder 2 along the screw groove. The molten or semi-molten metal material (hereinafter, referred to as molten metal) is stored in the front chamber 10 of the heating cylinder 2, and the screw 3 retreats accordingly. However, since the metal material has a low viscosity of the molten metal and does not generate enough pressure to retreat the screw 3 in the molten metal stored in the front chamber 10, pressure oil is supplied to the retreating side of the injection cylinder simultaneously with the rotation of the rotary motor 4. In many cases, the screw 3 is supplied to forcibly retract the screw 3.

In the next injection step, the entire injection unit is advanced, and the nozzle 8 attached to the heating cylinder head 7 at the tip of the heating cylinder is brought into contact with a sprue bush of a mold (not shown). When the screw 3 is moved forward by supplying pressure oil to the side, the molten metal stored in the front chamber 10 of the heating cylinder 2 is injected into the mold through the nozzle 8 and is filled in the cavity in the mold. After the molten metal filled in the cavity in the mold is cooled and solidified, the mold is opened to take out the metal molded product formed in the shape of the cavity.

By repeating the above operation, a metal molded product having the same shape can be efficiently produced.

[0009]

In the above-described metal injection device, a small amount of molten metal is mixed in the gap between the solid material chips in the screw groove at the center of the screw.
The screw is carried to the rear, that is, the material hopper side by the retreating operation of the screw. The molten metal whose inner surface temperature of the heating cylinder has reached a region lower than the melting temperature of the material chips is deprived of heat by the heating cylinder and surrounding material chips, and a part of the molten metal adheres to the screw surface and the inner surface of the heating cylinder. It solidifies (hereinafter, this attached matter is referred to as re-solidified matter).

[0010] The re-solidified material adhering to the screw surface is sent to the advanced position where the heating cylinder is heated to a higher temperature by the screw advancing operation in the next injection stroke, and heated.
And return to the molten metal.

Further, most of the re-solidified material adhering to the inner surface of the heating cylinder is peeled off from the screw thread of the screw by the forward movement of the screw in the next injection stroke, sent to the advanced position, heated and returned to the molten metal again. However, the rest is left in a state of being attached to the inner surface of the heating cylinder.

[0012] Most of the remaining re-solidified material is scraped off by the material chips moving forward in the next measuring step, but a part of the re-solidified material remains attached.
This re-solidified substance may accumulate and increase with the repetition of the molding cycle.

The molten metal has a very high chemical activity and easily reacts with oxygen and nitrogen in the air to produce oxygen compounds and nitrogen compounds (hereinafter, referred to as compounds, etc.). In addition, various compounds and the like are mixed in the molten metal because other metal elements are mixed in the magnesium alloy and the aluminum alloy according to the use.

Therefore, the re-solidified material is in a state in which the above-mentioned compound and the like are mixed in the original metal material and adheres and solidifies on the surface of the screw or the inner surface of the heating cylinder. Its removal creates great difficulties.

When the re-solidified material adheres to the surface of the screw, the cross-sectional area of the screw groove is reduced to hinder the flow of the material chips and the molten metal. When the re-solidified material adheres to the inner surface of the heating cylinder, the screw rotates smoothly and slides straight. Hinder movement. As a result, the metering operation and the injection operation become unstable or stop, and a stable molding operation cannot be performed.

For this reason, when the operation of the screw becomes unstable, or when the operating period is expected to become unstable, the supply of the material chips is stopped, and the weighing and injection operations are repeated. After discharging the molten metal in the heating cylinder, an operation of extracting the screw from the heating cylinder and removing the re-solidified matter adhered to the screw and the heating cylinder is performed.

The re-solidified material adhering to the inner surface of the heating cylinder is mechanically removed by a wire brush, a grinder, a grindstone or the like, but the removal requires a large force. Also, if the surface of the re-solidified material is polished or ground during the mechanical removal process and has a metallic luster, it is difficult to distinguish it from the inner surface of the heating cylinder, so cleaning is performed without noticing that the re-solidified material remains as a thin layer. Is easily terminated. For this reason, in the reassembly operation, when the screw is to be inserted, the screw may be prevented from being re-solidified as a thin layer remaining on the inner surface of the heating cylinder, or may not be able to be inserted and removed.

