JP3730131B2 - Heating cylinder cleaning device for metal injection molding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating cylinder cleaning apparatus that removes residues fixed to a heating cylinder inner surface hole of a metal injection molding apparatus for injection molding a metal material such as magnesium alloy, aluminum alloy, and zinc alloy.
[0002]
[Prior art]
FIG. 3 shows an example of a metal injection molding apparatus.
[0003]
As shown in the figure, a heating cylinder 2 is attached to the front part of the injection unit 1, and a rotary motor 4 is attached to the rear part. A heater 6 is attached to the outer periphery of the heating cylinder 2, and a material hopper 5 is attached to the rear part of the heating cylinder 2. A screw 3 having a spiral groove on the outer surface (hereinafter referred to as screw groove) is inserted into the inner surface hole 11 of the heating cylinder 2 so as to be rotatable and slidable 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 rotated by a rotary motor 4.
[0004]
At the rear part of the heating cylinder 2, there is provided a material charging port 9 that connects the inner surface hole 11 and the lower part of the material hopper.
[0005]
Next, the operation of the metal injection molding apparatus will be described.
[0006]
In the measurement process, a metal material (hereinafter referred to as a material chip) such as a granule, a cut piece, and a crushed piece is put into the material hopper 5. When the material chip falls from the material hopper 5 through the material inlet 9 to the inner surface hole 11 of the heating cylinder 2 and the rotation of the rotary motor 4 is transmitted to the screw 3, the material chip is moved forward of the heating cylinder 2 along the screw groove. It is heated and stirred while being sent. 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 is retracted accordingly. However, since the viscosity of the molten metal is low and sufficient pressure to retract the screw 3 is not generated in the molten metal stored in the front chamber 10, pressure oil is applied to the retreat side of the injection cylinder simultaneously with the rotation of the rotary motor 4. In many cases, the screw 3 is forcibly retracted after being supplied.
[0007]
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), and pressure is applied to the advance side of the injection cylinder. When oil is supplied and the screw 3 is advanced, the molten metal stored in the front chamber 10 of the heating cylinder 2 is injected into the mold through the nozzle 8 and 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 and the metal molded product formed in the shape of the cavity is taken out.
[0008]
By repeating the above operation, a metal molded product having the same shape is efficiently produced.
[0009]
[Problems to be solved by the invention]
In the metal injection apparatus, a small amount of molten metal is mixed in the gap between the solid material chips in the screw groove at the central portion of the screw, and is carried to the rear, that is, the material hopper side by the retreating operation of the screw. The molten metal that has reached the region where the inner surface temperature of the heating cylinder is lower than the melting temperature of the material chip is deprived of heat by the heating cylinder and surrounding material chips, and part of the molten metal adheres to the surface of the screw and the inner surface of the heating cylinder. Solidify (hereinafter, this deposit is referred to as a re-solidified product).
[0010]
The re-solidified material adhering to the surface of the screw is heated to the advanced position where the heating cylinder is heated to a higher temperature by the advance operation of the screw in the next injection stroke, and returned to the molten metal.
[0011]
In addition, most of the resolidified material adhering to the inner surface of the heating cylinder is peeled off by screw advancement of the screw in the next injection stroke, sent to the advance position, heated, and returned to the molten metal again. The rest is left in a state of adhering to the inner surface of the heating cylinder.
[0012]
Most of the remaining re-solidified product is scraped off by a material chip moving forward in the next measuring step, but a part of the re-solidified product remains attached. This adhered resolidified product may accumulate and increase with repeated molding cycles.
[0013]
The molten metal is chemically very active and easily reacts with oxygen and nitrogen in the air to easily generate oxygen compounds and nitrogen compounds (hereinafter referred to as compounds and the like). Moreover, since other metal elements are blended in the magnesium alloy and aluminum alloy depending on the application, various compounds and the like are mixed in the molten metal.
[0014]
Therefore, the re-solidified product becomes a state in which the above-mentioned compound is mixed in the original metal material, and when it adheres to the surface of the screw or the inner surface of the heating cylinder and solidifies, it does not melt easily even if it is heated again. Cause great difficulties.
[0015]
If the re-solidified product adheres to the surface of the screw, the cross-sectional area of the screw groove is reduced to prevent the flow of material chips or molten metal, and if it adheres to the inner surface of the heating cylinder, it prevents smooth rotation or linear sliding of the screw. . As a result, the weighing operation and the injection operation become unstable or stop, and a stable molding operation cannot be performed.
