JP3524849B2 - Method and apparatus for cleaning the inside of a cylinder in a metal injection molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cleaning the inside of a cylinder of a metal injection molding machine using a metal material such as a magnesium alloy, an aluminum alloy, a zinc alloy and a lead alloy.

[0002]

2. Description of the Related Art FIG. 4 is a schematic cross-sectional view of a main part of an in-line screw type metal injection molding machine. In the figure, reference numeral 1 is a cylinder, and a screw 2 provided inside the cylinder 1 is rotated by a hydraulic device 3 connected to the rear end of the screw 2 to feed the molding material to the tip of the cylinder, and the high speed is achieved. The molding material which is advanced and heated and melted is injected into the mold. A feeder 4 for supplying the chip-shaped molding material into the cylinder 1 at a constant speed is provided on the upper upstream side of the cylinder 1. A cylinder head 5 is bolted to the tip of the cylinder 1, and a nozzle 6 is attached to the cylinder head 5. A cylinder heater 9 is attached to the outer circumference of the cylinder 1.

A mold clamping device 7 is arranged in front of the cylinder 1. Mold 8 fixed to this mold clamping device 7
The desired molding material is molded by injecting the heat-melted molding material.

In the above metal injection molding machine, the screw 2
If the remaining molding material adheres to the inner surface of the cylinder when the screw is pulled out, the screw 2 may not be inserted even if the screw 2 is inserted again. Therefore, it is necessary to remove the molding material on the inner surface of the cylinder.

To clean the inside of the cylinder 1, the screw is rotated and injected at the molding temperature to discharge the molding material in the cylinder 1 to the outside, then the nozzle 6 and the cylinder head 5 are removed, and the screw in the cylinder 1 is removed. Extract 2 and perform.

When the amount of the molding material deposited is small, FIG.
As shown in, at a high temperature of about 300 ° C. or higher, by inserting the metal brush 10 having a long handle with a stick into the cylinder 1 and polishing the metal brush 10, it sometimes burns and becomes an oxide.
The molding material 11, for example, AZ91D magnesium alloy, which is sometimes mechanically peeled off and adhered and remains in the cylinder, can be removed.

When the amount of the molding material 11 adhered is large, after the temperature of the cylinder 1 is lowered, the remaining molding material adhered to the inside of the cylinder 1 is mechanically treated with a grinding tool such as a grinder inserted from the end face of the cylinder. It is necessary to remove them, or to remove the cylinder 1 from the molding machine by machining the inner surface of the cylinder.

[0008]

In the conventional method for cleaning the inside of the cylinder, in the method of cleaning by inserting a grinder or the like from the end face of the cylinder, the grinder may not reach if the cylinder becomes long. Further, if the grinder is lengthened according to the cylinder length, it becomes difficult to apply a force to press the tip of the grinder against the inner surface of the cylinder, and the polishing effect is reduced. In addition, when the cylinder is removed from the molding machine and the inner surface is machined, the cylinder is cooled down, and the removal work is further performed, so that the working time, that is, the molding machine movable stop time becomes long. In addition, a special machining device is required, and it is necessary to send the cylinder to a manufacturer such as a cylinder manufacturer who has a machine capable of processing.

In any of the methods, both the places where the rest of the molding material is adhered and the places where the remainder is not adhered are polished. Therefore, if incorrect machining is performed, the cylinder itself will be attached together with the adhered substances. Will be cut off. If the cylinder is trimmed more than the allowable amount, the clearance with the screw will be large, and the transportation of the molding material transported by screw rotation will be poor, and the molten metal at the time of injection will cause backflow at that clearance. May occur.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and cleaning of a cylinder capable of simply removing the deposit of the molding material adhered to the inner surface of the cylinder. It is an object to provide a method and an apparatus thereof.

[0011]

A method and apparatus for cleaning a cylinder according to the present invention removes deposits of molding material remaining in the cylinder of a metal injection molding machine by filling the cylinder with an acid aqueous solution. Is characterized by.

It is preferable that both end surfaces of the cylinder are closed with lids, the cylinder is filled with an acid aqueous solution, and the acid aqueous solution is circulated by a pump through holes provided in both lids.

Further, both ends of the cylinder are sealed with a lid, the cylinder is filled with an acid aqueous solution, and a pump is provided through a hole provided in one lid and a hopper port for supplying a molding material. It is preferable to circulate.

The aqueous acid solution is a 1 to 20% hydrochloric acid aqueous solution, or 1 to 20% of one or more acids such as hydrochloric acid and sulfuric acid together with 10% or less of a surfactant,
An aqueous solution containing at least one of a reducing agent of 0% or less and an organic corrosion inhibitor of 10% or less is preferable.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described.