As a method of solving the above-mentioned difficulty in mechanical removal, a method of chemically decomposing a re-solidified product with hydrochloric acid or the like and removing it has been attempted. This is a method of immersing a part to which the re-solidified substance is fixed in a container filled with a cleaning solution composed of an acid aqueous solution and removing the re-solidified substance attached to the outer surface such as a screw.

However, when the cleaning liquid stays, the concentration of the portion in contact with the re-solidified material decreases, and the chemical reaction decreases.
For this reason, the chemical reaction of a component having a re-solidified substance adhered to the inner surface thereof, such as a heating cylinder, becomes dull immediately even when immersed in the cleaning liquid. In addition, the outer surface on which the re-solidified material did not adhere sometimes corroded due to long-term immersion. Further, since the large opening of the container filled with the cleaning liquid is left in the atmosphere for a long time, there is a possibility of causing a problem in safety.

The present invention has been made to solve the above-mentioned problems in the conventional cleaning operation of the inner surface of the heating cylinder, and can easily and safely remove the re-solidified material fixed to the inner surface hole of the heating cylinder. An object of the present invention is to provide a heating cylinder cleaning device.

[0021]

According to the present invention, a heating cylinder detached from an injection unit is placed in a tray provided on an upper surface of a movable stand, and an inner surface hole of the heating cylinder is filled with a cleaning liquid. The cleaning liquid is circulated by a circulating pump and a connection pipe provided in the above.

Liquid-tight lids are attached to the front end and the rear end of the heating cylinder, and a pipe connected to the discharge port of the circulation pump is connected to a material input port or the like opened at the rear upper surface of the heating cylinder. The pipe connected to the suction port is connected to an outlet provided at the front end of the heating cylinder, and the inner surface of the heating cylinder is filled with the cleaning liquid and circulated with the material inlet open to the atmosphere.

The acid in the cleaning liquid filled in the inner hole of the heating cylinder chemically reacts with the metal component in the re-solidified substance attached to the inner hole of the heating cylinder, whereby the re-solidified substance is decomposed into the cleaning liquid. By being mixed, the re-solidified material is removed from the inner surface hole of the heating cylinder.

A gas such as hydrogen generated by the chemical reaction is released into the atmosphere from a material inlet opening at the rear upper surface of the heating cylinder.

Further, by circulating the cleaning liquid, a vigorous chemical reaction is maintained, and re-solidified substances are removed within a short time.

After the removal of the re-solidified material is completed, the washing liquid leaking when the lids attached to the front end and the rear end of the heating cylinder or the pipe connected to the circulation pump are removed is collected in the receiving tray on the upper surface of the stand. After being collected and filtered to remove dirt and mixed solids, it is transferred to a storage container.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises a movable support for holding a heating cylinder, and a cleaning liquid circulating device for circulating a cleaning liquid to an inner surface hole of the heating cylinder, wherein the movable support comprises a stand, and the stand. And a tray provided on the upper surface of the heating device, wherein the heating tube is held in the tray.

It is preferable that the bottom surface of the receiving tray is inclined, a filter is inserted into a collecting hole provided in the lowest surface portion, and an opening / closing valve is attached below the collecting hole.

It is preferable that a lower tray is provided below the stand, a recovery container for recovering the cleaning liquid is placed on the lower tray, and a recovery hose connected to the opening / closing valve can be inserted.

The washing liquid circulating apparatus comprises a circulating pump attached to a stand, lids respectively attached to a front end port and a rear end port of an inner surface hole of the heating cylinder, and a connection pipe. It is preferable that the discharge port of the circulation pump is connected to one end of the inner surface hole of the heating cylinder, the suction port is connected to one lid, and a part of the flow path of the cleaning liquid is opened to the atmosphere.

[0031]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional front view of a main part of a cleaning apparatus for a heating cylinder according to the present invention, and FIG. 2 is a top view of FIG.

As shown in FIG. 1 and FIG. 2, the heating cylinder cleaning apparatus of the present embodiment comprises a heating cylinder 2 for forming a magnesium alloy.
And a cleaning liquid circulating device B that circulates the cleaning liquid through the inner hole 11 of the heating cylinder 2.

The movable support table A comprises a stand 21 and a tray 22 provided on the upper surface of the stand 21. A plurality of supports 23 and 24 are mounted in the tray 22.
The heating cylinder 2 is held thereon. A plurality of handles 41 are attached to the upper side surface of the stand 21, and a plurality of casters 40 with stoppers are attached to the lower end.