[0016]
For this reason, when the screw operation becomes unstable or when the operation period that is expected to become unstable is reached, the supply of material chips is stopped, and the metering and injection operations are repeated, After discharging the molten metal, an operation is performed to remove the screw from the heating cylinder and remove the re-solidified material adhering to the screw and the heating cylinder.
[0017]
The resolidified 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 a large force is required for the removal. Also, if the surface of the re-solidified product is polished or ground in the process of mechanical removal and has a metallic luster, it is difficult to distinguish it from the inner surface of the heating cylinder. Is easy to end. For this reason, when attempting to insert a screw in the reassembly operation, there are cases where the resolidified material remaining as a thin layer on the inner surface of the heating cylinder is blocked or cannot be inserted or removed.
[0018]
As a method for solving the difficulty in the mechanical removal described above, an attempt has been made to chemically decompose and remove the resolidified product with hydrochloric acid or the like. This is a method in which a part to which the re-solidified substance is fixed is immersed in a container filled with a cleaning solution made of an acid aqueous solution, and is used to remove the re-solidified substance adhering to the outer surface such as a screw.
[0019]
However, when the cleaning liquid stays, the concentration of the portion that comes into contact with the resolidified product decreases, and the chemical reaction decreases. For this reason, the chemical reaction of the component having the re-solidified material adhering to the inner surface, such as a heating cylinder, becomes dull immediately even when immersed in the cleaning liquid. Moreover, the outer surface to which the re-solidified product does not adhere may corrode due to the long 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 that a safety problem may occur.
[0020]
The present invention has been made to solve the problems in the conventional cleaning operation of the inner surface of the heating cylinder as described above, and is a heating cylinder cleaning capable of easily and safely removing the re-solidified material fixed to the inner surface hole of the heating cylinder. The object is to provide a device.
[0021]
[Means for Solving the Problems]
In this invention, the heating cylinder removed from the injection unit is placed in a tray provided on the upper surface of the movable stand, the inner surface hole of the heating cylinder is filled with cleaning liquid, and the circulation pump and the connecting pipe provided on the stand are used. The cleaning liquid is circulated.
[0022]
A liquid-tight lid is attached to the front end and 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 opened on the upper surface of the rear of the heating cylinder, and connected to the suction port of the circulation pump. The connected pipe is connected to an outlet provided at the front end of the heating cylinder, and the cleaning liquid is filled and circulated in the inner surface hole of the heating cylinder with the material input port open to the atmosphere.
[0023]
The acid in the cleaning liquid filled in the inner hole of the heating cylinder chemically reacts with the metal component in the resolidified material adhering to the inner hole of the heating cylinder, thereby decomposing the resolidified substance and mixing it in the cleaning liquid. Thus, the resolidified material is removed from the inner surface hole of the heating cylinder.
[0024]
A gas such as hydrogen generated by a chemical reaction is released into the atmosphere from a material inlet opening on the upper surface of the rear portion of the heating cylinder.
[0025]
Furthermore, a vigorous chemical reaction is maintained by circulating the cleaning liquid, and the re-solidified product is removed within a short time.
[0026]
After the removal of the re-solidified product is completed, the cleaning liquid that leaks when the lid attached to the front end and rear end of the heating cylinder is removed, or when the pipe connected to the circulation pump is removed, is collected in a tray on the top of the stand. After removing dust and mixed solids with a filter, it is transferred to a storage container.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes a movable support base that holds a heating cylinder and a cleaning liquid circulation device that circulates cleaning liquid through an inner surface hole of the heating cylinder, and the movable support base is provided on a stand and an upper surface of the stand. It consists of a saucer and the said heating cylinder is hold | maintained in this saucer, It is characterized by the above-mentioned.
[0028]
It is preferable that the bottom surface of the tray is inclined, a filter is inserted into a recovery hole provided in the lowest surface portion, and an open / close valve is attached to the lower portion of the recovery hole.
[0029]
Moreover, it is preferable that a lower tray is provided at the lower part of the stand, a recovery container for recovering the cleaning liquid is placed thereon, and a recovery hose connected to the open / close valve can be inserted.
[0030]
The cleaning liquid circulation device includes a circulation pump attached to a stand, a lid attached to each of a front end port and a rear end port of an inner surface hole of the heating cylinder, and a connection pipe. The connection pipe is connected to the circulation pump. It is preferable that the discharge port 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]
【Example】
An embodiment of the present invention will be described below with reference to the drawings.