In the present invention, an acid aqueous solution (hereinafter,
By filling with the acid solution), the acid solution preferentially corrodes the rest of the molding material rather than the cylinder body, and it is possible to remove the deposit in the cylinder.

Since the molding material remaining in the cylinder, particularly magnesium alloy and aluminum alloy, is electrically base compared with the steel material forming the cylinder, it preferentially reacts and melts when an acid solution is applied. Therefore, the dissolution of the cylinder by the acid solution can be almost prevented.

It is possible to clean the inside of the cylinder by closing both ends of the cylinder only with a disk and a seal ring or clay, and leaving it for a certain period of time while being filled with the acid solution.
As it is, the acid solution becomes stagnant and the corrosion rate, that is, the cleaning rate becomes slow.

Therefore, when a lid with a hole is used as a lid on both end faces of the cylinder, and a joint and a hose are connected to the hole to circulate the acid solution inside via a pump, the dissolved concentration reacts with the molding material to obtain a dissolved concentration. Instead of the elevated acid solution, a new acid solution always comes into contact with the deposits on the inner surface of the cylinder, thus increasing the cleaning speed.

It is also possible to use a lid with a hole on one end surface of the cylinder on the nozzle side to connect a joint and a hose, and the other end to circulate the acid solution using a hopper port. At that time, by opening the hopper port, the gas generated by the reaction between the acid solution and the molding material can be discharged to the outside. An exhaust duct is preferably installed at the hopper port.

In carrying out this method, the cylinder may be removed from the molding machine and the both ends may be hermetically sealed so that the acid solution may be added, or both ends may be hermetically sealed and the acid solution may be injected while the cylinder is attached to the molding machine. In either case, the inside of the cylinder can be cleaned quickly and effectively without removing the heater attached to the outer circumference of the cylinder.

When the gas such as hydrogen gas generated by the reaction between the acid liquid and the molding material does not come out from the hopper port or the like, the cleaning is terminated, the acid liquid is drained and the inside of the cylinder is washed with water.

The dissolution rate of the molding material can be adjusted by the concentration of the acid liquid, the cylinder temperature at the time of filling the acid liquid, and the temperature of the acid liquid. That is, the thicker the acid solution and the higher the temperature, the faster the corrosion rate. Therefore, the amount of the molding material adhered and the required cleaning time can be adjusted at any time.

[0024]

Embodiments of the present invention will be described with reference to the drawings.
In addition, the same or equivalent portions as those of the conventional example will be described using the same reference numerals.

In FIG. 1, both ends of the cylinder are sealed with lids,
It shows a device for filling the cylinder with an acid solution to remove deposits in the cylinder.

As shown in the figure, a lid 12 for sealing the cylinder 1 is fixed to both end faces of the cylinder 1 by bolts 13. A rubber plate is provided inside the lid 12 in order to enhance the sealing property. The acid liquid 14 is injected into the cylinder 1 from a hopper port 15 or the like. In addition, what is indicated by reference numeral 11 is a molding material that remains attached to the inner surface of the cylinder.

FIG. 2 shows a device for removing an adhering substance in the cylinder by circulating an acid solution through lids having holes fixed to both end faces of the cylinder.

As shown in the figure, on both end faces of the cylinder,
Each lid 12 with a hole is fixed. A pump 16 for circulating the acid liquid in the cylinder 1 is provided in the vicinity of the cylinder 1.
Is provided. The discharge port and the suction port of the pump 16 are respectively connected via hoses 17 to joints 18 attached to holes formed in the lid 12 on both end surfaces of the cylinder.

The acid liquid 14 injected into the cylinder 1 through the hopper port 15 and the like is sucked by the pump 16 through one lid 12 and returned into the cylinder 1 through the other lid 12.

FIG. 3 shows an apparatus for removing the deposits in the cylinder by circulating an acid solution through a lid with a hole fixed to the end surface of the cylinder on the nozzle side and a hopper port.

As shown in the figure, a lid 12 with holes is fixed to the end surface of the cylinder 1 on the nozzle side, and a lid 12 without holes is fixed to the end surface of the cylinder 1 on the hopper side. A pump 16 for circulating the acid solution in the cylinder 1 is provided near the cylinder 1. The suction port of the pump 16 is connected to a joint 18 attached to the lid 12 on the end face on the nozzle side via a hose 17, and the discharge port is connected to a hopper port 15 via the hose 17.

The acid solution 14 injected into the cylinder 1 through the hopper port 15 or the like is sucked by the pump 16 through the one lid 12 and returned into the cylinder through the hopper port 15.