The bottom surface of the tray 22 is slightly inclined in the longitudinal direction, and a recovery hole 34 into which a filter 35 is inserted is provided at the lowermost portion. An open / close valve 37 in a closed state is attached to a lower portion of the recovery hole 34, and a recovery hose 36 is connected to the open / close valve 37. The other end of the recovery hose 36 is provided at a lower portion of the stand 21. Collection container 3 placed on the lower tray 39
8 is inserted.

The cleaning liquid circulating apparatus B has lids 13 and 14 attached to the front end and rear end of the inner hole 11 of the heating cylinder 2 with bolts 17 and 18 via seals 15 and 16 respectively.
A discharge pipe 31 fixed to the lid 13 at the front end and inserted into the inner surface hole 11;
A plate 19 which is attached to the mounting flange 12 with bolts 20 and has a hole at the position of the material inlet 9;
An injection pipe 30 fixed to the plate 19 and inserted into the material input port 9, and a stand 2 above the lower tray 39.
1 and a discharge hose 27 connected to a discharge port of the circulation pump 25.
And a suction hose 26 connected to a suction port of the circulation pump 25.

The discharge hose 27 is connected to the injection pipe 30 via a one-touch joint 32 through a pipe 29 which penetrates the receiving tray 22 in a liquid-tight manner. The suction hose 26 is connected to the discharge pipe 31 via a one-touch joint 33 through a pipe 28 that penetrates the receiving tray 22 in a liquid-tight manner.

Next, the cleaning operation of the heating cylinder will be described.

The suction hose 26 is detached from the discharge pipe 31 by the one-touch joint 33, and inserted into the collection container 38 having the cleaning liquid. The circulation pump 25 is driven to suck the cleaning liquid stored in the collection container 38, and the discharge hose 2
7. The material is supplied to the material inlet 9 through the injection pipe 30 and is filled in the inner surface hole 11 of the heating cylinder 2. Next, the circulation pump 25 is stopped, and the suction hose 26 is attached to the discharge pipe 31 by the one-touch joint 33. The circulation pump 25 is driven again to circulate the cleaning liquid. The cleaning solution has a concentration of 5-1.
A 0% aqueous hydrochloric acid solution is used. When the required amount of the cleaning liquid is small, the cleaning liquid may be directly injected from the material inlet 9.

The injected cleaning liquid chemically reacts with magnesium mixed in the resolidified substance adhered to the inner surface hole 11 to gradually decompose the resolidified substance and remove it from the inner surface of the heating cylinder 2.
When magnesium and hydrochloric acid undergo a chemical reaction, magnesium chloride and hydrogen are generated, and the magnesium chloride is mixed and held in the cleaning solution. Since hydrogen is released into the atmosphere from the material input port 9, it is necessary to carry out the cleaning operation in a place with sufficient ventilation and to keep fire away during the operation.

The generation state of hydrogen bubbles released from the material inlet 9 is monitored, and the cleaning is terminated when the generation of the bubbles stops.

As another embodiment, if the injection pipe 30 is attached to the lid 14 at the rear end, the generation state of the air bubbles emitted from the material inlet 9 can be more easily monitored.

When a large amount of air bubbles is generated during the injection of the cleaning liquid from the material inlet 9, the injection amount of the cleaning liquid is suppressed to half of the inner hole 11. When the amount of generated bubbles decreases, a cleaning solution is added to fill the entire inner surface hole. Thereby, it is possible to prevent the cleaning liquid from overflowing from the material inlet 9.

Conversely, if the generation of air bubbles is weak even after about 5 minutes from the start, the concentration of hydrochloric acid has decreased, so it is preferable to add hydrochloric acid or dilute hydrochloric acid to increase the concentration.

When the heights of the supports 23 and 24 are adjusted and the rear side of the heating cylinder 2 is raised to incline the inner surface hole 11 from the horizontal, generated bubbles are easily released from the material inlet 9. be able to.

The time required for cleaning depends on the size of the heating cylinder 2 and the amount of adhered resolidified material, and is 3 to 24 hours, but is usually 5 to 8 hours. The concentration of hydrochloric acid is selected according to the material of the heating cylinder 2 so as not to corrode the heating cylinder main body, but usually 5 to 10% is appropriate.