[0032]
FIG. 1 is a cross-sectional front view of an essential part of a heating cylinder cleaning apparatus according to the present invention, and FIG. 2 is a top view of FIG.
[0033]
As shown in FIG. 1 and FIG. 2, the heating cylinder cleaning apparatus of the present embodiment is a cleaning liquid that circulates the cleaning liquid in the movable support base A that holds the heating cylinder 2 for forming the magnesium alloy and the inner surface hole 11 of the heating cylinder 2. And a circulation device B.
[0034]
The movable support A comprises a stand 21 and a tray 22 provided on the upper surface thereof. A plurality of supports 23 and 24 are mounted in the tray 22 and 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.
[0035]
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 bottom surface portion. A closed open / close valve 37 is attached to the lower portion of the collection hole 34, and a collection hose 36 is connected to the open / close valve 37. The other end of the collection hose 36 is provided at the lower portion of the stand 21. It is inserted into the collection container 38 placed on the lower receiving tray 39.
[0036]
The cleaning liquid circulating device B is fixed to the front end port and the rear end port of the inner surface hole 11 of the heating cylinder 2 with bolts 17 and 18 attached to the front end port and the rear end port via the seals 15 and 16, respectively, and the front end port cover 13. A discharge pipe 31 inserted into the inner surface hole 11, a plate 19 attached to the mounting flange 12 of the material input port 9 at the rear of the heating cylinder 2 with a bolt 20, and provided with a hole at the position of the material input port 9; The injection pipe 30 fixed to the plate 19 and inserted into the material inlet 9, the circulation pump 25 attached to the stand 21 above the lower tray 39, and the discharge port of the circulation pump 25 are connected. The discharge hose 27 and the suction hose 26 connected to the suction port of the circulation pump 25 are configured.
[0037]
The discharge hose 27 passes through a pipe 29 penetrating the receiving tray 22 in a liquid-tight manner and is connected to the injection pipe 30 via a one-touch joint 32. The suction hose 26 passes through a pipe 28 penetrating the receiving tray 22 in a liquid-tight manner, and is connected to the discharge pipe 31 via a one-touch joint 33.
[0038]
Next, the cleaning operation of the heating cylinder will be described.
[0039]
The suction hose 26 is removed 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 recovery container 38, and is supplied to the material charging port 9 through the discharge hose 27 and the injection pipe 30 to fill 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 redriven to circulate the cleaning liquid. Note that a hydrochloric acid aqueous solution having a concentration of 5 to 10% is used as the cleaning liquid. Further, when the required amount of the cleaning liquid is small, the cleaning liquid may be directly injected from the material inlet 9.
[0040]
The injected cleaning liquid chemically reacts with magnesium mixed in the resolidified material adhering to the inner surface hole 11 to gradually decompose the resolidified material and remove it from the inner surface of the heating cylinder 2. When magnesium and hydrochloric acid react chemically, magnesium chloride and hydrogen are produced, and magnesium chloride is mixed and held in the cleaning liquid. Further, since hydrogen is released from the material inlet 9 into the atmosphere, the cleaning work should be performed in a well-ventilated place, and care must be taken not to bring fire close during the work.
[0041]
The generation state of hydrogen bubbles released from the material inlet 9 is monitored, and when the generation of bubbles stops, the cleaning is finished.
[0042]
As another embodiment, if the injection pipe 30 is attached to the lid 14 at the rear end port, the generation state of bubbles released from the material input port 9 can be monitored more easily.
[0043]
In the middle of injecting the cleaning liquid from the material inlet 9, when the amount of bubbles generated is large, the amount of the cleaning liquid injected is suppressed to half of the inner surface hole 11. When the amount of generated bubbles is reduced, a cleaning liquid is added so that the entire inner surface hole is filled. Thereby, it is possible to prevent the cleaning liquid from overflowing from the material inlet 9.
[0044]
Conversely, if the generation of bubbles is weak even after about 5 minutes have passed since the start, the hydrochloric acid concentration has decreased, so it is advisable to add hydrochloric acid or dilute hydrochloric acid to increase the concentration.
[0045]
Further, when the height of the supports 23 and 24 is adjusted, the rear side of the heating cylinder 2 is raised, and the inner surface hole 11 is inclined from the horizontal, the generated bubbles can be easily released from the material inlet 9. .