The thicker the acid solution, the faster the removal rate of the deposits. However, if the deposit is left as it is after it has been removed, the speed at which the cylinder material is corroded also increases, although it is slower than the removal rate of the deposit. Therefore, an excessively concentrated acid solution must be handled carefully, and if it is left open, a large amount of acid gas is generated.

Therefore, a 1 to 20%, preferably 5 to 10% hydrochloric acid aqueous solution is used as the acid solution. Hydrochloric acid is inexpensive, and unlike sulfuric acid, does not easily corrode the iron in the surrounding area.

In the acid solution, 1 to 20%, preferably 5 to 10% of one or more kinds of acids such as hydrochloric acid and sulfuric acid and 10% or less of an interface such as polyoxyalkylene alkyl phenyl ether are used. An aqueous solution containing at least one of an additive such as an activator, a reducing agent such as 10% or less of a carboxylic acid, and an organic corrosion inhibitor containing 10% or less of Si is used.

[0036]

As described above, according to the present invention, since both ends of the cylinder can be hermetically closed, the remainder of the molding material adhered to the inner surface of the cylinder can be removed by using the acid aqueous solution.
The cylinder can be cleaned with almost no damage and without machining the inner surface of the cylinder. All you have to do is to arrange the sealing lids of different sizes.
It can be used to clean cylinder barrels of any size and has the advantage that it can be used anywhere.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cleaning device in a cylinder according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a cleaning device in a cylinder according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a cleaning device inside a cylinder according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a main part of an in-line screw type metal injection molding machine.

FIG. 5 is an explanatory diagram of a conventional method for cleaning the inside of a cylinder.

[Explanation of symbols]

1 cylinder 2 screws 3 hydraulic system 4 feeder 5 cylinder head 6 nozzles 7 Clamping device 8 mold 9 Cylinder heater 10 wire brush 11 Molding material 12 lid 13 volt 14 Acid solution (acid solution) 15 hopper mouth 16 pumps 17 Hose 18 joints

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-53-71630 (JP, A) JP-A-2001-62553 (JP, A) JP-A-2001-219260 (JP, A) JP-A-2002-254151 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 17/00-17/32 B22D 43/00

Claims (9)

(57) [Claims] 1. A deposit of a molding material (11) remaining in a cylinder (1) of a metal injection molding machine is removed by filling the cylinder (1) with an aqueous acid solution (14). Cleaning method for the inside of a cylinder in a metal injection molding machine. 2. A cover (1) is provided on each end face of the cylinder (1).
Seal with 2), and put acid aqueous solution (14) in the cylinder (1).
The method for cleaning the inside of a cylinder of a metal injection molding machine according to claim 1, characterized in that the acid aqueous solution (14) is circulated by a pump (16) through holes provided in both lids (12). . 3. A cover (1) is provided on each end face of the cylinder (1).
Seal with 2), and put acid aqueous solution (14) in the cylinder (1).
And a hopper mouth (1) for supplying the molding material (11) with a hole in which the acid aqueous solution (14) is provided in one lid (12).
The method for cleaning the inside of a cylinder in a metal injection molding machine according to claim 1, characterized in that it is circulated by a pump (16) via 5). 4. The acid aqueous solution (14) is a hydrochloric acid aqueous solution having a concentration of 1 to 20%.
A method for cleaning the inside of a cylinder of the metal injection molding machine as described above. 5. The acid aqueous solution (14) together with 1 to 20% or less of one or more kinds of acids such as hydrochloric acid and sulfuric acid,
10% or less surfactant, 10% or less reducing agent, 10%
The method for cleaning the inside of a cylinder in a metal injection molding machine according to claim 1, 2 or 3, which is an aqueous solution containing at least one of the following organic corrosion inhibitors . Wherein said surfactant is a polyoxyalkylene alkylphenyl ether, in the reducing agent is a carboxylic acid, metal injection molding machine according to claim 5, wherein the organic corrosion inhibitor is intended to include Si How to clean the inside of the cylinder. 7. A metal injection machine characterized in that a lid (12) for filling an acid aqueous solution (14) in the cylinder (1) is provided on both end surfaces of the cylinder (1) of the metal injection molding machine. Cleaning device inside the cylinder of the molding machine. 8. The cylinder in a metal injection molding machine according to claim 7, wherein each of the lids (12) is provided with a hole, and a pump (16) for circulating the aqueous acid solution (14) is connected to the hole. Cleaning device. 9. A hole is provided in one of the lids (12), and a pump (16) for circulating an acid aqueous solution (14) is connected to the hole and a hopper port (15) for supplying a molding material (11). The cleaning device for the inside of the cylinder of the metal injection molding machine according to claim 7.