After the washing operation, the circulation pump 25 is stopped, and the discharge hose 27 is connected to the injection pipe 3 by the one-touch joint 32.
0 and inserted into the collection hole 34, and the open / close valve 37
open. Next, the circulation pump 25 is driven again to
After removing large contaminants in step 5, the mixture is collected in a collection container 38 through a collection hose 36.

After the removal of the re-solidified material is completed, the heating cylinder 2
The cleaning liquid leaking when the lids 13 and 14 attached to the front end and the rear end of the stand are removed, and when the pipe connected to the circulation pump 25 is detached, the receiving liquid 22 on the upper surface of the stand.
After the filter 35 removes dust and mixed solids, it is transferred to a storage container 38.

The filter 35 has an aperture of 0.2 to 1
It is preferable to use a stainless steel wire mesh of about mm. If a polyethylene tank is used as the collection container 38, it is convenient for transportation and storage.

If the amount of contaminants in the cleaning liquid increases due to repeated cleaning, the recovered liquid is neutralized with an alkali, and the water is removed and discarded. Dispose of as industrial waste.

As the cleaning solution, an aqueous solution of another acid such as sulfuric acid or a mixed solution thereof, or an aqueous solution further containing a surfactant or a reducing agent, may be used depending on the components of the object to be cleaned or the re-solidified material. May be used.

In the above embodiment, the inner surface of the heating cylinder is to be cleaned. However, the inner surface of the cylinder head shown in FIG. 3 and the inner surface of an injection sleeve or a melting cylinder of a metal forming apparatus using an injection plunger are cleaned. Can also be applied.

[0053]

As described above, according to the present invention, the re-solidified material adhering to the inner surface hole of the heating cylinder is chemically removed, so that a large mechanical force is not required, and dust and noise are generated accordingly. do not do. Also, since the surface of the cleaning liquid used for the cleaning operation is slightly exposed to the atmosphere, the operation is safe, and the cleaning liquid does not leak to the floor surface even at the end of the operation, so that the cleaning liquid can be stored in the storage container. It can be easily transported, so it is environmentally safe. Further, since the cleaning device itself can be easily moved, workability is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view of a main part of a heating cylinder cleaning device according to an embodiment of the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a diagram illustrating an example of a metal injection molding apparatus.

[Explanation of symbols]

 2 Heating cylinder 9 Material inlet 11 Inner hole 13, 14 Lid 21 Stand 22 Receiving tray 25 Circulation pump 26 Suction hose 27 Discharge hose 30 Injection pipe 31 Discharge pipe 32, 33 One-touch joint 34 Recovery hole 35 Filter 36 Recovery hose 37 Open / close valve 38 Collection container 39 Receiving tray 40 Caster A Movable support base B Cleaning liquid circulation device

Claims (4)

[Claims] 1. A movable support (A) for holding a heating cylinder (2), and a cleaning liquid circulating device (B) for circulating a cleaning liquid through an inner hole (11) of the heating cylinder (2), The movable support (A) comprises a stand (21) and a tray (22) provided on the upper surface of the stand (21), and the heating tube (2) is held in the tray (22). A heating cylinder cleaning apparatus for a metal injection molding apparatus. 2. A bottom surface of the tray (22) is inclined,
A filter (3) is inserted into the collection hole (34) provided on the lowest surface.
5) and insert the open / close valve (3) at the bottom of the collection hole (34).
7. The apparatus for cleaning a heated cylinder of a metal injection molding apparatus according to claim 1, further comprising: 3. A lower receiving tray (39) is provided below the stand (21), and a collecting container (38) for collecting a cleaning liquid is placed thereon, and a collecting hose (36) connected to the open / close valve (37). 3. The apparatus for cleaning a heated cylinder of a metal injection molding apparatus according to claim 2, wherein the apparatus can be inserted. 4. The cleaning liquid circulation device (B) comprises: a circulation pump (25) attached to a stand (21);
The heating pipe (2) comprises lids (13, 14) attached to the front end port and the rear end port of the inner surface hole, respectively, and a connection pipe. The connection pipe connects a discharge port of the circulation pump (25) to the heating pipe. The first, second, and third ports are connected to one end of the inner surface hole (11) of (2), the suction port is connected to one lid (13), and a part of the flow path of the cleaning liquid is opened to the atmosphere. Or a heating cylinder cleaning device for a metal injection molding device according to item 3.