[0046]
The time required for cleaning varies depending on the size of the heating cylinder 2 and the amount of the re-solidified product, and is 3 to 24 hours, but usually 5 to 8 hours. The hydrochloric acid concentration is selected according to the material of the heating cylinder 2 so as not to corrode the heating cylinder body, but normally 5 to 10% is appropriate.
[0047]
After the cleaning operation, the circulation pump 25 is stopped, the discharge hose 27 is detached from the injection pipe 30 by the one-touch joint 32 and inserted into the recovery hole 34, and the open / close valve 37 is opened. Next, the circulation pump 25 is driven again, and a large mixture is removed by the filter 35. Then, the circulation pump 25 is collected in the collection container 38 through the collection hose 36.
[0048]
After the removal of the re-solidified product is completed, the cleaning liquid that leaks when the lids 13 and 14 attached to the front end port and the rear end port of the heating cylinder 2 are removed or the pipe connected to the circulation pump 25 is removed is After being collected by the tray 22 and removing dust and mixed solids by the filter 35, it is transferred to the storage container 38.
[0049]
As the filter 35, a wire mesh made of stainless steel wire having an opening of about 0.2 to 1 mm may be used. Further, if a polyethylene tank is used as the collection container 38, it is convenient for transportation and storage.
[0050]
If the contamination in the cleaning liquid increases due to repeated cleaning, neutralize the recovered liquid with alkali and dispose of it after removing water, or dispose of it in a state where the hydrochloric acid concentration is low. Treat as a thing.
[0051]
In addition, as the cleaning liquid, an aqueous solution of other acids such as sulfuric acid or a mixed solution thereof, or an aqueous solution to which a surfactant or a reducing agent is further added, is used depending on the components to be cleaned and re-solidified products. May be.
[0052]
In the above embodiment, the inner surface of the heating cylinder is the object to be cleaned. However, the present invention is also applicable to cleaning of the inner surface of the cylinder head shown in FIG. 3 and the inner surfaces of the injection sleeve and the melting cylinder of the metal forming apparatus using the injection plunger. be able to.
[0053]
【The invention's effect】
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 the accompanying dust and noise are not generated. In addition, since the liquid level of the cleaning liquid used for the cleaning work is exposed to the atmosphere only a little, the work is safe, and the cleaning liquid does not leak to the floor surface at the end of the work. Since it can be easily transported, it is safe in terms of environment. In addition, 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 an essential part of a heating cylinder cleaning apparatus according to an embodiment of the present invention.
FIG. 2 is a top view of FIG.
FIG. 3 is a view showing an example of a metal injection molding apparatus.
[Explanation of symbols]
2 Heating cylinder 9 Material inlet 11 Internal hole 13, 14 Lid 21 Stand 22 Receptacle 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 Opening and closing valve 38 Recovery container 39 Catch plate 40 Caster A Movable support base B Cleaning liquid circulation device

Claims (4)

The movable support base (A) that holds the heating cylinder (2), and a cleaning liquid circulation device (B) that circulates the cleaning liquid to the inner surface hole (11) of the heating cylinder (2),
The movable support base (A) includes a stand (21) and a tray (22) provided on the upper surface of the stand (21), and the heating cylinder (2) is placed in the tray (22). A heating cylinder cleaning apparatus for a metal injection molding apparatus, wherein the apparatus is held. The bottom surface of the tray (22) is inclined, the filter (35) is inserted into the recovery hole (34) provided in the lowest surface portion, and the open / close valve (37) is attached to the lower part of the recovery hole (34). A heating cylinder cleaning apparatus for a metal injection molding apparatus according to claim 1. A lower tray (39) is provided at the lower part of the stand (21), a recovery container (38) for recovering the cleaning liquid is placed on the lower tray (39), and a recovery hose (36) connected to the open / close valve (37) can be inserted. The heating cylinder cleaning apparatus for a metal injection molding apparatus according to claim 2. The cleaning liquid circulation device (B) includes a circulation pump (25) attached to a stand (21) and lids (13, 14) attached to the front end port and the rear end port of the inner surface hole of the heating cylinder (2), respectively. The connection pipe connects the discharge port of the circulation pump (25) to one end of the inner surface hole (11) of the heating cylinder (2), and connects the suction port to one lid (13). The heating cylinder cleaning device for a metal injection molding apparatus according to any one of claims 1 to 3, wherein a part of the flow path of the cleaning liquid is connected to open to the atmosphere.

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